This document discusses three types of dewatering systems:
1. Open dewatering systems utilize sumps along excavation slopes and centrifugal pumps to directly remove groundwater. They are easy to install and operate.
2. Well point dewatering systems lower groundwater levels for large construction sites using well points installed along trenches, connected to headers and pumped by gravity or vacuum.
3. Deep well dewatering systems lower groundwater to considerable depths using submersible pumps in wells over 150mm in diameter, with discharge pipes connected to a common line.
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
This document discusses dewatering methods used in construction. It begins with an introduction defining dewatering as the separation of water from soil. It then discusses where dewatering is required such as in deep basements, tunnels, and pumping stations. The main purposes of dewatering are to control seepage, lower the water table, and remove water from excavated areas. Several common dewatering methods are described in detail, including open sumps and ditches, well point systems, deep well drainage, vacuum dewatering, electro osmosis, and freezing. The document concludes with an overview of the design steps for dewatering systems, which include subsoil investigation, determining water sources and tables, well
1. Grouting is a process of injecting fluid materials like cement into subsurface soils or rocks to fill pores and fissures.
2. There are different types of grouting materials and methods depending on the permeability and structure of the soil or rock.
3. Grouting is used for ground improvement on construction projects, fixing anchors, repairing defects, and other applications.
Field control of compaction and compaction Equipmentaishgup
This document discusses field compaction control and compaction equipment. It notes that field compaction depends on placement water content, compaction equipment type, and soil type. Placement water content should be within 2% of optimum moisture content from lab tests. Different soils require different moisture levels - cohesive soils are compacted dry of optimum while earth dam cores are compacted wet of optimum. Compaction can be measured using methods like core cutting or nuclear gauges. Common compaction equipment includes smooth drum rollers, pneumatic rubber-tired rollers, sheepfoot rollers, and vibratory rollers, each suited to different soil types. Relative compaction is used to check compaction levels in the field.
1. Plate load tests are conducted to determine the ultimate bearing capacity of soil and settlement under a given load by applying loads to circular or square steel plates embedded in an excavated pit.
2. The test setup involves excavating a pit below the depth of the proposed foundation, placing the test plate with a central hole at the bottom, and applying load using a hydraulic jack while measuring settlement.
3. The results provide the subgrade modulus, ultimate bearing capacity divided by a safety factor to determine the safe bearing capacity, and insight into foundation behavior and allowable settlement for design.
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.
Dewatering involves controlling groundwater by pumping, to locally lower groundwater levels in the vicinity of the excavation. The simplest form of dewatering is sump pumping, where groundwater is allowed to enter the excavation where it is then collected in a sump and pumped away by robust solids handling pumps.
This document discusses three types of dewatering systems:
1. Open dewatering systems utilize sumps along excavation slopes and centrifugal pumps to directly remove groundwater. They are easy to install and operate.
2. Well point dewatering systems lower groundwater levels for large construction sites using well points installed along trenches, connected to headers and pumped by gravity or vacuum.
3. Deep well dewatering systems lower groundwater to considerable depths using submersible pumps in wells over 150mm in diameter, with discharge pipes connected to a common line.
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
This document discusses dewatering methods used in construction. It begins with an introduction defining dewatering as the separation of water from soil. It then discusses where dewatering is required such as in deep basements, tunnels, and pumping stations. The main purposes of dewatering are to control seepage, lower the water table, and remove water from excavated areas. Several common dewatering methods are described in detail, including open sumps and ditches, well point systems, deep well drainage, vacuum dewatering, electro osmosis, and freezing. The document concludes with an overview of the design steps for dewatering systems, which include subsoil investigation, determining water sources and tables, well
1. Grouting is a process of injecting fluid materials like cement into subsurface soils or rocks to fill pores and fissures.
2. There are different types of grouting materials and methods depending on the permeability and structure of the soil or rock.
3. Grouting is used for ground improvement on construction projects, fixing anchors, repairing defects, and other applications.
Field control of compaction and compaction Equipmentaishgup
This document discusses field compaction control and compaction equipment. It notes that field compaction depends on placement water content, compaction equipment type, and soil type. Placement water content should be within 2% of optimum moisture content from lab tests. Different soils require different moisture levels - cohesive soils are compacted dry of optimum while earth dam cores are compacted wet of optimum. Compaction can be measured using methods like core cutting or nuclear gauges. Common compaction equipment includes smooth drum rollers, pneumatic rubber-tired rollers, sheepfoot rollers, and vibratory rollers, each suited to different soil types. Relative compaction is used to check compaction levels in the field.
1. Plate load tests are conducted to determine the ultimate bearing capacity of soil and settlement under a given load by applying loads to circular or square steel plates embedded in an excavated pit.
2. The test setup involves excavating a pit below the depth of the proposed foundation, placing the test plate with a central hole at the bottom, and applying load using a hydraulic jack while measuring settlement.
3. The results provide the subgrade modulus, ultimate bearing capacity divided by a safety factor to determine the safe bearing capacity, and insight into foundation behavior and allowable settlement for design.
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.
Dewatering involves controlling groundwater by pumping, to locally lower groundwater levels in the vicinity of the excavation. The simplest form of dewatering is sump pumping, where groundwater is allowed to enter the excavation where it is then collected in a sump and pumped away by robust solids handling pumps.
The presentation illustrates a technique for ground improvement, Grouting. In India, grouting is still not being used very much. In this presentation, I have demonstrated the basic types of grouting, goals of ground improvement and two case studies of grouting.
Dewatering is the removal of water from solid material or soil by wet classification, centrifugation , filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as part of various industrial processes.
1. Dams are constructed across rivers to store flowing water and come in various types like earth, rockfill, gravity, steel, timber and arch dams. The selection of dam type depends on site conditions like topography, geology and availability of construction materials.
2. Gravity dams derive their strength from their weight and weight of water pressure pushing them into the ground. They are made of concrete or masonry and work by balancing the water pressure on upstream side with weight and pressure on downstream side.
3. Factors considered in gravity dam design include water pressure, seismic forces, uplift pressure, weight of dam, and ensuring stability against sliding, overturning and cracking. Galleries are provided for drainage,
Vibration method for ground improvement techniqueABHISHEK THAKKAE
This document discusses various ground improvement techniques, including vertical drains, soil nailing, stone columns, vibro compaction, and dynamic compaction. Vertical drains accelerate consolidation by facilitating drainage of pore water through columns of pervious material placed in soil. Soil nailing uses steel tendons drilled and grouted into soil to create a reinforced composite mass. Stone columns form vertical columns of compacted aggregate through problem soils to increase strength and reduce compressibility. Vibro compaction densifies loose sands using vibratory probes to achieve a denser soil structure. Dynamic compaction improves soil by repeatedly dropping heavy weights onto the ground from heights of 40 to 80 feet.
This document provides information about construction dewatering and permanent groundwater control techniques. It discusses the differences between construction dewatering, which involves temporarily lowering the groundwater table during construction, and permanent groundwater control, which blocks long-term groundwater flow. Various dewatering techniques are described, including sump pumping, shallow wells, well points, and deep wells. Methods for permanent groundwater control include ground freezing, slurry trench walls, steel sheet piling, grouted barriers, thin grouted membranes, contiguous piling, diaphragm walls, and grouting. The document also provides examples of applying these techniques and outlines their advantages and disadvantages.
This document provides an overview of subsurface exploration, which involves site investigation and soil exploration to assess soil conditions for engineering projects. It discusses the objectives, phases and methods of subsurface exploration. The main methods covered are open excavation techniques like test pits and trenches, as well as boring techniques like auger, wash, percussion and rotary boring. It also describes different sampling techniques for obtaining disturbed and undisturbed soil samples, and different types of in-situ tests like standard penetration tests and cone penetration tests.
Dewatering is the artificial removal of groundwater or surface water to allow for construction. It plays a vital role in excavation by controlling hydrostatic pressure and soil stability. There are three main dewatering methods: active dewatering uses pumping, interception prevents water from reaching the excavation, and isolation excludes water via cut-off walls. Proper method selection depends on soil type and desired drawdown. Without control, dewatering can cause ground subsidence, flooding, or structural collapse due to increased soil loading.
A well point system consists of multiple well points spaced around an excavation site that are connected to a header pipe and pump. The well points are driven or jetted into the ground and draw groundwater into the riser pipes. This water is then pumped out through the header pipe. Spacing of well points typically ranges from 0.75m to 3m, though clay seals and sand filters can improve performance in silts. Well point systems are effective in sandy soils and can lower groundwater levels up to 5-6 meters, making them a relatively cheap and flexible dewatering option. However, they are not effective beyond 4-6 meters of drawdown and may require multiple stages.
This document discusses different grouting methods. It describes permeation grouting where grout is injected to fill voids without disturbing soil grains. Displacement grouting displaces soil grains, including compaction grouting using thick grout to form bulb shapes, and soil fracture grouting using lean grout to form root-like lenses. Jet grouting forms grouted columns by partly replacing and mixing with soil. Permeation grouting is used to form seepage barriers and stabilize tunnels. Displacement-compaction grouting involves high pressure injection of a soil-cement grout mixture to form 0.5-1m bulbous intrusions.
This document discusses various methods of boring into soil and rock to obtain samples at different depths. It describes auger boring, which uses hand or powered soil augers to drill holes. It also outlines shell and auger boring, wash boring using pressurized water, percussion boring using repeated blows, and rotary drilling which rotates a cutting bit to extract cylindrical core samples. The purpose of boring is to gather reliable subsurface information for engineering design and construction projects.
This document discusses soil mechanics concepts related to lateral earth pressure. It defines active and passive earth pressures and describes Rankine's theory and assumptions for calculating lateral pressures on retaining walls. Equations are provided for determining active and passive earth pressure coefficients and distributions for cohesionless and cohesive soils. The effects of groundwater, surcharges, and sloping backfills are also examined. Sample problems are included to calculate lateral earth pressures and forces on retaining walls for different soil and loading conditions.
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 the consolidation of soil. It defines important terms like compression, compressibility, and consolidation. It outlines the differences between compaction and consolidation. The importance of consolidation theory is that it provides information on total settlement, time for settlement, and types of settlement. Terzaghi's spring analogy is described to explain the consolidation process. A one-dimensional consolidation test procedure is outlined. Important definitions related to consolidation like compression index, swelling index, and coefficients are provided. The document also discusses normally, under, and over consolidated soils and how to determine preconsolidation pressure. Terzaghi's one-dimensional consolidation theory and solution are presented. Methods to determine degree of consolidation and coefficient of consolidation from laboratory test data are
The document discusses various ground improvement techniques including removal and replacement, in-situ densification methods like dynamic compaction, preloading, use of vertical drains and stone columns. It provides details on specific in-situ densification methods like vibro-float compaction using a vibrating probe, dynamic compaction using heavy weights, and explosive compaction using detonated charges. The document also summarizes advantages and limitations of preloading using surcharge fills and uses of vertical drains and geosynthetics to accelerate consolidation.
Class 5 Permeability Test ( Geotechnical Engineering )Hossam Shafiq I
This document discusses permeability testing methods for geotechnical engineering laboratory class. It describes two common permeability test methods: the constant-head test and falling-head test. The constant-head test applies a constant head of water to a soil specimen in a permeameter to measure hydraulic conductivity. The falling-head test similarly uses a permeameter but measures the change in head over time. Both tests aim to determine the hydraulic conductivity value k, which indicates a soil's ability to transmit water and is important for analyzing seepage, settlement, and slope stability.
Stream Gauging: Necessity; Selection of gauging sites; Methods of discharge measurement; Area-Velocity method; Venturi flume; Chemical method; weir method; Measurement of velocity; Floats Surface float, Sub–surface float or Double float, Twin float, Velocity rod or Rod float; Pitot tube; Current meter; Working of current meter; rating of current meter; Measurement of area of flow; Measurement of width - Pivot point method; Measurement of depth Sounding rod, Echo- sounder.
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.
This document discusses different types of in-situ soil tests used for subsurface exploration, including penetrometer tests. It describes the standard penetration test (SPT), which involves driving a split-spoon sampler into the soil using blows from a hammer. It also discusses the static cone penetration test (SCPT) and dynamic cone penetration test (DCPT), which measure soil resistance during penetration. SPT values are corrected based on overburden pressure and dilatancy. DCPT can identify soil variability but is not suitable for cohesive soils or depths with rod friction. SCPT and DCPT provide continuous resistance profiles without boreholes.
Canal fall- necessity and location- types of falls- Cross regulator and
distributory head regulator- their functions, Silt control devices, Canal
escapes- types of escapes.
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.
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.
The presentation illustrates a technique for ground improvement, Grouting. In India, grouting is still not being used very much. In this presentation, I have demonstrated the basic types of grouting, goals of ground improvement and two case studies of grouting.
Dewatering is the removal of water from solid material or soil by wet classification, centrifugation , filtration, or similar solid-liquid separation processes, such as removal of residual liquid from a filter cake by a filter press as part of various industrial processes.
1. Dams are constructed across rivers to store flowing water and come in various types like earth, rockfill, gravity, steel, timber and arch dams. The selection of dam type depends on site conditions like topography, geology and availability of construction materials.
2. Gravity dams derive their strength from their weight and weight of water pressure pushing them into the ground. They are made of concrete or masonry and work by balancing the water pressure on upstream side with weight and pressure on downstream side.
3. Factors considered in gravity dam design include water pressure, seismic forces, uplift pressure, weight of dam, and ensuring stability against sliding, overturning and cracking. Galleries are provided for drainage,
Vibration method for ground improvement techniqueABHISHEK THAKKAE
This document discusses various ground improvement techniques, including vertical drains, soil nailing, stone columns, vibro compaction, and dynamic compaction. Vertical drains accelerate consolidation by facilitating drainage of pore water through columns of pervious material placed in soil. Soil nailing uses steel tendons drilled and grouted into soil to create a reinforced composite mass. Stone columns form vertical columns of compacted aggregate through problem soils to increase strength and reduce compressibility. Vibro compaction densifies loose sands using vibratory probes to achieve a denser soil structure. Dynamic compaction improves soil by repeatedly dropping heavy weights onto the ground from heights of 40 to 80 feet.
This document provides information about construction dewatering and permanent groundwater control techniques. It discusses the differences between construction dewatering, which involves temporarily lowering the groundwater table during construction, and permanent groundwater control, which blocks long-term groundwater flow. Various dewatering techniques are described, including sump pumping, shallow wells, well points, and deep wells. Methods for permanent groundwater control include ground freezing, slurry trench walls, steel sheet piling, grouted barriers, thin grouted membranes, contiguous piling, diaphragm walls, and grouting. The document also provides examples of applying these techniques and outlines their advantages and disadvantages.
This document provides an overview of subsurface exploration, which involves site investigation and soil exploration to assess soil conditions for engineering projects. It discusses the objectives, phases and methods of subsurface exploration. The main methods covered are open excavation techniques like test pits and trenches, as well as boring techniques like auger, wash, percussion and rotary boring. It also describes different sampling techniques for obtaining disturbed and undisturbed soil samples, and different types of in-situ tests like standard penetration tests and cone penetration tests.
Dewatering is the artificial removal of groundwater or surface water to allow for construction. It plays a vital role in excavation by controlling hydrostatic pressure and soil stability. There are three main dewatering methods: active dewatering uses pumping, interception prevents water from reaching the excavation, and isolation excludes water via cut-off walls. Proper method selection depends on soil type and desired drawdown. Without control, dewatering can cause ground subsidence, flooding, or structural collapse due to increased soil loading.
A well point system consists of multiple well points spaced around an excavation site that are connected to a header pipe and pump. The well points are driven or jetted into the ground and draw groundwater into the riser pipes. This water is then pumped out through the header pipe. Spacing of well points typically ranges from 0.75m to 3m, though clay seals and sand filters can improve performance in silts. Well point systems are effective in sandy soils and can lower groundwater levels up to 5-6 meters, making them a relatively cheap and flexible dewatering option. However, they are not effective beyond 4-6 meters of drawdown and may require multiple stages.
This document discusses different grouting methods. It describes permeation grouting where grout is injected to fill voids without disturbing soil grains. Displacement grouting displaces soil grains, including compaction grouting using thick grout to form bulb shapes, and soil fracture grouting using lean grout to form root-like lenses. Jet grouting forms grouted columns by partly replacing and mixing with soil. Permeation grouting is used to form seepage barriers and stabilize tunnels. Displacement-compaction grouting involves high pressure injection of a soil-cement grout mixture to form 0.5-1m bulbous intrusions.
This document discusses various methods of boring into soil and rock to obtain samples at different depths. It describes auger boring, which uses hand or powered soil augers to drill holes. It also outlines shell and auger boring, wash boring using pressurized water, percussion boring using repeated blows, and rotary drilling which rotates a cutting bit to extract cylindrical core samples. The purpose of boring is to gather reliable subsurface information for engineering design and construction projects.
This document discusses soil mechanics concepts related to lateral earth pressure. It defines active and passive earth pressures and describes Rankine's theory and assumptions for calculating lateral pressures on retaining walls. Equations are provided for determining active and passive earth pressure coefficients and distributions for cohesionless and cohesive soils. The effects of groundwater, surcharges, and sloping backfills are also examined. Sample problems are included to calculate lateral earth pressures and forces on retaining walls for different soil and loading conditions.
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 the consolidation of soil. It defines important terms like compression, compressibility, and consolidation. It outlines the differences between compaction and consolidation. The importance of consolidation theory is that it provides information on total settlement, time for settlement, and types of settlement. Terzaghi's spring analogy is described to explain the consolidation process. A one-dimensional consolidation test procedure is outlined. Important definitions related to consolidation like compression index, swelling index, and coefficients are provided. The document also discusses normally, under, and over consolidated soils and how to determine preconsolidation pressure. Terzaghi's one-dimensional consolidation theory and solution are presented. Methods to determine degree of consolidation and coefficient of consolidation from laboratory test data are
The document discusses various ground improvement techniques including removal and replacement, in-situ densification methods like dynamic compaction, preloading, use of vertical drains and stone columns. It provides details on specific in-situ densification methods like vibro-float compaction using a vibrating probe, dynamic compaction using heavy weights, and explosive compaction using detonated charges. The document also summarizes advantages and limitations of preloading using surcharge fills and uses of vertical drains and geosynthetics to accelerate consolidation.
Class 5 Permeability Test ( Geotechnical Engineering )Hossam Shafiq I
This document discusses permeability testing methods for geotechnical engineering laboratory class. It describes two common permeability test methods: the constant-head test and falling-head test. The constant-head test applies a constant head of water to a soil specimen in a permeameter to measure hydraulic conductivity. The falling-head test similarly uses a permeameter but measures the change in head over time. Both tests aim to determine the hydraulic conductivity value k, which indicates a soil's ability to transmit water and is important for analyzing seepage, settlement, and slope stability.
Stream Gauging: Necessity; Selection of gauging sites; Methods of discharge measurement; Area-Velocity method; Venturi flume; Chemical method; weir method; Measurement of velocity; Floats Surface float, Sub–surface float or Double float, Twin float, Velocity rod or Rod float; Pitot tube; Current meter; Working of current meter; rating of current meter; Measurement of area of flow; Measurement of width - Pivot point method; Measurement of depth Sounding rod, Echo- sounder.
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.
This document discusses different types of in-situ soil tests used for subsurface exploration, including penetrometer tests. It describes the standard penetration test (SPT), which involves driving a split-spoon sampler into the soil using blows from a hammer. It also discusses the static cone penetration test (SCPT) and dynamic cone penetration test (DCPT), which measure soil resistance during penetration. SPT values are corrected based on overburden pressure and dilatancy. DCPT can identify soil variability but is not suitable for cohesive soils or depths with rod friction. SCPT and DCPT provide continuous resistance profiles without boreholes.
Canal fall- necessity and location- types of falls- Cross regulator and
distributory head regulator- their functions, Silt control devices, Canal
escapes- types of escapes.
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.
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.
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.
This document discusses different types of subsurface drainage systems including relief drainage, interceptor drainage, and their open ditch and buried components. It also describes various subsurface drainage methods such as tile drains, mole drains, drainage wells, and deep open drains. Specifically, it provides details on tile drainage systems including layouts, depth and spacing considerations, sizes and materials of tiles, installation processes, and other related elements. Mole drainage systems are also summarized, highlighting how they are created using mole plow equipment.
ENVIRONMENTAL POLLUTION CONTROL METHOD ADOPTED BY NTPC LTD. IN ASH DYKE (STAR...Sukesh Nayak
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.
Dewatering process and control in building projectsUmar Faruk
Dewatering is the process of controlling groundwater levels during construction by pumping water out of excavation sites. There are several techniques used for dewatering including pumping methods like sump pumping, well points, and deep wells. Exclusion methods prevent water from entering sites using techniques like ground freezing, sheet piling, slurry trench cut-off walls, and grouted cut-offs. The appropriate dewatering method depends on factors such as ground permeability, excavation size and depth, and proximity to existing structures. Common pumping techniques are sump pumping, well points, and deep wells which use pumps in shallow wells, closely spaced shallow wells, or widely spaced deep wells respectively. Exclusion methods form impermeable
The document discusses various methods for railway track construction, maintenance, and operation. It describes the process for earthwork and preparing the track bed, including stabilizing poor soils. It then covers several tunneling methods for passing through rock and soft ground, as well as underwater. These include the full face method, heading and benching, drift system, pilot tunnel method, shield tunneling, and cut and cover method. It also discusses forepoling for tunneling through soft ground.
This document discusses various methods for dewatering excavation sites, including open dewatering systems using sumps and ditches, well point systems, deep well systems, vacuum systems, electro-osmosis, freezing methods, and grouting. It explains what dewatering is, why it is required, outlines different dewatering methods and considerations for selecting a method based on the size and depth of excavation, soil characteristics, and other factors. The key methods covered are well point systems, deep well systems, and freezing, with explanations of how each works and when it is suitable.
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.
The document discusses drainage systems for foundations. It includes definitions of key terms like foundation dewatering and filter. It describes different types of drains like open drains, lined drains, closed drains, wells, and miscellaneous methods. Open drains include catch drains, open channels, and lined options like kerb and gutter drains. Closed drains include tile drains, blanket drains, and composite drains. Wells for drainage include deep wells, horizontal wells, and well points. The document also discusses standards and materials used for drains.
Groundwater is a common problem in mining that requires control through planned dewatering programs. Successful dewatering requires hydrogeological assessment and selecting the appropriate technique, such as in-pit pumping, perimeter dewatering wells, or slope depressurization drains. Dewatering provides benefits like improved safety and efficiency through more stable slopes and dry working conditions.
Excavation and Ground water control1.pptxssusercbae26
This document summarizes different types of excavation including topsoil excavation, rock excavation, muck excavation, and earth excavation. It then discusses various purposes of excavation such as cut and fill excavation, trench excavation, basement excavation, and dredging excavation. Finally, it covers topics related to controlling groundwater and surface water during excavation projects through methods like pumping, cutoff walls, and special techniques.
Week 01 Preliminaries Works, Soil Investigate & Ground Water Controlnik kin
The document discusses site preparation for construction projects, including site investigation, soil investigation, and ground water control. Site investigation involves collecting data about the site, including topography, hydrology, and existing infrastructure. Soil investigation determines site suitability and foundation design through methods like trial pits, augers, and sampling. Ground water control includes temporary dewatering methods like sumps and wellpoints, and permanent barriers like grouted membranes, contiguous piling, and diaphragm walls. Preliminaries works establish temporary facilities and ensure safety/compliance for a construction project.
The document provides information about tunnel construction. It begins with an introduction and then discusses why tunnels are constructed, the history and classification of tunnels, different tunnel shapes, the tunnel construction process, and various tunnel construction methods. It also outlines the advantages of tunnels. Key points include that tunnels provide underground passages for transportation and utilities, and that modern construction methods include cut-and-cover, drill-and-blast, tunnel boring machines (TBM), and New Austrian tunneling.
This document provides guidelines for laying cement concrete and stone slab lining on canals. It discusses preparing the subgrade, including dealing with expansive soils and over-excavation. It also covers compaction requirements depending on soil type and drainage. Guidelines are provided for laying in-situ concrete lining, including concrete mix design, thickness based on canal capacity, and tolerances for alignment and thickness. Precast concrete tiles and stone slabs are also included within the scope of acceptable lining materials.
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
Presentation on surface investigation techniques for foundationashishcivil098
This document provides an overview of various surface investigation techniques for foundation design, including:
- Site exploration is important before designing foundations to obtain reliable data about soil conditions.
- Methods discussed include trial pits, auger boring, wash boring, rotary drilling, and percussion drilling. Each method is suited for different soil/rock conditions.
- The presentation covers the steps in soil exploration, factors affecting exploration programs, and classes of subsurface investigations.
Necessity/advantage of a tunnel, Classification of Tunnels,
Size and shape of a tunnel, Alignment of a Tunnel, Portals and Shafts,
Methods of Tunneling in Hard Rock and Soft ground, Mucking, Lighting
and Ventilation in tunnel, Dust control, Drainage of tunnels, Safety in
tunnel construction.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
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Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
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Answers about how you can do more with Walmart!"
Andreas Schleicher presents PISA 2022 Volume III - Creative Thinking - 18 Jun...EduSkills OECD
Andreas Schleicher, Director of Education and Skills at the OECD presents at the launch of PISA 2022 Volume III - Creative Minds, Creative Schools on 18 June 2024.
How Barcodes Can Be Leveraged Within Odoo 17Celine George
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The chapter Lifelines of National Economy in Class 10 Geography focuses on the various modes of transportation and communication that play a vital role in the economic development of a country. These lifelines are crucial for the movement of goods, services, and people, thereby connecting different regions and promoting economic activities.
This presentation was provided by Rebecca Benner, Ph.D., of the American Society of Anesthesiologists, for the second session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Two: 'Expanding Pathways to Publishing Careers,' was held June 13, 2024.
A Visual Guide to 1 Samuel | A Tale of Two HeartsSteve Thomason
These slides walk through the story of 1 Samuel. Samuel is the last judge of Israel. The people reject God and want a king. Saul is anointed as the first king, but he is not a good king. David, the shepherd boy is anointed and Saul is envious of him. David shows honor while Saul continues to self destruct.
1. 9-1
9. DEWATERING – CONTROL OF GROUNDWATER
Construction of buildings, powerhouses, dams, locks and many other structures requires
excavation below the water table into water-bearing soils. Such excavations require lowering
the water table below the slopes and bottom of the excavation to prevent raveling or sloughing
of the slope and to ensure dry, firm working conditions for construction operations.
Groundwater can be controlled by means of one or more types of dewatering systems
appropriate to the size and depth of the excavation, geological conditions, and characteristics
of the soil.
Construction sites are dewatered for the following purposes:
1- To provide suitable working surface of the bottom of the excavation.
2- To stabilize the banks of the excavation thus avoiding the hazards of slides and
sloughing.
3- To prevent disturbance of the soil at the bottom of excavation caused by boils or
piping. Such disturbances may reduce the bearing power of the soil.
Lowering the water table can also be utilized to increase the effective weight of the soil and
consolidate the soil layers. Reducing lateral loads on sheeting and bracing is another way of
use.
A number of methods are available for controlling the inflow of water into an excavation; the
choice of method will depend on the nature and permeability of the ground, the extent of the
area to be dewatered, the depth of the water table below ground level and the amount by
which it has to be lowered, the proposed methods of excavation and ground support, the
proximity of existing structures, the proximity of water courses etc.
2. 9-2
The available methods of groundwater control fall into the following basic groups:
1. Surface water control like ditches, training walls, embankments. Simple methods of
diverting surface water, open excavations. Simple pumping equipment.
2. Gravity drainage. Relatively impermeable soils. Open excavations especially on
sloping sites. Simple pumping equipment.
3. Sump pumping (see below)
4. Wellpoint systems with suction pumps. (See below)
5. Shallow (bored) wells with pumps. (See below)
6. Deep (bored) wells with pumps. (See below).
7. Eductor system (See below)
8. Drainage galleries. Removal of large quantities of water for dam abutments, cut-offs,
landslides etc. Large quantities of water can be drained into gallery (small diameter
tunnel) and disposed of by conventional large – scale pumps.
9. Electro-osmosis. Used in low permeability soils (silts, silty clays, some peats) when
no other method is suitable. Direct current electricity is applied from anodes (steel
rods) to cathodes (well-points, i.e. small diameter filter wells)
Exclusion methods; (not covered in this note)
1. Ground freezing (ammonium brine refrigeration or liquid nitrogen refrigeration). All
types of saturated soils.
2. Slurry trench cut-off walls with bentonite or native clay and Diaphragm concrete
walls. All soils. Curtain walls around excavations with flat buckets.
3. Impervious soil barrier. All soils. Relatively shallow applications (5-6m max.). Back-
hoes form the clay filled barriers some distance from the excavation boundaries.
4. Sheet piling. All soils except soils with large boulders.
5. Secant (interlocked) piling or tangent piling with grouting in between. All soils except
boulders.
6. Compressed air. All types of saturated soils and rock. Applications in tunnels, shafts
and caissons.
7. Grouted cut-offs (jet grouting, cementatious grouts, chemical grouts etc.)
3. 9-3
9.1.Sumps and sump pumping
A sump is merely a hole in the ground from which water is being pumped for the purpose of
removing water from the adjoining area (Fig 9.1). They are used with ditches leading to them
in large excavations. Up to maximum of 8m below pump installation level; for greater depths
a submersible pump is required. Shallow slopes may be required for unsupported excavations
in silts and fine sands. Gravels and coarse sands are more suitable. Fines may be easily
removed from ground and soils containing large percent of fines are not suitable. If there are
existing foundations in the vicinity pumping may cause settlement of these foundations.
Subsidence of adjacent ground and sloughing of the lower part of a slope (sloped pits) may
occur. The sump should be preferably lined with a filter material which has grain size
gradations in compatible with the filter rules. For prolonged pumping the sump should be
prepared by first driving sheeting around the sump area for the full depth of the sump and
installing a cage inside the sump made of wire mesh with internal strutting or a perforating
pipe filling the filter material in the space outside the cage and at the bottom of the cage and
withdrawing the sheeting. Two simple sumping details are shown in Figures 2 and 3.
4. 9-4
9.2.Wellpoint systems
A wellpoint is 5.0-7.5 cm diameter metal or plastic pipe 60 cm – 120 cm long which is
perforated and covered with a screen. The lower end of the pipe has a driving head with
water holes for jetting (Fig 9.4.a,b). Wellpoints are connected to 5.0-7.5 cm diameter pipes
known as riser pipes and are inserted into the ground by driving or jetting. The upper ends of
the riser pipes lead to a header pipe which, in turn, connected to a pump. The ground water is
drawn by the pump into the wellpoints through the header pipe and discharged (Fig 9.5). The
wellpoints are usually installed with 0.75m – 3m spacing (See Table 1). This type of
dewatering system is effective in soils constituted primarily of sand fraction or other soil
containing seams of such materials. In gravels spacing required may be too close and
impracticable. In clays it is also not used because it is too slow. In silts and silt – clay
mixtures the use of well points are aided by upper (0.60m – 0.90m long) compacted clay seals
and sand-filtered boreholes (20cm – 60cm diameter). Upper clay seals help to maintain
higher suction (vacuum) pressures and sand filters increase the amount of discharge. Filtered
boreholes are also functional in layered soil profiles (Figures 9.6.a,b,c,d,e)
6. 9-6
Table 9.1 Typical spacings for some common soil types and the
approximate time required for effective drawdown
Soil Typical Spacing (m) Time (days)
Silty sand 1.5-2 7-21(Could be longer)
Clean fine to coarse sand 1.0-1.5 3-10
and sandy gravel
Fine to coarse gravel 0.5-1.0 1-2
The header pipe (15-30 cm diameter, connecting all wellpoints) is connected to a vacuum
(Suction assisted self – priming centrifugal or piston) pump. The wellpoints can lower a water
level to a maximum of 5.5 m below the centerline of the header pipe. In silty fine sands this
limit is 3-4 m. Multiple stage system of wellpoints are used for lowering water level to a
greater depth. Two or more tiers (stages) are used. (Fig 9.7). More pumps are needed and due
to the berms required the excavation width becomes wider. A single wellpoint handles
between 4 and 0.6 m3
/hr depending on soil type. For a 120 m length (40 at 3 m centers) flow
is therefore between 160 and 24 m3
/hr.
Nomograms for selecting preliminary wellpoint spacing in clean uniform sand and gravel, and
stratified clean sand and gravel are shown in Figures 9.8 and 9.9.
8. 9-8
Horizontal wellpoints are used mainly for pipeline water. They consist of perforated pipes
laid horizontally in a trench and connected to a suitable pump.
9.3.Shallow Wells
Shallow wells comprise surface pumps which draw water through suction pipes installed in
bored wells drilled by the most appropriate well drilling and or bored piling equipment. The
limiting depth to which this method is employed is about 8 m. Because wells are prebored,
this method is used when hard or variable soil conditions preclude the use of a wellpoint
system. These wells are used in very permeable soils when wellpointing would be expensive
and often at inconveniently close centers. The shallow well can be used to extract large
quantities of water from a single hole. On congested sites use of smaller number dewatering
points is preferred (no hiderance to construction operations) hence shallow wells may be
preferred to wellpoints. Since the initial cost of installation is more compared to wellpoints it
is preferred in cases where dewatering lasts several months or more. Another field of
application is the silty soils where correct filtering is important.
9.4.Deep Wells
When water has to be extracted from depths greater than 8 m and it is not feasible to lower the
type of pump and suction piping used in shallow wells to gain a few extra meters of depth the
deep wells are such and submersible pumps installed within them. A cased borehole can be
sunk using well drilling or bored piling rigs to a depth lower than the required dewatered
level. The diameter will be 150 – 200 mm larger then the well inner casing, which in turn is
sized to accept the submersible pump. The inner well casing has a perforated screen over the
depth requiring dewatering and terminates below in 1 m of unperforated pipe which may
serve as a sump for any material which passes the filter. After the slotted PVC or metal well
screen (casing) has been installed it is surrounded by backfill over the unperforated pipe
length and with graded filter material over the perforated length as the outer casing
progressively withdrawn (Fig 9.10). As with the shallow wells the initial pumping may
involve twice the volumes when equilibrium is achieved.
9. 9-9
Deep well systems are of use in gravels to silty fine sands and in water bearing rocks. They
are priority or use with deep excavations and where artesian water is present below an
impermeable stratum. If this type of installation is to be designed economically the ground
permeability must be assessed from full scale pumping tests. Because of their depth and the
usually longer pumping period these installations are more likely to cause settlement of
nearby structures, and the use of recharge methods may have to be considered.
9.5.Eductor System
This system also known as the ‘jet eductor system’ or ‘ejector system’ or ‘eductor wellpoint
system’ is similar to the wellpoint system. Instead of employing a vacuum to draw water to
the wellpoints, the eductor system uses high pressure water and riser units, each about 30-40
mm in diameter. A high pressure supply main feeds water through a venturi tube immediately
above the perforated well screen, creating a reduction in pressure which draws water through
the large diameter rise pipe. The high pressure main feeds off the return water. The advantage
of the eductor system is that in operating many wellpoints from a single pump station, the
water table can be lowered in one stage from depths of 10-45 m. This method becomes
economically competitive at depth in soils of low permeability.
Tentative economic ranges for groundwater lowering methods are shown in Fig 9.11.
10. 9-10
9.6.EXAMPLE – SHALLOW WELLS
Consider the need to lower the water table for the construction of a 7 m deep basement, 80 m
by 50 m at its base. The soil profile is shown below.
Drawdown to at least +69.0 m at the centre of excavation required which is 7 m minimum.
This will require a number of wells surrounding the proposed basement area, the yield
11. 9-11
(discharge) from which may be computed assuming a single well with an equivalent radius rs.
This approach is known as “big well” approximate analysis. Another approach is to
superpose the drawdowns due to several wells at the centre of the building. In both cases the
well formulae are needed for the soil and hydraulic conditions at the site. The radius of the
assumed “big well” is;
m
xBxL
rs 5.41
9060
===
ππ
where
B = width of excavation, b + 10m
L = length of excavation, +10m
In other words the wells are at 5m distance to the building. The radius of influence (Ro) is the
radius within which the drawdown occurs. Drawdown of the water table at a point produces a
cone of depression and the radius of influence (Ro) is a function of the drawdown (h) and the
permeability (k) of the soil as shown below.
12. 9-12
More permeable the soil means greater the radius of influence is Ro = Ch√k is a proposed
equation to calculate Ro where c is a factor equal to 3000 for radial flow to pumped wells and
between 1500 and 2000 for line flow to trenches or to a line of wellpoints. Ro at the present
case is, Ro = 3000(76-69) 4
105 −
x ; Ro= 470 m. The percent drawdown of the water table at
any distance from the center of cone can be obtained from the following figure.
Drawdown at centre of excavation by peripheral wells:
Distance from perimeter to centre = 41.5m
Percentage distance along radius of influence (Ro) :
%8.8100
470
5.41
=x
m
m
⇒ From the above figure % drawdown is 58 %.
Therefore, required drawdown at wells to obtain 7m drawdown at centre of excavation will be
m12
58.0
7
= . In practice since each line of wells will contribute to the drawdown, a
somewhat lesser drawdown at the wells will be required. Alternatively, assuming a full 12 m
drawdown will allow a margin of error.
For the confined aquifer case the flow (or yield) can be calculated by the following formula
(Refer to sources containing well formulae for various profiles. References 2, 3 and 4 provide
such formulae).
5.41
470
)921(171052)(2 4
n
xxxxx
r
R
n
hHkD
Q
s
o
w
−
=
−
=
−
ππ
13. 9-13
Q = 0.264 m3
/s = 246 lt/s
Where;
Q = discharge from assumed single well (m3
/s)
k = coefficient o permeability (m/s)
D = height of piezometric level above base of aquifer (m)
hw= height of water at outside edge of pumping wells
after drawdown (m)
Ro = radius of influence (m)
rs = equivalent radius of assumed single well (m)
Assuming 450 mm diameter wells find the area of wetted depth (hw) of wells for calculated
yield using the following graph for k = 5x10-4
m/s : Yield per metre of wetted depth = 2.1 lt/s
Total wetted depth required
1.2
264
=126 m approx. For drawdown to +64.0m at the wells (i.e.
hw≅9m) the intake level of the pumps must be at a level sufficiently lower to allow for the
length of the pump and to avoid cavitation of the water above the pump. (Allow 1.5m for the
14. 9-14
length of pump and 5m for cavitation) It would there fore be necessary to set the pump inlet
at, say, +57m. Allow also 2-3m below the pump inlet and bottom of the well screen should
be at, say, 54.0m.
Yield per well = 9m x 2.1 lt/s = 18.9 lt/s .
Hence theoretical numbero f wells required:
14
9.18
264
=
Add three (about 20%) to allow for variations in soil conditions, pump breakdowns etc. Plus
margin of error and reserve capacity to establish equilibrium.
Selection of the pump:
Yield per pump : 264/14 = 18.9 lt/s
Total pumping head from pumping level = 12m. (76m – 64m)
Allow 4 m for velocity head and friction losses.
Therefore the total head is appoximately 16 m.
From pump manufacturer’s performance curves (submersible pumps) select suitable pumps
for installation inside 200/300 mm diameter casing screen (i.e. 450 mm less 75 mm annulus
for gravel pack).
Check also conveying pipe sizes (250 mm dia. minimum required, allow 305 mm dia).
Design of wellpoints can be made after calculating the yield (flow) using formulae for
trenchs (line sources) and then using the given nomograms.
REFERENCES
1. Quinion, D.W. and Quinion, G.R.(1987), Control of Groundwater, ICE Works
Construction Guides, Thomas Telford Pub.Co., London.
2. Somerville, S.H.(1986), Control of Groundwater for Temporary Works, CIRIA
(Construction Industry Research and Information Association) Report No.113.
3. Mansur, C.I. and Kaufman, R.I. (1962) Dewatering, in Foundation Engineering Ed.by
G.A. Leonards pp.241-350, Mc Graw-Hill Book Co.
4. Powers, J.P. (1992), Construction Dewatering, 492p., 2nd
ed. John Wiley and Sons
Inc.
5. Teng, V.C.(1962) Foundation Design, 466 p., Ch.5, Prentice-Hall, IAC.,Englewood
Cliffs, N.J.