The document summarizes the environmental pollution control methods used by NTPC Ltd. for ash dykes. It describes how fly ash from power plants is mixed with water and pumped into ash ponds located near the plants. Ash ponds are constructed in stages with 3m height increments to reduce costs. The upstream construction method is most common, where new segments are built on top of deposited ash. Plastic liners are installed at the bottom and sides of new ash ponds to prevent groundwater pollution from decanted water.
Crown corrosion - wwwe - By Mr. Mayank Oza - water and waste water engineeringMayank Oza
The document discusses crown corrosion in sewers. Crown corrosion occurs when bacteria in sewage slime convert sulphates to sulphides, which release hydrogen sulphide gas. To control corrosion, sewer design should provide self-cleansing flow, ventilation, and flushing to prevent stagnation. Pipes made of inert materials or lined with sulphate-resistant cement can increase longevity by preventing corrosion.
Irrigation and Hydraulic Structures
Detailed discussion on forces acting on gravity dam as per the JNTU Anantapur Autonomous syllabus.
Use full for B.Tech Civil Engineering Students
Cross drainage works (CDWs) are structures constructed where canals intersect natural drainages like rivers or streams. There are three main types of CDWs depending on the relative bed levels: 1) aqueducts or siphon aqueducts where the canal passes over the drainage, 2) super passages or siphon super passages where the drainage passes over the canal, and 3) level crossings where the canal and drainage intersect at the same level. The appropriate type of CDW is selected based on factors like relative bed levels, availability of suitable foundation, economic considerations, and discharge of the drainage. Key steps in planning CDWs include selecting a suitable site where the drainage crosses the canal alignment at a right angle and on
This document provides an introduction and overview of dewatering methods used in construction projects. It discusses how the water table and groundwater conditions can impact foundations and excavations. Several key dewatering methods are described, including sumps, wells, well points, drainage galleries, and exclusion methods like ground freezing. Sumps involve pumping from perforated drums in a gravel-filled excavation and work best in fine-grained soils. Wells use large-diameter casings and pumps to dewater large areas to depth in permeable soils. Well points are smaller and more shallow but can effectively dewater coarse-grained soils through a vacuum system. Selection of the appropriate dewatering method depends on factors like soil type, excav
Tunnelling methods can be chosen based on geological conditions, tunnel size and length, experience, and cost considerations. Classical methods from the 19th century included the English, Austrian, German, Belgian, and Italian systems which used hand excavation and timber supports. Modern methods include mechanical drilling/cutting, tunnel boring machines (TBMs), the New Austrian Tunnelling Method (NATM), immersed tunnels, and specialized methods. The tunnelling process typically involves probe drilling, grouting, excavation, supporting, muck removal, lining, drainage, and ventilation. Cut-and-cover can maintain surface traffic with reduced street widths or temporary bypasses, and uses concrete curtain walls for trench stability in urban areas.
Groundwater Engineering is an international company that specializes in dewatering, groundwater control, and water well engineering for construction, mining, and oil and gas clients. The document defines dewatering as pumping from wells or sumps to lower groundwater levels and allow excavations below the water table. It describes commonly used dewatering techniques like sump pumping, wellpoints, deepwells and eductor wells. Less common techniques including horizontal wellpoints, relief wells, artificial recharge and groundwater remediation are also outlined.
Earthen dams are constructed using natural materials like clay, sand, gravel and rock. They are designed based on principles of soil mechanics. There are two main types - homogeneous and zoned. Zoned dams have an impervious core and outer shells. Components include the core, shells, rock toe, pitching, berms and drains. Stability requires the seepage line be within the downstream slope with minimum 2m cover. Common causes of failure are hydraulic (overtopping, erosion), seepage (piping through core or foundations) and structural issues like cracking. Proper design and construction can prevent these failures.
Crown corrosion - wwwe - By Mr. Mayank Oza - water and waste water engineeringMayank Oza
The document discusses crown corrosion in sewers. Crown corrosion occurs when bacteria in sewage slime convert sulphates to sulphides, which release hydrogen sulphide gas. To control corrosion, sewer design should provide self-cleansing flow, ventilation, and flushing to prevent stagnation. Pipes made of inert materials or lined with sulphate-resistant cement can increase longevity by preventing corrosion.
Irrigation and Hydraulic Structures
Detailed discussion on forces acting on gravity dam as per the JNTU Anantapur Autonomous syllabus.
Use full for B.Tech Civil Engineering Students
Cross drainage works (CDWs) are structures constructed where canals intersect natural drainages like rivers or streams. There are three main types of CDWs depending on the relative bed levels: 1) aqueducts or siphon aqueducts where the canal passes over the drainage, 2) super passages or siphon super passages where the drainage passes over the canal, and 3) level crossings where the canal and drainage intersect at the same level. The appropriate type of CDW is selected based on factors like relative bed levels, availability of suitable foundation, economic considerations, and discharge of the drainage. Key steps in planning CDWs include selecting a suitable site where the drainage crosses the canal alignment at a right angle and on
This document provides an introduction and overview of dewatering methods used in construction projects. It discusses how the water table and groundwater conditions can impact foundations and excavations. Several key dewatering methods are described, including sumps, wells, well points, drainage galleries, and exclusion methods like ground freezing. Sumps involve pumping from perforated drums in a gravel-filled excavation and work best in fine-grained soils. Wells use large-diameter casings and pumps to dewater large areas to depth in permeable soils. Well points are smaller and more shallow but can effectively dewater coarse-grained soils through a vacuum system. Selection of the appropriate dewatering method depends on factors like soil type, excav
Tunnelling methods can be chosen based on geological conditions, tunnel size and length, experience, and cost considerations. Classical methods from the 19th century included the English, Austrian, German, Belgian, and Italian systems which used hand excavation and timber supports. Modern methods include mechanical drilling/cutting, tunnel boring machines (TBMs), the New Austrian Tunnelling Method (NATM), immersed tunnels, and specialized methods. The tunnelling process typically involves probe drilling, grouting, excavation, supporting, muck removal, lining, drainage, and ventilation. Cut-and-cover can maintain surface traffic with reduced street widths or temporary bypasses, and uses concrete curtain walls for trench stability in urban areas.
Groundwater Engineering is an international company that specializes in dewatering, groundwater control, and water well engineering for construction, mining, and oil and gas clients. The document defines dewatering as pumping from wells or sumps to lower groundwater levels and allow excavations below the water table. It describes commonly used dewatering techniques like sump pumping, wellpoints, deepwells and eductor wells. Less common techniques including horizontal wellpoints, relief wells, artificial recharge and groundwater remediation are also outlined.
Earthen dams are constructed using natural materials like clay, sand, gravel and rock. They are designed based on principles of soil mechanics. There are two main types - homogeneous and zoned. Zoned dams have an impervious core and outer shells. Components include the core, shells, rock toe, pitching, berms and drains. Stability requires the seepage line be within the downstream slope with minimum 2m cover. Common causes of failure are hydraulic (overtopping, erosion), seepage (piping through core or foundations) and structural issues like cracking. Proper design and construction can prevent these failures.
This document discusses two dry bottom ash removal and transport systems for coal-fired boilers. The first system uses a storage hopper to collect, cool, and crush bottom ash before pneumatically conveying it to storage. The second system uses a vibrating conveyor to extract and cool bottom ash before transferring it to another conveyor for transport. Both systems aim to dry cool bottom ash for potential beneficial use and reduce operations and maintenance costs compared to conventional wet systems.
This document discusses reservoir sedimentation. It begins by defining reservoirs and classifying them. It then explains how sedimentation occurs as rivers carry sediments that are deposited when the river flow is blocked by a reservoir. This leads to a reduction in water storage capacity over time. The document lists indicators of reservoir sedimentation and discusses trap efficiency. It also outlines the different forms of sediment transport in rivers and the impacts of reservoir sedimentation, such as reduced storage and hydroelectric power generation. In conclusion, sedimentation diminishes storage capacity and benefits of the reservoir over the long run.
Best numerical problem group pile capacity (usefulsearch.org) (useful search)Make Mannan
A circular well with an external diameter of 4.5m and steel thickness of 0.75m is embedded 12m deep in uniform sand. The sand has an angle of internal friction of 30 degrees and submerged unit weight of 1 t/m3. The well is subjected to a horizontal force of 50t and bending moment of 400tm at the scour level. Assuming the well acts as a lightweight retaining wall, the allowable total equivalent resting force due to earth pressure with a safety factor of 2 is calculated.
The document summarizes various types of heavy equipment used in open-cast mining:
1) Front-end loaders are used to load dump trucks for transporting material.
2) Scrapers excavate and transport loose materials like soil using a bowl-shaped blade and dumping mechanism.
3) Dozers are used for pushing and grading materials, digging, compacting haul roads, and assisting scrapers. Variations include wheel dozers and ripper dozers.
4) Motor graders level and smooth haul road surfaces.
Cross drainage works are structures constructed where canals cross natural drainages like rivers or streams. There are several types of cross drainage works depending on the relative bed levels of the canal and drainage. The document discusses determining the maximum flood discharge of a drainage using various empirical formulas and methods. It also covers topics like fluming of canals, which involves contracting the canal width to reduce the size of cross drainage structures.
sewers and sewer netwrok - design construction and maintenanceManish Goyal
This document discusses the design of sewer systems. It begins by classifying sewers into domestic, storm, and combined sewers based on what they are designed to carry. It notes the advantages and disadvantages of combined sewers. The document then discusses methods for estimating sewage flow rates, including population forecasting, per capita flow rates, and peak flow factors. It also covers stormwater runoff estimation and the rational method formula. Finally, it discusses some hydraulic design considerations for sewers, such as designing for partial flow rather than full flow due to gas generation in sewers.
This document discusses land disposal of sewage and the standards for wastewater effluents that are discharged onto land for irrigation. It outlines the Bureau of Indian Standards quality standards that set limits on pollutants in wastewater used for irrigation. Land disposal is appropriate when natural waterways are not nearby, irrigation water is scarce, or rainfall is low. The document describes different techniques for irrigating crops with sewage and measures to prevent "sewage sickness" of the land from overuse.
1. The document discusses various methods of measuring and estimating evaporation and transpiration from soil and plants. It describes the processes of interception, depression storage, evaporation and factors affecting evaporation.
2. Methods of measuring evaporation include pan observations using evaporation pans, atmospheric methods using atmometers, and empirical equations. Transpiration can be measured using a phytometer.
3. Evapotranspiration refers to the total water lost from an area due to evaporation from the soil and transpiration from plants. It is estimated using lysimeter methods, field experimental plots, or empirical equations like Blaney-Criddle.
The document discusses different types of reservoirs and their purposes. It describes storage/conservation reservoirs which retain excess water supplies during high flows for gradual release during low flows. Flood control reservoirs store flood waters to minimize downstream flood peaks. Multipurpose reservoirs serve multiple functions like water supply, flood control, power generation, and irrigation. Distribution reservoirs supply water to consumers according to demand fluctuations and provide local storage in emergencies.
The presentation discussed various methods of dewatering on construction sites, including sump pumping, wellpoint systems, ejector wells, ground freezing, and deep wells. It described the purpose of dewatering, factors that influence selection of methods, and advantages and limitations of each approach. The methods vary in their suitability based on soil type, required depth of drawdown, and other site-specific factors. Proper dewatering is important for construction efficiency and stability.
Well point dewatering involves installing small diameter wells around an excavation area and connecting them to a pump via header pipes to drain permeable ground and allow excavation. It is commonly used for foundations, basements, tunnels and other underground construction. The well points must be properly spaced and installed, and the system regularly monitored, to safely and effectively lower the water table during excavation work within permitted timelines.
dewatering in different soil conditions, methods, explanation of dewatering methods, : open sumps & ditches, vaccumm method deppwell point method electro osmosis metheod
This document provides information on fly ash, which is a byproduct of coal combustion in coal-fired power plants. It discusses that fly ash is produced in large quantities annually in places like the US. The document covers the chemical composition and classes of fly ash, as well as how fly ash is used in concrete, bricks, embankments, soil stabilization, and other applications. It also addresses the recycling of fly ash, environmental impacts, and references for further information.
Ready-mix concrete is concrete that is manufactured in a batch plant, according to a set engineered mix design.Ready-mix concrete is normally delivered in two ways. First is the barrel truck or in–transit mixers.This type of truck delivers concrete in a plastic state to the site.
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Dewatering is the process of removing water from construction sites to allow excavation work to be done safely and efficiently below the water table. There are several reasons why dewatering is needed, including providing a dry work area, improving stability, and increasing safety. Common dewatering techniques include sump pumping, well points, deep wells, and trenches. Each method has advantages and disadvantages depending on the site conditions and depth of water lowering required. Proper planning and design of a dewatering system is important to effectively control groundwater and allow construction work to progress smoothly.
Case study on effect of water table on bearing capacityAbhishek Mangukiya
The document discusses the effect of water table on soil bearing capacity. It states that a water table located within the width of a foundation's base will reduce the soil's bearing capacity. The bearing capacity equation is provided, along with factors to account for water table depth. If the water table is below the base width, it has no effect on bearing capacity. A case study finds that for a given project, the water table depth exceeds the foundation depth, so there is no water table effect on soil bearing capacity. In summary, the proximity of the water table can impact a soil's ability to support structural loads, and established methods account for water table levels in bearing capacity calculations.
This presentation discusses various ground improvement techniques for transportation projects. It introduces vertical drains, soil nailing, stone columns, vibro compaction, and dynamic compaction. Vertical drains like sand drains and wick drains accelerate consolidation by facilitating drainage. Soil nailing reinforces soil by drilling and grouting steel tendons. Stone columns form compacted aggregate columns to increase shear strength and reduce compressibility. Vibro compaction densifies loose sands. Dynamic compaction drops heavy weights to compact soils at depth. The presentation provides details on how each technique is implemented to improve weak soils for construction.
Rapid urban and industrial growth demands more land for further development, to meet this demand land reclamation and utilization of unsuitable and environmentally affected lands have been taken up and converted to useful ones by adopting one or more Ground Improvement Techniques
This document discusses different types of bitumen, asphalt, and tar used in civil engineering materials. It provides details on:
- Bitumen is derived from petroleum distillation and exists in liquid, semi-solid or solid forms. Its main uses include making flexible pavements for roads and waterproofing buildings. The main types of bitumen are straight-run, blown, emulsion, cut-back, and plastic bitumen.
- Asphalt is a mixture of bitumen and inert materials left after petroleum distillation. It is used mainly in road construction. The two types are natural asphalt found in lakes/rocks, and residual asphalt from petroleum distillation.
Techniques of rain water harvesting in urban and rural areasIEI GSC
Rainwater harvesting (RWH)is the process of arresting and storing rain water for efficient application and conservation. This is an effective way of utilising large quantum of water which otherwise goes as surface runoff. RWH has 2 components: 1)Rain water collection for storage
2)Recharging groundwater The talk cum presentation shall demonstrate several ways & methods to harvest rainwater in urban as well as rural areas
This document discusses two dry bottom ash removal and transport systems for coal-fired boilers. The first system uses a storage hopper to collect, cool, and crush bottom ash before pneumatically conveying it to storage. The second system uses a vibrating conveyor to extract and cool bottom ash before transferring it to another conveyor for transport. Both systems aim to dry cool bottom ash for potential beneficial use and reduce operations and maintenance costs compared to conventional wet systems.
This document discusses reservoir sedimentation. It begins by defining reservoirs and classifying them. It then explains how sedimentation occurs as rivers carry sediments that are deposited when the river flow is blocked by a reservoir. This leads to a reduction in water storage capacity over time. The document lists indicators of reservoir sedimentation and discusses trap efficiency. It also outlines the different forms of sediment transport in rivers and the impacts of reservoir sedimentation, such as reduced storage and hydroelectric power generation. In conclusion, sedimentation diminishes storage capacity and benefits of the reservoir over the long run.
Best numerical problem group pile capacity (usefulsearch.org) (useful search)Make Mannan
A circular well with an external diameter of 4.5m and steel thickness of 0.75m is embedded 12m deep in uniform sand. The sand has an angle of internal friction of 30 degrees and submerged unit weight of 1 t/m3. The well is subjected to a horizontal force of 50t and bending moment of 400tm at the scour level. Assuming the well acts as a lightweight retaining wall, the allowable total equivalent resting force due to earth pressure with a safety factor of 2 is calculated.
The document summarizes various types of heavy equipment used in open-cast mining:
1) Front-end loaders are used to load dump trucks for transporting material.
2) Scrapers excavate and transport loose materials like soil using a bowl-shaped blade and dumping mechanism.
3) Dozers are used for pushing and grading materials, digging, compacting haul roads, and assisting scrapers. Variations include wheel dozers and ripper dozers.
4) Motor graders level and smooth haul road surfaces.
Cross drainage works are structures constructed where canals cross natural drainages like rivers or streams. There are several types of cross drainage works depending on the relative bed levels of the canal and drainage. The document discusses determining the maximum flood discharge of a drainage using various empirical formulas and methods. It also covers topics like fluming of canals, which involves contracting the canal width to reduce the size of cross drainage structures.
sewers and sewer netwrok - design construction and maintenanceManish Goyal
This document discusses the design of sewer systems. It begins by classifying sewers into domestic, storm, and combined sewers based on what they are designed to carry. It notes the advantages and disadvantages of combined sewers. The document then discusses methods for estimating sewage flow rates, including population forecasting, per capita flow rates, and peak flow factors. It also covers stormwater runoff estimation and the rational method formula. Finally, it discusses some hydraulic design considerations for sewers, such as designing for partial flow rather than full flow due to gas generation in sewers.
This document discusses land disposal of sewage and the standards for wastewater effluents that are discharged onto land for irrigation. It outlines the Bureau of Indian Standards quality standards that set limits on pollutants in wastewater used for irrigation. Land disposal is appropriate when natural waterways are not nearby, irrigation water is scarce, or rainfall is low. The document describes different techniques for irrigating crops with sewage and measures to prevent "sewage sickness" of the land from overuse.
1. The document discusses various methods of measuring and estimating evaporation and transpiration from soil and plants. It describes the processes of interception, depression storage, evaporation and factors affecting evaporation.
2. Methods of measuring evaporation include pan observations using evaporation pans, atmospheric methods using atmometers, and empirical equations. Transpiration can be measured using a phytometer.
3. Evapotranspiration refers to the total water lost from an area due to evaporation from the soil and transpiration from plants. It is estimated using lysimeter methods, field experimental plots, or empirical equations like Blaney-Criddle.
The document discusses different types of reservoirs and their purposes. It describes storage/conservation reservoirs which retain excess water supplies during high flows for gradual release during low flows. Flood control reservoirs store flood waters to minimize downstream flood peaks. Multipurpose reservoirs serve multiple functions like water supply, flood control, power generation, and irrigation. Distribution reservoirs supply water to consumers according to demand fluctuations and provide local storage in emergencies.
The presentation discussed various methods of dewatering on construction sites, including sump pumping, wellpoint systems, ejector wells, ground freezing, and deep wells. It described the purpose of dewatering, factors that influence selection of methods, and advantages and limitations of each approach. The methods vary in their suitability based on soil type, required depth of drawdown, and other site-specific factors. Proper dewatering is important for construction efficiency and stability.
Well point dewatering involves installing small diameter wells around an excavation area and connecting them to a pump via header pipes to drain permeable ground and allow excavation. It is commonly used for foundations, basements, tunnels and other underground construction. The well points must be properly spaced and installed, and the system regularly monitored, to safely and effectively lower the water table during excavation work within permitted timelines.
dewatering in different soil conditions, methods, explanation of dewatering methods, : open sumps & ditches, vaccumm method deppwell point method electro osmosis metheod
This document provides information on fly ash, which is a byproduct of coal combustion in coal-fired power plants. It discusses that fly ash is produced in large quantities annually in places like the US. The document covers the chemical composition and classes of fly ash, as well as how fly ash is used in concrete, bricks, embankments, soil stabilization, and other applications. It also addresses the recycling of fly ash, environmental impacts, and references for further information.
Ready-mix concrete is concrete that is manufactured in a batch plant, according to a set engineered mix design.Ready-mix concrete is normally delivered in two ways. First is the barrel truck or in–transit mixers.This type of truck delivers concrete in a plastic state to the site.
ready mix concrete supplier
ready mix concrete columbus ohio
ready mix concrete near me
local ready mix concrete companies
ready mix concrete company near me
ready mix concrete prices
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ready mix companies near me
how is ready mix concrete manufactured
ready mix companies near me
ready mix usa locations
ready mix suppliers near me
ready made concrete mix
ready mixed cement
ready mix price per yard
how to mix cement
Dewatering is the process of removing water from construction sites to allow excavation work to be done safely and efficiently below the water table. There are several reasons why dewatering is needed, including providing a dry work area, improving stability, and increasing safety. Common dewatering techniques include sump pumping, well points, deep wells, and trenches. Each method has advantages and disadvantages depending on the site conditions and depth of water lowering required. Proper planning and design of a dewatering system is important to effectively control groundwater and allow construction work to progress smoothly.
Case study on effect of water table on bearing capacityAbhishek Mangukiya
The document discusses the effect of water table on soil bearing capacity. It states that a water table located within the width of a foundation's base will reduce the soil's bearing capacity. The bearing capacity equation is provided, along with factors to account for water table depth. If the water table is below the base width, it has no effect on bearing capacity. A case study finds that for a given project, the water table depth exceeds the foundation depth, so there is no water table effect on soil bearing capacity. In summary, the proximity of the water table can impact a soil's ability to support structural loads, and established methods account for water table levels in bearing capacity calculations.
This presentation discusses various ground improvement techniques for transportation projects. It introduces vertical drains, soil nailing, stone columns, vibro compaction, and dynamic compaction. Vertical drains like sand drains and wick drains accelerate consolidation by facilitating drainage. Soil nailing reinforces soil by drilling and grouting steel tendons. Stone columns form compacted aggregate columns to increase shear strength and reduce compressibility. Vibro compaction densifies loose sands. Dynamic compaction drops heavy weights to compact soils at depth. The presentation provides details on how each technique is implemented to improve weak soils for construction.
Rapid urban and industrial growth demands more land for further development, to meet this demand land reclamation and utilization of unsuitable and environmentally affected lands have been taken up and converted to useful ones by adopting one or more Ground Improvement Techniques
This document discusses different types of bitumen, asphalt, and tar used in civil engineering materials. It provides details on:
- Bitumen is derived from petroleum distillation and exists in liquid, semi-solid or solid forms. Its main uses include making flexible pavements for roads and waterproofing buildings. The main types of bitumen are straight-run, blown, emulsion, cut-back, and plastic bitumen.
- Asphalt is a mixture of bitumen and inert materials left after petroleum distillation. It is used mainly in road construction. The two types are natural asphalt found in lakes/rocks, and residual asphalt from petroleum distillation.
Techniques of rain water harvesting in urban and rural areasIEI GSC
Rainwater harvesting (RWH)is the process of arresting and storing rain water for efficient application and conservation. This is an effective way of utilising large quantum of water which otherwise goes as surface runoff. RWH has 2 components: 1)Rain water collection for storage
2)Recharging groundwater The talk cum presentation shall demonstrate several ways & methods to harvest rainwater in urban as well as rural areas
Dewatering is the process of removing water from construction sites to allow for excavation and construction in dry conditions below the water table. It is done through various techniques like sump pumping, well points, deep wells, and eductor systems. The main purposes of dewatering are to provide a dry excavation area, improve stability, and allow for efficient construction. Proper planning and techniques are needed to safely lower the water table and discharge water without causing erosion or other issues.
This document discusses the design of road side ditches. It describes different types of ditch cross-sections including triangular, parabolic, and trapezoidal. The trapezoidal section is most commonly used as it is acceptable from both hydraulic and construction perspectives. The document provides guidelines for side slopes, minimum widths and depths. It also discusses different types of ditch linings like turfing, concrete, and brick that are used depending on site conditions and flow velocities. Finally, it provides steps for designing a ditch for a given discharge and slope using Manning's equation.
This document discusses the design and construction of grassed waterways. It begins by defining grassed waterways as natural or man-made channels with vegetation cover used to safely transport runoff from fields. It then discusses the purposes of grassed waterways, which include preventing erosion and sedimentation while transporting water. The document provides details on the design process, including calculating dimensions based on watershed characteristics and expected runoff. It recommends shapes, grades, and flow velocities for effective design. Construction and maintenance are also outlined, emphasizing establishing vegetation cover and conducting repairs to ensure proper functioning of grassed waterways over time.
The document provides guidance on properly using common best management practices (BMPs) to control sediment and erosion. It describes 10 BMPs, including silt fence, wattles, hydroseeding, check dams, catch basin inserts, sediment cages, riprap outlets, sediment traps, sweeping, and material site ditches. For each BMP, it explains the purpose, proper installation techniques, common failures if improperly used, and maintenance needs such as sediment removal. It emphasizes that combining BMPs is often most effective and that regular maintenance is essential.
Gully Erosion Control Measures
Temporary check dam
Brushwood dams
One row or single post brush wood dam
Double row post brush wood dams.
Semi permanent dams
Loose rock dam
Netting dam
Log check dam
Permanent check dam
Drop Spillway
Drop inlet spillway
Chute spillway
The document discusses the types, construction, and design considerations of earth dams. It describes three main types of earth dams: homogeneous, zoned, and diaphragm. Construction methods include rolled fill and hydraulic fill. Key aspects of earth dam design include the impervious core, filters and drains to control seepage, cutoff trenches, and spillway capacity. Failure analysis indicates the most common causes are related to hydraulic overload, seepage, and structural issues. The document provides guidelines for safe design and construction of earth dams.
The document discusses several important considerations for designing and constructing earth dams, including:
1) Thoroughly investigating the foundation through testing to identify any weak or unstable soils that need removal.
2) Designing appropriate cut-offs and drainage systems depending on the foundation material and reservoir depth, such as trenches, concrete walls, or central clay cores.
3) Carefully designing the upstream and downstream slopes based on available construction materials and the needed stability, drainage, and erosion protection.
Special Methods of Sub Surface Drainage: Agricultural Draining EngineeringVenkata Sai Kari
This document discusses various methods of subsurface drainage including mole drainage, vertical drainage, bio drainage, and drainage design for heavy clay soils with multiple layers. Mole drainage involves creating unlined underground channels using a mole plough, and works well in stable clay soils but has a limited lifespan. Vertical drainage uses wells or multiple well points to lower the water table from depth. Bio drainage uses deep-rooted plants like eucalyptus to transpire large amounts of water from the subsurface. Designing drainage in layered clay soils requires considering perched water tables and installing drains in the more permeable layer. Computer modeling programs can aid in drainage system design by simulating subsurface flow.
Chapter 4 control of ground water in excavationsKHUSHBU SHAH
This document discusses various methods for controlling groundwater during excavation projects. It describes 9 common dewatering methods: sumps and ditches, shallow well systems, deep well systems, well point systems, vacuum methods, cement grouting, chemical grouting, freezing processes, and electro-osmosis. For each method, it provides details on how the method works and its suitability for different soil and water conditions. The document aims to help construction professionals select the appropriate dewatering approach based on the unique factors of their project site.
NABARD TRAINING PROGRAM_for NABARDDDMS.pdfssuserb170111
The document provides information about a NABARD training program on watershed projects. It begins with basic definitions related to watersheds and hydrology. It then discusses watershed management approaches, including area treatment, drainage treatment, capacity building, and implementation. Specific drainage line treatment measures are described such as gully plugs, check dams, sod flumes, and loose boulder check dams. Design principles, benefits and limitations of these structures are covered. Examples of designing loose boulder check dams are provided with details on spillway sizing and structure spacing.
This document discusses important geological considerations for constructing dams. Location, permeability of surrounding rock, and stability are some key factors. Different dam types suit different geological conditions - for example, gravity dams require hard rock foundations while rockfill dams can be built where foundations are less stable. Curtain grouting can restrict seepage in permeable rock. Engineering geology aims to evaluate factors like seismic activity, landslides, and environmental impacts when planning dam projects.
This document discusses important geological considerations for constructing dams. Location, permeability of surrounding rock, and stability are some key factors. Different dam types suit different geological conditions - for example, gravity dams require hard rock foundations while rockfill dams can be built where foundations are less stable. Curtain grouting can restrict seepage in permeable rock. Engineering geology aims to evaluate factors like seismic activity, landslides, and environmental impacts when planning dam projects.
This document summarizes information about ground hydrology and well completion. It discusses the different types of wells, including shallow and deep wells. It also describes various well construction methods, such as digging, boring, and drilling. Additionally, it covers topics like well casing, cementing, gravel packing, and screen placement. Proper well completion is emphasized as being important for maximizing well yield and longevity.
The document discusses foundation treatment for dams. It covers treating rock foundations by excavating to solid rock, cleaning rock surfaces, treating defects like seams, and using grouting. It also discusses treating earth foundations to provide bearing strength, prevent sliding and seepage, and protect against piping. Common earth foundation treatments include cutoff walls, impervious blankets, drainage systems, and using piles. The effectiveness of partial versus complete cutoff walls is analyzed.
Similar to ENVIRONMENTAL POLLUTION CONTROL METHOD ADOPTED BY NTPC LTD. IN ASH DYKE (STARTER & WORKING) (20)
ARENA - Young adults in the workplace (Knight Moves).pdfKnight Moves
Presentations of Bavo Raeymaekers (Project lead youth unemployment at the City of Antwerp), Suzan Martens (Service designer at Knight Moves) and Adriaan De Keersmaeker (Community manager at Talk to C)
during the 'Arena • Young adults in the workplace' conference hosted by Knight Moves.
Fonts play a crucial role in both User Interface (UI) and User Experience (UX) design. They affect readability, accessibility, aesthetics, and overall user perception.
PDF SubmissionDigital Marketing Institute in NoidaPoojaSaini954651
https://www.safalta.com/online-digital-marketing/advance-digital-marketing-training-in-noidaTop Digital Marketing Institute in Noida: Boost Your Career Fast
[3:29 am, 30/05/2024] +91 83818 43552: Safalta Digital Marketing Institute in Noida also provides advanced classes for individuals seeking to develop their expertise and skills in this field. These classes, led by industry experts with vast experience, focus on specific aspects of digital marketing such as advanced SEO strategies, sophisticated content creation techniques, and data-driven analytics.
Technoblade The Legacy of a Minecraft Legend.Techno Merch
Technoblade, born Alex on June 1, 1999, was a legendary Minecraft YouTuber known for his sharp wit and exceptional PvP skills. Starting his channel in 2013, he gained nearly 11 million subscribers. His private battle with metastatic sarcoma ended in June 2022, but his enduring legacy continues to inspire millions.
Architectural and constructions management experience since 2003 including 18 years located in UAE.
Coordinate and oversee all technical activities relating to architectural and construction projects,
including directing the design team, reviewing drafts and computer models, and approving design
changes.
Organize and typically develop, and review building plans, ensuring that a project meets all safety and
environmental standards.
Prepare feasibility studies, construction contracts, and tender documents with specifications and
tender analyses.
Consulting with clients, work on formulating equipment and labor cost estimates, ensuring a project
meets environmental, safety, structural, zoning, and aesthetic standards.
Monitoring the progress of a project to assess whether or not it is in compliance with building plans
and project deadlines.
Attention to detail, exceptional time management, and strong problem-solving and communication
skills are required for this role.
ENVIRONMENTAL POLLUTION CONTROL METHOD ADOPTED BY NTPC LTD. IN ASH DYKE (STARTER & WORKING)
1. ENVIRONMENTAL POLLUTION CONTROL METHOD ADOPTED
BY NTPC LTD. IN ASH DYKE (STARTER & WORKING)
Location: NTPC Vindhyachal (4260MW)
Shahpur (In Use) & Baliyari (Under Construction)
1. INTRODUCTION
Out of various alternatives for disposal of fly ash, use of ash pond in
which ash slurry is discharged is most widely used by thermal power plants.
Fly ash and bottom ash from the power plant is mixed with water in a ratio
varying from 1 part ash and 4 to 20 parts of water. The slurry is then pumped
upto the ash pond which are located within few kilometres distance from the
power plant. Depending on the distance and elevation difference, energy
required for pumping is very high and often requires booster pumps at
intermediate locations. There is a basic difference between an ash pond and a
water reservoir. The major differences are highlighted below.
Only the ash particles settle close to the bund and the water after
decantation travel away from the bund forming a sloping beech.
The bund is not subjected to hydrostatic pressure over the full height of the
bund as the water travels away from the bund. Due to provision for good
drainage all along the bund, the phreatic line is maintained at very low level to
ensure that the bund section and the deposited ash particles closer to the bund
are in dry condition.
The water, after decantation is not allowed to accumulate in the pond but it
is removed from the pond to ensure that the phreatic line is maintained at lower
level. The ash pond can be designed economically utilizing the advantage of
low phreatic line as mentioned above.
2. TYPE OF DYKE
Unlike water reservoir, the ash pond is constructed in stages. Each stage
has an incremental height of 3m. The advantage of constructing the ash pond in
2. stages is that their initial cost is very low. It also saves the overall cost compare
to a single stage construction.
Following methods are commonly adopted:
Methods Of Raising Dyke Height
(a) Upstream Construction Method (Used In NTPC Vindhyachal)
This is most referred design as the earthwork quantity required is minimum.
Certain points are essential while designing and construction of this type of
dyke
The drain provided on the upstream face needs to be suitably connected to
the drain of the earlier segment. If this is not carried out properly, the drainage
can be ineffective resulting in rising of phreatic line and reducing the stability
of slope.
Since the entire segment of new construction is supported on deposited
ash, liquefaction analysis of the deposited ash is very important. If the deposit
is not safe against liquefaction, suitable remedial measures needs to be adopted
before raising dyke.
While raising the height of the dyke, it is not possible to operate the pond
as it needs to be dried, particularly along the periphery to initiate the
construction. The upstream method is mostly chosen due to its minimum cost.
The aspects to be taken care are adequacy of the deposited particles to
support the additional weight. Apart from the stability of the dyke, following
features is included in the design:
The entire upstream face of the dyke is provided with stone pitching or
brick lining or precast tile lining to prevent erosion of the slope by wave action
during heavy wind.
The entire downstream slope is provided with grass turfing to prevent
erosion of the downstream side during rains.
3. A rock toe and toe drain is provided for safe exit of seepage water into a
natural drain without any inundation of the downstream area and thereby
softening of the natural strata.
Adequate transverse and longitudinal drains are provided on the
downstream face. Wherever the height of the dyke is exceeding 5m, berms are
provided at ever 3m vertical intervals with a longitudinal drain to prevent
erosion.
Decanting system (Overflow Well) is provided to ensure that free water
inside the ash pond does not pile up to a large head. After decantation, the clear
water shall be drained off ensuring minimum height of water above the ash
deposition at the outlet such that the suspended particles are within the
permissible limit of 100ppn.
(b) Downstream Construction Method
After the pond gets filled upto the first stage of construction, the pond height is
increased by depositing the earth / fly ash on the downstream face of the dyke
ash shown in the figure. In this case it is possible to raise the height of the pond
even when the pond is in operation. However there is no reduction in the
quantity of construction which is same as a single stage construction.
(c)Centre Line construction Method
In this method, after the pond gets filled upto the first stage, material is placed
for raising height of the dyke on either side of centre line of the dyke such that
the center line of the dyke remains at the same location. This requires part of
the raw material to be placed on the deposited ash and part of the material on
the downstream face of the existing dyke. The earth work required in this case
is less compared to the construction while downstream method. However, as
the material is required to be deposited on the settled fly ash, it is not possible
to carry out the construction when the pond is in operation. This method can be
adopted only if the total area of ash pond is divided into compartments.
3. CONSTRUCTION METHOD (Starter Dyke)
Some of the ash dykes have large length (exceeding 5-8km) and large height
(Starter Dyke: 20-30m). Such structure can be classified as large dam as per the
4. prevailing classification of earthen dams. It is therefore very important that all
the Geotechnical aspects in the design are carefully looked into. The main
issues are as follows:
Detailed Geotechnical investigation along the dyke alignment and at few
locations in the ash pond area is essential. As per standard practice, the soil
data is available for every 50m distance along the length of the dyke. The
investigation is carried out upto a hard strata or upto a depth likely to be
influenced by the construction of ash pond, whichever is earlier. Presence of
weak layer such as soft clay or loose sand which is likely to liquefy have to be
established by this investigation. In addition tests are also required to be carried
out on identified borrow soil to check its suitability for construction of ash
dyke. At present, most of the existing power plants utilize fly ash itself as
borrow soil to construct the ash dyke. This reduces cost of construction and
increases the storage capacity of the pond depending on volume of fly ash
excavated. However, fly ash can get easily eroded under flow of water. It is
therefore necessary to provide an earth cover (generally thickness varies from
0.5m) to protect the compacted ash against erosion. Soil used for such earth
cover is of CI/CL/GC type having liquid limit less than 50% and clay content
not more than 30%. Similarly the fly ash used is collected closer to the
discharge point were the particles are of larger size and expected to give a
higher angle of friction. It is possible to compact fly ash at varying degree of
moisture content. The optimum moisture content generally varies from 2.5-
3.5%. As such it is possible to carry out the construction even during monsoon.
The fly ash or excavated soil is normally placed in layers not exceeding
300mm in loose thickness and compacted to 95% related density using a
vibratory roller. Stringent quality control is necessary to check the type of
material used, construction method, degree of compaction, etc. It is also
important to monitor the performance of the dyke using following instruments:
• Settlement gauges
• Peizometers to check the pore water pressures and to establish the phreatic
line.
At such location, relief wells are installed. The relief well permits safe passage
for the water under excess hydraulic pressure to exit vertically up to the ground
level, through the less pervious strata without the risk of piping failure. The
water drained out from the relief well is safely drained to a natural strip such
5. that downstream area is not in undated. This makes the downstream area in dry
condition with much better shear strength than the situation expected without
the relief wells. The upstream face needs protection against erosion from
decanted water, in the event of no deposition along the dyke. This is normally
achieved by stone pitching or brick lining or using precast tile. This more
essential were the size of the pond is large and with long fetch available, the
waves generated during the cyclonic wind can be high.
There are several instances of deep gulley formation on the downstream face of
the ash dyke. To prevent such erosion, it is better to provide berms at vertical
intervals of 3m along the downstream face (In case of Starter Dyke). This will
dampen the continuous runoff or the downstream face and thereby reduce the
velocity of runoff. In addition, grass turfing is also required to protect the
surface against erosion. Also drains are provided at regular interval for
drainage of water on road surface of dyke top.
4. ENVIRONMENTAL POLLUTION ISSUES
a) Starter Dyke
Though fly ash is known to be an inert material, there is an appearansion
about certain soluble chemicals in the decanted water which can have adverse
effect if such decanted water is let into a river body or ground water. For this
purpose, the norms of Pollution Control Board insist on providing a plastic
liner over the entire bottom of the pond and upstream face of the ash dyke.
New ash ponds being constructed have to provide the plastic liner (Impervious
Linner with permeability less than 1X 10-6
to prevent pollution of ground
water. Due to the presence of plastic liner, provision of the drainage becomes
difficult and as result the deposited sediments could not get consolidated to the
same extent as that anticipated in the pond without plastic liner. For this
reason, whenever plastic liner is provided, it is important to check the adequacy
of strength parameters for the deposited ash for supporting the next section of
the dyke if upstream method of construction is adopted.
b) Working & Abandoned
Apart from pollution to ground water, another major concern is dust
pollution in the surrounding area during heavy wind. To prevent dust pollution,
water sprinklers is arranged in the beach area which is in dry condition. The
6. dust pollution is more from the pond which is not in operation and where
construction is in progress by excavating the fly ash. For the pond which has
reached the ultimate height and no further extension of height is warranted, the
surface is covered with a 300mm thick soil layer. Suitable vegetation is grown
over the area which ensures no dust pollution.
5. MAINTENANCE OF ASH DYKE
These guidelines for maintenance of the pond are based on various
observations made at various project sites. The guidelines cover important
points to be observed during operation of the dyke.
(a). Decanting System
The elevation of cascade wall or flash bar or opening in decanting shaft is
very important. This is chosen to ensure the following:
i. Minimum beach length as mentioned above is formed. If the elevation of
outlet wall is increased, the beach length will get reduced.
ii. The quality of decanted water should be satisfactory with total suspended
solids less than 100ppm. If the elevation of outlet is low, the suspended solids
will increase.
At any time during operation, if the out flowing water does not meet the
requirement, the elevation of the exit of the pond is raised. Water samples are
regularly collected at interval of 1 week and check for total suspended solids. A
register is maintained with records of such measurements. Higher
concentration of particles is likely to create more deposition in the recirculation
sump raising the outlet elevation and it may require evacuation. A delay in
raising the outlet elevation will result in high concentration of ash. On the other
hand, too early raising will result in increased area of decanted water pond and
reduce the beach length.
(b). Raising of Ash Dyke
The pond which has already been filled-up is allowed to dry without any
further discharge of slurry for a minimum period of 1 month before the
construction for raising the height is taken up.
The pond which is not being used is provided with water sprinklers at
regular intervals to ensure that the surface of the pond is maintained moist to
7. prevent dust pollution. Too much of water spraying is avoided as this is likely
to make the surface slushy and movement of the vehicles for construction
purpose will be difficult.
(c). Maintenance of Ash Dyke (Working & Abandoned)
It is very important to constantly supervise the ash dyke and carryout
necessary remedial measures. Following aspects have to be considered during
inspection of the dyke
i. Wet patches on downstream slope
This is possible only if the beach length is not adequate and/or the drainage is
choked. Corrective measures are taken immediately. If the wet patches
continue to appear, the area is protected by placing a sand filter layer followed
by a layer of stones to prevent piping failure. Wherever relief wells are
provided, the outflow from the relief wells is monitored. A register is
maintained recording rate of flow from each relief well. Such measurements
are taken a frequency of 15 days. If any of the discharge pipes from the relief
well is found to have been blocked, the same is cleared for effective relief of
the seepage water.
ii. Gulley formation
The downstream face can have gulley formation due to surface water flow
during rain. This can be prevented by maintaining grass turfing and by
selecting non erodible earth cover during the dyke construction. If any gulley
formation is noticed, the same is back-filled with cohesive soil (not fly ash) and
covered with grass turfing.
iii. Rat holes / animal burrows
During inspection if any rat holes or animal burrows are noticed, the same is
plugged using cohesive soil and covered with grass turfing.
iv. Softening of downstream area
Apart from the dyke slope, they are adjacent to downstream of the rock toe
shall also be inspected. If any softening of the ground is noticed due to seepage
of water, the area is provided with an inverted filter blanket. At such locations,
relief well is installed for safe exit of the seepage water.
v. Growth of plants
No plants / trees are allowed to grow on the downstream face. If any such
growth is noticed, the area is cleared by removing all the roots, plug the area
with selected cohesive soil and cover with grass turfing.
8. vi. Choking of surface strains
Due to deposition of soil particles in the toe drain or drains provided on the
downstream face, the function of the drain is affected. This results in stagnation
of seepage water in the drain which is not desirable. All toe drains and surface
drains are cleared by removing soil or vegetation for smooth flow.
vii. Along the ash dyke, if reduced free board is noticed at a local point due to
settlement of the dyke of erosion of earth cover at the surface, the same shall be
rectified by providing additional earth fill on the top of the dyke. If the earth
cover is formed to be missing or eroded, the area is covered by additional earth
cover of minimum 0.5m thickness.
ix. The dyke is visited particularly after events like earthquake, cyclone, heavy
rains, high flood in the river, etc. and a report prepared based on the
observation. If any damage is noticed, the same is rectified as per the
guidelines given in this note. If no suitable guidelines are found for the nature
of the damage, the designer of the dyke is consulted immediately.
x. The beach area of the pond which is under operation is inspected. If any
subsidence or sink holes are noticed along the beach, the downstream side at
the same location is inspected. A site report of such observations shall be
communicated to the designer.
(d). Monitoring the Dyke
In view of various uncertainties in the design of ash pond, it is preferable to
monitor the performance of the bund throughout its operation. The equipments
for such monitoring are same as that used for monitoring of dams. These are
readily available in the market and do not cost much. Instruments commonly
provided for such monitoring are listed below:
(i) Settlement gauges along the top of the bund.
(ii) Piezometers, minimum 3 to 4 nos. at critical sections to check the phreatic
line during various stages of operation to verify the efficiency of internal
drains.
All the instruments for monitoring purpose mentioned above are protected
against damage by the local people and by movement of vehicles. The
measuring instruments is kept under safe custody at site office and regularly
cleared to prevent corrosion and malfunctioning. The batteries, if any is
regularly charged or replaced. It is recommended that on each of the ponds,
two locations are identified on each side of the dyke and these locations are
provided with instruments mentioned above. The measurements on these
9. instruments are regularly carried out (every month) and the results are
maintained in a register for review.
(e) Other General Recommendations
Following are desirable for effective operation and maintenance of the ash
dyke:
(i) The entire area of the ash dyke is provided with fencing and unauthorized
entry within this ash pond area is strictly prohibited. Security guards are posted
for vigilance of the ash dyke area round the clock. This is very important as
there are chances of sabotage.
(ii) The entire dyke perimeter shall have accessible roads with atheist WBM
topping.
(iii) The entire dyke area is provided with street lights or flood lights for
inspection purpose. These lights need to be turned on only in case of inspection
during night.
(iv) A site office is constructed with a full time Engineer responsible for
inspection and monitoring of the ash dyke.