**Explanation:** Karl Terzaghi is credited with coining the term Soil Mechanics. His pioneering work laid the foundation for the field.

**Explanation:** This definition is widely accepted in geotechnical engineering, emphasizing the origin and composition of soil.

**Explanation:** The geological cycle typically begins with weathering, followed by transportation, deposition, and sometimes upheaval in the formation of soil.

**Explanation:** Clay particles are the smallest among the options and possess unique properties influencing soil behavior.

**Explanation:** Chemical weathering involves various processes, including oxidation, carbonation, and hydration, collectively contributing to the breakdown of rocks into soil.

**Explanation:** Physical weathering includes processes such as temperature changes, ice wedging, and actions of plant roots, all physically breaking down rocks.

**Explanation:** Hygroscopic water, tightly held by soil particles, can be removed by heating, reducing its affinity to soil particles.

**Explanation:** Residual soil remains above the parent rock from which it is derived, often due to weathering and decomposition of the underlying rock.

**Explanation:** Soil can be transported by various agents, including wind, water, and gravity, depending on environmental conditions.

**Explanation:** Cohesionless soils, such as sands, are primarily formed through the physical disintegration of rocks, without significant chemical alteration.

**Explanation:** Peat is an organic soil composed mainly of partially decomposed plant material.

**Explanation:** Honeycombed structure is common in fine-grained soils, especially in fine silt and clays.

**Explanation:** Lacustrine soil is soil that has been transported by water and deposited at the bottom of a lake.

**Explanation:** Gravel and sand are categorized as cohesionless soils due to their lack of fine particles and low cohesion.

**Explanation:** Alluvial soils are typically transported and deposited by water.

**Explanation:** Skip-graded soil lacks particles of intermediate sizes.

**Explanation:** Well-graded soil has particles of different sizes in good proportion.

**Explanation:** Uniform soil has particles of almost the same size.

**Explanation:** The coefficient of curvature for well-graded soil typically falls within the range of 1 to 3.

**Explanation:** Soils are considered three-phase systems comprising solid particles, water, and air.

**Explanation:** The three-phase system in soil mechanics refers to the simultaneous presence of solid particles, water, and air in the soil. This concept is particularly relevant to partially saturated soils, where the voids contain a combination of both water and air. Understanding the distribution of these three phases is crucial in analyzing the mechanical and hydraulic behavior of soils.

**Explanation:** These statements describe the conditions of void spaces in different states of soil. In a dry soil, the voids are filled with air, while in a saturated soil, they are filled with water. In a partly saturated soil, the voids contain both air and water, illustrating the coexistence of these phases within the soil structure.

**Explanation:** The degree of saturation represents the ratio of the volume of water to the total void volume in a soil sample. Expressed as a percentage, it falls within the range of 0% (completely dry) to 100% (fully saturated). This parameter is essential for understanding the water content in relation to the total void space available in the soil.

**Explanation:** Soil classification systems are based on various properties, with a primary focus on grain size distribution and plasticity characteristics. The distribution of particle sizes and the plasticity of the soil help classify it into different groups, providing valuable information about its engineering behavior and potential uses.

**Explanation:** Soils are complex mixtures composed of both organic and inorganic materials. Inorganic components include minerals, rocks, and water, while organic materials consist of decomposed plant and animal matter. The combination of these components forms the soil, contributing to its physical and chemical properties.

**Explanation:** Weathering of soils results from various factors, including periodical temperature changes, the mechanical impact of flowing water, and the biological activities of plants and animals. These processes contribute to the breakdown of rocks into soil particles, influencing the soil’s composition and properties over time.

**Explanation:** Talus is soil material that undergoes transportation and deposition due to the force of gravity. It often accumulates at the base of slopes or cliffs where erosion and gravitational forces contribute to its movement. Understanding talus formation is crucial in geological and engineering assessments.

**Explanation:** Loess is a fine-grained sediment, primarily silty clay, that is formed by the action of wind. Windblown particles accumulate over time, creating deposits that are often fertile and agriculturally productive. The unique characteristics of loess make it significant in both geological and environmental studies.

**Explanation:** Drift refers to material that undergoes a series of processes, including picking up, mixing, disintegration, transportation, and repositioning. This complex sequence of events is often associated with glacial activity, where the movement of ice and water contributes to the formation and redistribution of drift material.

**Explanation:** Cohesionless soil, also known as granular soil, lacks cohesive forces between particles. Sand is a typical example of cohesionless soil, characterized by its individual grains and a lack of fine particles that would impart cohesive properties. Understanding the cohesion or lack thereof is essential in analyzing soil behavior in engineering applications.

**Explanation:** Cohesion is the internal molecular attraction that resists the rupture or shear of a material. Among the options, silt has more cohesion compared to sand. Silt particles are smaller than sand but larger than clay, allowing for greater cohesion between particles.

**Explanation:** The behavior of silt is influenced by both mass energy and surface energy. Mass energy refers to the overall energy associated with the movement and arrangement of particles, while surface energy is related to the interactions at the particle boundaries. Both factors play a role in determining the behavior of silt.

**Explanation:** Silts generally exhibit limited or no plasticity compared to clay. Plasticity refers to the ability of soil to undergo deformation without cracking. While silts can be plastic, their plasticity is not as pronounced as that of clay.

**Explanation:** Clay particles are very fine, with a maximum size typically less than 0.002mm. The small size of clay particles contributes to their unique properties, including high plasticity and cohesion.

**Explanation:** The specific gravity of sandy soils and gravel is typically greater than 2.5. Specific gravity is a measure of the density of a material relative to the density of water, and values above 2.5 indicate relatively dense materials.

**Explanation:** The specific gravity of soil varies, but for most soils, it is greater than 2.5. This property is determined by factors such as the mineral composition and density of the soil particles.

**Explanation:** The core-cutter method is commonly used to determine the in-situ density of soil. It involves extracting a cylindrical sample of soil from the ground, measuring its volume, and calculating its density. This method is crucial for various geotechnical assessments.

**Explanation:** Hydrometer analysis relies on Stoke’s law, which describes the settling of particles in a fluid. The hydrometer measures the settling rate of soil particles in water, providing information about the distribution of particle sizes in the soil.

**Explanation:** Bulk density is defined as the ratio of the total mass of soil to its total volume, including both solids and void spaces. It is expressed as the unit weight of soil.

**Explanation:** Dry density represents the weight of the solids in a soil sample divided by the total volume of the soil. It provides a measure of the compactness of the soil and is an important parameter in geotechnical engineering.

**Explanation:** The density of soil can be increased by reducing the air voids (compaction), compressing soil grains elastically, and expelling water from soil pores. These methods result in a denser arrangement of soil particles, leading to an increase in overall soil density.

**Explanation:** The relation between dry density (yd), bulk density (y), and water content (w) is given by yd = y / (1 + w). This equation represents the relationship between the dry density, bulk density, and water content of a soil sample.

**Explanation:** Saturated soil is considered a two-phase system, consisting of solid particles and water occupying the void spaces. The air phase is absent in saturated soil.

**Explanation:** The saturated density of soil is expressed as the unit weight of saturated soil. It considers the weight of soil and water in the voids, providing a measure of the density of fully saturated soil.

**Explanation:** A pycnometer is a device used to determine the water content and specific gravity of soil. It involves measuring the volume of a known mass of soil and water, allowing for the calculation of both water content and specific gravity.

**Explanation:** The water content of soils is accurately determined by the oven drying method. This involves weighing a soil sample, drying it in an oven to remove all moisture, and then reweighing to calculate the water content.

**Explanation:** The porosity of loose sand can range from 40 to 50%. Porosity is the ratio of void volume to total volume and is influenced by factors such as particle size and packing arrangement.

**Explanation:** Hydrometer readings are corrected for both temperature and meniscus corrections to ensure accurate measurements of particle settling rates in hydrometer analysis. These corrections account for variations that could affect the readings.

**Explanation:** The thickness of adsorbed layers of soil, referring to the layers of water molecules adhering to soil particles, is measured in angstroms (Å). An angstrom is a unit of length equivalent to 10^(-10) meters.

**Explanation:** Particle size range in soil is measured by the uniformity coefficient, which is calculated as the ratio of the particle size at the 60% passing point to the particle size at the 10% passing point in a grain size distribution curve. It provides information about the range of particle sizes in a soil sample.

**Explanation:** Void ratio (e) in soil mechanics is defined as the ratio of the volume of voids to the volume of solids in a soil mass. It is a measure of how much void space is present compared to the solid particles.

**Explanation:** Theoretically, void ratio in soils can be greater than 1, less than 1, or between 0 and 1, depending on the arrangement and packing of soil particles. All these scenarios are possible in different soil types and conditions.

**Explanation:** Void ratio (e) can be greater than zero, indicating the presence of void spaces in the soil. It can vary between 0 and infinity, with higher values indicating a greater volume of voids compared to solids.

**Explanation:** Void ratio (e) is calculated as the ratio of the volume of voids to the volume of solids. In this case, e = 0.2 / 0.3 = 0.67. Porosity (n) is calculated as the ratio of the volume of voids to the total volume, so n = 0.2 / (0.2 + 0.3) = 0.40.

**Explanation:** The ratio of the volume of air voids to the total volume of voids in a soil mass is known as air content. It represents the proportion of voids that are filled with air.

**Explanation:** The relation between dry density (ρd), bulk density (ρ), and water content (w) is given by ρd = ρ / (1 + w). This equation represents the relationship between these three important soil properties.

**Explanation:** Water content in soil is defined as the ratio of the weight of water to the weight of solids in a given mass of soil. It is a crucial parameter in understanding the moisture content of soil.

**Explanation:** The ratio of the volume of air voids to the total volume of a soil mass is known as the percentage of air voids. It provides information about the volume of voids that are filled with air.

**Explanation:** Porosity is defined as the ratio of the volume of voids to the total volume of a given soil mass. It provides information about the void space available in the soil.

**Explanation:** Water content in soil is defined as the ratio of the weight of water to the weight of solids in a given mass of soil. It is a fundamental parameter in geotechnical engineering and influences various soil properties.

**Explanation:** The degree of saturation (Sr) is defined as the ratio of the volume of water to the volume of voids in the soil. It represents the portion of void space filled with water.

**Explanation:** The relationship between void ratio (e) and porosity ratio (n) is given by e = n / (1-n). This equation expresses the connection between two fundamental properties of soil, representing the relationship between voids and solids.

**Explanation:** The functional equation relating specific gravity (G), water content (w), void ratio (e), and degree of saturation (Sr) is expressed as e = wG / Sr. This equation illustrates the interdependence of these soil properties.

_{a}, specific gravity (G), water content (w), and dry density (γ

_{d}) is

_{d}= {(1-n

_{a})G} / (1+WG)y

_{w}

_{d}= {(1-n

_{a})G} y

_{w}/ (1+WG)

_{d}= [(1+WG) / n

_{a}G]y

_{d}

_{d}= {(1-W)Gn

_{a}} / 1+y

_{w}

**Explanation:** The fundamental relation between percentage air voids (n_{a}), specific gravity (G), water content (w), and dry density (γ_{d}) is expressed as γ_{d} = {(1-n_{a})G} y_{w} / (1+WG). This equation is significant in soil mechanics and compaction studies.

**Explanation:** The ratio described is commonly known as the degree of density, density index, or relative density. These terms are used interchangeably to express the difference in void ratios under different compaction states.

**Explanation:** The water content of soils is defined as the ratio of the weight of water to the dry weight of the soil. It is a crucial parameter in determining the moisture content of soil.

**Explanation:** The percentage of air voids can be calculated as the complementary value to the degree of saturation. In this case, percentage of air voids = 100% – 30% = 70%.

_{v}/ V

_{s}

_{v}/ V

_{v}/ V

_{w}

_{w}/ w

_{s}

**Explanation:** The correct representation for the volume ratio of voids to water volume is \(s = V_v / V_w\), not \(s = V_v / V_w\).

**Explanation:** The void ratio (e) can be calculated using the formula \(e = (G * W) / (1 + W) = (2.6 * 0.3) / (1 + 0.3) = 1.56\).

**Explanation:** The calcium carbide method is a rapid technique for determining the water content of soils. It involves the reaction of calcium carbide with water to produce acetylene gas, and the amount of gas produced is proportional to the water content.

**Explanation:** The three-phase diagram of soil represents the three main components: solids, water, and air. It illustrates the distribution and relationships among these phases in a soil mass.

**Explanation:** A fully saturated soil is considered a two-phase system with soil and water. In this state, the voids are completely filled with water.

**Explanation:** The degree of saturation (Sr) represents the ratio of the volume of water to the total volume of voids and can vary from 0% (unsaturated) to 100% (fully saturated).

**Explanation:** The percentage voids (n) represents the volume of voids in soil as a percentage of the total volume and is always between 0% and 100%.

**Explanation:** If the volume of voids is equal to the volume of solids, then porosity (n) is 0.5, and voids ratio (e) is 1.

**Explanation:** In a partially saturated soil, the air content can be calculated as 100% – Degree of Saturation. Therefore, the air content is 60%.

**Explanation:** In a fully saturated soil, the voids are completely filled with water, and the water content is 100%. The voids ratio is equal to the specific gravity of the soil.

**Explanation:** In the densest state, the relative density (Dr) of sand is equal to 1, indicating that the sand is fully dense.

_{10}represents the size in mm such that 10% of the particles are the finer than this size)

_{10}

_{20}

_{30}

_{60}

**Explanation:** The effective size of soil particles is represented by D_{10}, which indicates the particle size at which 10% of the particles are finer.

_{10}of the soil is the diameter in mm such that

**Explanation:** D_{10} represents the size at which 10% of the soil particles are finer than this diameter.

**Explanation:** A decrease in water content affects the volume of soil in various states—liquid, plastic, or semi-liquid—resulting in changes in soil behavior.

**Explanation:** The plastic limit is the water content at which the soil starts to crumble when rolled into threads of 3 mm in diameter.

**Explanation:** The shrinkage limit is the maximum water content at which a reduction in water content does not cause a decrease in the volume of the soil mass.

**Explanation:** Plasticity index is calculated as the difference between the liquid limit and the plastic limit of a soil.

**Explanation:** The activity ratio or number is the ratio of the plasticity index to the clay fraction in a soil.

**Explanation:** The flow index is the slope of the flow curve obtained during the liquid limit test.

**Explanation:** The toughness index is the ratio of the plasticity index to the flow index in a soil.

**Explanation:** When the water content is equal to the liquid limit, the relative consistency is 0.

**Explanation:** The shrinkage index is the difference between the plastic limit and the shrinkage limit of a soil.

**Explanation:** The liquid limit is the water content at which the soil transitions from a liquid state to a plastic state.

**Explanation:** The plasticity index is the difference in the range of water content between the liquid limit and the plastic limit of a soil.

_{30}

^{2}/ (D

_{10}× D

_{60})

**Explanation:** The coefficient of curvature (Cc) is defined as D_{30}^{2} / (D_{10} × D_{60}) in particle size distribution analysis.

_{30}represents the size in mm such that 30% of the particles are finer than this size.)

_{60}/ D

_{10}

_{10}/ D

_{60}

_{30}/ D

_{10}

**Explanation:** The uniformity coefficient (Cu) is defined as D_{60} / D_{10} in particle size distribution analysis.

**Explanation:** In the Unified Soil Classification System, inorganic soils with low plasticity are denoted by the symbol ML.

**Explanation:** The change in moisture content of soils can affect various properties, including angle of repose, cohesive strength, and compaction requirements.

**Explanation:** Permeability is the property of soil that allows water to flow through it.

**Explanation:** Well-compacted solids generally exhibit more cohesion in soil.

**Explanation:** As the moisture content of soil increases, the cohesion of the soil tends to decrease.

**Explanation:** Permeability varies inversely with the square of grain size according to Darcy’s law.

**Explanation:** Darcy’s law describes the relationship between the velocity of flow through a porous medium and the hydraulic gradient.

**Explanation:** Piping in soils occurs when water infiltrating through the soil creates high-velocity seepage flow. This flow can erode and remove fine soil particles, forming channels or pipes within the soil mass. This phenomenon is particularly problematic in dam construction and can lead to soil instability.

**Explanation:** The coefficient of permeability represents the rate at which water can flow through soil. It is expressed in units of length per time, and common units include cm/sec. This unit indicates the distance water can travel through the soil in one second.

**Explanation:** Permeability is influenced by the particle size of soil. Gravel, with its larger particles, generally has the highest permeability among the options listed. Larger particles create more interconnected void spaces, allowing water to flow more easily through the soil.

**Explanation:** The falling head permeability test is suitable for soils with low permeability, such as clayey soils. In this test, the water level in a standpipe falls over time as water permeates through the soil sample. It is particularly effective for soils with slower permeability.

**Explanation:** The coefficient of permeability of 0.08 cm/sec suggests that the soil has a moderate permeability, characteristic of sandy soils. Sand has larger particles compared to clay or silt, allowing water to move more freely through the soil.

**Explanation:** The quantity of seepage is directly proportional to the coefficient of permeability. Higher permeability allows more water to flow through the soil, leading to an increased quantity of seepage.

**Explanation:** The quantity of water seeping through a soil is proportional to the total head loss, which includes both the head at the upstream and the head at the downstream. The greater the total head loss, the larger the quantity of seepage.

**Explanation:** Conducting a pumping test in situ is an effective way to determine the permeability of a soil deposit. This test involves pumping water from or into a well and monitoring the water level changes over time, providing valuable information about in situ permeability.

**Explanation:** Quick sand refers to a condition where a cohesionless soil, often sand, loses its strength due to the upward flow of water. In this state, the soil behaves like a liquid, and structures built on or in it can sink or collapse.

**Explanation:** The head required for the quick condition in a sand stratum depends on specific gravity and voids ratio. In this case, the head required is calculated to be 1.5m. This indicates the depth of water needed to induce the quick condition in the specified soil.

**Explanation:** The critical exit gradient is defined by the expression (G-1)/(1+e), where G is the specific gravity of soil particles and e is the void ratio. This critical exit gradient is a crucial factor in analyzing seepage conditions in soil mechanics.

**Explanation:** The critical exit gradient may occur under various conditions, including when flow is in an upward direction, when seepage pressure is in an upward direction, and when effective pressure is zero. These conditions are critical in terms of seepage and soil stability.

**Explanation:** The critical exit gradient increases with an increase in the specific gravity of soil particles. Specific gravity is a measure of the density of soil particles, and higher values lead to a higher critical exit gradient.

**Explanation:** The critical exit gradient increases as the void ratio of the soil decreases. The void ratio is a measure of the porosity of the soil, and lower porosity corresponds to a higher critical exit gradient.

**Explanation:** The direction of seepage in a soil is perpendicular to the equipotential lines. Equipotential lines represent points in the soil with equal total head, and water tends to flow from higher to lower total head perpendicular to these lines.

**Explanation:** The seepage force in the soil is perpendicular to the equipotential lines. This force is a result of the hydraulic gradient and is exerted in the direction perpendicular to the equipotential lines.

**Explanation:** The seepage force is proportional to the exit gradient. The exit gradient is the change in total head per unit length and plays a crucial role in determining the force exerted by seeping water in the soil.

**Explanation:** The seepage force is proportional to the head loss. The head loss represents the change in total head between the upstream and downstream points, and this factor influences the magnitude of the seepage force.

**Explanation:** A flow net is a graphical representation of equipotential lines and flow lines in a soil mass. It can be used to determine various parameters, including seepage flow rate, hydrostatic pressure, and seepage pressure, providing valuable insights into the behavior of water flow in the soil.

**Explanation:** The flow path or flow channel is the space between two adjacent flow lines in a flow net. It represents the pathway through which water flows in the soil. The flow lines indicate the direction of flow, and the channels between them are critical in understanding the seepage pattern in the soil.

**Explanation:** Flow lines and equipotential lines in a flow net intersect at 90 degrees. This orthogonal intersection is a key characteristic of flow nets, aiding in the graphical representation and analysis of seepage patterns in soils.

**Explanation:** In a flow net, flow lines (representing the direction of flow) and equipotential lines (connecting points of equal head) intersect at right angles, orthogonally. This characteristic simplifies the analysis of seepage patterns.

**Explanation:** The phreatic line is the line within a dam section where the hydrostatic pressure is positive. It represents the boundary above which water pressure is sufficient to cause seepage.

**Explanation:** The discharge (q) through the complete flow is given by q = KH(Nf/Nd), where K is the coefficient of permeability, H is the total hydraulic head difference, Nf is the total number of flow channels, and Nd is the total number of potential drops.

**Explanation:** The upstream (u/s) face of an earthen dam is represented by an equipotential line in a flow net. Equipotential lines connect points with the same total head.

**Explanation:** The phreatic line corresponds to the top flow line in a flow net. It represents the boundary above which seepage occurs and below which the soil is saturated.

**Explanation:** The electrical analogy method is a technique used to draw flow nets. It involves representing the flow of water in soil by analogies to the flow of electricity in a network of resistors.

**Explanation:** The top flow line in seepage flow through an earthen dam often has the shape of a parabola. This shape is a result of the flow pattern and is a characteristic feature in flow net analysis.

**Explanation:** In an earthen dam, the phreatic line is often represented as a parabolic line in a flow net. This parabolic shape is a consequence of the seepage flow pattern.

**Explanation:** A dam is a three-dimensional structure, as it has length, width, and height. This three-dimensional nature is considered in the analysis of seepage and stability of dams.

**Explanation:** Kozeny’s parabola is used to represent the flow net in a dam. The seepage flow rate (q) per unit length is given by the product of the coefficient of permeability (k) and the focal length of Kozeny’s parabola (s).

_{x}k

_{z}

_{x}k

_{z})

_{x}k

_{z})

^{1.5}

_{x}k

_{z})

^{2}

**Explanation:** For anisotropic soils with different permeabilities in different directions (k_{x} and k_{z}), the modified coefficient of permeability (k’) is given by the square root of their product.

**Explanation:** Seepage flow through a porous medium is generally laminar, especially in soils. This is characterized by smooth and continuous flow paths without significant mixing.

_{s}, and Darcy’s velocity, v, are related as

_{s}/n

_{s}= v/n

_{s}= v.n

_{s}= n/v

**Explanation:** The seepage velocity (v_{s}) is related to Darcy’s velocity (v) by the porosity (n) of the soil. The relationship is v_{s} = v/n.

**Explanation:** The pressure-void ratio curve typically exhibits a linear relationship when plotted on semi-logarithmic paper. This type of plotting is used to represent a wide range of values more conveniently.

**Explanation:** The Standard Proctor test is conducted to determine the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD) of a soil, which is crucial for compaction purposes.

**Explanation:** The primary objective of soil compaction is to decrease the void ratio, leading to increased soil density and improved engineering properties such as strength and stability.

**Explanation:** The maximum dry density of a soil occurs at the Optimum Moisture Content (OMC), which represents the moisture content at which the soil can be compacted most effectively.

**Explanation:** Compaction helps in removing air voids from the soil, resulting in increased soil density and improved engineering properties.

**Explanation:** An increase in compaction effort typically decreases the Optimum Moisture Content (OMC) while increasing the Maximum Dry Density (MDD) of the soil.

**Explanation:** The compaction process can involve various methods, including rolling, tamping, and vibration, depending on the type of soil and the project requirements.

**Explanation:** In congested areas, where space is limited, a rammer is a suitable type of compaction equipment for both cohesive and cohesionless soils.

**Explanation:** Vibrofloatation is effective for compacting cohesionless soils with large thickness, providing improved compaction in such conditions.

**Explanation:** Vibration is often the most effective method for compacting sand, ensuring better soil densification and stability.

**Explanation:** The optimum moisture content for silt is typically around 15%, representing the moisture content at which the soil can be compacted most effectively.

**Explanation:** The plasticity needle or Proctor needle is used to measure penetration resistance, helping to control field compaction during construction.

**Explanation:** In the modified Proctor test, the drop height of the rammer is 45cm, which is a standard height used for compaction.

**Explanation:** Stabilization involves improving the engineering properties of soil to enhance its stability and performance in construction applications.

**Explanation:** Mechanical stabilization involves improving soil properties through proper grading, ensuring an optimal mix of particle sizes for enhanced stability.

**Explanation:** Cement stabilization is commonly used for stabilizing soil, improving its strength and durability, and making it suitable for various construction applications.

**Explanation:** Various admixtures such as cement, lime, or bitumen can be used in soil stabilization to improve its properties for construction purposes.

**Explanation:** Clays containing organic matter can be stabilized by adding a small percentage of hydrated lime, which helps enhance their engineering properties.

**Explanation:** When the shearing stress is zero on two planes, the angle between the two planes is 90 degrees.

**Explanation:** Consolidation is the process involving the gradual expulsion of pore water under long-term static load, resulting in compression of the soil.

**Explanation:** Consolidation theory was enunciated by Karl Terzaghi, a pioneering figure in soil mechanics and geotechnical engineering.

**Explanation:** Consolidation is a gradual process involving the expulsion of pore water from the soil under long-term static loads.

**Explanation:** The rate of consolidation generally increases with an increase in temperature.

**Explanation:** Sands typically undergo faster consolidation when subjected to a static load compared to clays or silty soils.

**Explanation:** The square root of time fitting method is used to calculate the coefficient of consolidation in geotechnical engineering.

_{c}and the liquid limit (LL) of normally loaded clays of low to medium sensitivity is

_{c}= 0.009(LL-10%)

_{c}= 0.009(10%-LL)

_{c}= 0.09{1/LL(-10%)}

_{c}= 0.1(LL-25%)

**Explanation:** This empirical relationship expresses the compression index (C_{c}) in terms of the liquid limit (LL) for normally loaded clays of low to medium sensitivity.

_{v}, the coefficient of consolidation C

_{v}, the length of the drainage path d, and time t is given by

_{v}= C

_{v}.d

^{2}/ t

_{v}= C

_{v}.t / d

^{2}

_{v}= C

_{v}.t / d

_{v}= C

_{v}.t

^{2}/ d

^{2}

**Explanation:** The relationship between time factor (T_{v}), coefficient of consolidation (C_{v}), length of drainage path (d), and time (t) is given by T_{v} = C_{v}.t / d^{2}.

**Explanation:** Compression of soils occurs rapidly when voids are occupied by air, which is more compressible than water.

**Explanation:** The degree of consolidation is the ratio of settlement at any time to the final settlement, expressing the extent of consolidation that has occurred.

**Explanation:** Overconsolidated soil has experienced higher pressures in the past than the current overburden pressure.

**Explanation:** Underconsolidated soil has not fully settled under the existing overburden pressure.

**Explanation:** Normally consolidated soil has settled fully under the existing overburden pressure.

**Explanation:** Overconsolidation can occur due to the weight of removed ice sheets or landslides.

**Explanation:** Bleeder wells are used to relieve pressure in impervious layers and control seepage in dams.

**Explanation:** Effective stress is the difference between total stress and pore water pressure in a soil mass.

**Explanation:** Effective stress in a soil represents the stress shared by the solid particles of the soil, and it is equal to the difference between total stress and pore water pressure.

**Explanation:** The neutral stress in a soil mass is the stress carried by the pore water within the soil.

**Explanation:** The total stress in a soil is the total force applied per unit area, considering both the solid particles and the pore water.

**Explanation:** The strength of a soil is commonly identified by its ultimate shear strength, representing the maximum shear stress the soil can withstand.

**Explanation:** The shear strength of a soil typically increases with an increase in normal stress applied to the soil.

**Explanation:** The shear strength of a soil is influenced by cohesion, angle of friction, and normal stress.

**Explanation:** Shear strength is primarily related to effective stress, which accounts for the stress carried by the soil skeleton.

**Explanation:** Shear strength is proportional to the tangent of the angle of internal friction.

**Explanation:** Shear strength in the laboratory is determined through tests such as unconfined shear test, triaxial shear test, and direct shear test.

**Explanation:** Shear resistance in soils is due to both intergranular friction and cohesion/adhesion between soil particles.

**Explanation:** In an undrained condition, the shear strength of plastic clay is primarily due to cohesion.

**Explanation:** The shearing strength of cohesionless soil is influenced by normal stress, which is the force applied perpendicular to the shear plane. The normal stress plays a crucial role in determining the resistance of the soil to shearing forces. Other factors, such as particle arrangement, shape, and size, also contribute to the overall shearing strength of cohesionless soils.

_{u}. of saturated clay tested in unconfined compression is given in terms of unconfined compressive strength q

_{u}as

_{u}= 1/2 q

_{u}

_{u}= q

_{u}

_{u}= 2q

_{u}

_{u}2/3 q

_{u}

**Explanation:** The relationship between undrained shear strength (C_{u}) and unconfined compressive strength (q_{u}) in saturated clay under unconfined compression is expressed by C_{u} = 1/2 q_{u}.

**Explanation:** The unconfined compression test is commonly recommended for testing the shear strength of saturated clay. This test involves applying axial load to a cylindrical soil specimen without confining pressure, providing insights into the undrained shear strength of the clay.

**Explanation:** Cohesive soils, such as clays, often experience a decrease in shear strength upon wetting. This is attributed to factors like swelling and changes in pore water pressure, which can lead to a reduction in the soil’s ability to resist shear forces.

**Explanation:** Cohesive soils, like clays, exhibit plastic behavior and are compressible. Their plasticity is characterized by the ability to undergo deformation without rupture, and their compressibility is evident in volume changes under applied loads.

**Explanation:** The length/diameter ratio of cylindrical specimens used in a triaxial test is generally maintained at 2 for standard testing procedures. This ratio ensures that the test results are representative and reliable for evaluating soil behavior under different stress conditions.

**Explanation:** The triaxial apparatus is versatile and can be used for various tests, including unconsolidated-untrained tests, consolidated-untrained tests, and drained tests. This flexibility makes it a valuable tool for studying different aspects of soil mechanics.

**Explanation:** The vane shear test is specifically designed for in-situ determination of the undrained shear strength of intact fully saturated cohesive soils, including clays. It involves rotating a vane blade in the soil and measuring the torque required for shearing.

^{2}(45 + Φ/2) is called

**Explanation:** The value NΦ, defined as tan^{2} (45 + Φ/2), is commonly referred to as the flow value. It is utilized in geotechnical engineering to assess the flow characteristics of cohesionless soils, providing insights into their behavior under different conditions.

**Explanation:** The failure plane in soil mechanics does not necessarily carry the maximum shear stress. The location and orientation of the failure plane depend on factors such as soil type, stress conditions, and the presence of water. The determination of failure planes is crucial for understanding soil stability and designing foundations and slopes.

**Explanation:** The shear strength of cohesive soil (C) is commonly expressed as half of the unconfined compressive strength (q), and the relationship is represented by C = q/2.

**Explanation:** The angle of internal friction for clayey soils typically falls in the range of 5-20°. This low angle is indicative of the cohesive nature of clay, which doesn’t exhibit significant frictional characteristics.

**Explanation:** Silty sands generally have an angle of internal friction in the range of 27-33°. This range reflects the intermediate frictional characteristics of soils containing a significant proportion of silt in addition to sand.

_{d}

_{d}

_{d}

_{d}

**Explanation:** The angle of internal friction for granular soils with less than 5% silt content can be determined by the expression 30 + 0.15 D_{d}, where D_{d} is the percentage of silt.

_{1}and σ

_{3}are major principal stress and τ is the shear stress on these planes

_{1}-σ

_{3})+τ

_{1}-σ

_{3})+τ]

_{1}-σ

_{3})}

^{2}+τ

^{2}]

_{1}-σ

_{3})+τ

^{2}]

**Explanation:** The radius of Mohr’s stress circle is calculated as √[{1/2(σ_{1}-σ_{3})}^{2}+τ^{2}]. This represents the distance from the center of the circle to the Mohr-Coulomb failure envelope.

**Explanation:** Dilatancy is the phenomenon where dense sand tends to expand or dilate when subjected to shearing loads. This behavior is characterized by an increase in volume and is opposite to thixotropy, where a material becomes less viscous over time.

**Explanation:** The angle between the maximum shear stress plane (Mohr-Coulomb failure plane) and the horizontal plane is 45° according to Mohr’s circle of stress. This is a fundamental principle in soil mechanics.

**Explanation:** The difference between the undisturbed shear strength of soil and its remoulded shear strength is referred to as remoulding less. This phenomenon is associated with changes in soil structure and properties during the process of remoulding.

**Explanation:** The major principal stress occurs on the plane where the stress is maximum. This is a fundamental concept in stress analysis, and the major principal stress is represented by σ_{1}.

**Explanation:** The stress-strain curves A, B, and C correspond to dense sand, loose sand, and clay, respectively. Each curve represents the material’s response to applied stress, illustrating variations in stress and strain for different types of soils.

**Explanation:** The angle of internal friction is generally lower for cohesive soils like clay. Clay particles have a plate-like structure, and their ability to interlock results in lower internal friction compared to granular soils.

^{2}

**Explanation:** In a soil layer with double drainage, the drainage path is equal to half the thickness of the soil layer (H/2). This configuration allows drainage from both the top and bottom of the layer.

**Explanation:** Westergaard’s theory is commonly used for the analysis of layered soils. It provides solutions for stress distribution in layered systems.

**Explanation:** Absorbed water in soil refers to the water that is chemically combined within the crystal structure of the soil particles. It is not free to move through the soil by gravity.

**Explanation:** The angle of internal friction is influenced by various factors, including particle shape and roughness, normal direct pressure, and the amount of interlocking between soil particles.

**Explanation:** The penetration number is determined by the number of blows required to penetrate the sampler and cone to a specified depth, such as 30cm & 20cm. It is a measure of the resistance of the soil to penetration.

**Explanation:** An isobar is a line connecting points below the groundwater level (GL) that have equal total stress. It helps visualize stress distribution in soil beneath the ground surface.

**Explanation:** The shape and structure of an isobar are often likened to that of an onion. It represents lines of equal stress below the groundwater table in the soil.

**Explanation:** Soft chalk is typically a weak and compressible soil, leading to a lower safe load compared to the other mentioned soils. Safe load capacity is influenced by the strength and compressibility of the soil.

**Explanation:** Active earth pressure is the lateral pressure exerted by the soil when the retaining wall tends to move away from the backfill. It is a critical consideration in the design of retaining structures.

**Explanation:** When the lateral earth pressure moves towards the retaining wall, it indicates active earth pressure. This occurs when the wall tends to move away from the backfill.

**Explanation:** Active earth pressure is generally less than passive earth pressure. It occurs when the retaining wall tends to move away from the backfill.

**Explanation:** Passive earth pressure occurs when the retaining wall tends to move towards the backfill.

**Explanation:** The total lateral earth pressure is proportional to the square of the depth of the soil. This relationship is part of the equations used to calculate lateral earth pressure.

**Explanation:** Passive earth pressure occurs when the retaining wall tends to move into the soil. It is the lateral pressure exerted by the soil in this condition.

**Explanation:** Earth pressure at rest occurs when the retaining wall has no movement relative to the backfill. It represents the lateral pressure exerted under this condition.

^{2}(45°-Φ/2)

^{2}(45°+Φ/2)

**Explanation:** The active earth pressure is proportional to tan^{2} (45°-Φ/2), where Φ is the angle of internal friction of the soil.

^{2}(45°-Φ/2)

^{2}(45°+Φ/2)

**Explanation:** The passive earth pressure is proportional to tan^{2} (45°+Φ/2), where Φ is the angle of internal friction of the soil.

^{2}(45°-Φ/2)

^{2}(45°+Φ/2)

**Explanation:** The earth pressure at rest is proportional to μ / (1-μ), where μ is Poisson’s ratio, and Φ is the angle of internal friction of the soil.

**Explanation:** The coefficient of earth pressure at rest is greater than the active earth pressure but lesser than the passive earth pressure. It represents the lateral pressure when the wall has no movement relative to the backfill.

_{a}is equal to:

**Explanation:** The coefficient of the active earth pressure (K_{a}) is given by (1 – sin Φ) / (1 + sin Φ).

**Explanation:** Rankine’s theory assumes that the soil is semi-finite, homogeneous, dry, and cohesionless, the ground surface is a plane (inclined or horizontal), and the back of the wall is vertical and smooth.

_{c}= 4c/γ tan(45°+Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°-Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°+Φ)

_{c}= {μγ/2(1-μ)}h

^{2}

**Explanation:** The active earth pressure (H_{c}) is given by γh^{2}/2 tan^{2}(45°-Φ), where γ is the unit weight of the soil and Φ is the angle of internal friction.

_{c}= 4c/γ tan(45°+Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°-Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°+Φ)

_{c}= {μγ/2(1-μ)}h

^{2}

**Explanation:** The earth pressure at rest (H_{c}) is given by {μγ/2(1-μ)}h^{2
}

_{c}= 4c/σ tan(45+Φ)

_{c}= 4c/σ tan

^{2}(45-Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°+Φ)

_{c}= rh

^{2}/2 . μ/1-μ

**Explanation:** The passive earth pressure (H_{c}) is proportional to γh^{2}/2 tan^{2}(45°+Φ), where γ is the unit weight of the soil and Φ is the angle of internal friction.

_{c}= 4c/γ tan(45°+Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°-Φ)

_{c}= γh

^{2}/2 tan

^{2}(45°+Φ)

_{c}= {μγ/2(1-μ)}h

^{2}

**Explanation:** The critical vertical depth H of free-standing soil can be up to H_{c} = 4c/γ tan(45°+Φ), where c is the cohesion and γ is the unit weight of the soil.

**Explanation:** The correct sequence regarding different coefficients of friction in increasing order is Ka (active)-Ko (at rest)-Kp (passive).

**Explanation:** The coefficient of active earth pressure (Ka) is reciprocal to the coefficient of passive earth pressure (Kp). Therefore, if Kp is 1/3, then Ka is 3.

**Explanation:** The maximum permissible eccentricity for a retaining wall not to fail in tension is B/6.

**Explanation:** In the case of a backfill with a sloping surface, the total active pressure on the wall of height H acts at H/3 above the base parallel to the sloping surface.

**Explanation:** Submerged backfill exerts more earth pressure compared to dry backfill.

**Explanation:** The California Bearing Ratio (CBR) test is used to find the thickness of a flexible pavement.

**Explanation:** The position of the backfill above a horizontal plane at the elevation of the top of the structure is known as surcharge.

**Explanation:** The lateral pressure exerted by a uniform surcharge is q times the lateral pressure within the surface.

**Explanation:** The earth pressure acting at a height of h/3 in the case of an inclined surcharge.

**Explanation:** Rankine’s earth pressure theory assumes that the wall face is smooth and vertical.

**Explanation:** The assumption of Rankine’s theory includes the soil being semi-finite, homogeneous, dry, and cohesionless, the ground surface being a plane (inclined or horizontal), and the back of the wall being vertical and smooth.

**Explanation:** The distribution of earth pressure with depth is hydrostatic.

**Explanation:** The assumption of wedge-shaped failure is made by Coulomb.

**Explanation:** If the resultant force at the face of the retaining wall is much more than frictional resistances at the bottom, the failure will be due to sliding.

**Explanation:** If the resultant force at the bottom of the retaining wall lies outside the middle third, the failure will be due to crushing.

**Explanation:** In the case of retaining walls, surcharge refers to the extra load on the horizontal backfill.

**Explanation:** In cohesive soils, the depth of the vertical cut up to which no lateral support is required is given by 4c/γ.

**Explanation:** One of the graphical methods for earth pressure determination is Culmann’s method.

**Explanation:** Sheet pile walls are used as retaining walls for waterfront construction.

**Explanation:** Sheet piles are held in position by tie rods that are anchored.

**Explanation:** For the design of sheet pile walls, both active and passive earth pressure are considered as they are embedded in soil.

**Explanation:** The bearing capacity of soil primarily depends on the size of the footing.

**Explanation:** The most suitable method for increasing the bearing capacity of black cotton soil is the replacement of black cotton soil by sand.

**Explanation:** Black cotton soil is not suitable for foundations due to its swelling and shrinkage nature.

**Explanation:** The bearing capacity of soil is significantly influenced by its water content. Changes in water content can alter soil properties, affecting its strength and load-bearing capacity.

**Explanation:** The bearing capacity of soil is closely related to the grain size of the soil particles. The arrangement and size of particles affect the overall strength and load-bearing ability of the soil.

**Explanation:** Various methods, such as increasing foundation depth, soil compaction, and replacing weak soil with stronger materials, can enhance the bearing capacity of weak soils. Combining these methods may provide effective improvement.

**Explanation:** Cohesive soils, while having high shear strength, can generate significant lateral pressure, making them less suitable for backfills where excessive pressure can impact retaining structures.

**Explanation:** Cohesion, representing the internal molecular attraction of soil particles, tends to be higher in well-compacted clays, contributing to the soil’s overall strength.

**Explanation:** The bearing capacity of soil depends on various factors, including the size and shape of particles as well as cohesive properties. All these factors collectively influence the soil’s ability to bear loads.

**Explanation:** Bearing capacity is determined through tests like the plate load test and the standard cone test. These tests help assess the soil’s strength and load-bearing characteristics.

**Explanation:** Moist clay, especially when saturated, often exhibits the minimum or least bearing capacity among various soil types due to its compressible nature and sensitivity to moisture content changes.

**Explanation:** The safe bearing capacity represents the maximum load intensity that a soil can safely support without undergoing excessive settlement or failure. It is the limit beyond which loading should not proceed to ensure stability.

**Explanation:** The ultimate bearing capacity is the maximum load that a soil can withstand before failure occurs. It represents the point at which the soil structure collapses or undergoes excessive deformation.

_{c}, N

_{q}, N

_{y}are B.C factors for general shear failure N

^{‘}

_{c}, N

^{‘}

_{q}, N

^{‘}

_{y}are B.C factors for general corresponding tan B = width or diameter of footing D

_{f}= depth of foundation γ = density of soil θ = angle of internal fraction )

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

_{y}

_{c}+ γD

_{f}N

_{q}+ 0.4γB.N

_{y}

^{‘}

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

^{‘}

_{y}

**Explanation:** Not available

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

_{y}

_{c}+ γD

_{f}N

_{q}+ 0.4γB.N

_{y}

^{‘}

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

^{‘}

_{y}

**Explanation:** Not available

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

_{y}

_{c}+ γD

_{f}N

_{q}+ 0.4γB.N

_{y}

^{‘}

_{c}+ γD

_{f}N

_{q}+ 0.5γB.N

^{‘}

_{y}

**Explanation:** Not available

**Explanation:** The bearing capacity factors are functions of the angle of internal friction and are crucial parameters in determining the bearing capacity of soil.

**Explanation:** Terzaghi’s analysis makes assumptions including homogeneous and isotropic soil, well-defined elastic and plastic zones, and failure zones not extending above the horizontal plane through the base of the footing.

**Explanation:** Terzaghi’s theory provides an expression for the ultimate bearing capacity at the ground surface, and for purely cohesive soils with a smooth base, it is given by 5.14c.

**Explanation:** The ultimate bearing capacity for frictionless soils typically falls in the range of 4.5c to 6c, where c is the cohesion of the soil.

**Explanation:** The rise of the water table impacts soil cohesion and the effective angle of shearing resistance, both of which are critical in determining the bearing capacity.

**Explanation:** The rise of the water table in cohesionless soils up to the ground surface can lead to a reduction of approximately 50% in the net ultimate bearing capacity.

**Explanation:** When the water table is at a depth equal to the width of the footing below the footing, there is no reduction in the bearing capacity, and the reduction factor is 1.00.

**Explanation:** The reduction factor for the water table at a depth equal to half of the width of the footing is 0.75, indicating a reduction in bearing capacity due to the influence of the water table.

**Explanation:** The reduction factor for the water table just below the footing is 0.50, indicating a significant reduction in bearing capacity due to the proximity of the water table.

**Explanation:** Initially, raising the water table increases bearing capacity, but there is a point beyond which further rise decreases bearing capacity due to excessive pore water pressure.

**Explanation:** The safe bearing capacity is the maximum pressure a soil can withstand without shear failure, ensuring a factor of safety against failure.

**Explanation:** Net bearing capacity is the minimum net pressure intensity causing shear failure of the soil, considering both cohesion and friction.

**Explanation:** Negative skin friction occurs when the fill settles relative to the pile, causing additional downward load on the pile.

**Explanation:** Negative skin friction reduces the effective load-carrying capacity of the pile by introducing additional downward forces.

**Explanation:** Skin friction is typically higher in sands compared to other soil types, contributing significantly to the load-carrying capacity of piles.

**Explanation:** Skin friction contributes to the load-carrying capacity of the pile, increasing its overall capacity to resist vertical loads.

**Explanation:** The allowable bearing pressure for a foundation is influenced by both the allowable settlement criteria and the ultimate bearing capacity of the soil, ensuring a balance between safety and serviceability.

**Explanation:** Well foundations in sandy soils derive their bearing capacity from both skin friction along the shaft and point bearing at the base of the well.

**Explanation:** The bottom plug in a well foundation is used to transfer the load from the steining (the vertical shaft of the well) to the underlying soil.

**Explanation:** The well in a well foundation is typically filled with sand, and consolidation is done to ensure stability and load transfer to the underlying soil.

**Explanation:** The minimum depth of a building foundation depends on the type of soil. For sandy soils, it is typically 80 cm to 100 cm, for clay soils 90 cm to 160 cm, and for rocky soils 5 cm to 50 cm.

**Explanation:** Well foundations are commonly used under structures located on river beds, where the load-bearing capacity of the soil is improved by the well structure.

**Explanation:** The minimum depth of a footing carrying a heavy load is given by the provided formula, which considers the total load, friction factor, and the length of the footing.

^{2}

^{2}

**Explanation:** According to Rankine’s analysis, the minimum depth of the foundation is given by the provided formula, considering the applied load, soil density, and the angle of internal friction.

**Explanation:** A raft foundation is a type of shallow foundation that spreads the load over a large area, preventing excessive settlement.

**Explanation:** A foundation is classified as shallow if its depth is less than its width. This indicates that the foundation relies on the bearing capacity of the near-surface soils.

**Explanation:** A foundation is classified as deep if the depth to width ratio exceeds a certain threshold, indicating that the foundation extends deep into the soil to achieve the required bearing capacity.

**Explanation:** A spread foundation is classified based on the length to width ratio, and it is considered spread when this ratio is between 1 and 2.

**Explanation:** A continuous foundation is classified based on the length to width ratio, and it is considered continuous when this ratio is more than 2.

**Explanation:** A strip foundation is characterized by its length being very large compared to its width, distributing the load over a strip of soil.

**Explanation:** Combined footings are used when there are two columns and they are spaced close to each other, requiring a combined foundation.

**Explanation:** A grillage foundation, which consists of closely spaced beams and joists, is used under heavy loaded situations to distribute the load.

**Explanation:** Pile foundations are used when the required bearing area is not available at the shallow depth, and they are suitable for various soil conditions.

**Explanation:** Pile foundations are commonly used in tall buildings to transfer the loads to deeper, more stable soil layers.

**Explanation:** A minimum of two piles is needed to support a wall to provide stability and prevent rotation.

**Explanation:** A minimum of three piles is needed to support a column, providing stability and preventing translation and rotation.

**Explanation:** Negative skin friction, caused by downward movement of soil, tends to reduce the load-carrying capacity of the pile by creating additional downward forces.

**Explanation:** The permissible settlement for an isolated foundation on clayey soils is generally considered to be around 65 mm.

**Explanation:** The maximum allowable differential settlement for a foundation on clayey soils is typically considered to be around 40 mm.

**Explanation:** The stability analysis for normally consolidated clay deposits is often appropriate using the Swedish circular arc method.

**Explanation:** Base failure refers to a failure surface that is below the toe of the slope, indicating failure at the base of the slope.

**Explanation:** Toe failure is more likely to occur in the case of steep slopes, where the toe of the slope is a critical point.

**Explanation:** Masonry retaining walls derive their stability from their self-weight, making them stable against overturning.

**Explanation:** Increasing the stability of slopes can be achieved by adopting gentler slopes, which reduce the risk of slope failure.

**Explanation:** The terms “natural slope line,” “stable line,” and “repose line” are often used interchangeably to refer to a plane inclined at an angle to the horizontal where soil is expected to remain stable without lateral support.

**Explanation:** The critical height in the stability of the soil is the maximum height at which the stability of the slope is still possible without failure.

**Explanation:** Stability analysis should be conducted considering effective stresses, as these account for the intergranular stresses and are more relevant to soil stability.

**Explanation:** Berms are horizontal shelves or steps built into the slopes of embankments to increase the factor of safety by reducing the potential for sliding.

**Explanation:** The factor of safety for slopes is defined as the ratio of shear strength to shear stress to ensure stability against sliding.

**Explanation:** The factor of safety for embankments is typically required to be at least 1.5 to ensure stability and safety against failure.

**Explanation:** The factor of safety (FS) is calculated as the ratio of resisting moment to overturning moment. In this case, FS = 5 KN-m / 10 KN-m = 0.5.

**Explanation:** Coulomb’s theory assumes that the backfill is dry, homogeneous, isotropic, and cohesionless. It also assumes a linear rupture plane passing through the toe of the wall, and it considers the sliding wedge as a rigid body in equilibrium.

**Explanation:** A breast wall is a retaining wall constructed to prevent earth from slipping on the hillside of a roadway.

**Explanation:** The total pressure on a vertical wall due to liquid pressure acts at a distance of 2H/3 from the base of the wall.

**Explanation:** While a foundation contributes to providing a stable and level base for building construction, its primary purposes are to distribute the weight of the structure and increase the safe bearing capacity of the soil.

**Explanation:** Saturated soil has its voids completely filled with water, resulting in a moisture content of 100%.

**Explanation:** The consolidation test is conducted to determine the decrease in the total volume of a soil sample over time, providing information about its consolidation characteristics.

**Explanation:** The bearing capacity of soils is influenced by both the physical characteristics of soil particles and the moisture content of the soil.

**Explanation:** A retaining wall is specifically designed to resist horizontal pressure from soil or other materials and to maintain the desired ground level on one side of the wall.

**Explanation:** Cohesion refers to the attraction between molecules of the same material, particularly in cohesive soils.

**Explanation:** Aeolian soil is soil that has been transported and deposited by the wind.

**Explanation:** Tractive force is the force exerted by flowing water on sediment particles, causing them to move.

**Explanation:** The bearing capacity is the maximum stress that the soil can withstand without undergoing shear failure.

**Explanation:** Clay typically has a lower angle of internal friction compared to granular soils.

**Explanation:** The shear resistance between soil particles is provided by adhesive forces.

**Explanation:** Beyond the shrinkage limit, further reduction in water content leads to a solid state in the soil.

**Explanation:** Shear stress is a stress applied parallel to a face of the material, causing deformation by sliding one part of the material parallel to another part.

**Explanation:** The uniformity coefficient (Cu) of a soil is the ratio of the size of the particles at the 60% finer point to the size of particles at the 10% finer point. It can be greater than 1.

**Explanation:** Shear tests on soils are often performed under controlled drainage conditions to simulate field conditions.

**Explanation:** The angle of repose is the maximum angle between the horizontal and the slope of a pile of granular material under the influence of gravity.

**Explanation:** Cohesive soils have high plasticity and tend to stick together. They exhibit cohesive properties due to the presence of clay minerals.

**Explanation:** The coefficient of earth pressure for loose sand is approximately 1/3 times the vertical effective stress.

**Explanation:** Over-consolidation can occur due to various factors, including erosion, glacial processes, and permanent changes in water table levels.

**Explanation:** The angle of repose is the maximum angle at which a pile of material remains stable without sliding.

**Explanation:** Specific gravity can be determined using various methods, including the Shrinkage Limit Method, Gas Jar Method, and Density Bottle Method.

**Explanation:** Elastic soils recover their volume after the removal of external loads, indicating elastic behavior.

**Explanation:** In soil mechanics, the angle between the directions of failure and the major principal plane is related to the angle of shearing resistance.

**Explanation:** Toe failure in slope stability refers to failure occurring at the toe (bottom) of a slope.

**Explanation:** Terzaghi’s theory assumes homogeneity, full saturation, and incompressibility of water and soil particles. Deformation is considered due to volume change.

**Explanation:** Cohesive soils, such as clays, typically have zero angle of internal friction.

**Explanation:** The common classification includes coarse-grained soils (sands and gravels), fine-grained soils (clays and silts), and organic soils.

**Explanation:** Porosity is the ratio of void volume to total volume, and voids ratio is the ratio of void volume to solids volume. When the volume of voids equals the volume of solids, porosity is 0.5, and voids ratio is 1.0.

**Explanation:** Net allowable bearing pressure is related to the allowable settlement of the foundation.

**Explanation:** The coefficient of curvature for well-graded soils falls typically between 1 and 3.

**Explanation:** Specific gravity is the ratio of the unit weight of soil solids to the unit weight of water.

**Explanation:** The bearing capacity of soil is influenced by particle characteristics, cohesive properties, and internal frictional resistance.

**Explanation:** The shearing strength of cohesionless soils is influenced by factors such as confining pressure, which is the pressure applied to the soil in addition to the vertical stress.