This document discusses soil formation and characterization. It begins by defining different types of rocks - igneous, sedimentary, and metamorphic - and how they are formed. It then discusses how weathering breaks rocks down into smaller particles that make up soil. Mechanical and chemical weathering processes are described. Soils are classified based on particle size into categories like clay, silt, sand, and gravel. Soils are also classified as either residual soils, which form in place from weathering bedrock, or transported soils, which are eroded and deposited elsewhere.
Petrology
Definition of a rock, petrology. Classification of rocks-Geological classification of rocks. Rock Cycle. Classification of igneous Forms, structures and textures of igneous rocks. Classification of sedimentary rocks, and its structures and textures. Classification of metamorphic rocks, its structures and textures.
Megascopic Study of Granite, Dolerite, Basalt, Pegmatite, Charnockite, Sandstone, Shale, Limestone, Gneiss, Schist, Quartzite, Marble and Slate.
Sedimentary rocks are formed by the lithification of sediments and include clastic sedimentary rocks such as sandstone and shale that are formed from fragments of pre-existing rocks transported by water, wind or ice. They also include chemical sedimentary rocks such as limestone that are formed via precipitation from solution. Sedimentary structures within these rocks provide clues about the depositional environment, and sedimentary rocks are classified based on their mineral composition, grain size, sorting and rounding. Common sedimentary rocks used in construction include sandstone, limestone and shale.
This document discusses weathering and soil formation. It describes two types of weathering - mechanical and chemical. Mechanical weathering breaks rocks into smaller pieces without changing their chemical composition, while chemical weathering alters the rocks' chemical makeup. Weathering occurs due to factors like temperature changes, frost action, abrasion, and acids. Over time, weathering breaks rocks down into soil. Soil provides nutrients for plants and animals and is important for life. The document also examines different types of soil like residual and transported soil and how soil composition varies by location.
weathering is the process of disintegration (physical breakdown) and decomposition (chemical breakdown) of rocks and minerals. In physical weathering, rocks are reduced in size but the chemical composition remains unaltered. In contrast, chemical weathering alter the chemical composition of rocks by changing the mineral constitutes. In weathering, primary minerals are decomposed to form secondary minerals. Weathering plays a vital role in soil formation.
This document discusses parent material, which refers to the unconsolidated organic or mineral material in which soils form. It describes the different types of parent material including residuum produced by weathering of rock in place, and transported materials such as alluvium deposited by water, loess deposited by wind, and glacial till deposited directly by glaciers. It provides details on the characteristics of these various parent materials and their influence on soil formation.
Shale is a fine-grained sedimentary rock formed from compacted silt and clay-sized particles. It is characterized by being fissile, meaning it splits easily into thin layers, and laminated, consisting of many thin layers. Shale is composed mainly of clay-sized mineral grains such as clay minerals, quartz, and feldspar. It forms through the compaction and consolidation of silt and clay over time. Shale is classified based on its mineral composition and has a variety of uses including in brick and tile manufacturing.
Petrology
Definition of a rock, petrology. Classification of rocks-Geological classification of rocks. Rock Cycle. Classification of igneous Forms, structures and textures of igneous rocks. Classification of sedimentary rocks, and its structures and textures. Classification of metamorphic rocks, its structures and textures.
Megascopic Study of Granite, Dolerite, Basalt, Pegmatite, Charnockite, Sandstone, Shale, Limestone, Gneiss, Schist, Quartzite, Marble and Slate.
Sedimentary rocks are formed by the lithification of sediments and include clastic sedimentary rocks such as sandstone and shale that are formed from fragments of pre-existing rocks transported by water, wind or ice. They also include chemical sedimentary rocks such as limestone that are formed via precipitation from solution. Sedimentary structures within these rocks provide clues about the depositional environment, and sedimentary rocks are classified based on their mineral composition, grain size, sorting and rounding. Common sedimentary rocks used in construction include sandstone, limestone and shale.
This document discusses weathering and soil formation. It describes two types of weathering - mechanical and chemical. Mechanical weathering breaks rocks into smaller pieces without changing their chemical composition, while chemical weathering alters the rocks' chemical makeup. Weathering occurs due to factors like temperature changes, frost action, abrasion, and acids. Over time, weathering breaks rocks down into soil. Soil provides nutrients for plants and animals and is important for life. The document also examines different types of soil like residual and transported soil and how soil composition varies by location.
weathering is the process of disintegration (physical breakdown) and decomposition (chemical breakdown) of rocks and minerals. In physical weathering, rocks are reduced in size but the chemical composition remains unaltered. In contrast, chemical weathering alter the chemical composition of rocks by changing the mineral constitutes. In weathering, primary minerals are decomposed to form secondary minerals. Weathering plays a vital role in soil formation.
This document discusses parent material, which refers to the unconsolidated organic or mineral material in which soils form. It describes the different types of parent material including residuum produced by weathering of rock in place, and transported materials such as alluvium deposited by water, loess deposited by wind, and glacial till deposited directly by glaciers. It provides details on the characteristics of these various parent materials and their influence on soil formation.
Shale is a fine-grained sedimentary rock formed from compacted silt and clay-sized particles. It is characterized by being fissile, meaning it splits easily into thin layers, and laminated, consisting of many thin layers. Shale is composed mainly of clay-sized mineral grains such as clay minerals, quartz, and feldspar. It forms through the compaction and consolidation of silt and clay over time. Shale is classified based on its mineral composition and has a variety of uses including in brick and tile manufacturing.
Physical and Chemical Properties of Soil of Bangladesh by Masud Hiruhiru masud
This document summarizes the physical and chemical properties of soil in Bangladesh. It discusses the texture, structure, color, density, temperature, and organic matter content of Bangladeshi soils. The document also examines the cation exchange capacity and pH of Bangladeshi soils. In conclusion, it states that soil texture, organic matter status, particle density, and bulk density are especially important for agricultural uses of soil in Bangladesh.
The document discusses soil profiles, soil genesis, and parent material classification. It defines a soil profile as the vertical cross section of soil horizons. Soil genesis refers to the evolution of soil from parent material, influenced by climate, organisms, relief, and time. Parent material is the geological material from which soil forms, and can be classified based on its mode of transportation (ice, water, wind, gravity) and degree of particle sorting. The document provides examples of different parent material types including glacial till, alluvium, loess, and residuum.
Introduction and classification of rocksTarun kumar
Introduction and classification of rocks for building and construction materials... types of rocks and their classifications, and types of stone quarrying.
Physical Properties of different types of Metamorphic Rocks (Geology)Raboon Redar
Metamorphic rocks are rocks that have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Change to these extreme conditions changes the mineralogy, texture, and chemical composition of the rocks.
Soil is formed by the weathering and disintegration of rock. Key factors that influence soil formation are climate, organisms, topography, parent material and time. Soils are composed mainly of silicates, with quartz being the most abundant mineral. Other common minerals include feldspars, micas and clay minerals like kaolinite, illite and montmorillonite. Laboratory testing of soils helps characterize properties like particle size distribution, moisture content, liquid limit, plastic limit and organic content which inform geotechnical analysis and design.
This document summarizes the key characteristics and formation processes of the three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma. Sedimentary rocks are formed at the Earth's surface from the compaction and cementation of sediments. Metamorphic rocks are formed from the alteration of existing rocks through heat, pressure, and chemical changes in the Earth's crust.
The document discusses rocks and soil. It defines rocks as being made up of two or more minerals, and describes three main types of rocks: igneous, metamorphic, and sedimentary. Igneous rocks form from cooling magma, metamorphic rocks change form due to temperature and pressure, and sedimentary rocks form from layers of compacted debris. Soil is described as being made up of small rocks, decomposed plant and animal matter, and waste. The properties of soil include color, water and nutrient retention, and texture.
The document discusses weathering, soil formation, and erosion. It defines weathering as the breaking down of rocks on Earth's surface through mechanical or chemical processes. Mechanical weathering breaks rocks into smaller pieces without changing their chemical makeup, while chemical weathering changes the chemical makeup of rocks. The main agents of erosion that move weathered materials include gravity, wind, running water, glaciers, and waves. Erosion transports weathered materials from one location to another, while deposition is the laying down of sediments in new locations. Mass movements involve the downslope movement of loose materials due to gravity.
This document discusses sedimentary rocks, including their formation, classification, and characteristic textures and structures. Sedimentary rocks form through the lithification of sediments deposited under water. They are classified based on their composition into clastic rocks (formed from fragments of pre-existing rocks), chemical/evaporite rocks (formed by chemical precipitation), and organic rocks (containing organic matter). Key textures include grain size, shape, packing, and fabric. Common structures include stratification, lamination, cross-bedding, graded bedding, and ripple marks, which provide information about depositional environments.
Metamorphic rocks are rocks that have changed from one type to another due to high heat and pressure underground over millions of years. This process of metamorphism can change a rock's texture, chemical composition, and internal structure. Jade rock specifically forms where tectonic plates meet in areas with high underground heat and pressure, as this environment transforms pyroxene rock into crystalline jade over long periods of time.
This document describes metamorphic rock and the processes of metamorphism. It explains that rocks can undergo metamorphism through heat, pressure, or both, which causes changes to their structure, texture, or composition. There are two types of metamorphism: contact metamorphism near magma intrusions, and regional metamorphism deep underground from pressure. Original minerals change into more stable minerals indicating temperature and pressure. Metamorphic rocks exhibit foliated or non-foliated textures and structures like folds that result from deformation during metamorphism.
The document discusses the three main rock types - igneous, sedimentary, and metamorphic rocks. It describes the rock cycle which shows how the different rock types are interrelated through geological processes. Igneous rocks form from the cooling of magma, either below ground (intrusive) or on the surface (extrusive). Sedimentary rocks form through the weathering of existing rocks, erosion and deposition of sediments, and compaction and cementation over time. Metamorphic rocks form from the alteration of existing rocks deep underground under high pressures and temperatures.
Rocks are naturally occurring mixtures of minerals, mineraloids, glass or organic matter that are divided into three main types - igneous, sedimentary, and metamorphic - based on how they were formed. Rocks are continually changed over time by various geological processes through the rock cycle, where one type of rock can be transformed into another through weathering, erosion, melting and other changes. The core, mantle and crust act as a recycling machine that redistributes rocks.
The document discusses different types of rocks and stones used in construction, including their origins, properties, and applications. It describes three main types of rocks - igneous, sedimentary, and metamorphic - and how they are formed. Specific rock and stone materials like granite, limestone, marble, sandstone, and crushed stone are explained in terms of their composition, colors, textures, and common uses in building and other construction projects.
Rocks are naturally occurring solid mixtures of minerals or organic matter. They are classified based on how they form, their composition, and texture. Rocks change over time through the rock cycle. There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from cooling magma, sedimentary rocks form through the compaction and cementation of sediments, and metamorphic rocks form from changes to existing rocks through heat, pressure, and deformation.
CLASSIFICATION OF ROCKS:
GEOLOGICAL:IGNEOUS,SEDIMENTRY,METAMORPHIC ROCKS
PHYSICAL:STRATIFIED,UNSTRATIFIED,FOLIATED.
CHEMICAL:SILICEOUS,CALCAREOUS,AGRILLACEOUS ROCKS.
CHARACTERSTICS OF STONES AND USES OF STONES
1) Gneiss is a common metamorphic rock formed from igneous or sedimentary rocks under high-grade regional metamorphism. It is medium- to coarse-foliated with little mica or other platy minerals.
2) Marble is a non-foliated metamorphic rock formed from limestone composed primarily of calcite. It is widely used as a building material.
3) Migmatite forms under extreme heat during metamorphism, where partial melting occurs in pre-existing rocks resulting in a mixture of newly crystallized and older resistant materials.
Petrology is the study of rocks and their origins, compositions, textures, and structures. There are three main types of rocks: igneous rocks formed from cooled magma, sedimentary rocks formed from compressed sediments, and metamorphic rocks formed from existing rocks subjected to heat and pressure. Rocks are constantly changing between these types through geological processes in the rock cycle, powered by Earth's interior heat and the energy from the sun. Igneous rocks can become sedimentary rocks through weathering and erosion then become metamorphic rocks through burial and increased heat and pressure, and metamorphic rocks can melt to form new magma and igneous rocks.
The document discusses different types of rocks:
1. Igneous rocks form from cooling magma and include intrusive granitic rocks, extrusive volcanic rocks like basalt, and hypabyssal rocks.
2. Sedimentary rocks form through the lithification of sediments and include clastic rocks like sandstone, chemical rocks like limestone, and organic rocks like coal.
3. Metamorphic rocks form from the alteration of existing rocks under heat, pressure, and fluids, changing their texture and minerals. Foliated rocks include schist and gneiss, while non-foliated rocks include marble and quartzite.
The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material.
This document discusses clay, its properties, formation, and varieties. Clay is a fine-grained mineral composed of particles less than 2 microns that are plastic when wet and solidify when dried. It forms under limited geologic conditions like weathering rock formations or deeply buried sediments containing pore water. Different clays have varying properties making them suitable for different uses, and clay art is discussed as an application.
Sandstone is a sedimentary rock composed of sand-sized grains of minerals and rock fragments bound together by a cement, such as silica or calcium carbonate. It forms under both marine and terrestrial environments. Sandstone has been widely used as a building material in structures like temples, homes, and monuments due to its hardness yet ability to be carved. It is also used for grindstones, statues, and filtering pollutants from water due to its porous nature. Major deposits of sandstone can be found around the world, including in the United States, South Africa, and Europe.
Physical and Chemical Properties of Soil of Bangladesh by Masud Hiruhiru masud
This document summarizes the physical and chemical properties of soil in Bangladesh. It discusses the texture, structure, color, density, temperature, and organic matter content of Bangladeshi soils. The document also examines the cation exchange capacity and pH of Bangladeshi soils. In conclusion, it states that soil texture, organic matter status, particle density, and bulk density are especially important for agricultural uses of soil in Bangladesh.
The document discusses soil profiles, soil genesis, and parent material classification. It defines a soil profile as the vertical cross section of soil horizons. Soil genesis refers to the evolution of soil from parent material, influenced by climate, organisms, relief, and time. Parent material is the geological material from which soil forms, and can be classified based on its mode of transportation (ice, water, wind, gravity) and degree of particle sorting. The document provides examples of different parent material types including glacial till, alluvium, loess, and residuum.
Introduction and classification of rocksTarun kumar
Introduction and classification of rocks for building and construction materials... types of rocks and their classifications, and types of stone quarrying.
Physical Properties of different types of Metamorphic Rocks (Geology)Raboon Redar
Metamorphic rocks are rocks that have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Change to these extreme conditions changes the mineralogy, texture, and chemical composition of the rocks.
Soil is formed by the weathering and disintegration of rock. Key factors that influence soil formation are climate, organisms, topography, parent material and time. Soils are composed mainly of silicates, with quartz being the most abundant mineral. Other common minerals include feldspars, micas and clay minerals like kaolinite, illite and montmorillonite. Laboratory testing of soils helps characterize properties like particle size distribution, moisture content, liquid limit, plastic limit and organic content which inform geotechnical analysis and design.
This document summarizes the key characteristics and formation processes of the three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma. Sedimentary rocks are formed at the Earth's surface from the compaction and cementation of sediments. Metamorphic rocks are formed from the alteration of existing rocks through heat, pressure, and chemical changes in the Earth's crust.
The document discusses rocks and soil. It defines rocks as being made up of two or more minerals, and describes three main types of rocks: igneous, metamorphic, and sedimentary. Igneous rocks form from cooling magma, metamorphic rocks change form due to temperature and pressure, and sedimentary rocks form from layers of compacted debris. Soil is described as being made up of small rocks, decomposed plant and animal matter, and waste. The properties of soil include color, water and nutrient retention, and texture.
The document discusses weathering, soil formation, and erosion. It defines weathering as the breaking down of rocks on Earth's surface through mechanical or chemical processes. Mechanical weathering breaks rocks into smaller pieces without changing their chemical makeup, while chemical weathering changes the chemical makeup of rocks. The main agents of erosion that move weathered materials include gravity, wind, running water, glaciers, and waves. Erosion transports weathered materials from one location to another, while deposition is the laying down of sediments in new locations. Mass movements involve the downslope movement of loose materials due to gravity.
This document discusses sedimentary rocks, including their formation, classification, and characteristic textures and structures. Sedimentary rocks form through the lithification of sediments deposited under water. They are classified based on their composition into clastic rocks (formed from fragments of pre-existing rocks), chemical/evaporite rocks (formed by chemical precipitation), and organic rocks (containing organic matter). Key textures include grain size, shape, packing, and fabric. Common structures include stratification, lamination, cross-bedding, graded bedding, and ripple marks, which provide information about depositional environments.
Metamorphic rocks are rocks that have changed from one type to another due to high heat and pressure underground over millions of years. This process of metamorphism can change a rock's texture, chemical composition, and internal structure. Jade rock specifically forms where tectonic plates meet in areas with high underground heat and pressure, as this environment transforms pyroxene rock into crystalline jade over long periods of time.
This document describes metamorphic rock and the processes of metamorphism. It explains that rocks can undergo metamorphism through heat, pressure, or both, which causes changes to their structure, texture, or composition. There are two types of metamorphism: contact metamorphism near magma intrusions, and regional metamorphism deep underground from pressure. Original minerals change into more stable minerals indicating temperature and pressure. Metamorphic rocks exhibit foliated or non-foliated textures and structures like folds that result from deformation during metamorphism.
The document discusses the three main rock types - igneous, sedimentary, and metamorphic rocks. It describes the rock cycle which shows how the different rock types are interrelated through geological processes. Igneous rocks form from the cooling of magma, either below ground (intrusive) or on the surface (extrusive). Sedimentary rocks form through the weathering of existing rocks, erosion and deposition of sediments, and compaction and cementation over time. Metamorphic rocks form from the alteration of existing rocks deep underground under high pressures and temperatures.
Rocks are naturally occurring mixtures of minerals, mineraloids, glass or organic matter that are divided into three main types - igneous, sedimentary, and metamorphic - based on how they were formed. Rocks are continually changed over time by various geological processes through the rock cycle, where one type of rock can be transformed into another through weathering, erosion, melting and other changes. The core, mantle and crust act as a recycling machine that redistributes rocks.
The document discusses different types of rocks and stones used in construction, including their origins, properties, and applications. It describes three main types of rocks - igneous, sedimentary, and metamorphic - and how they are formed. Specific rock and stone materials like granite, limestone, marble, sandstone, and crushed stone are explained in terms of their composition, colors, textures, and common uses in building and other construction projects.
Rocks are naturally occurring solid mixtures of minerals or organic matter. They are classified based on how they form, their composition, and texture. Rocks change over time through the rock cycle. There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from cooling magma, sedimentary rocks form through the compaction and cementation of sediments, and metamorphic rocks form from changes to existing rocks through heat, pressure, and deformation.
CLASSIFICATION OF ROCKS:
GEOLOGICAL:IGNEOUS,SEDIMENTRY,METAMORPHIC ROCKS
PHYSICAL:STRATIFIED,UNSTRATIFIED,FOLIATED.
CHEMICAL:SILICEOUS,CALCAREOUS,AGRILLACEOUS ROCKS.
CHARACTERSTICS OF STONES AND USES OF STONES
1) Gneiss is a common metamorphic rock formed from igneous or sedimentary rocks under high-grade regional metamorphism. It is medium- to coarse-foliated with little mica or other platy minerals.
2) Marble is a non-foliated metamorphic rock formed from limestone composed primarily of calcite. It is widely used as a building material.
3) Migmatite forms under extreme heat during metamorphism, where partial melting occurs in pre-existing rocks resulting in a mixture of newly crystallized and older resistant materials.
Petrology is the study of rocks and their origins, compositions, textures, and structures. There are three main types of rocks: igneous rocks formed from cooled magma, sedimentary rocks formed from compressed sediments, and metamorphic rocks formed from existing rocks subjected to heat and pressure. Rocks are constantly changing between these types through geological processes in the rock cycle, powered by Earth's interior heat and the energy from the sun. Igneous rocks can become sedimentary rocks through weathering and erosion then become metamorphic rocks through burial and increased heat and pressure, and metamorphic rocks can melt to form new magma and igneous rocks.
The document discusses different types of rocks:
1. Igneous rocks form from cooling magma and include intrusive granitic rocks, extrusive volcanic rocks like basalt, and hypabyssal rocks.
2. Sedimentary rocks form through the lithification of sediments and include clastic rocks like sandstone, chemical rocks like limestone, and organic rocks like coal.
3. Metamorphic rocks form from the alteration of existing rocks under heat, pressure, and fluids, changing their texture and minerals. Foliated rocks include schist and gneiss, while non-foliated rocks include marble and quartzite.
The three main types, or classes, of rock are sedimentary, metamorphic, and igneous and the differences among them have to do with how they are formed. Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material.
This document discusses clay, its properties, formation, and varieties. Clay is a fine-grained mineral composed of particles less than 2 microns that are plastic when wet and solidify when dried. It forms under limited geologic conditions like weathering rock formations or deeply buried sediments containing pore water. Different clays have varying properties making them suitable for different uses, and clay art is discussed as an application.
Sandstone is a sedimentary rock composed of sand-sized grains of minerals and rock fragments bound together by a cement, such as silica or calcium carbonate. It forms under both marine and terrestrial environments. Sandstone has been widely used as a building material in structures like temples, homes, and monuments due to its hardness yet ability to be carved. It is also used for grindstones, statues, and filtering pollutants from water due to its porous nature. Major deposits of sandstone can be found around the world, including in the United States, South Africa, and Europe.
The document provides an overview of earth and life sciences topics including minerals, rocks, and the three main types of rocks - igneous, sedimentary, and metamorphic. It discusses how rocks are formed, classified, and the importance of studying rocks and minerals. It also summarizes the rock cycle and exogenic processes of weathering and erosion, describing the physical and chemical agents that break down rocks and how eroded materials are transported and deposited in new locations.
The document provides an overview of earth and life sciences topics including minerals, rocks, and the rock cycle. It discusses the three main types of rocks - igneous, sedimentary, and metamorphic - and how they are formed. The document also summarizes the processes of weathering and erosion, describing how physical and chemical breakdown of rocks is transported by agents and deposited in new locations.
The document discusses different types of rocks and the rock cycle. It explains that there are three main types of rocks - sedimentary, metamorphic, and igneous - and that rocks can change between these types through geological processes. The rock cycle model shows how rocks are formed from magma or other existing rocks and how they can be transformed over time by heat, pressure, and erosion.
This document discusses the key factors and processes involved in soil formation. It describes the five main soil forming factors as parent material, climate, topography, living matter, and time. The main processes that form soil horizons are addition, losses, translocation, and transformation. Additions come from rainfall, atmosphere, organic matter decomposition, erosion, and nutrients. Losses occur through evapotranspiration, leaching, erosion, and chemical/biological processes. Translocation moves materials within the soil profile. Transformation alters the physical and chemical properties of parent materials through weathering. The interaction of these factors and processes over long periods of time leads to the development of unique soil types in different environments.
Rocks are composed of minerals and are classified based on their origin and formation process. The three main types of rocks are igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma either deep underground, near the surface, or on the surface. Sedimentary rocks form from the compaction and cementation of sediments. Metamorphic rocks form from the alteration of existing igneous and sedimentary rocks through heat, pressure, and chemical processes usually associated with tectonic activity. Rocks serve many important purposes and understanding their classification provides insight into the geological history of the earth's crust.
The document discusses the three main rock types - igneous, sedimentary, and metamorphic rocks. It describes the rock cycle which shows how the different rock types are interrelated through geological processes. Igneous rocks form from the cooling of magma, either below ground (intrusive) or on the surface (extrusive). Sedimentary rocks form through the weathering of existing rocks, erosion, deposition of sediments, and compaction/cementation. Metamorphic rocks form from the alteration of existing rocks deep underground under high pressures and temperatures.
Weathering, erosion, and deposition are exogenic (surface) geologic processes that shape the landscape over time. Weathering breaks down rock through physical or chemical means. Erosion is the transport of weathered material by forces like water, wind, or gravity. Deposition occurs when eroded materials are deposited in a new location. Together these processes recycle earth materials and influence landform development through geologic timescales.
Earth materials, internel structure of the earth, composition of the earth Jahangir Alam
The document discusses key concepts about earth materials including:
- The earth's crust is composed of three basic rock types: igneous, sedimentary, and metamorphic. Igneous rocks form from cooling magma, sedimentary rocks form from compacted sediments, and metamorphic rocks form from changes to pre-existing rocks.
- Common rock-forming minerals include quartz, feldspars, micas, amphiboles, olivine, and calcite. These minerals are arranged in crystalline structures to form the three basic rock types.
- Weathering and erosion break down and transport rock materials over time in a cycle that is linked to tectonic plate movements and the formation of new
The document summarizes key information about shales, argillite, and siltstone. It discusses the rock cycle and how these sedimentary rocks form. Shales form through compaction of fine particles in slow-moving water. Their composition includes clay minerals, quartz, and feldspar. Shales exhibit fissility and laminations. Argillite is a metamorphosed shale or siltstone with increased induration. Siltstone contains silt-sized particles cemented together. These mudrocks are economically important raw materials.
Sedimentary rocks form through the compaction and cementation of sediments. There are two main types - clastic sedimentary rocks, which form from eroded fragments of pre-existing rocks, and chemical sedimentary rocks, which form through precipitation or biochemical processes. Sedimentary rocks are classified based on their mineral composition, grain size, sorting, and rounding. Sedimentary structures within the rocks provide clues about the depositional environment.
Igneous rocks form when magma cools and crystallizes either underground or at the surface. Sedimentary rocks form through the lithification of sediments. Metamorphic rocks form from pre-existing rocks undergoing changes due to heat, pressure, and chemically active fluids in the Earth's crust. The rock cycle illustrates how igneous, sedimentary, and metamorphic rocks are interrelated as they form and change over time through geological processes within the Earth.
Igneous rocks form when magma cools and crystallizes either underground or at the surface. Sedimentary rocks form through the lithification of sediments. Metamorphic rocks form from pre-existing rocks undergoing changes due to heat, pressure, and chemically active fluids in the Earth's crust. The rock cycle illustrates how igneous, sedimentary, and metamorphic rocks are interrelated as they form and change over time through geological processes within the Earth.
This document provides information about igneous, sedimentary, and metamorphic rocks. It begins with the lesson objectives of classifying rocks into these three categories. It then discusses each rock type in detail, including their formation processes and examples. Various diagrams illustrate concepts like the rock cycle and types of metamorphism. Activities are included to help students understand rock identification and transformations through the rock cycle.
Rocks form through three main processes: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling of magma either below ground as intrusive rocks or above ground as extrusive rocks. Sedimentary rocks are formed at the surface from the weathering and lithification of pre-existing rocks. Metamorphic rocks are formed by the alteration of other rocks through heat, pressure, and chemically active fluids in the Earth's crust and mantle.
ROCKS BY PATRICK AFFUL (OCCLUDED PROF.)PATRICKAFFUL
This document discusses the three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma either underground (plutonic rocks), just below the surface (hypabyssal rocks), or on the surface (extrusive rocks). Sedimentary rocks form through the lithification of sediments, either mechanically from weathered rock debris, organically from remains of living organisms, or chemically from mineral precipitation. Metamorphic rocks form from the alteration of existing rocks through heat, pressure, and fluids, resulting in recrystallization and changes to texture and mineral composition. Examples of each rock type are provided.
Weathering is the physical and chemical breakdown of rocks at Earth's surface. Physical weathering breaks rocks into smaller pieces through frost cracking, plant root growth, abrasion by water, ice or wind. Chemical weathering alters the composition of rocks through oxidation, hydrolysis and carbonation. The rate of weathering depends on climate, mineral composition, and surface area. Weathering produces sediments and soils through mechanical and chemical breakdown over time.
The document discusses the formation of soil through weathering processes. It describes mechanical weathering which breaks down rock physically via frost wedging, pressure release, hydraulic action, salt crystal growth and thermal stress. It also describes chemical weathering which alters the molecular structure of rocks through dissolution, carbonation, hydration, hydrolysis and oxidation. The weathered rocks and minerals are broken down into clay, silt, sand and nutrients that combine with organic materials to form various soil types.
This document discusses lateral earth pressure on retaining walls. It introduces Rankine's and Coulomb's theories for estimating active and passive earth pressures. Rankine proposed that a semi-infinite mass of soil could reach states of plastic equilibrium under horizontal stretching (active state) or compression (passive state). Mohr circles are used to determine the principal stresses and orientation of potential failure planes for each state. The active pressure coefficient KA is related to the friction angle, while the passive pressure coefficient KP is also a function of friction angle.
The document discusses the stability of slopes, including natural and man-made slopes. It defines infinite and finite slopes and provides examples. Slope stability is important for earth dams and failures can be catastrophic. Factors that cause slope instability are gravitational forces, seepage water, erosion, lowering of adjacent water levels, and earthquakes. Stability is analyzed by testing soil samples, studying failure factors, and computation. Factors of safety are defined with respect to strength, cohesion, and height. Infinite slope stability is analyzed for sand and clay, with equations developed relating slope angle to soil friction angle and critical depth.
The document discusses soil exploration, which involves investigating subsoil conditions through field and laboratory tests to obtain information needed for foundation design. It describes various boring and sampling methods used to collect disturbed and undisturbed soil samples at different depths for testing and analysis. The goal is to determine soil type, strength, compressibility and other parameters critical to foundation type selection and design of safe bearing pressures.
1. Shear strength is the ability of soil to resist sliding along internal surfaces and is one of the most important engineering properties of soil.
2. Coulomb proposed that shear strength (s) of soil is equal to apparent cohesion (c) plus normal stress (σ) multiplied by the tangent of the angle of shearing resistance (φ).
3. The direct shear test and triaxial compression test are commonly used laboratory methods to determine the shear strength parameters c and φ of soils, while field methods include the vane shear test.
This document provides an overview of soil compressibility and consolidation. It defines consolidation as the process by which saturated clay compresses over time as water drains out of the soil mass and load is gradually transferred from pore water to the soil skeleton. A key aspect of consolidation discussed is the one-dimensional consolidation theory, which models clay layers constrained laterally between impermeable boundaries. The document also describes the consolidometer test apparatus used to measure a soil's compressibility properties and generate pressure-void ratio curves through standardized loading and unloading steps.
This document discusses stress distribution in soils due to surface loads. It introduces Boussinesq's formula and Westergaard's formula for calculating vertical stress at a point in soil from a surface point load, based on elastic theory. Boussinesq's formula assumes the soil is elastic, isotropic, and homogeneous, while Westergaard's formula accounts for soil anisotropy. Formulas are also provided for calculating stress from line loads, strip loads, and loads beneath the corner of a rectangular foundation. Examples are given to demonstrate calculating stress at different points using the formulas.
The document discusses effective stress and pore water pressure in soils. It defines effective stress as the pressure transmitted through grain-to-grain contact points, which is responsible for changes in soil volume. Pore water pressure tries to separate grains and increases soil volume. Experiments show that effective stress increases when water flows downward through saturated soil, and decreases when flow is upward. The critical hydraulic gradient is the point when effective stress is zero and soil can experience a "quick" condition. Capillary rise causes water to rise above the water table in small soil pores due to surface tension.
The document discusses soil permeability and seepage. It defines soil permeability as the ease with which water flows through permeable materials like soil. Darcy's law states that the rate of water flow through a soil is proportional to the hydraulic gradient and the soil's hydraulic conductivity. The hydraulic conductivity depends on factors like soil type, density, temperature, and viscosity of water. Laboratory tests like constant head and falling head permeability tests are used to measure a soil's hydraulic conductivity.
This chapter discusses Terzaghi's bearing capacity theory for determining the ultimate bearing capacity of shallow foundations. It summarizes the key assumptions of Terzaghi's theory, including homogeneous, isotropic soil; two-dimensional problem; general shear failure; and vertical, symmetrical loading. It describes the failure mechanism with three zones - an elastic central zone beneath the footing, and two radial shear zones on the sides that meet the ground surface at angles of 45° - φ/2. Terzaghi's theory uses a semi-empirical equation to calculate ultimate bearing capacity based on soil properties of cohesion, friction, and the effective overburden pressure at the foundation level.
1) Two approaches are used to determine the safe bearing pressure of soil: allowable bearing pressure based on shear failure criteria, and safe bearing pressure based on settlement criteria.
2) Plate load tests can be used to estimate the safe bearing pressure that results in a given permissible settlement. Tests are conducted with plates of different sizes and the load-settlement data is used to calculate settlement of prototype foundations using empirical equations.
3) Housel's method involves conducting two plate load tests and solving equations involving load, plate area and perimeter to determine constants, which are then used to calculate load and size of a prototype foundation that results in the permissible settlement.
This document discusses different types of shallow foundations including cantilever footings, combined footings, and mat foundations. It provides details on:
1. The design process for cantilever footings which involves iterative calculations to determine reactions and footing sizes to achieve uniform soil pressure.
2. Factors that influence the choice of foundation type including soil bearing capacity and building layout.
3. Design considerations for mat foundations on sand and clay soils including allowable bearing pressures.
This document provides an overview of pile foundations, including different types of piles classified by material, length, orientation, and installation method. Piles transfer structural loads to deeper firm soil layers when the top soil is loose, soft, or swelling. Piles are long slender columns that can be driven, bored, or cast in place using materials like concrete, steel, or timber. Driven piles compact the surrounding soil to increase capacity, while cast-in-place piles are constructed by drilling holes and filling with concrete to avoid disturbing soil. The document discusses advantages and disadvantages of different pile types.
1) The document discusses the behavior of laterally loaded vertical and batter piles used as deep foundations. It describes Winkler's hypothesis which models soil-pile interaction using independent springs.
2) It presents the differential equation that governs the deflection of laterally loaded piles, involving terms for deflection, slope, moment, shear, and soil reaction. The equation is solved using p-y curves which model the nonlinear soil-pile interaction.
3) It summarizes previous research on model and field tests of vertical and batter piles under lateral loads. Batter piles are used to resist higher horizontal loads than vertical piles alone. The research provides data to develop solutions for analyzing laterally loaded pile behavior.
This document discusses drilled pier foundations, which are similar to pile foundations but installed through excavation rather than driving. It describes the four main types of drilled piers: straight-shaft end-bearing, straight-shaft sidewall-friction, combination end-bearing and sidewall-friction, and underreamed or belled piers. The document also outlines the advantages and disadvantages of drilled pier foundations and discusses historical and modern methods of construction, including the dry method, casing method, and slurry method.
This document discusses collapsible soils and how to assess their collapse potential and calculate expected settlements. There are two types of soils that exhibit volume changes with water content changes - collapsible soils that decrease in volume (collapse) when wetted and expansive soils that increase in volume (swell) when wetted. The document outlines methods to determine collapse potential from consolidation tests and calculate collapse settlements using a double oedometer test procedure. It provides examples of applying these methods to calculate collapse settlements for normally consolidated and overconsolidated soil conditions. Foundation design in collapsible soils requires special consideration due to the risk of large wetting-induced settlements.
This document discusses concrete retaining walls, including:
1. Conditions for applying Rankine and Coulomb theories of earth pressure to cantilever and gravity walls. Rankine is applicable to cantilever walls, while Coulomb is applicable to solid gravity walls.
2. Common minimum dimensions for cantilever, counterfort, and gravity walls based on the wall height.
3. Use of charts to estimate active earth pressures on the wall based on backfill type and geometry.
4. Stability checks including sliding, overturning, bearing capacity, and base shear failure with required safety factors.
5. Drainage provisions such as vertical and inclined drains, bottom drains, and weep holes.
This document discusses sheet pile walls and braced cuts. It describes different types of sheet piles (timber, reinforced concrete, steel), their uses, and common sheet pile structures. Methods for analyzing the depth of embedment and bending moments in free cantilever sheet pile walls are presented for cases with the water table at a great depth or within the backfill. Approximate depths of embedment are provided based on relative soil density.
This document discusses soil improvement techniques for foundations. It describes mechanical compaction as the least expensive method, which involves removing weak soil and refilling/replacing it in layers with compaction. Two common compaction tests are described - the Standard Proctor Test and Modified Proctor Test - which involve compacting soil in a mold to determine the optimum moisture content and maximum dry density. Factors like moisture content and compactive effort influence compaction results.
This document discusses soil phase relationships and classification. It defines key terms like void ratio, porosity, degree of saturation, density, specific gravity, water content and unit weight. It explains the relationships between these parameters and provides typical values for various soil types. For example, it states that the void ratios of natural sand deposits range from 0.51 to 0.85 and dry unit weights of granular soils range from 14 to 18 kN/m3. The document also includes two examples problems demonstrating calculations using the defined relationships.
This document provides an introduction and brief history of soil mechanics and foundation engineering. It discusses how Karl Terzaghi is considered the father of soil mechanics for establishing the field's scientific basis in his 1925 book. While ancient structures were built without modern soil mechanics principles, the field has progressed from an empirical to a scientific stage. Modern foundation design relies on theories developed from fundamental soil properties, but field conditions can differ and require observational methods.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
Batteries -Introduction – Types of Batteries – discharging and charging of battery - characteristics of battery –battery rating- various tests on battery- – Primary battery: silver button cell- Secondary battery :Ni-Cd battery-modern battery: lithium ion battery-maintenance of batteries-choices of batteries for electric vehicle applications.
Fuel Cells: Introduction- importance and classification of fuel cells - description, principle, components, applications of fuel cells: H2-O2 fuel cell, alkaline fuel cell, molten carbonate fuel cell and direct methanol fuel cells.
Comparative analysis between traditional aquaponics and reconstructed aquapon...bijceesjournal
The aquaponic system of planting is a method that does not require soil usage. It is a method that only needs water, fish, lava rocks (a substitute for soil), and plants. Aquaponic systems are sustainable and environmentally friendly. Its use not only helps to plant in small spaces but also helps reduce artificial chemical use and minimizes excess water use, as aquaponics consumes 90% less water than soil-based gardening. The study applied a descriptive and experimental design to assess and compare conventional and reconstructed aquaponic methods for reproducing tomatoes. The researchers created an observation checklist to determine the significant factors of the study. The study aims to determine the significant difference between traditional aquaponics and reconstructed aquaponics systems propagating tomatoes in terms of height, weight, girth, and number of fruits. The reconstructed aquaponics system’s higher growth yield results in a much more nourished crop than the traditional aquaponics system. It is superior in its number of fruits, height, weight, and girth measurement. Moreover, the reconstructed aquaponics system is proven to eliminate all the hindrances present in the traditional aquaponics system, which are overcrowding of fish, algae growth, pest problems, contaminated water, and dead fish.
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Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
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of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
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precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
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Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
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Embedded machine learning-based road conditions and driving behavior monitoring
Chapter 02
1. CHAPTER 2
SOIL FORMATION AND CHARACTERIZATION
2.1 INTRODUCTION
The word 'soil' has different meanings for different professions. To the agriculturist, soil is the top
thin layer of earth within which organic forces are predominant and which is responsible for the
support of plant life. To the geologist, soil is the material in the top thin zone within which roots
occur. From the point of view of an engineer, soil includes all earth materials, organic and
inorganic, occurring in the zone overlying the rock crust.
The behavior of a structure depends upon the properties of the soil materials on which the
structure rests. The properties of the soil materials depend upon the properties of the rocks from
which they are derived. A brief discussion of the parent rocks is, therefore, quite essential in order
to understand the properties of soil materials.
2.2 ROCK CLASSIFICATION
Rock can be defined as a compact, semi-hard to hard mass of natural material composed of one or
more minerals. The rocks that are encountered at the surface of the earth or beneath, are commonly
classified into three groups according to their modes of origin. They are igneous, sedimentary and
metamorphic rocks.
Igneous rocks are considered to be the primary rocks formed by the cooling of molten
magmas, or by the recrystallization of older rocks under heat and pressure great enough to render
them fluid. They have been formed on or at various depths below the earth surface. There are two
main classes of igneous rocks. They are:
1. Extrusive (poured out at the surface), and
2. Intrusive (large rock masses which have not been formed in contact with the atmosphere).
2. 6 Chapter 2
Initially both classes of rocks were in a molten state. Their present state results directly from
the way in which they solidified.Due to violent volcanic eruptions in the past, some of the molten
materials were emitted into the atmosphere with gaseous extrusions. These cooled quickly and
eventually fell on the earth's surface as volcanic ash and dust. Extrusiverocks are distinguished,in
general, by their glass-like structure.
Intrusive rocks, cooling and solidifying at great depths and under pressure containing
entrapped gases, are wholly crystalline in texture. Such rocks occur in masses of great extent, often
going to unknown depths. Some of the important rocks that belong to the igneous group are granite
and basalt. Granite is primarily composed of feldspar, quartz and mica and possesses a massive
structure. Basalt is a dark-colored fine-grained rock. It is characterized by the predominance of
plagioclase, the presence of considerable amounts of pyroxene and some olivine and the absence of
quartz. The color varies from dark-grey to black. Both granite and basalt are used as building
stones.
When the products of the disintegration and decomposition of any rock type are
transported, redeposited, and partly or fully consolidated or cemented into a new rock type, the
resulting material is classified as a sedimentary rock. The sedimentary rocks generally are
formed in quite definitely arranged beds, or strata, which can be seen to have been horizontal at
one time although sometimes displaced through angles up to 90 degrees. Sedimentary rocks are
generally classified on the basis of grain size, texture and structure. From an engineering point of
view, the most important rocks that belong to the group are sandstones, limestones, and shales.
Rocks formed by the complete or incomplete recrystallization of igneous or sedimentary
rocks by high temperatures, high pressures, and/or high shearing stresses are metamorphic rocks.
The rocks so produced may display features varying from complete and distinct foliation of a
crystalline structure to a fine fragmentary partially crystalline state caused by direct compressive
stress, including also the cementation of sediment particles by siliceous matter. Metamorphic rocks
formed without intense shear action have a massive structure. Some of the important rocks that
belong to this group are gneiss, schist, slate and marble. The characteristic feature of gneiss is its
structure, the mineral grains are elongated, or platy, and banding prevails. Generally gneiss is a
good engineering material. Schist is a finely foliated rock containing a high percentage of mica.
Depending upon the amount of pressure applied by the metamorphic forces, schist may be a very
good building material. Slate is a dark colored, platy rock with extremely fine texture and easy
cleavage. Because of this easy cleavage, slate is split into very thin sheets and used as a roofing
material. Marble is the end product of the metamorphism of limestone and other sedimentary rocks
composed of calcium or magnesium carbonate. It is very dense and exhibits a wide variety of
colors. In construction, marble is used for facing concrete or masonry exterior and interior walls
and floors.
Rock Minerals
It is essential to examine the properties of the rock forming minerals since all soils are derived
through the disintegration or decomposition of some parent rock. A 'mineral' is a natural inorganic
substance of a definite structure and chemical composition. Some of the very important physical
properties of minerals are crystal form, color, hardness, cleavage, luster, fracture, and specific
gravity. Out of these only two, specific gravity and hardness, are of foundation engineering interest.
The specific gravity of the minerals affects the specific gravity of soils derived from them. The
specific gravity of most rock and soil forming minerals varies from 2.50 (some feldspars) and 2.65
(quartz) to 3.5 (augite or olivine). Gypsum has a smaller value of 2.3 and salt (NaCl) has 2.1. Some
iron minerals may have higher values, for instance, magnetite has 5.2.
It is reported that about 95 percent of the known part of the lithosphere consists of igneous
rocks and only 5 percent of sedimentary rocks. Soil formation is mostly due to the disintegration of
igneous rock which may be termed as a parent rock.
3. Soil Formation and Characterization 7
Table 2.1 Mineral composition of igneous rocks
Mineral Percent
Quartz 12-20
Feldspar 50-60
Ca, Fe and Mg, Silicates 14-17
Micas 4-8
Others 7-8
The average mineral composition of igneous rocks is given in Table 2.1. Feldspars are the most
common rock minerals, which account for the abundance of clays derived from the feldspars on the
earth's surface. Quartz comes next in order of frequency. Most sands are composed of quartz.
2.3 FORMATION OF SOILS
Soil is defined as a natural aggregate of mineral grains, with or without organic constituents, that
can be separated by gentle mechanical means such as agitation in water. By contrast rock is
considered to be a natural aggregate of mineral grains connected by strong and permanent cohesive
forces. The process of weathering of the rock decreases the cohesive forces binding the mineral
grains and leads to the disintegration of bigger masses to smaller and smaller particles. Soils are
formed by the process of weathering of the parent rock. The weathering of the rocks might be by
mechanical disintegration, and/or chemical decomposition.
Mechanical Weathering
Mechanical weathering of rocks to smaller particles is due to the action of such agents as the
expansive forces of freezing water in fissures, due to sudden changes of temperature or due to the
abrasion of rock by moving water or glaciers. Temperature changes of sufficient amplitude and
frequency bring about changes in the volume of the rocks in the superficial layers of the earth's
crust in terms of expansion and contraction. Such a volume change sets up tensile and shear stresses
in the rock ultimately leading to the fracture of even large rocks. This type of rock weathering takes
place in a very significantmanner in arid climates where free, extreme atmospheric radiation brings
about considerable variation in temperature at sunrise and sunset.
Erosion by wind and rain is a very important factor and a continuing event. Cracking forces
by growing plants and roots in voids and crevasses of rock can force fragments apart.
Chemical Weathering
Chemical weathering (decomposition) can transform hard rock minerals into soft, easily erodable
matter. The principal types of decomposition are hydmtion, oxidation, carbonation, desilication
and leaching. Oxygen and carbon dioxide which are always present in the air readily combine with
the elements of rock in the presence of water.
2.4 GENERAL TYPES OF SOILS
It has been discussed earlier that soil is formed by the process of physical and chemical
weathering. The individual size of the constituent parts of even the weathered rock might range
from the smallest state (colloidal) to the largest possible (boulders). This implies that all the
weathered constituents of a parent rock cannot be termed soil. According to their grain size, soil
4. 8 Chapter 2
particles are classified as cobbles, gravel, sand, silt and clay. Grains having diameters in the range
of 4.75 to 76.2 mm are called gravel. If the grains are visible to the naked eye, but are less than
about 4.75 mm in size the soil is described as sand. The lower limit of visibility of grains for the
naked eyes is about 0.075 mm. Soil grains ranging from 0.075 to 0.002 mm are termed as silt and
those that are finer than 0.002 mm as clay. This classification is purely based on size which does
not indicate the properties of fine grained materials.
Residual and Transported Soils
On the basis of origin of their constituents, soils can be divided into two large groups:
1. Residual soils, and
2. Transported soils.
Residual soils are those that remain at the place of their formation as a result of the
weathering of parent rocks. The depth of residual soils depends primarily on climatic conditions
and the time of exposure. In some areas, this depth might be considerable. In temperate zones
residual soils are commonly stiff and stable. An important characteristic of residual soil is that the
sizes of grains are indefinite. For example, when a residual sample is sieved, the amount passing
any given sieve size depends greatly on the time and energy expended in shaking, because of the
partially disintegrated condition.
Transported soils are soils that are found at locations far removed from their place of
formation. The transporting agencies of such soils are glaciers, wind and water. The soils are named
according to the mode of transportation. Alluvial soils are those that have been transported by
running water. The soils that have been deposited in quiet lakes, are lacustrine soils. Marine soils
are those deposited in sea water. The soils transported and deposited by wind are aeolian soils.
Those deposited primarily through the action of gravitational force, as in land slides, are colluvial
soils. Glacial soils are those deposited by glaciers. Many of these transported soils are loose and
soft to a depth of several hundred feet. Therefore, difficulties with foundations and other types of
construction are generally associated with transported soils.
Organic and Inorganic Soils
Soils in general are further classified as organic or inorganic. Soils of organic origin are chiefly
formed either by growth and subsequent decay of plants such as peat, or by the accumulation of
fragments of the inorganic skeletons or shells of organisms. Hence a soil of organic origin can be
either organic or inorganic. The term organic soil ordinarily refers to a transported soil consistingof
the products of rock weathering with a more or less conspicuous admixture of decayed vegetable
matter.
Names of Some Soils that are Generally Used in Practice
Bentonite is a clay formed by the decomposition of volcanic ash with a high content of
montmorillonite. It exhibits the properties of clay to an extreme degree.
Varved Clays consist of thin alternating layers of silt and fat clays of glacial origin. They possess
the undesirable properties of both silt and clay. The constituents of varved clays were transported
into fresh water lakes by the melted ice at the close of the ice age.
Kaolin, China Clay are very pure forms of white clay used in the ceramic industry.
Boulder Clay is a mixture of an unstratified sedimented deposit of glacial clay, containing
unsorted rock fragments of all sizes ranging from boulders, cobbles, and gravel to finely pulverized
clay material.
5. Soil Formation and Characterization 9
Calcareous Soil is a soil containing calcium carbonate. Such soil effervesces when tested with
weak hydrochloric acid.
Marl consists of a mixture of calcareous sands, clays, or loam.
Hardpan is a relatively hard, densely cemented soil layer, like rock which does not soften when
wet. Boulder clays or glacial till is also sometimes named as hardpan.
Caliche is an admixture of clay, sand, and gravel cemented by calcium carbonate deposited from
ground water.
Peat is a fibrous aggregate of finer fragments of decayed vegetable matter. Peat is very
compressible and one should be cautious when using it for supporting foundations of structures.
Loam is a mixture of sand, silt and clay.
Loess is a fine-grained, air-borne deposit characterized by a very uniform grain size, and high void
ratio. The size of particles ranges between about 0.01 to 0.05 mm. The soil can stand deep vertical
cuts because of slight cementation between particles. It is formed in dry continental regions and its
color is yellowish light brown.
Shale is a material in the state of transitionfrom clay to slate. Shale itself is sometimes considered
a rock but, when it is exposed to the air or has a chance to take in water it may rapidly decompose.
2.5 SOIL PARTICLE SIZE AND SHAPE
The size of particles as explained earlier, may range from gravel to the finest size possible. Their
characteristics vary with the size. Soil particles coarser than 0.075 mm are visible to the naked eye
or may be examined by means of a hand lens. They constitute the coarser fractions of the soils.
Grains finer than 0.075 mm constitute the finer fractions of soils. It is possible to distinguish the
grains lying between 0.075 mm and 2 JL (1 [i = 1 micron = 0.001 mm) under a microscope. Grains
having a size between 2 ji and 0.1 JLA can be observed under a microscope but their shapes cannot be
made out. The shape of grains smaller than 1 ja can be determined by means of an electron
microscope. The molecular structure of particles can be investigated by means of X-ray analysis.
The coarser fractions of soils consist of gravel and sand. The individual particles of gravel,
which are nothing but fragments of rock, are composed of one or more minerals, whereas sand
grains contain mostly one mineral which is quartz.The individual grains of gravel and sand may be
angular, subangular, sub-rounded, rounded or well-rounded as shown in Fig. 2.1. Gravel may
contain grains which may be flat. Some sands contain a fairly high percentage of mica flakes that
give them the property of elasticity.
Silt and clay constitute the finer fractions of the soil. Any one grain of this fraction generally
consists of only one mineral. The particles may be angular, flake-shaped or sometimes needle-like.
Table 2.2 gives the particle size classification systems as adopted by some of the
organizations in the USA. The Unified Soil Classification System is now almost universally
accepted and has been adopted by the American Society for Testing and Materials (ASTM).
Specific Surface
Soil is essentially a paniculate system, that is, a system in which the particles are in a fine state of
subdivision or dispersion. In soils, the dispersed or the solid phase predominates and the dispersion
medium, soil water, only helps to fill the pores between the solid particles. The significanceof the
concept of dispersion becomes more apparent when the relationship of surface to particle size is
considered. In the case of silt, sand and larger size particles the ratio of the area of surface of the
particles to the volume of the sample is relatively small. This ratio becomes increasingly large as
6. Chapter 2
Angular Subangular Subrounded
Rounded Well rounded
Figure 2.1 Shapes of coarser fractions of soils
size decreases from 2 JL which is the upper limit for clay-sized particles. A useful index of relative
importance of surface effects is the specific surface of grain. The specific surface is defined as the
total area of the surface of the grains expressed in square centimeters per gram or per cubic
centimeter of the dispersed phase.
The shape of the clay particles is an important property from a physical point of view. The
amount of surface per unit mass or volume varies with the shape of the particles. Moreover, the
amount of contact area per unit surface changes with shape. It is a fact that a sphere has the smallest
surface area per unit volume whereas a plate exhibits the maximum. Ostwald (1919) has
emphasized the importance of shape in determining the specific surface of colloidal systems. Since
disc-shaped particles can be brought more in intimate contact with each other, this shape has a
pronounced effect upon the mechanical properties of the system. The interparticle forces between
the surfaces of particles have a significant effect on the properties of the soil mass if the particles in
the media belong to the clay fraction. The surface activity depends not only on the specific surface
but also on the chemical and mineralogical composition of the solid particles. Since clay particles
Table 2.2 Particle size classification by various systems
Name of the organization
Massachusetts Institute of
Technology (MIT)
US Department of Agriculture (USDA)
American Association of State
Highway and Transportation
Officials (AASHTO)
Unified Soil Classification System,
US Bureau of Reclamation, US Army
Corps of Engineers and American
Society for Testing and Materials
Particle size (mm)
Gravel Sand Silt Clay
> 2 2 to 0.06 0.06 to 0.002 <
> 2 2 to 0.05 0.05 to 0.002 <
76.2 to 2 2 to 0.075 0.075 to 0.002 <
76.2 to 4.75 4.75 to 0.075 Fines (silts and clays)
< 0.075
0.002
0.002
0.002
7. Soil Formation and Characterization 11
are the active portions of a soil because of their high specific surface and their chemical
constitution, a discussion on the chemical composition and structure of minerals is essential.
2.6 COMPOSITION OF CLAY MINERALS
The word 'clay' is generally understood to refer to a material composed of a mass of small mineral
particles which, in association with certain quantities of water, exhibits the property of plasticity.
According to the clay mineral concept, clay materials are essentially composed of extremely small
crystalline particles of one or more members of a small group of minerals that are commonly
known as clay minerals. These minerals are essentially hydrous aluminum silicates, with
magnesium or iron replacing wholly or in part for the aluminum, in some minerals. Many clay
materials may contain organic material and water-soluble salts. Organic materials occur either as
discrete particles of wood, leaf matter, spores, etc., or they may be present as organic molecules
adsorbed on the surface of the clay mineral particles. The water-soluble salts that are present in clay
materials must have been entrapped in the clay at the time of accumulation or may have developed
subsequently as a consequence of ground water movement and weathering or alteration processes.
Clays can be divided into three general groups on the basis of their crystalline arrangement
and it is observed that roughly similar engineering properties are connected with all the clay
minerals belonging to the same group. An initial study of the crystal structure of clay minerals leads
to a better understanding of the behavior of clays under different conditions of loading. Table 2.3
gives the groups of minerals and some of the important minerals under each group.
2.7 STRUCTURE OF CLAY MINERALS
Clay minerals are essentially crystalline in nature though some clay minerals do contain
material which is non-crystalline (for example allophane). Two fundamental building blocks
are involved in the formation of clay mineral structures. They are:
1. Tetrahedral unit.
2. Octahedral unit.
The tetrahedral unit consists of four oxygen atoms (or hydroxyls, if needed to balance
the structure) placed at the apices of a tetrahedron enclosing a silicon atom which combines
together to form a shell-like structure with all the tips pointing in the same direction. The
oxygen at the bases of all the units lie in a common plane.
Each of the oxygen ions at the base is common to two units. The arrangement is shown in
Fig. 2.2. The oxygen atoms are negatively charged with two negative charges each and the silicon
with four positive charges. Each of the three oxygen ions at the base shares its charges with the
Table 2.3 Clay minerals
Name of mineral Structural formula
I. Kaolin group
1. Kaolinite Al4Si4O10(OH)g
2. Halloysite Al4Si4O6(OH)16
II. Montmorillonite group
Montmorillonite Al4Si8O20(OH)4nH2O
III. Illite group
Illite Ky(Al4Fe2.Mg4.Mg6)Si8_y
Aly(OH)4020
8. 12 Chapter 2
adjacent tetrahedral unit. The sharing of charges leaves three negative charges at the base per
tetrahedral unit and this along with two negative charges at the apex makes a total of 5 negative
charges to balance the 4 positive charges of the silicon ion. The process of sharing the oxygen ions
at the base with neighboring units leaves a net charge of -1 per unit.
The second buildingblock is an octahedral unit with six hydroxylions at apices of an octahedral
enclosing an aluminum ion at the center. Iron or magnesium ions may replace aluminum ions in some
units. These octahedral units are bound together in a sheet structure with each hydroxyl ion common to
three octahedral units. This sheet is sometimes called asgibbsite sheet. TheAl ion has 3 positive charges
and each hydroxylion divides its -1 charge with two other neighboring units. This sharing of negative
charge with other units leaves a total of 2 negative charges per unit [(1/3) x 6]. The net charge of a unit
with an aluminum ion at the center is +1. Fig. 2.3 gives the structural arrangements of the units.
Sometimes, magnesium replaces the aluminum atoms in the octahedral units in this case, the
octahedral sheet is called a brucite sheet.
Formation of Minerals
The combination of two sheets of silica and gibbsite in different arrangements and conditions lead
to the formation of different clay minerals as given in Table 2.3. In the actual formation of the sheet
silicate minerals, the phenomenon of isomorphous substitution frequently occurs. Isomorphous
(meaning same form) substitutionconsists of the substitutionof one kind of atom for another.
Kaoiinite Mineral
This is the most common mineral of the kaolin group. The building blocks of gibbsite and
silica sheets are arranged as shown in Fig. 2.4 to give the structure of the kaolinite layer. The
structure is composed of a single tetrahedral sheet and a single alumina octahedral sheet
combined in units so that the tips of the silica tetrahedrons and one of the layers of the
octahedral sheet form a common layer. All the tips of the silica tetrahedrons point in the same
direction and towards the center of the unit made of the silica and octahedral sheets. This gives
rise to strong ionic bonds between the silica and gibbsite sheets. The thickness of the layer is
about 7 A (one angstrom = 10~8
cm) thick. The kaolinite mineral is formed by stacking the
layers one above the other with the base of the silica sheet bonding to hydroxyls of the gibbsite
sheet by hydrogen bonding. Since hydrogen bonds are comparatively strong, the kaolinite
(a) Tetrahedral unit (b) Silica sheet
Silicons
Oxygen
]_ Symbolic representation
of a silica sheet
Figure 2.2 Basic structural units in the silicon sheet (Grim, 1959)
9. Soil Formation and Characterization 13
(a) Octahedral unit (b) Octahedral sheet
0 Hydroxyls
I Symbolic representation
of a octahedral sheet
Aluminums,
magnesium or iron
Figure 2.3 Basic structural units in octahedral sheet (Grim, 1959)
crystals consist of many sheet stackings that are difficult to dislodge. The mineral is therefore,
stable, and water cannot enter between the sheets to expand the unit cells. The lateral
dimensions of kaolinite particles range from 1000 to 20,000 A and the thickness varies from
100 to 1000 A. In the kaolinite mineral there is a very small amount of isomorphous substitution.
Halloysite Mineral
Halloysite minerals are made up of successive layers with the same structural composition as those
composing kaolinite. In this case, however, the successive units are randomly packed and may be
separated by a single molecular layer of water.The dehydration of the interlayers by the removalof
the water molecules leads to changes in the properties of the mineral. An important structural
feature of halloysite is that the particles appear to take tubular forms as opposed to the platy shape
of kaolinite.
Ionic bond
Hydrogen bond
Gibbsite sheet
Silica sheet
T
7A
7A
7A
Figure 2.4 Structure of kaolinite layer
10. 14 Chapter 2
Montmorillonite Mineral
Montmorillonite is the most common mineral of the montmorillonite group. The structural
arrangement of this mineral is composed of two silica tetrahedral sheets with a central alumina
octahedral sheet. All the tips of the tetrahedra point in the same direction and toward the center of the
unit. The silica and gibbsite sheets are combined in such a way that the tips of the tetrahedrons of each
silica sheet and one of the hydroxyl layers of the octahedral sheet form a common layer. The atoms
common to both the silica and gibbsite layer become oxygen instead of hydroxyls. The thickness of
the silica-gibbsite-silica unit is about 10A (Fig. 2.5). In stacking these combined units one above the
other, oxygen layers of each unit are adjacent to oxygen of the neighboring units with a
consequence that there is a very weak bond and an excellent cleavage between them. Water can
enter between the sheets, causing them to expand significantly and thus the structure can break into
10 A thick structural units. Soils containing a considerable amount of montmorillonite minerals
will exhibit high swelling and shrinkage characteristics. The lateral dimensions of montmorillonite
particles range from 1000 to 5000 A with thickness varying from 10 to 50 A. Bentonite clay
belongs to the montmorillonite group. In montmorillonite, there is isomorphous substitution of
magnesium and iron foraluminum.
Illite
The basic structural unit of illite is similar to that of montmorillonite except that some of the
silicons are always replaced by aluminum atoms and the resultant charge deficiency is balanced by
potassium ions. The potassium ions occur between unit layers. The bonds with the
nonexchangeable K+
ions are weaker than the hydrogen bonds, but stronger than the water bond of
montmorillonite. Illite, therefore, does not swell as much in the presence of water as does
montmorillonite. The lateral dimensions of illite clay particles are about the same as those of
montmorillonite, 1000 to 5000 A, but the thickness of illite particles is greater than that of
montmorillonite particles, 50 to 500 A. The arrangement of silica and gibbsite sheets are as shown
in Fig. 2.6.
2.8 CLAY PARTICLE-WATER RELATIONS
The behavior of a soil mass depends upon the behavior of the discrete particles composing the mass
and the pattern of particle arrangement. In all these cases water plays an important part. The
Figure 2.5 Structure of montmorillonite layer
11. Soil Formation and Characterization 15
10A
T I I I I
T
loA
I I I I I I I I I I I I I I I I H T M — Potassium molecules
II I Mil I I I I I I III III
1 1 1 1 1 1 1 1 1 1 1 1 I I 1 1 1 1 1 V«— Fairly strong bond
Silica sheet
Gibbsite sheet
Figure 2.6 Structure of illite layer
behavior of the soil mass is profoundly influenced by the inter-particle-water relationships, the
ability of the soil particles to adsorb exchangeable cations and the amount of water present.
Adsorbed Water j
The clay particles carry a net negative charge ^n their surface. This is the result of both
isomorphous substitution and of a break in the continuity of the structure at its edges. The intensity
of the charge depends to a considerable extent on tljie mineralogical character of the particle. The
physical and chemical manifestations of the surface charge constitute the surface activity of the
mineral. Minerals are said to have high or low surface activity, depending on the intensity of the
surface charge. As pointed out earlier, the surface activity depends not only on the specific surface
but also on the chemical and mineralogical composition of the solid particle. The surface activityof
sand, therefore, will not acquire all the properties of ^ true clay, even if it is ground to a fine powder.
The presence of water does not alter its propertie
changing its unit weight. However, the behavior ol
of coarser fractions considerably excepting
' a saturated soil mass consisting of fine sand
might change under dynamic loadings. This aspect of the problem is not considered here. This
article deals only with clay particle-water relations.
In nature every soil particle is surrounded by ^ater. Since the centers of positive and negative
charges of water molecules do not coincide, the molecules behave like dipoles. The negative charge
on the surface of the soil particle, therefore, attracts the positive (hydrogen) end of the water
molecules. The water molecules are arranged in a definite pattern in the immediate vicinity of the
boundary between solid and water. More than one layer of water molecules sticks on the surface with
considerable force and this attractive force decreases with the increase in the distance of the water
molecule from the surface. The electrically attracted water that surrounds the clay particle is known as
the diffused double-layer of water. The water located within the zone of influence is known as the
adsorbed layer as shown in Fig. 2.7. Within the zone of influence the physical properties of the water
are very different from those of free or normal water at the same temperature. Near the surface of the
particle the water has the property of a solid. At the middle of the layer it resembles a very viscous
liquid and beyond the zone of influence, the propenles of the water become normal. The adsorbed
water affects the behavior of clay particles when subjected to external stresses, since it comes between
the particle surfaces. To drive off the adsorbed water, the clay particle must be heated to more than
200 °C, which would indicate that the bond between the water molecules and the surface is
considerably greater than that between normal water molecules.
12. 16
Particle surface
Chapter 2
Adsorbed
water
Distance
Figure 2.7 Adsorbed water layer surrounding a soil particle
The adsorbed film of water on coarse particles is thin in comparison with the diameter of the
particles. In fine grained soils, however, this layer of adsorbed water is relatively much thicker and
might even exceed the size of the grain. The forces associated with the adsorbed layers therefore
play an important part in determining the physical properties of the very fine-grained soils, but have
little effect on the coarser soils.
Soils in which the adsorbed film is thick compared to the grain size have properties quite different
from other soils having the same grain sizes but smaller adsorbed films. The most pronounced
characteristic of the former is their ability to deform plastically without cracking when mixed with
varying amounts of water. This is due to the grains moving across one another supported by the viscous
interlayers of the films. Such soils are called cohesive soils, for they do not disintegrate with pressure but
can be rolled into threads with ease. Here the cohesion is not due to direct molecular interaction between
soil particles at the points of contact but to the shearing strength of the adsorbed layers that separate the
grains at these points.
Base Exchange
Electrolytes dissociate when dissolved in water into positively charged cations and negatively
charged anions. Acids break up into cations of hydrogen and anions such as Cl or SO4. Salts and
bases split into metallic cations such as Na, K or Mg, and nonmetallic anions. Even water itself is an
electrolyte, because a very small fraction of its molecules always dissociates into hydrogen ions H+
and hydroxyl ions OH". These positively charged H+
ions migrate to the surface of the negatively
charged particles and form what is known as the adsorbed layer. These H+
ions can be replaced by
other cations such as Na, K or Mg. These cations enter the adsorbed layers and constitute what is
termed as an adsorption complex. The process of replacing cations of one kind by those of another
in an adsorption complex is known as base exchange. By base exchange is meant the capacity of
13. Soil Formation and Characterization 1 7
Table 2.4 Exchange capacity of some clay minerals
Mineral group Exchange capacity (meq per 100 g)
Kaolinites 3.8
Illites 40
Montmorillonites 80
Table 2.5 Cations arranged in the order of decreasing shear strength of clay
NH/ > H+
> K+
> Fe+++
>A1+++
> Mg+
> Ba++
> Ca++
> Na+
> Li+
colloidal particles to change the cations adsorbed on their surface. Thus a hydrogen clay (colloid
with adsorbed H cations) can be changed to sodium clay (colloid with adsorbed Na cations) by a
constant percolation of water containing dissolved Na salts. Such changes can be used to decrease
the permeability of a soil. Not all adsorbed cations are exchangeable. The quantity of exchangeable
cations in a soil is termed exchange capacity.
The base exchange capacity is generally defined in terms of the mass of a cation which may
be held on the surface of 100 gm dry mass of mineral. It is generally more convenient to employ a
definition of base exchange capacity in milli-equivalents (meq) per 100 gm dry soil. One meq is
one milligram of hydrogen or the portion of any ion which will combine with or displace
1 milligram of hydrogen.
The relative exchange capacity of some of the clay minerals is given in Table 2.4.
If one element, such as H, Ca, or Na prevails over the other in the adsorption complex of a
clay, the clay is sometimes given the name of this element, for example H-clay or Ca-clay. The
thickness and the physical properties of the adsorbed film surrounding a given particle, depend to a
large extent on the character of the adsorption complex. These films are relatively thick in the case
of strongly water-adsorbent cations such as Li+
and Na+
cations but very thin for H+
. The films of
other cations have intermediate values. Soils with adsorbed Li+
and Na+
cations are relatively more
plastic at low water contents and possess smaller shear strength because the particles are separated
by a thicker viscous film. The cations in Table 2.5 are arranged in the order of decreasing shear
strength of clay.
Sodium clays in nature are a product either of the deposition of clays in sea water or of their
saturation by saltwater flooding or capillary action. Calcium clays are formed essentially by fresh
water sediments. Hydrogen clays are a result of prolonged leaching of a clay by pure or acidic
water, with the resulting removal of all other exchangeable bases.
2.9 SOIL MASS STRUCTURE
The orientation of particles in a mass depends on the size and shape of the grains as well as upon
the minerals of which the grains are formed. The structure of soils that is formed by natural
deposition can be altered by external forces. Figure 2.8 gives the various types of structures of
soil. Fig. 2.8(a) is a single grained structure which is formed by the settlement of coarse grained
soils in suspension in water. Fig. 2.8(b) is aflocculent structure formed by the deposition of the
fine soil fraction in water. Fig. 2.8(c) is a honeycomb structure which is formed by the
disintegration of a flocculent structure under a superimposed load. The particles oriented in a
flocculent structure will have edge-to-face contact as shown in Fig. 2.8(d) whereas in a
14. Chapter 2
(a) Single grain structure (b) Flocculent structure (c) Honeycombstructure
(d) Flocculated type structure
(edge to face contact)
(e) Dispersed structure
(face to face contact)
(f) Undisturbedsalt water deposit (g) Undisturbed fresh water deposit
Figure 2.8 Schematic diagrams of various types of structures (Lambe, 1 958a)
honeycomb structure, the particles will have face-to-face contact as shown in Fig. 2.8(e). Natural
clay sediments will have more or less flocculated particle orientations. Marine clays generally
have a more open structure than fresh water clays. Figs. 2.8(f) and (g) show the schematic views
of salt water and fresh water deposits.