Cement Stabilization Is Best Suited For Which Soil?

Cement Stabilization Is Best Suited For Which Soil
13.1.1 Soil classification for stabilised soil blocks (SSBs) – Soil is the basic material for the manufacture of SSBs. It is therefore essential to understand the types of soils and methods of selecting the correct stabiliser additives. There are several soil classification systems based on properties such as grain size distribution, Atterberg’s limits, etc.

the basic purpose of such soil classifications is to facilitate an understanding of the properties and behaviour of a soil to be used for a specific engineering application (soil classification systems were dealt with in detail in an earlier chapter of this book). the type and percentage of clay mineral present in a soil dictates the selection of the stabilising additive needed for SSB production.

Large varieties of clay minerals exist in nature. Kaolinite, illite and montmorillonite are the most commonly occurring clay minerals in soils. For SSB purposes, soils can be broadly classified into two categories: expansive and less expansive soils. Expansive soils are those with excessive swelling clay minerals such as montmorillonite.

  1. The presence of expansive clay minerals in soils can cause excessive swelling when the soil comes into contact with water and also shrinkage when it undergoes drying.
  2. Using such soils for SSB production demands the use of a sufficient quantity of lime (calcium hydroxide).
  3. Lime reacts with expansive clay minerals and forms cementitious hydrates of calcium–silicate, calcium–aluminates, etc., responsible for the development of strength in lime-stabilised SSBs.

Less expansive soils, such as those containing minerals such as kaolinite and illite, do not swell and shrink as much as expansive soils. Cement stabilisation is best suited for less expansive soils and for the production of SSBs using such soils. Identification of a soil with respect to its swelling and shrinking characteristics is essential when selecting a suitable stabiliser additive for the production of SSBs.

Which type of soil is best suited for cement stabilization?

Stabilisation of Soils MCQ – Objective Question Answer for Stabilisation of Soils Quiz – Download Now! Mechanical stabilization requires

  1. mixing of two or more types of natural soils
  2. addition of chemicals to soils
  3. addition of lime to soils
  4. addition of cementing materials to soils

Option 1 : mixing of two or more types of natural soils

  • Explanation:
  • Soil stabilization is the process of improving the engineering properties of the soil and thus making it more stable.
  • Mechanical Stabilization:
  • Mechanical stabilization is the process of improving properties of soil by changing its gradation.
  • Two or more types of natural soil is are mixed to obtain a composite material which is superior to any of its components.
  • To achieve desired grading, sometimes the soils with coarse particles are added or the soils with fine particles are removed.
  • Mechanical stabilization is also known as granular stabilization.
  • For the purpose of mechanical stabilization soil is subdivided into two categories: 1. Aggregates 2. Binders

Additional Information Soil stabilization either achieved by mechanical, physical and chemical stabilization. Physical Stabilization:

  1. Cement Stabilization
  2. Lime Stabilization
  3. Bitumen Stabilization
  4. Chemical Stabilization
  5. Resin Stabilization

Chemical Stabilization:

  1. Calcium Chloride Stabilization
  2. Sodium Chloride Stabilization
  3. Sodium Silicate Stabilization
  4. Polymer Stabilization
  5. Chrome Lignin Stabilization

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students The process of maintaining or improving the performance of a soil as a constructional material, usually by the use of admixtures, is known as:

  1. Soil exploration
  2. Soil stabilization
  3. Soil compaction
  4. Soil consolidation

Option 2 : Soil stabilization

  1. Explanation:
  2. Soil stabilization:
  3. Soil stabilization aims at improving soil strength and increasing resistance to softening by water by bonding the soil particles together, waterproofing the particles, or a combination of the two.
  4. Soil Stabilization is either achieved by Mechanical, Physical, Chemical or Physio chemical Stabilization.
  5. Physical stabilization may be achieved by the addition of:
  6. 1. Cement stabilisation
  7. 2. Lime stabilisation
  8. 3. Bitumen stabilisation
  9. 4. Chemical stabilization
  10. 5. Resin stabilisation
  11. Chemical stabilization may be achieved by the addition of:
  12. 1. Calcium Chloride
  13. 2. Sodium Chloride
  14. 3. Sodium Silicate
  15. 4. Polymers
  16. 5. Chrome Lignin

6. Other Chemicals, etc. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Best suited material for stabilization of black cotton soils is

  1. Sodium silicate
  2. Calcium chloride
  3. Hydrated lime
  4. Bitumen

Explanation: Stabilization of Black Cotton Soils:

  • Black cotton soil is not suitable for construction work on account of its volumetric changes.
  • It swells and shrinks excessively with the change in water content. Such tendency of soil is due to the presence of fine clay particles(Montmorillonite mineral) which swell, when they come in contact with water, resulting in alternate swelling and shrinking of soil due to which differential settlement of structure takes place.
  • So the stabilization of black cotton soil is done using hydrated lime as Lime stabilization helps in increasing the strength, durability and also minimizes the moisture variations in the soil.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students With the increase in value of plasticity index of soil, the quantity of lime required for stabilisation,

  1. Increases
  2. Decreases
  3. Remains unaffected
  4. first increases and then decreases

Explanation: Lime Stabilization of Soil

  • Hydrated lime is used to stabilize highly plastic soils such as black cotton soils. The volume of lime required for such stabilization is about 4-6 % of the volume of soil.
  • In lime stabilization, the liquid limit decreases but the plastic limit and shrinkage limit increases. Therefore, with the increase in the value of the plasticity index of soil, the quantity of lime is required for stabilization.
  • Soil becomes more friable and workable as the optimum moisture content (OMC) increases and the maximum dry density (γd­) decreases.
  • The strength and durability of the stabilized soil is higher than the ordinary one.
  • Lime increases the unconfined compressive strength as high as 60 times and the modulus of elasticity also increases substantially. This is an experimental result. However, this is due to a large increase in cohesion with small increases in the angle of shearing resistance.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Hydrated lime Ca(OH) 2 can be effectively used for stabilization of

  1. Sandy soils
  2. Silty soils
  3. Plastic clayey soils
  4. None of these

Option 3 : Plastic clayey soils Concept: Lime stabilization of Soil:

  • It is the process of stabilizing soils by adding lime to reactive soils to generate long-term strength gain through a pozzolanic reaction.
  • It is used to improve the strength, stiffness, and durability of fine-grained clayey soils.
  • The addition of lime to soils produces a maximum density under a higher optimum moisture content than in the untreated soil, thus leading to flocculated or aggregated larger particle groups which are fairly stable.
  • An increase in lime content causes a considerable reduction in swelling pressure and thus an increase in shrinkage limit and plastic limit. Subsequently, it decreases the liquid limit.
  • Adding lime to soils increases soil resilient modulus shear strength substantially.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students With the increase in value of plasticity index of soil, the quantity of lime required for stabilisation,

  1. Increases
  2. Decreases
  3. Remains unaffected
  4. first increases and then decreases

Explanation: Lime Stabilization of Soil

  • Hydrated lime is used to stabilize highly plastic soils such as black cotton soils. The volume of lime required for such stabilization is about 4-6 % of the volume of soil.
  • In lime stabilization, the liquid limit decreases but the plastic limit and shrinkage limit increases. Therefore, with the increase in the value of the plasticity index of soil, the quantity of lime is required for stabilization.
  • Soil becomes more friable and workable as the optimum moisture content (OMC) increases and the maximum dry density (γd­) decreases.
  • The strength and durability of the stabilized soil is higher than the ordinary one.
  • Lime increases the unconfined compressive strength as high as 60 times and the modulus of elasticity also increases substantially. This is an experimental result. However, this is due to a large increase in cohesion with small increases in the angle of shearing resistance.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students For sandy soils the most common method of stabilization is

  1. soil-cement stabilization
  2. mechanical stabilization
  3. soil-lime stabilization
  4. soil-bitumen stabilization

Option 1 : soil-cement stabilization

  • Concept:
  • Sandy soils are generally stabilized with cement.
  • The amount of cement required to stabilize depends upon the quantity and quality of fines contained in sandy soils and final compacted density.
  • The cement required for sandy soils range between 5 and 12% by weight.
  • Stabilization of soil with cements consists of adding cement to pulverized soil and permitting the mixture to harden by hydration of cement.
  • The quantity of cement required for stabilization increases as soil plasticity increases.
  • Important Point:

Soil-lime stabilization: It is the process of adding lime to the soil to improve its properties like density, bearing capacity etc. The principle involved in lime-soil stabilization is the exchange of ions between lime and soil when added. When clayey soil is treated with lime, cation exchange takes place between them which increases plastic limit and reduces plasticity index which finally results in increase in stability of soil.

  1. This method is used mostly for clayey flocculated soil.
  2. Soil-bitumen stabilization: It is applied to highways and airfield construction.
  3. It is the method of designing and mixing local soil or aggregates with bituminous materials to form a stable and waterproof base course.
  4. Bitumen stabilization is used for:- a) For binding soil particles together for purpose of supplying cohesion for non-mechanical stabilized granular material.

b) For waterproofing, mechanical stabilized granular mixtures or for waterproofing cohesieve soils. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Deflection of a sheet pile in a braced cut

  1. increases from top to bottom
  2. decreases from top to bottom
  3. increases from top and then decreases
  4. decreases from top and then increases

Option 1 : increases from top to bottom Concept: Cement Stabilization Is Best Suited For Which Soil Lateral earth pressure is the pressure that soil exerts against a structure in a sideways, mainly horizontal direction. Since most open cuts are excavated in stages within the boundaries of sheet pile walls or walls consisting of soldier piles and laggings and since struts are inserted progressively as the excavation proceeds, the walls are likely to deform (as shown in the figure).

  1. lateral resistance of soil
  2. self-weight
  3. the dead man
  4. the anchor rod

Option 1 : lateral resistance of soil

  1. Sheet pile:
  2. A sheet pile wall consists of a series of sheet piles driven side by side into the ground, thus forming a continuous vertical wall for the purpose of retaining an earth bank.
  3. They are commonly used for waterfront structures temporary construction and lightweight construction where sub-soil is poor for supporting a retaining wall.
  4. A sheet pile wall may be of three types.
  5. 1. Cantilever sheet piling
  6. 2. Anchored sheet pilling

3. Braced sheeting. Certain configurations of sheet pilling are termed as bulkheads or cofferdams. A bulkhead is a sheet pile retaining wall of water front, backed up ground. A cantilever sheet pile wall or bulkhead derives its stability entirely from the lateral resistance of the soil into which it is driven,

  • It is the process of stabilizing soils by adding lime to reactive soils to generate long-term strength gain through a pozzolanic reaction.
  • It is used to improve the strength, stiffness, and durability of fine-grained clayey soils.
  • The addition of lime to soils produces a maximum density under a higher optimum moisture content than in the untreated soil, thus leads to flocculated or aggregated larger particle groups which are fairly stable.
  • An increase in lime content causes a considerable reduction in swelling pressure and thus an increase in shrinkage limit and plastic limit. Subsequently, it decreases the liquid limit.
  • Adding lime to soils increases soil resilient modulus shear strength substantially.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students

  • Which of the following factors affect the cement stabilization of soil?
  • I) amount of cement
  • II) amount of water
  1. Neither factor I nor II affects.
  2. Only factor I affects.
  3. Only factor II affects.
  4. Both factors I and II affect.

Option 4 : Both factors I and II affect. Concept : Cement Stabilization:

  • Cement has been widely used for surface treatment of soil used in subgrades of highways or railways.
  • Clays with calcium ions are easily stabilized by cement, whereas clays with sodium are better stabilized by lime stabilization.

The following table shows the percentage by volume of cement required for the stabilization of soil:

Type of soil Percentage of cement
Sandy soil 6 – 10 %
Silts and clays of low plasticity 8 – 12 %
Clays of high plasticity 10 – 14%

The following factors affect the cement stabilization of soil:

  1. Type of soil
  2. Quantity of cement
  3. Quantity of water
  4. Mixing, compaction and curing
  5. Admixtures

Additional Information Soil Stabilization:

  • It is also known as soil improvement,
  • It is defined as the process of alteration of properties of soil to improve its engineering performance,
  • The following are the methods of soil improvement:
  1. Compaction (Mechanical or Dynamic)
  2. Vibroflotation
  3. Preloading
  4. Sand and stone columns
  5. Use of admixtures (like lime, cement, fly ash)

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Lime stabilization is very effective in treating

  1. sandy soils
  2. silty soils
  3. non-plastic soils
  4. plastic clayey soils

Option 4 : plastic clayey soils

  1. Lime stabil ization
  2. Lime stabilization is generally done by addition of lime to the soil.
  3. Lime stabilization is helpful in the stabilization of clayey soil.
  4. Plasticity of soil affected when lime is added to the soil and react with it.

It is more suitable for subgrade construction. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Hydrated lime Ca(OH) 2 can be effectively used for stabilization of

  1. Sandy soils
  2. Silty soils
  3. Plastic clayey soils
  4. None of these

Option 3 : Plastic clayey soils Concept: Lime stabilization of Soil:

  • It is the process of stabilizing soils by adding lime to reactive soils to generate long-term strength gain through a pozzolanic reaction.
  • It is used to improve the strength, stiffness, and durability of fine-grained clayey soils.
  • The addition of lime to soils produces a maximum density under a higher optimum moisture content than in the untreated soil, thus leading to flocculated or aggregated larger particle groups which are fairly stable.
  • An increase in lime content causes a considerable reduction in swelling pressure and thus an increase in shrinkage limit and plastic limit. Subsequently, it decreases the liquid limit.
  • Adding lime to soils increases soil resilient modulus shear strength substantially.
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India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Best suited material for stabilization of black cotton soils is

  1. Sodium silicate
  2. Calcium chloride
  3. Hydrated lime
  4. Bitumen

Explanation: Stabilization of Black Cotton Soils:

  • Black cotton soil is not suitable for construction work on account of its volumetric changes.
  • It swells and shrinks excessively with the change in water content. Such tendency of soil is due to the presence of fine clay particles(Montmorillonite mineral) which swell, when they come in contact with water, resulting in alternate swelling and shrinking of soil due to which differential settlement of structure takes place.
  • So the stabilization of black cotton soil is done using hydrated lime as Lime stabilization helps in increasing the strength, durability and also minimizes the moisture variations in the soil.

India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students Which technique of stabilization for the sub-base is preferred for a heavy plastic soil?

  1. Cement stabilization
  2. Mechanical stabilization
  3. Lime stabilization
  4. Bitumen stabilization

Option 3 : Lime stabilization

  • Bitumen is used to stabilize the surface course of road.
  • Cement can stabilize all type of soils except organic clays or highly plastic or compressible clays.
  • Mechanical stabilization like by compaction can be used for sand.

Hydrated lime is used to stabilize highly plastic soils such as black cotton soils. The volume of lime required for such stabilization is about 4-6 % of the volume of soil. Other points about Lime stabilization of soil 1. In lime stabilization liquid limit decreases but the plastic limit increases.2.

Soil becomes more friable and workable; as the optimum moisture content (OMC) increases and the maximum dry density (γ d­ ) decreases.3. The strength and durability of the stabilized soil is higher than the ordinary one.4. Lime increases the unconfined compressive strength as high as 60 times and modulus of elasticity also increases substantially.

This is an experimental result. However, this is due to a large increase in cohesion with small increases in the angle of shearing resistance. India’s #1 Learning Platform Start Complete Exam Preparation Daily Live MasterClasses Practice Question Bank Mock Tests & Quizzes Trusted by 3.4 Crore+ Students : Stabilisation of Soils MCQ – Objective Question Answer for Stabilisation of Soils Quiz – Download Now!

Why is cement used for stabilization of soil?

Stabilization using cement – One of the common methods of chemical stabilization is to mix soil with cement to form a product named as soil–cement, Soil–cement can be defined as a mixture of soil and measured amounts of Portland cement and water and compacted to the desired density.

Soil–cement has been used as a base material as an adoption of improved measure in many projects, such as slope protection of dams and embankments, pavement of highways, building pads, terminals for rail and truck, composting facilities, cheap base for streets, parking lots, channels and reservoir linings, mass soil–cement placement for dikes, foundation stabilization etc.

The soil–cement technique has been practiced almost for 100 years. It serves to amend the mechanical and the engineering properties of the soil. The new performance depends on the ability of the additives to react with the mixing soil. There are four main properties of soil; strength, permeability, volume stability, and durability that can be enhanced with additives,

  • The choice of a specific additive depends on the type of soil, service that is required to serve and the surrounding environment.
  • When water is mixed with cement, hydration occurs, meaning cementing compounds of calcium–silicate–hydrate (C–S–H) and calcium–aluminate–hydrate (C–A–H) are formed and excess calcium hydroxide (CaOH) is released, approximately 31% by weight,

Formation of C–S–H and C–A–H occurs when crystals begin forming a few hours after the water and cement are mixed; crystals will continue to form as long as unreacted cement particles and free water remain within the mixture, Five standard types of Portland cement (Types I through V) are available as specified by ASTM C150.

  • The process of cementation and the results of soil–cement and lime stabilization are similar, they used in quantities too small to provide high-strength cementing action.
  • They reduce the plasticity of clay soils.
  • Calcium chloride or sodium chloride are added to the soil to retain moisture and also control dust, to hold fine material for better compaction, and to reduce frost heave by lowering the freezing point of water in the soil.

Kezdi reports that cement treatment slightly increases the maximum dry density of sand and highly plastic clays but it decreases the maximum dry density of silt, In contrast studies by Deng and Tabatabai shows that cement increases the optimum water content but decreases the maximum dry density of sandy soils,

  1. Cement increases plastic limit and reduces liquid limit, which mainly reduces plasticity index,
  2. The other significant effects of soil–cement stabilization is reduction in shrinkage and swell potential, increase in strength, elastic modulus, and resistance against the effect of moisture, freeze, and thaw.

Cement treated soils show a brittle behavior compare of non-treated soils, Cement can be applied to stabilize any type of soil, except soils with organic content greater than 2% or having pH lower than 5.3 (ACI 230.1R-90, 1990). The use of cement in granular soils has proven to be economical and effective because smaller amounts of cement are required.

  • In addition, soils that have a PI value higher than 30 are difficult to mix with cement.
  • To avoid this issue, lime can be added prior to mixing in cement; this initial step will keep soils more workable,
  • Hemissa and Mahamedi found that swell pressure decrease as the stabilizer content increased in cement treated samples.

Cementitious links develop between the calcium silicate and calcium aluminate found in Portland cement with the soil particles, Unlike lime, hydration in cement occurs at a faster pace which allows for an immediate strength gain. Therefore, there is no need of a mellowing period when stabilizing with cement; compaction of soil–cement samples is typically conducted within 2 h of initial mixing.

  1. The strength gain achieved during compaction may be below the ultimate strength of a soil–cement sample,
  2. However, the cement stabilized soil will continue to gain strength over the course of several days,
  3. There are many factors contributing to the length of curing time required for strength gain in soil–cement samples.

These include ambient air temperature, relative humidity, type of cement used, and concentration of cement used. Guthrie and Reese found that the relative strength is sensitive to the previously mentioned factors, while the relative compaction is not.

What is used for soil stabilization?

Soil Stabilization: Importance & Benefits is a process by which a soils physical property are transformed to provide long-term permanent strength gains. Stabilization is accomplished by increasing the shear strength and the overall bearing capacity of a soil.

Once stabilized, a solid monolith is formed that decreases the permeability, which in turn reduces the shrink/swell potential and harmful effects of freeze/thaw cycles. The shrink/swell potential of a soil is the amount that a soil can change in volume depending on the moisture content. Some expansive soils can expand as much as ten percent! This drastic change in volume can easily produce enough force to cause serious damage to a home, building or roadway.

Soil stabilization can improve in-situ, or natural state, soils eliminating the need for expensive remove-and-replace operations. Often soils that provide the structural base for roads, building pads or parking lots are chemically treated to control engineering properties of a soil, such as moisture content.

Soil stabilization is accomplished by using lime, lime-based products or other chemicals such as Portland cement. These chemicals rely on pozzolanic reactions to form permanent bonds between soil particles. Pre-project testing is essential to be sure that enough material is present to permanently stabilize the soil.

If the stabilized soil layer is incorporated into the structural design of the pavement, the subsequent layers will be thinner resulting in sizable cost savings. Lime Stabilized soils over perform non-stabilized soils when materials, design, and construction are properly considered.

What is the most commonly used material for Stabilisation of soils?

2.2.1 Cement This can be the reason why cement is used to stabilize a wide range of soils. Numerous types of cement are available in the market; these are ordinary Portland cement, blast furnace cement, sulfate resistant cement and high alumina cement.

What is used in soil stabilization works Mcq?

Pavement Design Questions and Answers – Soil Stabilization – 2 This set of Pavement Design Multiple Choice Questions & Answers (MCQs) focuses on “Soil Stabilization – 2”.1. What does HRB stand for? a) Hot Reaction Base b) High Resistance Bitumen c) Heavy Reinforcement Base d) Highway Research Board View Answer Answer: d Explanation: HRB stands for Highway Research Board.

The soil classification for the stabilization process is done with the help of HRB classification system. Another system used is the revised PRA system.2. _ geotextile is preferred in soil stabilization works. a) Knitted b) Woven c) Non-woven d) Grid View Answer Answer: b Explanation: Woven geotextiles are made by weaving polypropylene or polyester fibres together.

These provide better resistance against breaking because of their strong interlocking between fibres. These are useful in soil stabilization as they have great tensile strength.3. Which of the below cannot be used as a water retaining agent? a) Potassium carbonate b) Calcium chloride c) Silica d) Sodium hydroxide View Answer Answer: c Explanation: Water retaining agents can be used in soils that improve their property in the presence of some amount of water.

It is applicable to non-cohesive soils only. Silica is not a water retaining substance, it absorbs water. All other options indicate deliquescent materials.4. Organic stabilizers are found to be long lasting. a) True b) False View Answer Answer: b Explanation: Organic stabilizers are a good option if they are not affected by moisture content.

They get knocked down easily by rainwater and this can be prevented by providing a bituminous coating. Commonly used organic stabilizers are sodium silicate, lignin, resin and molasses.5. What is the essential feature to be checked in case of reinforced earth technique of soil stabilization? a) Friction b) Shear c) Compression d) Tension View Answer Answer: a Explanation: It is the friction between the reinforcement and the soil that is made use of in this particular technique.

  1. The soil transfers the force to the reinforcement by means of friction.
  2. The reinforcement is provided in the form of thin strips and is laid in the soil.
  3. Check this: | 6.
  4. Which type of soil sample can be used to test consolidation, permeability and shear strength tests? a) Non-representative b) Undisturbed c) Representative d) Disturbed View Answer Answer: b Explanation: Soil samples can be of two type – representative and non-representative.

Disturbed and undisturbed samples are types of representative samples. In undisturbed soil samples, in-situ structure and moisture content are retained and hence it can be used to test the engineering properties.7. What does LCF used for stabilization stand for? a) Lime Cement Fibre b) Light Cement Fly ash c) Lean Cement Film d) Lime Cement Fly ash View Answer Answer: d Explanation: LCF is a combination of lime, cement and fly ash used to stabilize the soil.

  1. It consists of proportioned amounts of all three stabilizers that are added to provide bearing strength to the soil.8.
  2. Which is the most common method of waterproofing in soils? a) Bitumen b) Concrete c) Polymer d) Geotextile View Answer Answer: a Explanation: In some soil types, the water flowing into the voids may weaken it.

Therefore, it is necessary to waterproof them. The most common and effective method is using bituminous materials.9. Black cotton soil can become non-plastic if an appropriate amount of lime is added to it. a) True b) False View Answer Answer: a Explanation: Black cotton soils have high plasticity and are also highly expansive in nature.

Stabilization can be effective by adding the right proportion of lime to the soil, it reduces the plasticity index of soil to almost zero and can make it behave like a non-plastic soil.10. What is the best possible method to stabilize desert sand? a) Proportioning b) Lime c) Cement d) Bitumen View Answer Answer: d Explanation: There is a problem of water scarcity and soil-cement stabilization method cannot be used.

Desert sand consists of fine sand particles and proportioning is difficult. Lime is also not employed. So, hot sand-bitumen is the most possible and preferred method. Sanfoundry Global Education & Learning Series – Pavement Design. To practice all areas of Pavement Design,,

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How do you stabilize sandy soil?

Stabilization of sandy soils using chemical additives and fibrous materials appreciably increases its strength and stability. Chemical additives like cement and lime proved to be an effective material for achieving the desired properties for sandy soils.

Which type of soil is not suited for cement stabilization for making the soil blocks?

12.2.2 Soil identification and classification – A typical soil profile is shown in Fig.12.2, Broadly, there are four different layers or horizons, which consist of visually and texturally distinct layers. The topsoil layer contains organic matter and is usually dark in color.

This layer is not suitable for stabilized soil-cement block production due to its high content of organic matter. The subsoil layer is an accumulation of iron, clay, aluminum and organic compounds formed through a process referred to as illuviation. It is very sticky if it has high clay content. This layer is the most suitable layer for soil-stabilized block production.

The weathered rock horizon is the third layer, which consists of mostly large broken rocks. This layer usually contains sandy soil that is easier to excavate. It is not suitable for block production due to the size of the gravels and inadequate clay content. Cement Stabilization Is Best Suited For Which Soil Fig.12.2, Typical soil profile. Soil particles obtained from the subsoil layer are broadly divided into three size classes: clay, silt and sand, as shown in Table 12.2, Soil materials intended for CSEB construction require the basic material made up of carefully controlled proportions of sand, clay and silt before any mixing with additives or with water.

  1. Basic soil particle grading is shown in Table 12.2,
  2. Sand components with particle sizes larger than 2 mm are classified as gravel and are generally omitted in the grading of the soil.
  3. Gravel is not normally used in soil-cement block production as the large particle size results in poor finishing.
  4. Table 12.2,

Soil particle grading.

Material Ranges Particle size
Gravel fraction Coarse gravel 60–20 mm
Medium gravel 20–6 mm
Fine gravel 6–2 mm
Sand fraction Coarse sand 2–0.6 mm
Medium sand 0.6–0.2 mm
Fine sand 0.2–0.06 mm
Silt fraction Coarse silt 0.06–0.02 mm
Medium silt 0.02–0.006 mm
Fine silt 0.006–0.002 mm
Clay fraction Passes the 0.002 sieve

Particle size analysis is used to determine the fraction of each particle size that falls within each of the size ranges shown in Table 12.2, A well-graded soil will produce a better packing of particles resulting in a denser and less permeable product.

  1. The distribution of particle sizes that provides the optimum packing of particles is known as the Fuller curve.
  2. It is based on the assumption that the smaller particles fill the voids between the larger particles resulting in the highest density.
  3. A soil may be considered well graded if the distribution of particles from fine silt to coarse sand is reasonably uniform.

Read full chapter URL: https://www.sciencedirect.com/science/article/pii/B9780081027042000123

How do you stabilize clay soil?

Clay soil can be stabilized by the addition of small percentages, by weight, of lime, thereby enhancing many of the engineering properties of the soil and producing an improved construction material.

How do you stabilize laterite soil?

Modifiers which have often been used include cement, lime and bitumen. Cement and lime are noted for changing the water film on the soil particles, modifying the clay minerals to some extent and decreasing the plasticity index.

Which type of stabilization will be the best for black cotton soil?

6. Conclusions – From the study carried out on brick powder and lime-stabilized black cotton soil mixture, the following conclusions can be drawn: (1) Lime stabilization of black cotton soil under study improved the strength characteristics of the soil, but not to the extent of suitability as subbase material.

(2) Mixing 20% brick powder and 80% lime-stabilized black cotton soil improved the maximum dry density and decreased the optimum moisture content in comparison to 4% lime stabilized soil. (3) 80% lime-stabilized black cotton soil and 20% brick powder mixture resulted in increase in the soaked CBR value by about 135%, when compared to 4% lime-stabilized soil, making it satisfactory for use as subbase material.

(4) Use of brick powder reduces the content of lime which in turn reduces the cost of project as brick powder is freely available. Also, use of brick powder reduces the problem of waste disposal. Hence brick powder and lime-stabilized black cotton soil mixture can be effectively used as subbase material in flexible pavements of rural areas where brick powder is available in good amounts and also in areas with less availability of good quality materials.

What is the most stable type of soil?

Soil Types | Environmental Safety Soil is a mixture of sand, gravel, silts, clay, water, and air. The amounts of these ingredients which determine its “cohesiveness”, or how well a soil will hold together. Cohesive soil does not crumble. It can be molded easily when wet, and is hard to break up when dry.

Clay is a very fine grained soil, and is very cohesive. Sand and gravel are course grained soils, having little cohesiveness and often called granular, Generally speaking, the more clay that is in the soil being excavated, the better the trench walls will hold up. Another factor in soil cohesiveness is water.

Soil that is filled with water is termed saturated, Saturated soil does not hold together well, and is particularly dangerous in excavation work. However, the opposite can also be true. Soil that has little or no water in it, or oven-dry, can crumble easily, and will not hold together when excavated.

Soil is heavy. A cubic foot can weigh as much as 114 pounds, and a cubic yard can weigh over 3,000 lb. — as much as a pick-up truck! Most workers don’t realize the force that will hit them when a cave in occurs. A person buried under only a few feet of soil can experience enough pressure in the chest area to prevent the lungs from expanding.

Suffocation can take place in as little as three minutes. Heavier soils can crush and distort the body in a matter of seconds. It’s no wonder trench accidents involve so many deaths and permanently disabling injuries. OSHA classifies soils into four categories: Solid Rock, Type A, Type B, and Type C.

Solid Rock is the most stable, and Type C soil is the least stable. Soils are typed not only by how cohesive they are, but also by the conditions in which they are found. Stable rock is practically unachievable in the excavation of a trench. This is because the excavation of rock typically requires drilling and blasting, which fractures the rock, making it less stable.

Type A soil can be clay, silty clay, or sandy clay. A soil cannot be considered Type A if it is fissured (cracks) or other conditions exist that can adversely affect it, such as:

subject to vibration from heavy traffic, pile driving, or similar effects having been previously disturbed/excavated where it is part of a layered system, where less stable soil is near the bottom of the excavation, with the more stable soils on top. subject to other factors which would make it unstable-such as the presence of ground water, or freezing and thawing conditions.

Many OSHA compliance personnel believe that construction equipment at the site create enough vibrations to prevent any soil from being typed as “A”. If vibrations can be felt while standing next to an excavation, the competent person should consider downgrading Type A soil to Type B or C.

  • Type B soils include both cohesive and non-cohesive soils.
  • They include silts, sandy loams, medium clays, and unstable rock.
  • Soils that might be classified as A, but have fissures, or are subject to vibration, may also be classified as “B” soils.
  • Type C soils are the most unstable (and therefore most dangerous) of the four soil types.

They are easily recognized by the continual sloughing of the sides of the walls of excavation. If soil is submerged, or water is seeping from the sides of an excavation, it’s probably “C” soil. Soil may be classified as Type C if an excavation is dug in “layered” soils, where different soil types lay on top of each other.

When an unstable soil type is underneath a stable soil type in an excavation, the “weakest link” will soon give way. In many construction projects, the soil that is being excavated has been previously disturbed, This means the soil has been dug up or moved in the past. This is another factor a competent person must consider when typing soils.

Previously disturbed soils are rarely as strong as undisturbed soils, and are usually typed as “C” soil. Previously disturbed soil is commonly found above existing utilities, such as water, sewer, electrical and gas lines. This makes work around these utilities more dangerous due to the unstable nature of the soil.

  • Much of the work performed in excavations are along right-of-ways, where the soil is almost always likely to be Type C.
  • Because of where we dig, it’s important to understand that once soil has been excavated, it will never be returned to the way it was naturally formed.
  • Per 1926 Subpart P, Appendix A (c)(2), a competent person must type soils by using at least one visual and one manual test.

A visual test can include inspecting the soil as it is being removed, and examining the spoil pile and the color and make-up of the excavation walls. A manual test means working with the soil with either your hands or with an instrument designed to measure soil strength.

  1. For example, if you can roll the soil in your hands into a long “worm” or ribbon, the soil is cohesive and may be classified as A or B, depending on other conditions.
  2. One useful instrument for measuring soil strength is a penetrometer,
  3. When you press this instrument into a soil sample, it measures its unconfined compressive strength in tons per square foot (tsf).

Regardless of the methods used, the typing of soils must be done by the competent person prior anyone entering the excavation, The weaker the soil, the greater the need for protective systems. Note: If you are uncertain of the soil type, ALWAYS assume Type C soil.

What is the most commonly used material for Stabilisation of soils Mcq?

Geotechnical Engineering Questions and Answers – Mechanical Stabilisation This set of Geotechnical Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Mechanical Stabilisation”.1. Stabilisation of soils are most commonly used in _ engineering works.

  • A) Air-field pavements b) Foundations of buildings c) Pile construction d) All of the mentioned View Answer Answer: a Explanation: The most common application of stabilisation is in the construction of roads and air-field pavements.2.
  • Method of stabilisation can be grouped under_ main types.
  • A) three b) two c) one d) four View Answer Answer: b Explanation: Method of stabilisation may be grouped under two main categories: i) modification of soil property of existing soil without any admixture ii) modification of soil property with the help of admixtures.3.

Example of modification of soil property with the help of admixtures is _ a) Compaction b) Drainage c) Mechanical stabilisation d) Particle size distribution View Answer Answer: c Explanation: Example of modification of soil property with the help of admixtures is: mechanical stabilization, stabilization with cement, lime, bitumen and chemicals etc.

  • Note: Join free Sanfoundry classes at or 4.
  • The important factors that governs the engineering behavior of soil are _ a) Densification b) Stabilisation c) Tensile strength d) Particle size distribution View Answer Answer: d Explanation: The particle size distribution and composition are the important factors governing the engineering behavior of soil.5.

Mechanical stabilisation of soil involves which of the following operation? a) Compaction and Changing the composition of soil b) Leveling c) None of the mentioned d) All of the mentioned View Answer Answer: a Explanation: Mechanical stabilisation involves two operations: i) changing the composition of soil by addition or removal of certain constituents, and ii) densification or compaction.

Check this: | 6. For mechanical stabilized bases, liquid limit should not exceed _ a) 35 % b) 25 % c) 50 % d) 10 % View Answer Answer: b Explanation: For bases, liquid limit should not exceed 25 % and plasticity index must not exceed 6.7. The properties of a soil under compaction depend upon _ a) Swelling b) Placement condition c) Water content d) Permeability View Answer Answer: c Explanation: The properties of soil under compaction depend upon the water content, amount of compaction, and the type of compaction.8.

The properties of soil that are affected by compaction are _ a) Swelling b) Water absorption c) Permeability d) All of the mentioned View Answer Answer: d Explanation: Compaction has a great effect on soil properties, such as strength and stress-strain characteristics, permeability, compression, swelling, and water absorption.9.

The soil stabilised with cement is called _ a) Lime cement b) Soil cement c) Cementing soil d) None of the mentioned View Answer Answer: b Explanation: The soil stabilised with cement (Portland cement) is usually known as soil cement.10. The important factor affecting soil cement is_ a) Admixtures b) Swelling c) Water absorption d) Permeability View Answer Answer: a Explanation: The important factors affecting the soil cement are: nature of soil, cement content, condition s of mixing, compaction and curing and admixtures.11.

The binding action of individual particles through cement is possible only in _ type of soil. a) Fine-grained soil b) Clayey soil c) Coarse-grained soil d) All of the mentioned View Answer Answer: c Explanation: The binding action of individual particles through cement may be only possible in coarse-grained soil., a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry, He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at, Subscribe to his free Masterclasses at & technical discussions at, : Geotechnical Engineering Questions and Answers – Mechanical Stabilisation

Which stabilization method is Cannot used for surface course?

Pavement Design Questions and Answers – Soil-Cement Stabilization – 1 This set of Pavement Design Multiple Choice Questions & Answers (MCQs) focuses on “Soil-Cement Stabilization – 1”.1. Which of the below is not an additive used to improve the properties of soil cement? a) Magnesium sulphate b) Calcium chloride c) Sodium hydroxide d) Sodium carbonate View Answer Answer: a Explanation: Sulphates are the soluble salts present in the mix and their maximum limit is 4%.

  1. Calcium chloride, sodium hydroxide and sodium carbonate are the three additives used to improve the properties when stabilizing clayey or organic soil using soil cement.2.
  2. Cement stabilization cannot be used in which of the below soil types? a) Granular b) Silty c) Lean clay d) Organic View Answer Answer: d Explanation: The method of cement stabilization can be used in most of the soil types like granular, silty and lean clays.

Cement cannot be employed in organic soils because the process causes a delay in setting and a reduction in strength.3. Soil cement cannot be used as a surface course. a) True b) False View Answer Answer: a Explanation: Soil cement can be used as a base or sub-base course.

It cannot be used as the surface course as it has poor resistance to abrasion and impact. These properties are the important properties required for a surface course.4. Which of the below soil type and the amount of cement required pairs has been matched correctly? a) Gravel – 15 to 20% b) Sand – 7 to 12% c) Silt – 12 to 15% d) Clay – 12 to 20% View Answer Answer: a Explanation: It is important to know the appropriate amount of cement required to be added to the particular soil type.

For gravel type, the amount of cement to be added varies from 5 to 10%.5. Which of the below type of soil cement contains less amount of cement? a) Soil cement base b) Cement treated base c) Cement modified base d) Acrylic copolymer View Answer Answer: c Explanation: CMS or cement modified base contains less amount of cement compared to ordinary soil cement.

  • Soil cement base contains a higher amount of cement compared to CMS.
  • Get Free Now! 6.
  • By what mechanism does the cement stabilization take place in granular soils? a) Formation of matrix b) Reduction in plasticity c) Vibro compaction d) Hydration of cement View Answer Answer: d Explanation: The hydration process of cement leads to the development of the bond between hydrated cement and soil particles in case of granular soils.

The reduction in plasticity and the formation of matrix around clay lumps helps in stabilizing fine-grained soils.7. It is necessary to maintain the water-cement ratio in the cement stabilization. a) True b) False View Answer Answer: b Explanation: There is no such thing as a water-cement ratio while conducting a cement stabilization.

The water is added to the mix until an adequate amount of compaction is achieved.8. Which formula gives the amount of cement required for soil stabilization if other parameters are given? a) \((\frac )\times(\frac )\) b) \((\frac )\times(\frac )\) c) \((\frac )\times(\frac )\) d) \((\frac )\times(\frac )\) View Answer Answer: a Explanation:\((\frac )\times(\frac )\) is the right amount of cement required for soil stabilization.

The explanations for the terms used in the equation are: A – surface area of the soil layer (m 2 ), H – thickness (cm), r d – dry density (tonnes/m 3 ) and p – percentage of cement required 9. The percentage of soil particles passing 4.75 mm sieve must be _ to be used in soil-cement.

  1. A) 50% c) 40% View Answer Answer: b Explanation: The recommended amount of particles passing 4.75 mm sieve must be more than 50%, so as to be used for the soil stabilization using soil-cement.
  2. The amount of particles passing 0.075 mm sieve must be less than 50% and the liquid limit must be less than 40%.10.

What is the British method of the mix design of the soil-cement mix based on? a) Stability b) Durability c) Compressive strength at 28 days d) Compressive strength at 7 days View Answer Answer: d Explanation: There are two methods that are commonly used to design the soil-cement mix.

They are the British method and the PCA method. The British method is based on the compressive strength of samples cured for seven days and the PCA method is based on the durability of the mix. Sanfoundry Global Education & Learning Series – Pavement Design. To practice all areas of Pavement Design for Quizzes,,

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Are sandy soils stable?

Moisture And Soil – Different soil types are affected by moisture in different ways. Each of these three soils react to water differently:

Sandy Soils – Water passes through sandy soils rather than being absorbed. This fact makes sandy soils very stable. Instead of expanding as they absorb moisture and contracting as they dry out, sandy soils maintain a fairly consistent volume and density. Because of their stability and good load-bearing qualities, sandy soils are less likely to shift and settle, so they rarely cause foundation problems. Unfortunately, sandy soils are less commonly found than other more problematic soil types. Clay Soils – Soils rich in clay and silt have the greatest potential to damage a foundation. Clay absorbs water easily, expanding in volume as it becomes more saturated. So-called “expansive clays” can cause foundations to crack, heave and shift.When clay soils dry out, they shrink and crack, leaving gaps around a house where water from the next storm can penetrate easily and deeply to repeat the expansion cycle. Clay-rich soils usually cause more foundation damage by expanding than by contracting. Sandy Loam Soils – Loamy soils are usually a very stable soil that shows little change with the increase or decrease of moisture temperature.The primary concern with foundations built on loamy soils is erosion. When soils underneath your foundation erode, they may begin to be inappropriate strata for sustaining the weight of a foundation and home structure.

Because of the constant cycle of wet and dry periods that occur as the weather changes, certain types of soil can expand and contract indefinitely, subjecting your foundation to settling or expansive stresses that often cause damage.

What is the best soil improver for sandy soil?

Turn Sandy Soil into Sandy Loam – Okay, so it’s not very scientific, but the test I’ve just described is good enough for most gardeners. If you want more detail, try the Jar Test, The next step requires a little more work. Sandy soils are less fertile than other soil types, and more prone to drying out, because they’re made up of relatively large particles.

This means there are cavernous gaps between the particles, making it easy for water (and water-soluble nutrients) to filter down through the soil, out of the reach of plant roots. We need to partially plug up those gaps and help the soil to hold on to water and nutrients. So here’s how to do it: Add organic matter.

It really is that simple! Cement Stabilization Is Best Suited For Which Soil Organic matter such as manure helps sandy soil to retain moisture and nutrients Organic matter is a kind of cure-all in the garden. You can’t go wrong with organic matter. It will improve any soil type. Any organic matter will work to build soil structure and its ability to hold onto water.

Compost and manure are preferred because they are rich in nutrients, which they drip-feed to your plants. Over time, they’ll also help to increase the pH of acidic sandy soils. I won’t lie – sandy soils do need a lot of organic matter, frequently applied, to make a difference. The warmer your climate, the faster organic matter will break down, and the more often your soil will need replenishing.

Start with at least two bucketfuls of organic matter per square metre each autumn, added to the soil surface as a mulch where it will help to protect the soil from scouring rain and winds. Keep notes on how well your crops fare (our free Garden Journal can help with this) and, if you feel they’re underperforming, up the frequency to twice a year.

You could also try three bucketsful, or four. It’s worth adding more in summer if you can too. Grass clippings are a free, regularly available resource that help to reduce evaporation, and they’ll provide a modest flush of nitrogen to boost plant growth too. After adding all that organic matter you really will need a sit-down and a cuppa.

What the hell – make it a beer! Cement Stabilization Is Best Suited For Which Soil Tap-rooted vegetables such as carrots can easily drill down through light sandy soils

Which method is most suitable for compaction of sandy soil?

For compacting sandy and gravelly soil, vibratory rollers are most effective. If granular soils have some fines, both smooth wheel and pneumatic rollers can be used. Proper control of moisture content in soil is necessary for achieving desired density.

What are the main types of soil stabilization?

There are three broad types of soil stabilization: biological, physical and chemical.

Which type of soil is most stable?

Soil Classification | Transcript | Occupational Safety and Health Administration In the U.S., more than 800 construction workers die every year while on the job. One of the most dangerous types of construction work is trenching, which kills 40 construction workers every year.

  1. Workers can suffer death or serious injury within minutes of being caught in a trench cave-in.
  2. But these deaths can be prevented.
  3. The video you are about to see shows one of the steps, classifying soil, that employers must follow so that trenching work can be done safely.
  4. This video is not intended to be a complete educational tool, instead it is meant as an introduction for people who want to know more.

Employers have a responsibility to provide a safe workplace and required protective equipment. You’ll learn how having the right information about a construction site can help save lives. Each employee who enters a trench must be protected from cave-ins by a protective system if the excavation is 5 feet or greater in depth, unless it is dug into stable rock.

  • A support system is not required if the trench is less than 5 feet in depth and examination of the ground by a competent person provides no indication of a potential cave-in.
  • One cubic yard of soil can weigh as much as a car, 3,000 pounds, and comes in many varieties.
  • Some types of soil are stable and some are not.

When digging a trench, it’s important to know the type of soil you’re working with so you know how to properly slope, bench, or shore the trench. This can help prevent a cave-in. OSHA requires that employers have a competent person to determine the soil type.

  1. A competent person is someone who can identify conditions that are hazardous to employees and who also has the authorization to correct these hazards.
  2. All trenches that are five feet or deeper must follow OSHA’s rules.
  3. The appendices of the OSHA Excavation Standard show the various types of support systems that may be used, up to a maximum depth of 20 feet.

Any excavation deeper than 20 feet must use a protective system approved by a professional engineer. For all excavations, a competent person must conduct a full investigation every day, or when any trench conditions change, to identify and remove any potential hazards.

  • In this video, you will see how a visual inspection of a construction site’s soil is performed.
  • You will also see how to test the soil using three of the most common methods: the plasticity test, the thumb penetration test, and the pocket penetrometer test.
  • For best results, OSHA recommends that the competent person use more than one of these methods to test the soil.

Knowing the type of soil makes it possible to determine the right protective system to keep workers safe when they’re working in an excavation. Soil can either be cohesive or granular. Cohesive soil contains fine particles and enough clay so that the soil will stick to itself.

The more cohesive the soil, the more clay it has, and the less likely a cave-in will happen. Granular soils are made of coarse particles, such as sand or gravel. This type of soil will not stick to itself. The less cohesive the soil, the greater the measures needed to prevent a cave-in. OSHA uses a measurement called “unconfined compressive strength” to classify each type of soil.

This is the amount of pressure that will cause the soil to collapse. This value is usually reported in units of tons per square foot. Soils can be classified as Type A, Type B, or Type C. Type A soil is the most stable soil in which to excavate. Type C is the least stable soil.

  1. It’s important to remember that a trench can be cut through more than one type of soil.
  2. Let’s look at each type of soil.
  3. Type A soil is cohesive and has a high unconfined compressive strength; 1.5 tons per square foot or greater.
  4. Examples of type A soil include clay, silty clay, sandy clay, and clay loam.

Soil can not be classified as type A if it is fissured, if it has been previously disturbed, if it has water seeping through it, or if it is subject to vibration from sources such as heavy traffic or pile drivers. Type B soil is cohesive and has often been cracked or disturbed, with pieces that don’t stick together as well as Type A soil.

  1. Type B soil has medium unconfined compressive strength; between 0.5 and 1.5 tons per square foot.
  2. Examples of Type B soil include angular gravel, silt, silt loam, and soils that are fissured or near sources of vibration, but could otherwise be Type A.
  3. Type C soil is the least stable type of soil.
  4. Type C includes granular soils in which particles don’t stick together and cohesive soils with a low unconfined compressive strength; 0.5 tons per square foot or less.

Examples of Type C soil include gravel, and sand. Because it is not stable, soil with water seeping through it is also automatically classified as Type C soil, regardless of its other characteristics. Before testing the soil, it’s useful to perform a visual test of the construction site.

This will help determine if there are factors on site that will lower the strength of the soil. Here are some observations to make when performing a preliminary visual test of the soil around an excavation site: First, as the soil is being excavated, does it come out in clumps, or is it granular? Clumps mean that the soil is cohesive.

Are there sources of vibration near the excavation? Are there signs of previously disturbed soil, such as utility lines? Are there signs of water seeping through the soil? Is the soil fissured? Signs of fissuring include crack-like openings, or chunks of soil that crumble off the side of a vertical excavation wall.

  1. If any of these conditions are met, the soil cannot be classified as Type A.
  2. When performing a soil test, it’s important to choose a good soil sample.
  3. Soil samples should be typical of the surrounding soil in the excavation, and additional samples should be taken as the excavation gets deeper.
  4. While the excavation wall is one place to take samples, OSHA recommends taking a large clump from the excavated pile, as long as the soil in the pile is fresh and hasn’t been compacted.

Test results can change as the soil dries up, so for the best results, samples should be taken and tested as soon as practical. Now let’s look at the three main types of soil tests. The plasticity test, which is sometimes called the pencil test, is used to determine if the soil is cohesive.

This test is performed by rolling a moist soil sample into a thread that’s one-eighth of an inch thick and two inches long, resembling a short, slim pencil. If the sample can be held at one end without breaking, it is cohesive. Here’s an example of what the results will look like if the soil is cohesive.

Notice how the sample stays in one piece. Now look at what happens when the soil is not cohesive. The soil doesn’t have the strength to hold itself together. Any soil that is not cohesive is automatically classified as Type C, although some Type C soils are cohesive.

  • The thumb penetration test is used to quickly estimate the compressive strength of a cohesive soil sample.
  • To perform the thumb penetration test, simply press the end of your thumb into a fresh clump of soil.
  • If the soil sample is Type A, your thumb will only make an indentation in the soil with great effort, as you can see demonstrated here.

If the soil sample is Type B, your thumb will sink into the soil up to the end of your thumbnail, just like this. If the soil sample is Type C, your thumb will sink all the way into the soil clump, as you can see here. Your results for this test will probably be somewhere in between these results.

  • For a more numeric measurement, the pocket penetrometer test can be used.
  • A soil’s compressive strength can be given a numeric value by using the pocket penetrometer test.
  • There can be some variability in these results, so it’s a good idea to run this test on a few soil samples from the same part of the excavation, just to make sure your results are consistent.

A pocket penetrometer works much like a tire pressure gauge. A thin, metal piston is pushed into a soil sample, and the penetrometer records the compressive strength of the soil. Be sure that the scale indicator is inserted into the penetrometer body until only the “zero” mark is showing.

To conduct the test, push the piston into the soil until it reaches the engraved line. Then, simply take the reading from the scale indicator. It’s important to recognize that a penetrometer may give false results if the soil contains rocks or pebbles, which won’t compress. As you can see, Type A soil will measure at least 1.5 tons per square foot.

Be aware, however, that you can’t classify a soil as Type A if the excavation site didn’t meet all the conditions of the visual test: if it is granular, near a source of vibration, or there are signs of previously disturbed soil, water seepage, or fissured soil.

For Type B Soil, the reading will be between 0.5 and 1.5 tons per square foot. Type C soils are equal to or less than 0.5 tons per square foot. Let’s review the main points from the video. OSHA classifies soils into three main groups: Type A, Type B, and Type C. Type A is the most stable and Type C is the least stable soil.

To determine the soil type on a construction site, there are several tests that a competent person can use. After performing a visual test, you can use the plasticity test to determine if the soil is cohesive or granular. For cohesive soil, the thumb penetration and pocket penetrometer tests help determine the unconfined compressive strength.