This document discusses different types of soil admixtures used for ground improvement, including inert and chemical admixtures. It focuses on lime treatment of soils, describing how lime modifies soil properties through cation exchange, flocculation, and pozzolanic reactions. These reactions can increase shear strength, reduce permeability and swelling, and change plasticity. The document discusses factors in choosing lime modification or stabilization, describes lime treatment processes, and compares advantages and disadvantages of different lime application methods.
There are several techniques for improving the mechanical properties of soil, including densification, reinforcement, and stabilization methods. Densification techniques like vibro-compaction, vibro-flotation, dynamic compaction, and blasting work to compact soil particles into a denser configuration, increasing strength and stiffness. Reinforcement techniques include installing discrete inclusions like compaction piles to reinforce weak soils. Stabilization techniques chemically alter the soil, such as jet grouting which mixes soil with cement grout under high pressure to form columns of treated soil.
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.
The document summarizes key aspects of prefabricated vertical drains (PVDs) used for soil improvement. It discusses how PVDs work by shortening drainage paths in clay soils to accelerate consolidation from preloading. The document covers PVD installation methods, factors affecting their performance over time, advantages over sand drains, and applications such as embankment stabilization. It also reviews several studies on PVD performance in soft soil improvement projects.
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.
This document summarizes various physical soil improvement techniques including grouting, soil cement, heating, and freezing. Grouting involves injecting adhesives into soil to fill voids and increase strength. Types of grouting include penetration, compaction, and jet grouting. Soil cement mixes cement with soil to increase strength, stiffness, and durability. Heating soil to 300-1000°C changes its properties, making it harder. Freezing soil by refrigeration causes water to expand and bond particles, temporarily increasing strength for excavation support. The document provides details on each technique's process and applications.
Reinforced earth is a combination of earth and linear reinforcing strips that are capable of bearing large tensile stresses.
The reinforcement provided by these strips enable the mass to resist the tension in a way which the earth alone could not. The source of this resistance to tension is the internal friction of soil, because the stresses that are created within the mass are transferred from soil to the reinforcement strips by friction.
Grouting involves injecting a slurry or liquid into soil or rock to fill voids and fractures. There are three main modes of grouting: permeation where grout flows freely into voids, compaction where grout remains intact and exerts pressure, and hydraulic fracturing where grout rapidly penetrates fractured zones. Grouting is used for applications like seepage control, soil stabilization, and vibration control. Common grout materials include suspensions of cement and water, emulsions of asphalt and water, and chemical solutions. Injection methods include permeation, compaction, jet, and soil fracture grouting. Proper planning of the grouting process including ground investigation, hole pattern, and sequencing is
There are several techniques for improving the mechanical properties of soil, including densification, reinforcement, and stabilization methods. Densification techniques like vibro-compaction, vibro-flotation, dynamic compaction, and blasting work to compact soil particles into a denser configuration, increasing strength and stiffness. Reinforcement techniques include installing discrete inclusions like compaction piles to reinforce weak soils. Stabilization techniques chemically alter the soil, such as jet grouting which mixes soil with cement grout under high pressure to form columns of treated soil.
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.
The document summarizes key aspects of prefabricated vertical drains (PVDs) used for soil improvement. It discusses how PVDs work by shortening drainage paths in clay soils to accelerate consolidation from preloading. The document covers PVD installation methods, factors affecting their performance over time, advantages over sand drains, and applications such as embankment stabilization. It also reviews several studies on PVD performance in soft soil improvement projects.
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.
This document summarizes various physical soil improvement techniques including grouting, soil cement, heating, and freezing. Grouting involves injecting adhesives into soil to fill voids and increase strength. Types of grouting include penetration, compaction, and jet grouting. Soil cement mixes cement with soil to increase strength, stiffness, and durability. Heating soil to 300-1000°C changes its properties, making it harder. Freezing soil by refrigeration causes water to expand and bond particles, temporarily increasing strength for excavation support. The document provides details on each technique's process and applications.
Reinforced earth is a combination of earth and linear reinforcing strips that are capable of bearing large tensile stresses.
The reinforcement provided by these strips enable the mass to resist the tension in a way which the earth alone could not. The source of this resistance to tension is the internal friction of soil, because the stresses that are created within the mass are transferred from soil to the reinforcement strips by friction.
Grouting involves injecting a slurry or liquid into soil or rock to fill voids and fractures. There are three main modes of grouting: permeation where grout flows freely into voids, compaction where grout remains intact and exerts pressure, and hydraulic fracturing where grout rapidly penetrates fractured zones. Grouting is used for applications like seepage control, soil stabilization, and vibration control. Common grout materials include suspensions of cement and water, emulsions of asphalt and water, and chemical solutions. Injection methods include permeation, compaction, jet, and soil fracture grouting. Proper planning of the grouting process including ground investigation, hole pattern, and sequencing is
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.
Vibro replacement stone columns are a ground improvement technique to improve the load bearing capacity and reduce the settlement of the soil. On many occasions, it is noted that the local soil is, by nature, unable to bear the proposed structure, so the use of ground improvement techniques may be necessary. Use of stone columns is one such technique. The stone column consists of crushed coarse aggregates of various sizes. The ratio in which the stones of different sizes will be mixed is decided by design criteria
Stone columns are a versatile ground improvement technique used since the 1950s. They involve compacting coarse aggregate in columns in the ground to reinforce, densify and drain weak soils. Stone columns can improve bearing capacity, stability, reduce settlements and mitigate liquefaction. They work by transferring loads around them to stiffer columns, accelerating consolidation. Installation methods include ramming and vibro-replacement. Case studies show stone column embankments experience less settlement than untreated ground. In summary, stone columns are an effective ground improvement technique to strengthen weak soils.
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.
1) The document discusses ground improvement techniques of preloading and vertical drainage. Preloading involves applying a surcharge load to improve soil strength and reduce settlements before construction.
2) Vertical drains are often used with preloading to accelerate consolidation by shortening the drainage path. Common types are sand drains and prefabricated vertical drains.
3) Vacuum preloading is described as an alternative to conventional preloading using surcharge loads, applying atmospheric pressure via a membrane system instead. This requires an effective drainage and vacuum maintenance system.
Sand drains are vertical bore holes backfilled with sand to accelerate drainage in embankments. They work by allowing pore water pressure to dissipate horizontally through the surrounding sand and vertically towards the sand blanket on top. Spacing of drains is generally less than twice the embankment thickness to reduce drainage path lengths. Surcharge loads are applied to the sand blanket to further increase pore pressures and drive drainage. While effective, sand drains do not address secondary consolidation and may underestimate stress reductions in the soil from their presence.
This document provides an overview of soil nailing, including its origins, components, construction process, and applications. Soil nailing involves installing closely spaced reinforcing bars into sloped ground or excavations from top to bottom as construction proceeds. It originated from New Austrian Tunneling methods and was first used in the 1970s for railroad and highway projects. Key components include nail bars, grout, centralizers, and shotcrete facing. Construction involves excavating, drilling nail holes, grouting nails, and building subsequent wall levels. Soil nailing is used to stabilize slopes, excavations, bridge abutments, and can be less disruptive and more economical than other retaining wall methods.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
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.
1) The document discusses soil bearing capacity, which refers to the capacity of soil to support loads applied to the ground without failing.
2) Important factors in soil bearing capacity include the stability of foundations, which depends on the bearing capacity of soil beneath and the settlement of soil.
3) The document outlines several key terminologies used in soil bearing capacity such as ultimate bearing capacity, net ultimate bearing capacity, net safe bearing capacity, and more.
4) Several methods to increase the bearing capacity of black cotton soil are described, including increasing foundation depth, chemical treatment, grouting, compaction, drainage, and confining the soil.
This document discusses ground improvement technologies including stone column and band drain technologies. Stone columns involve compacting aggregates into vertical columns to improve soil conditions and increase load capacity. Band drains involve installing prefabricated vertical drains to accelerate consolidation of loose, saturated clays by providing lateral drainage pathways. A case study describes a highway project in India where both stone columns and band drains were used over 10km to improve ground conditions.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
This document discusses different types of well foundations used in construction. It describes three main types: open caissons, which have open tops and bottoms; pneumatic caissons, which use air pressure; and box caissons, which are closed at the bottom. It provides details on each type, including advantages and disadvantages. Open caissons can be built to greater depths but inspection of the bottom is not possible. Pneumatic caissons allow work under water but require complex machinery. Box caissons have a lower construction cost but the foundation base cannot be inspected.
Piles are deep foundations used to transfer structural loads through weak or wet soils to stronger soils below. Piles can be classified based on function (end bearing, friction, tension), material (concrete, timber, steel), or installation method (driven, cast-in-place). Key factors in pile design include soil properties, load types, and groundwater conditions. The ultimate load capacity of a pile considers end bearing and side friction, while the allowable load uses a factor of safety. Dynamic testing and soil parameters can be used to estimate pile capacities.
Bearing capacity of shallow foundations by abhishek sharma ABHISHEK SHARMA
elements you should know about bearing capacity of shallow foundations are included in it. various indian standards are also used. Bearing capacity theories by various researchers are also included. numericals from GATE CE and ESE CE are also included.
Dynamic compaction is a technique developed in the 1960s that involves repeatedly dropping a large weight from a crane onto the ground to compact soils for construction projects like roads, airports, and buildings. The weight can range from 6 to 172 tons and is dropped from heights of 10 to 40 meters to densify soils to depths of 3 to 12 meters depending on the weight and soil properties. It is conducted in multiple phases with progressively closer spacing of impacts and is effective on both saturated and dry granular soils for reclamation projects with variable soil conditions.
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
This document provides information on the standard penetration test (SPT), including the instruments, procedures, corrections, and applications. It describes that the SPT is commonly used to evaluate the in-situ properties of cohesionless soils. The key instruments are a split spoon sampler, drive-weight assembly with a 63.5 kg hammer, and cathead. The procedure involves drilling a borehole, driving the sampler with the hammer, and recording the number of blows to penetrate each 15 cm interval. Corrections are made to account for overburden pressure, dilatancy effects, and hammer energy efficiency. The SPT provides useful correlations to estimate properties like relative density, friction angle, and strength.
This document discusses soil stabilization techniques using lime and fly ash additions. It begins with an introduction to soil stabilization and describes how lime treatment improves soil properties like plasticity, compaction, and bearing capacity. It discusses the chemical reactions that occur with lime stabilization over time. The objectives of the project are outlined as exploring using fly ash in road construction and studying the effects of lime and fly ash on properties of clayey soil like density, moisture content, consistency limits, and CBR value. Finally, the literature review summarizes previous studies that found additions of waste plastics and lime increased the strength and load bearing capacity of soils.
This document discusses various methods of soil stabilization, including without additives (compaction and drainage) and with additives like cement, lime, fly ash, and bitumen. Cement stabilization involves mixing soil and cement to create a strong material called soil cement. Lime stabilization uses lime to decrease soil plasticity. Fly ash stabilization can increase soil strength and control shrink/swell. Bitumen stabilization coats soil particles with asphalt to prevent water penetration. The conclusion states that soil stabilization with these additives effectively increases soil strength and bearing capacity for construction.
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.
Vibro replacement stone columns are a ground improvement technique to improve the load bearing capacity and reduce the settlement of the soil. On many occasions, it is noted that the local soil is, by nature, unable to bear the proposed structure, so the use of ground improvement techniques may be necessary. Use of stone columns is one such technique. The stone column consists of crushed coarse aggregates of various sizes. The ratio in which the stones of different sizes will be mixed is decided by design criteria
Stone columns are a versatile ground improvement technique used since the 1950s. They involve compacting coarse aggregate in columns in the ground to reinforce, densify and drain weak soils. Stone columns can improve bearing capacity, stability, reduce settlements and mitigate liquefaction. They work by transferring loads around them to stiffer columns, accelerating consolidation. Installation methods include ramming and vibro-replacement. Case studies show stone column embankments experience less settlement than untreated ground. In summary, stone columns are an effective ground improvement technique to strengthen weak soils.
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.
1) The document discusses ground improvement techniques of preloading and vertical drainage. Preloading involves applying a surcharge load to improve soil strength and reduce settlements before construction.
2) Vertical drains are often used with preloading to accelerate consolidation by shortening the drainage path. Common types are sand drains and prefabricated vertical drains.
3) Vacuum preloading is described as an alternative to conventional preloading using surcharge loads, applying atmospheric pressure via a membrane system instead. This requires an effective drainage and vacuum maintenance system.
Sand drains are vertical bore holes backfilled with sand to accelerate drainage in embankments. They work by allowing pore water pressure to dissipate horizontally through the surrounding sand and vertically towards the sand blanket on top. Spacing of drains is generally less than twice the embankment thickness to reduce drainage path lengths. Surcharge loads are applied to the sand blanket to further increase pore pressures and drive drainage. While effective, sand drains do not address secondary consolidation and may underestimate stress reductions in the soil from their presence.
This document provides an overview of soil nailing, including its origins, components, construction process, and applications. Soil nailing involves installing closely spaced reinforcing bars into sloped ground or excavations from top to bottom as construction proceeds. It originated from New Austrian Tunneling methods and was first used in the 1970s for railroad and highway projects. Key components include nail bars, grout, centralizers, and shotcrete facing. Construction involves excavating, drilling nail holes, grouting nails, and building subsequent wall levels. Soil nailing is used to stabilize slopes, excavations, bridge abutments, and can be less disruptive and more economical than other retaining wall methods.
Class notes of Geotechnical Engineering course I used to teach at UET Lahore. Feel free to download the slide show.
Anyone looking to modify these files and use them for their own teaching purposes can contact me directly to get hold of editable version.
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.
1) The document discusses soil bearing capacity, which refers to the capacity of soil to support loads applied to the ground without failing.
2) Important factors in soil bearing capacity include the stability of foundations, which depends on the bearing capacity of soil beneath and the settlement of soil.
3) The document outlines several key terminologies used in soil bearing capacity such as ultimate bearing capacity, net ultimate bearing capacity, net safe bearing capacity, and more.
4) Several methods to increase the bearing capacity of black cotton soil are described, including increasing foundation depth, chemical treatment, grouting, compaction, drainage, and confining the soil.
This document discusses ground improvement technologies including stone column and band drain technologies. Stone columns involve compacting aggregates into vertical columns to improve soil conditions and increase load capacity. Band drains involve installing prefabricated vertical drains to accelerate consolidation of loose, saturated clays by providing lateral drainage pathways. A case study describes a highway project in India where both stone columns and band drains were used over 10km to improve ground conditions.
This document discusses different methods for soil stabilization, including mechanical, physical, chemical, and bituminous stabilization. Mechanical stabilization involves compacting soil to increase density and strength. Physical stabilization involves blending soils or adding admixtures to improve properties. Chemical stabilization uses lime, cement, or other chemicals like calcium chloride to react with soils and modify their characteristics. Bituminous stabilization involves adding bitumen or asphalt to seal soil pores and increase cohesion between particles. The document provides details on appropriate soil types, required quantities, and construction methods for each stabilization technique.
This document discusses different types of well foundations used in construction. It describes three main types: open caissons, which have open tops and bottoms; pneumatic caissons, which use air pressure; and box caissons, which are closed at the bottom. It provides details on each type, including advantages and disadvantages. Open caissons can be built to greater depths but inspection of the bottom is not possible. Pneumatic caissons allow work under water but require complex machinery. Box caissons have a lower construction cost but the foundation base cannot be inspected.
Piles are deep foundations used to transfer structural loads through weak or wet soils to stronger soils below. Piles can be classified based on function (end bearing, friction, tension), material (concrete, timber, steel), or installation method (driven, cast-in-place). Key factors in pile design include soil properties, load types, and groundwater conditions. The ultimate load capacity of a pile considers end bearing and side friction, while the allowable load uses a factor of safety. Dynamic testing and soil parameters can be used to estimate pile capacities.
Bearing capacity of shallow foundations by abhishek sharma ABHISHEK SHARMA
elements you should know about bearing capacity of shallow foundations are included in it. various indian standards are also used. Bearing capacity theories by various researchers are also included. numericals from GATE CE and ESE CE are also included.
Dynamic compaction is a technique developed in the 1960s that involves repeatedly dropping a large weight from a crane onto the ground to compact soils for construction projects like roads, airports, and buildings. The weight can range from 6 to 172 tons and is dropped from heights of 10 to 40 meters to densify soils to depths of 3 to 12 meters depending on the weight and soil properties. It is conducted in multiple phases with progressively closer spacing of impacts and is effective on both saturated and dry granular soils for reclamation projects with variable soil conditions.
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
This document provides information on the standard penetration test (SPT), including the instruments, procedures, corrections, and applications. It describes that the SPT is commonly used to evaluate the in-situ properties of cohesionless soils. The key instruments are a split spoon sampler, drive-weight assembly with a 63.5 kg hammer, and cathead. The procedure involves drilling a borehole, driving the sampler with the hammer, and recording the number of blows to penetrate each 15 cm interval. Corrections are made to account for overburden pressure, dilatancy effects, and hammer energy efficiency. The SPT provides useful correlations to estimate properties like relative density, friction angle, and strength.
This document discusses soil stabilization techniques using lime and fly ash additions. It begins with an introduction to soil stabilization and describes how lime treatment improves soil properties like plasticity, compaction, and bearing capacity. It discusses the chemical reactions that occur with lime stabilization over time. The objectives of the project are outlined as exploring using fly ash in road construction and studying the effects of lime and fly ash on properties of clayey soil like density, moisture content, consistency limits, and CBR value. Finally, the literature review summarizes previous studies that found additions of waste plastics and lime increased the strength and load bearing capacity of soils.
This document discusses various methods of soil stabilization, including without additives (compaction and drainage) and with additives like cement, lime, fly ash, and bitumen. Cement stabilization involves mixing soil and cement to create a strong material called soil cement. Lime stabilization uses lime to decrease soil plasticity. Fly ash stabilization can increase soil strength and control shrink/swell. Bitumen stabilization coats soil particles with asphalt to prevent water penetration. The conclusion states that soil stabilization with these additives effectively increases soil strength and bearing capacity for construction.
This document summarizes methods for reclaiming alkaline and saline soils. It discusses how excess sodium and poor drainage can lead to alkalinity in soils. The main reclamation methods described are leaching salts from the soil using drainage and flooding, and converting salts using amendments like gypsum, sulfur, or iron sulfate. These amendments cause chemical reactions that replace exchangeable sodium with calcium, forming leachable sodium sulfates. Careful irrigation is also important to prevent salt accumulation and allow for salt precipitation below the root zone.
The document defines and explains cation exchange capacity (CEC). CEC is the ability of soil to hold positively charged ions (cations) like calcium, magnesium, and potassium that plants need. Soils can retain these cations through electrostatic attraction between their negatively charged clay and organic matter particles and the positive cations. CEC depends on soil texture and organic matter content, with higher clay or organic matter soils having a greater CEC. This determines how well soils can retain and supply nutrients to plants. CEC is measured in units of cmolc/kg or meq/100g.
Minerology and classification of different problamaticsoilNihar Ranjan Dash
This document discusses different types of problematic soils, including physical, chemical, and biological problem soils. It focuses on the mineralogy and classification of soils with physical problems like slow permeability, crusting, hard pans, and shallowness. It also examines chemical problem soils that are alkaline, acidic, or saline. Alkaline soils are further classified as non-saline alkali or saline-alkali soils. Key factors that determine alkalinity like carbonate species, pH, sodium adsorption ratio, and residual sodium carbonate are defined. An experiment analyzing the mineral composition of different soils through X-ray diffraction is summarized.
Concrete Construction: Batching of mixes; casting process, compaction and curing;
requirement of mix design and casting of test cubes – removing cubes from moulds and
curing for strength tests; bar-bending equipments and preparation of reinforcement for
R C C works
Soil stabilization with cement, bitumen, lime, chemical stabilization,geotextile, grouting etc. are discussed. It is a method of improving soil properties by blending and mixing other materials.
This document provides a summary of a seminar report on soil stabilization using fly ash. It discusses the objectives of studying the effects of adding lime and fly ash to clayey soil. Literature on soil structure, stabilization techniques including lime stabilization, and the mechanisms of lime stabilization are reviewed. The document describes the materials used including clay soil, fly ash, and lime. It outlines the test program that involves testing untreated clay and clay mixtures with varying percentages of fly ash and lime to determine the optimum moisture content, CBR, and unconfined compression strength.
This document discusses soil stabilization techniques. It provides an overview of using cement and lime to stabilize soils, improving their engineering properties. Cement and lime reactions increase soil strength, stiffness and reduce shrinkage. However, sulfate-rich soils stabilized with calcium-based stabilizers can experience heaving due to ettringite formation. The document examines the fundamental principles and advantages of different soil stabilization methods used in civil engineering projects.
Soil colloids are very small organic and inorganic particles present in soil that determine its physical, chemical, and fertility properties. The four major colloid types are: 1) clay minerals like silicates, 2) iron and aluminum oxides, 3) allophane and amorphous clays, and 4) humus. Soil colloids influence soil properties through their large surface area, electric charge, and ability to undergo ion exchange with cations in the soil solution. The cation exchange capacity measures the ability of soil colloids to hold exchangeable cations and influences soil fertility and nutrient retention. Maintaining optimal soil pH through liming is important for nutrient availability and crop growth.
The document discusses various methods for soil stabilization, including mechanical, physical, chemical, and combined methods. Mechanical stabilization uses compaction to improve soil properties. Physical stabilization blends soils or adds admixtures like cement, lime, or bitumen. Chemical stabilization adds chemicals such as calcium chloride or sodium silicate. The key objectives are reducing voids, filling voids to lower permeability, and increasing bonding between grains. Proper soil selection, additive selection and mixing, compaction, and curing are important to the success of the various soil stabilization methods.
This document discusses various aspects of soil chemistry including chemical composition, ion exchange, soil pH, acid soil development, buffer capacity, and pH management. Specifically, it covers topics like cation exchange capacity, sources of soil acidity and alkalinity, the role of aluminum in acid soils, liming to adjust soil pH, and using sulfur to increase soil acidity. Maintaining optimal soil pH is important for nutrient availability and plant growth.
IRJET- Effect of Lime (Content & Duration) on Strength of Cohesive SoilIRJET Journal
This document summarizes a research paper that studied the effect of lime content and curing duration on the strength of cohesive soil. The researchers aimed to determine the suitable percentage of lime needed to stabilize clayey soil over different curing periods. They found that adding lime significantly changes soil characteristics by increasing strength and stability against water and frost. In general, lime treatment involves chemical reactions that bind soil particles together and reduce void spaces, improving soil permeability and mechanical strength. The researchers concluded that lime stabilization is an effective and economical technique for improving unstable soils and ensuring structures are founded on soils that can adequately support loads.
Explain Langmuir isotherm model and derive its equationZakir Ullah
The document discusses soil chemistry concepts including:
1) Classification of silicate minerals into 1:1 and 2:1 clays based on their structure.
2) Isomorphic substitution in silicate minerals where ions of similar size but different charge replace one another.
3) Calculation of permanent charge in a trioctahedral 2:1 silicate mineral based on isomorphic substitution.
Effect of Sand to Fly Ash Ratio on the Hardened Properties of Geopolymer Mortarijceronline
This study investigated the effect of sand to fly ash ratio on the hardened properties of geopolymer mortar. Geopolymer mortar cubes were prepared by varying the sand to fly ash ratio from 1:1 to 1:3. The cubes were heat cured at 850°C and 3000°C. Compressive strength was found to decrease with increasing sand content. Sorptivity, apparent porosity and water absorption were observed to increase with sand content, while apparent density decreased with more sand. The 1:1 fly ash to sand ratio produced mortar with the highest compressive strength and lowest sorptivity.
Mechanical and chemical stabilization can modify soil properties. Mechanical stabilization involves rearranging particles and improving gradation by adding aggregates. Chemical stabilization uses cementing agents like cement, lime, and calcium chloride to bond soil particles. Portland cement increases strength and reduces shrinkage by cementing particles. Lime also increases strength over time through chemical reactions. Bitumen or asphalt stabilizes soils by binding loose particles or waterproofing. Calcium chloride increases compaction and early strength by replacing sodium ions in the soil. Proper mixing, compaction, moisture content, and curing are important for effective stabilization.
This document discusses acid soils and calcareous soils. For acid soils, it defines them as soils with a pH below 6.0 due to the buildup of hydrogen and aluminum ions from leaching of bases. This causes physical, chemical, and biological problems for plant growth. Liming raises the pH and improves nutrient availability and soil health. Calcareous soils have a pH above 7.0 due to calcium carbonate. Fertilizer management is different as some nutrients like phosphorus are less available in high pH conditions. Applying acidifying fertilizers and amendments can help lower the pH.
Similar to ground improvement with admixtures (20)
Indoor air pollution is a significant health risk, especially for vulnerable groups like children, the elderly, and women. Poor indoor air quality can be caused by both natural sources like dust as well as anthropogenic sources like burning biomass fuels. Developing countries rely more on biomass fuels, resulting in high levels of indoor air pollution exposure. This document discusses the health impacts of indoor air pollution and the groups most vulnerable to exposure.
1) Water influences various behaviors of soil through physical and chemical properties like capillary rise, consolidation, dilatancy, fluctuation of groundwater table, compaction, apparent cohesion, and bulking of sand.
2) Chemically, water's high dielectric constant allows it to readily dissolve ions and undergo dissociation into protons and hydroxide ions, influencing processes like mineral weathering.
3) The document discusses various physical and chemical behaviors of water that control functioning in soils like influencing volume changes during compression, shear strength changes, and biochemical processes through water as a reaction medium.
Human activities like forest removal, construction, farming, and mining have significantly changed soil structures and increased soil loss. Forest removal and construction remove protective plant cover, allowing soil to wash or blow away. Farming methods over the past 10,000 years have improved but can still lead to soil loss. Mining exposes sulfide minerals which produce acid drainage that pollutes surrounding soil. However, various conservation methods like crop rotation, conservation tillage, terraces, and contour plowing can help protect soil and maintain its fertility.
Yoga is a practice that connects the body and mind through physical postures, breathing exercises, and meditation in order to benefit health and well-being. It aims to achieve a balanced state of being through eight limbs that involve ethical practices, physical postures, breathing techniques, withdrawal of senses, concentration, meditation, and enlightenment. Regular yoga practice can prevent and cure diseases by purifying the body and mind at internal and external levels. It also provides benefits like stress relief, increased immunity and longevity, and spiritual upliftment. Yoga connects people nationally and globally in promoting universal peace and brotherhood. It plays an important role in nation building by enhancing national integration, increasing work efficiency among youth, and developing feelings of patri
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ground improvement with admixtures
1. 01-Mar-19
1
GROUND
IMPROVEMENT
WITH
ADMIXTURES
Ground Improvement Methods
Dr. Shailen Deka
Tezpur University
SOIL ADMIXTURES
Anything that is added and mixed with soil to
modify some properties of soil:
Mechanically and/or
Chemically
The term means that the added material has to
be thoroughly mixed with the entire soil of layer
needed to be modified.
2
2. 01-Mar-19
2
INERT ADMIXTURES
Chemically inert (relatively) admixtures are used if only
mechanical or physical properties are to be modified.
The inert stabilizers do not react with the original soil
particles. They merely get evenly distributed in the
original soil matrix.
They modify properties such as:
Density
Grain size distribution
Porosity and permeability
Shear strength and bearing capacity
3
INERT ADMIXTURES
A. Adding soil of different gradation to the original
soil. For example,
Adding sand to gravels and cobbles – to fill up
the large voids, to increase density, to reduce
flow.
Adding gravels to sand and silt – to introduce
large particles to increase shear strength.
Adding clay to sand and gravels – to reduce
permeability.
Etc.
4
3. 01-Mar-19
3
B. Adding industrial, municipal, or other waste.
1. Adding non-self-cementing fly ash (without lime
or without cement) or bottom ash
a. To coarse grained soil – to decrease pore volumes.
b. To clays – to reduce swell-shrink
2. Adding brick-bats or brick dust– to increase φ.
3. Adding coal dust or slags from burnt coal.
4. Adding ashes – wood ash, rice husk ash, etc.
INERT ADMIXTURES
5
5. Adding shredded tyre or tyre chips.
6. Adding plastic waste (hard) chips
INERT ADMIXTURES
Brick dustBrick bats Coal dust
Coal slag Rice Husk Ash Tyre chips
6
4. 01-Mar-19
4
Chemical admixtures react with soil particles and
change the physical, engineering as well as chemical
properties of soil.
Different types of chemical admixtures are:
Lime
Cement
Industrial wastes like
Coal Combustion Products (Fly Ash or Bottom Ash)
Ground granulated blast furnace slag (GGBS)
Phosphogypsum
Cement kiln dust,
Lime kiln dust, etc.
+ Combinations of two or more of the above
+ Other patented / marketed chemicals
CHEMICAL ADMIXTURES
7
LIME TREATMENT OF SOIL
Lime treatment is done on clay soils or mix soils like clayey sand or clayey
silt.
Both quick lime (CaO) and hydrated lime (Ca(OH)2) can be used.
Generally 3-8% by weight of hydrated lime is mixed with the top layer of the
soil.
Use of lime-soil mixture is not new. It is reported that the Greeks and
Romans used lime-soil mixtures.
In modern times, lime was first used as a stabilizing agent of soil in 1924,
when some stretches of highways in the USA were strengthened by the
addition of hydrated lime.
Now lime stabilization of clay soil is widely used throughout the world in
constructions such as
subgrades and sub-bases for roads and airport pavements,
embankments,
as backfill for abutments and retaining walls,
for improvement of soil beneath foundation slabs,
in lime piles (deep treatment), etc.
8
5. 01-Mar-19
5
Lime helps to stabilise clay soil in the following ways:
Modification of soil (Immediate)
► Heat of hydration (in case of quick lime): When quick lime comes in
contact with water, it hydrates to form hydrated lime. The reaction
produces heat, which vaporises some more water and reduces
moisture content of the soil.
► Cation exchange: Hydrated lime again dissociates in water to form
Ca2+ and OH- ions. Ca2+ ions replaces exchangeable cations like Na+
and K+ from between the clay plates. This produces stronger bonds
between the clay plates hindering expansion.
► Flocculation and agglomeration: Because of the Ca2+ ions, clay
particles form flocs and clusters increasing aggregate sizes.
Stabilization (Long-term reactions)
► Pozzolanic reaction: The OH- ions increase the pH value of soil, which
starts pozzolanic reactions. It dissolves the silica (SiO2) and alumina
(Al2O3) particles and makes them react with Ca2+ ions to produce a
number of cementitious gels. Such gels sets (solidifies) as time
passes, binding the soil particles very strongly.
LIME TREATMENT OF SOIL
9
Clay structure before lime
treatment (dispersed)
Clay structure after lime
treatment (flocculated)
Cation Exchange:
In some clays, the inter-plate spaces are occupied by
cations (+ve ions) and water molecules. Exchangeable
monovalent cations like Na+ or K+ lodged between clay
plates are replaced by bivalent Ca2+ cations. This
increases the attraction between the plates and reduces
swelling.
LIME TREATMENT OF SOIL
10
6. 01-Mar-19
6
Results of soil modification with lime:
Modification reactions are immediate but reversible. Small
amount (1-3%) of lime is required for modification. In most clays
Liquid limit decreases
Plastic limit increases
Plasticity Index decreases
Swelling reduces
Shear strength increases
Optimum moisture content increases
Maximum dry density decreases
Clay becomes less sticky and more workable like granular soils.
Permeability increases.
LIME TREATMENT OF SOIL
11
Lime Stabilization (Pozzolanic Reaction): It continues for
months (and years). It is irreversible i.e. permanent.
A pozzolan (or pozzolanic material) is a silicious or
aluminous material, which in itself possesses little or no
cementation value, but will, in finely divided form and in
the presence of moisture, chemically react with calcium
hydroxide at ordinary temperatures to form compounds
possessing cementitious properties.
Most soils are compounds of silica or alumina or both,
and react with Ca(OH)2 solution.
In sufficiently alkaline environment, SiO2 and Al2O3 get
dissolved from clay particles and react with Ca(OH)2
forming a series of complex compounds.
LIME TREATMENT OF SOIL
12
7. 01-Mar-19
7
POZZOLANIC REACTIONS OF CLAY
At pH>12,
Ca++ + SiO2 + H2O → Calcium silicate hydrate (CSH or C-S-H)
Ca++ + Al2O3 + H2O → Calcium aluminate hydrate (CAH or C-A-
H)
CSH and CAH are not chemical formulas, but the Cement
Chemists’ Notations (CCN) for some types of intermediate
materials, which with time combine with more water molecules
and set (or become hard). These are pozzolanic products.
Another type of pozzolanic product is Calcium aluminate
silicate hydrate (CASH).
13
Material CCN Notation
CaO C
SiO2 S
H2O H
Al2O3 A
Fe2O3 F
POZZOLANIC REACTIONS OF CLAY
CSH or CAH or CASH are gels, they surround and bind the
remaining soil particles. After solidification, the stabilized
material becomes very hard. It gives a lot of shear strength.
CSH or CAH or CASH are also formed when water is added to
cement.
CSH gels seen under electron microscope
14
8. 01-Mar-19
8
Lime Fixation Point or Initial Lime Consumption:
Initial lime-soil reactions occur within about 1 hour of mixing.
When lime is added to a clay soil, it must first satisfy the affinity of the
soil for lime, that is, ions are adsorbed by clay minerals and are not
available for pozzolanic reactions until this affinity is satisfied.
Since the lime is fixed in the soil and is not available for other reactions,
the process has been referred to as lime fixation.
The lime fixation point corresponds with the point where further addition
of lime does not bring about further changes in the plastic limit.
This is the optimum addition of lime needed for maximum modification
of the soil and is normally between 1 and 3% of lime added by weight.
Beyond this point lime is available to participate in the pozzolanic
reactions.
Rule of thumb on the quantity of lime to be added: 1% by weight of lime
for each 10% of clay in the soil (Bell, 1996).
POZZOLANIC REACTIONS OF CLAY
15
Lime required for initiating pozzolanic reaction:
The lowest percentage of lime that gives a pH of 12.4 is the
approximate lime percentage for stabilizing the soil. There may be
soils in which the pH is greater than 12.4. If this occurs select the
lowest percentage of lime where the higher pH value does not rise
for at least two successive test samples at increasing lime
percentages” (ASTM 6276).
Lime may be added to soil at different percentages (e.g. 1%, 2%, so
on). For each sample, a slurry is to be made by adding 5 times water
by weight of soil. The pH value is tested by a pH meter after 1 hour
and a curve like the following is obtained. The lime percentage
beyond which there is no increase in pH value is the minimum
percentage of lime required to initiate pozzolanic reactions. More
lime than this is required to sustain the reaction.
POZZOLANIC REACTIONS OF CLAY
Lime (%)
pH
16
9. 01-Mar-19
9
Whether to modify or stabilize soil:
The choice depends on the purpose.
Modification is chosen if the purpose of treatment is only to make
the soil workable, or to stop swelling, or increase permeability, and
NOT increase of strength and bearing capacity.
Stabilization is adopted if increase in strength is essential. For
example, to increase the strength of subgrade for a road or airport
pavement.
For stabilization, strength gain is measured by conducting
unconfined compression (UC) tests on lime-treated soil samples
cured for sufficient days.
For stabilization, a strength gain of at least 350 kPa over the
original strength of soil is desirable for 5% lime addition and 48
hours curing.
CHOICE OF MODIFICATION OR STABILIZATION
17
STRENGTH GAIN FROM STABILIZATION
0
1000
2000
3000
4000
5000
6000
7000
8000
0 2 4 6 8
Unconfinedcompressivestrength(kPa)
Lime content (%)
1 day 7 days
30 days 90 days
The figure shows
strength gain of
lime-stabilized soil
obtained from
actual tests on a
particular soil.
• Strength
increases with
lime content.
• Strength
increases with
curing period.
18
10. 01-Mar-19
10
LIME APPLICATION IN FIELD
19
Steps in Lime Application:
• scarifying or partially pulverizing soil,
• spreading lime,
• adding water and mixing,
• compacting to maximum practical
density, and
• curing prior to placing the next layer or
wearing course.
Scarifying before lime appln
Lime spreading Scarifying after lime spreading
20
LIME APPLICATION IN FIELD
Adding water after lime application
Mixing soil, lime and water
thoroughly using rotary mixer
Initial compaction
using sheepfoot
or padfoot roller
Final compaction
using smoothwheel
roller
11. 01-Mar-19
11
ADVANTAGES AND DISADVANTAGES OF DIFFERENT LIME
APPLICATIONS
(Source – National Lime Association, USA)
The type of lime stabilization technique used on a project should be
based on multiple considerations, such as contractor experience,
equipment availability, location of project (rural or urban), and
availability of an adequate nearby water source.
Some of the advantages and disadvantages of different lime application
methods follow:
A. Dry hydrated lime:
Advantages: Can be applied more rapidly than slurry. Dry hydrated lime
can be used for drying clay, but it is not as effective as quicklime.
Disadvantages: Hydrated lime particles are fine. Thus, dust can be a
problem and renders this type of application generally unsuitable for
populated areas.
21
B. Dry Quicklime:
Advantages: Economical because quicklime is a more concentrated form of
lime than hydrated lime, containing 20 to 24 % more “available” lime oxide
content. Thus, about 3 % quicklime is equivalent to 4 % hydrated lime
when conditions allow full hydration of the quicklime with enough moisture.
Greater bulk density requires smaller storage facilities. The construction
season may be extended because the exothermic reaction caused with
water and quicklime can warm the soil. Dry quicklime is excellent for drying
wet soils. Larger particle sizes can reduce dust generation.
Disadvantages: Quicklime requires 32 % of its weight in water to convert to
hydrated lime and there can be significant additional evaporation loss due
to the heat of hydration. Care must be taken with the use of quicklime to
ensure adequate water addition, mellowing, and mixing. These greater
water requirements may pose a logistics or cost problem in remote areas
without a nearby water source. Quicklime may require more mixing than
dry hydrated lime or lime slurries because the larger quicklime particles
must first react with water to form hydrated lime and then be thoroughly
mixed with the soil.
22
ADVANTAGES AND DISADVANTAGES OF DIFFERENT LIME
APPLICATIONS
12. 01-Mar-19
12
C. Slurry Lime:
Advantages: Dust free application. Easier to achieve even
distribution. Spreading and sprinkling applications are
combined. Less additional water is required for final mixing.
Disadvantages: Slower application rates. Higher costs due to extra
equipment requirements. May not be practical in very wet
soils. Not practical for drying applications.
23
ADVANTAGES AND DISADVANTAGES OF DIFFERENT LIME
APPLICATIONS
LIME COLUMNS
Lime columns (or lime piles)
are insertions into soil, similar
to pile groups and SCP/GCP.
Boreholes are made into soil
in a rectangular grid, and
these are filled with lime,
usually CaO.
They are suitable for treatment
of compressible clay layers.
Unlike lime treatment of
surface soil, where the depth
of treatment is 300-600mm,
lime columns can treat clay
layers several meters deep.
24
The method was
first used by Broms
and Bomans (1975,
1979).
13. 01-Mar-19
13
Installation:
25
LIME COLUMNS
Lime columns have the following effects on the
adjacent soil:
a) Consolidation / dewatering effect
Quick lime, CaO, absorbs water from the surrounding soil,
causing the lime to swell and forms slaked lime, Ca(OH)2 as
per the following chemical reaction
CaO + H2O → Ca(OH)2 + 15.6 Kcal/mol
b) Ion exchange effect
c) Pozzolanic effect
Ions travel from lime columns to the surrounding soil and cause
effects b and c.
26
LIME COLUMNS
14. 01-Mar-19
14
As a result of the above effects, the surrounding soil
→get consolidated faster,
→increase in density,
→gets modified and stabilized.
As consequences,
Shear strength increases
Bearing capacity increases
Future settlement reduces
The lime columns and the included soil behave as a
composite foundation system like pile group for load
transfer.
27
LIME COLUMNS
CHOICE OF ADMIXTURE FOR TREATMENT
A. For modification:
Lime: For soils with PI ≥ 5% and more than 35% particles passing
through 75μ sieve.
Fly ash and lime fly ash blends: For soils with 5% < PI < 20% and
more than 35% particles passing through 75μ sieve.
Cement and/or Fly ash: For soils with PI < 5% and not more than
35% particles passing through 75μ sieve.
B. For stabilization:
Lime: For soils with PI > 10% and clay content (2μ) > 10%.
Cement: For soils with PI ≤ 10% and less than 20% particles through
75μ sieve.
28
15. 01-Mar-19
15
CEMENT TREATMENT OF SOIL
►Ordinary Portland cement (OPC) is used to stabilize soil
►Cement binds soil particles in the same way as lime does
through pozzolanic reactions.
►However, cement has less free lime compared to lime. So,
the variety of reactions is less in cement treatment of clay
soils. Lime treatment is therefore more effective than
cement treatment of clay soil. Moreover, clays which have
high affinity for water reduces water availability for cement
hydrations, so pozzolanic reactions may not be complete.
►Cement has shorter hydration and setting time than lime.
►Cement contains both lime and pozzolans (silica, alumina) in
it. Only water needs to be added for starting pozzolanic
reactions.
29
Typical constituents of Ordinary Portland cement
30
CEMENT TREATMENT OF SOIL
Constituent CCN Mass %
Calcium oxide, CaO C 61-67%
Silicon oxide, SiO2 S 19-23%
Aluminum oxide,
Al2O3
A 2.5-6%
Ferric oxide, Fe2O3 F 0-6%
Sulfate 1.5-4.5%
16. 01-Mar-19
16
Intermediary chemical components of OPC:
Cement Hydration Products: Similar to lime hydration products:
CSH
CAH
CASH
31
CEMENT TREATMENT OF SOIL
Intermediary components CCN Mass %
Tricalcium silicate (CaO)3 · SiO2 C3S 45-75%
Dicalcium silicate (CaO)2 · SiO2 C2S 7-32%
Tricalcium aluminate (CaO)3 · Al2O3 C3A 0-13%
Tetracalcium aluminoferrite (CaO)4 ·
Al2O3 · Fe2O3
C4AF 0-18%
Gypsum CaSO4 · 2 H2O 2-10%
Cement treated soil is called Soil-Cement or cement
modified soil (CMS).
Soil cement is often used in preparation of pavement
subgrade, sub-base, base and shoulders.
Minimum cement required for modification: approx. 4%
by weight of soil.
Minimum cement required for stabilization: Depend on
the type of soil and type of road. For roads with light
traffic, it may be 3-5%. For high traffic and heavy axle
load, it may be 7-10% by weight of soil.
32
CEMENT TREATMENT OF SOIL