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Past Questions — 2025
Which of the following is a protective coating for metals?
A)
Whitewash
B)
Lacquer
C)
Galvanization
D)
Emulsion paint
Step-by-step reasoning: 1. The question asks for a protective coating specifically for metals. 2. Galvanization is the process of applying a protective zinc coating to steel or iron to prevent rusting. The zinc acts as a sacrificial anode, protecting the underlying metal from corrosion. 3. Analyzing other options: (a) Whitewash is a mixture of slaked lime and water used primarily for walls and ceilings, not for metal protection. (b) Lacquer is a resin-based coating used for furniture or decorative finishes; while it can be used on some metals, it is not the primary industrial protective coating compared to galvanization. (d) Emulsion paint is a water-based paint used mainly for interior and exterior walls. Therefore, Galvanization is the most authoritative and standard protective coating for metals in civil engineering and materials science.
The primary use of varnish is to-
A)
Color the surface
B)
Fill gaps
C)
Provide protective and glossy finish
D)
Act as an adhesive
Varnish is a transparent, hard, protective finish or film primarily used in woodworking. It consists of a resin dissolved in a solvent.
1. Why Option (c) is correct: The primary purpose of varnish is to protect the underlying surface (usually wood) from moisture, heat, and scratches while enhancing the natural beauty of the grain by providing a glossy or semi-glossy transparent finish.
2. Why Option (a) is incorrect: Varnish is typically transparent. If the goal is to change the color of the surface, paints or stains are used.
3. Why Option (b) is incorrect: Filling gaps is the function of wood fillers, putties, or sealants, not varnish.
4. Why Option (d) is incorrect: While some resins used in varnish have adhesive properties, the primary application of varnish as a building material is as a top-coat finish, not as a structural adhesive.
Which of the following materials is used to fill joints in masonry walls?
A)
Grout
B)
Mortar
C)
Putty
D)
Cement paste
In masonry construction, mortar is the primary binding material used to fill the joints between individual masonry units (such as bricks or stones). Its primary functions are to bond the units together, distribute the load evenly across the wall, and seal the joints against air and water penetration.
Analysis of other options:
- Grout (a): While similar to mortar, grout is a fluid mixture used primarily to fill voids or gaps in concrete blocks or to reinforce masonry walls by filling the cores of blocks; it is not the standard material for filling the horizontal and vertical joints during the laying of masonry.
- Putty (c): Putty is used for filling small holes, cracks, or smoothing surfaces (typically in woodwork or plastering) before painting; it has no structural capacity for masonry joints.
- Cement paste (d): This is a mixture of cement and water only. It lacks the aggregate (sand) found in mortar, which is necessary to prevent shrinkage cracking and provide the required volume and strength for masonry joints.
Which of the following wood products is made by gluing thin layers of wood together?
A)
Particle board
B)
Block board
C)
Plywood
D)
Fiberboard
Step-by-step reasoning:
1. **Plywood**: This is an engineered wood product made by gluing together thin layers of wood veneers. These layers (plies) are glued with their grains oriented perpendicular to each other (cross-graining), which provides high strength, stability, and resistance to splitting.
2. **Particle board**: This is made from wood chips, sawmill shavings, or sawdust bonded together with a resin under heat and pressure. It does not consist of 'thin layers' of wood veneers.
3. **Block board**: This consists of a core of solid wood strips (blocks) sandwiched between two layers of veneer. While it uses veneers on the surface, the core is not made of thin layers glued together, but rather solid blocks.
4. **Fiberboard (MDF/HDF)**: This is made by breaking down wood residuals into fibers, combining them with wax and resin, and forming panels under high temperature and pressure. It is a homogeneous material rather than a layered veneer product.
Therefore, the product specifically defined by gluing thin layers (veneers) together is Plywood.
The rise of water in capillary tube is inversely proportional to-
A)
Grain size
B)
Pore size
C)
Saturation ratio
D)
Dry density
The rise of water in a capillary tube (capillary rise) is governed by the physics of surface tension. The height of capillary rise (h) is given by the formula: h = (4T cos θ) / (γw d), where T is the surface tension of water, θ is the contact angle, γw is the unit weight of water, and d is the diameter of the capillary tube (which corresponds to the pore size in soil). From this formula, it is evident that the height (h) is inversely proportional to the diameter (d) of the tube. In soil mechanics, the voids between soil particles act as capillary tubes; therefore, the smaller the pore size, the higher the capillary rise. While pore size is related to grain size (smaller grains generally create smaller pores), the direct physical relationship is with the pore size itself. Saturation ratio and dry density do not have a direct inverse proportional relationship with the height of capillary rise in the fundamental physical formula.
The most suitable stone for construction of heavy engineering structures like bridge piers is-
A)
Limestone
B)
Laterite
C)
Granite
D)
Marble
To determine the most suitable stone for heavy engineering structures like bridge piers, we must evaluate the mechanical properties required for such structures: high compressive strength, high durability, and resistance to weathering and water erosion.
1. **Granite (Option c):** Granite is an igneous rock characterized by a coarse-grained crystalline structure. It possesses exceptionally high compressive strength, low porosity, and high durability. These properties make it ideal for structures that must support massive loads and withstand constant exposure to water and environmental stressors, such as bridge piers, dams, and retaining walls.
2. **Limestone (Option a):** While used in construction, limestone is a sedimentary rock that is generally softer than granite and can be susceptible to chemical weathering (especially by acidic rain), making it less ideal for heavy-duty load-bearing piers.
3. **Laterite (Option b):** Laterite is a soil-like rock rich in iron and aluminum. It is relatively soft when quarried and hardens upon exposure to air, but it lacks the structural strength and density required for heavy engineering works.
4. **Marble (Option d):** Marble is a metamorphic rock primarily used for ornamental and architectural purposes due to its aesthetic appeal. It is softer than granite and prone to weathering, making it unsuitable for heavy structural engineering applications.
Therefore, Granite is the most suitable choice due to its superior strength and durability.
The grade of cement generally used for RCC works is-
A)
33 grade
B)
43 grade
C)
53 grade
D)
22 grade
The grade of cement is defined by its compressive strength after 28 days of curing (measured in MPa).
1. **53 Grade Cement (Option c):** This is an Ordinary Portland Cement (OPC) with a minimum compressive strength of 53 MPa. Due to its high early strength and superior load-bearing capacity, it is the standard choice for Reinforced Cement Concrete (RCC) works, high-rise buildings, and heavy structural components where high strength is critical.
2. **43 Grade Cement (Option b):** This has a strength of 43 MPa. While it can be used for RCC, it is more commonly used for general construction, plastering, and masonry work where extreme strength is not the primary requirement.
3. **33 Grade Cement (Option a):** This has a strength of 33 MPa. It is generally used for low-strength works, such as small-scale residential masonry or non-structural elements, and is rarely used for modern RCC works.
4. **22 Grade Cement (Option d):** This is not a standard grade for Ordinary Portland Cement used in structural engineering.
Therefore, for RCC works, where structural integrity and high compressive strength are paramount, 53 grade cement is the most generally preferred and used grade.
Which of the following woods is most resistant to termite attack?
A)
Pine
B)
Teak
C)
Cedar
D)
Sal
Termite resistance in wood is primarily determined by the presence of natural oils, resins, and extractives (like tannins and silica) that act as chemical deterrents to insects.
1. **Teak (Tectona grandis):** Teak is world-renowned for its exceptional durability and resistance to termites and decay. This is due to its high content of natural oils and silica, which make the wood unpalatable and toxic to termites.
2. **Sal (Shorea robusta):** While Sal is a very hard, heavy, and durable wood often used for railway sleepers and heavy construction, it is generally considered slightly less resistant to certain types of termite attacks compared to the high oil content of Teak, although it is still highly durable.
3. **Cedar:** Cedar contains natural oils that repel insects, but it is a softer wood and generally less resistant to heavy-duty termite infestations compared to Teak.
4. **Pine:** Pine is a softwood and is highly susceptible to termite attacks and decay unless it is chemically treated (pressure-treated).
Therefore, among the given options, Teak is the most resistant to termite attack.
The factor of safety in slope stability analysis is defined as the ratio of-
A)
Active to passive pressure
B)
Weight to height of slope
C)
Shear strength to shear stress
D)
Cohesion to slope angle
In slope stability analysis, the Factor of Safety (FoS) is a measure of the stability of a soil slope against failure. Failure occurs when the shear stress ($ au$) acting along a potential failure surface exceeds the shear strength ($s$ or $ au_f$) of the soil. Therefore, the Factor of Safety is defined as the ratio of the resisting forces (shear strength) to the driving forces (shear stress). Mathematically: FoS = (Available Shear Strength) / (Mobilized Shear Stress).
Why other options are incorrect:
- Option (a): The ratio of active to passive pressure is used in the design of retaining walls to check for stability against sliding or overturning, but it is not the definition of the factor of safety for slope stability.
- Option (b): Weight and height are parameters used to calculate stresses, but their ratio does not define the stability factor.
- Option (d): Cohesion is a component of shear strength (according to Mohr-Coulomb theory), and the slope angle affects the driving stress, but their direct ratio is not the definition of the factor of safety.
The equation representing the hydrological cycle is known as-
A)
Hydrograph equation
B)
Water budget equation
C)
Darey’s law
D)
Continuity equation
The hydrological cycle is governed by the principle of conservation of mass. For a given catchment area or a specific volume of the earth's atmosphere/crust over a specific time interval, the inflow must equal the outflow plus the change in storage. This is mathematically expressed as: (Inflow - Outflow = Change in Storage). This fundamental relationship is known as the Water Budget Equation.
Why other options are incorrect:
- a. Hydrograph equation: A hydrograph is a plot of discharge versus time at a specific point in a river; it is a tool for analysis, not the governing equation of the entire cycle.
- c. Darcy's law: This describes the flow of a fluid through a porous medium (like soil), which is only a small part of the hydrological cycle (infiltration/groundwater flow).
- d. Continuity equation: While the water budget equation is a specific application of the continuity equation (conservation of mass), in the context of Hydrology, the term 'Water Budget Equation' is the standard terminology used to represent the cycle's balance.
Two soils have the same dry density but different grain size distribution. Which one is likely more stable under loading?
A)
Soil with higher void ratio
B)
Well-graded soil
C)
Uniformly graded soil
D)
Plastic soil
Stability under loading in soil mechanics refers to the soil's ability to resist deformation (settlement) and shear failure.
1. **Well-graded soil**: A well-graded soil contains a wide variety of particle sizes. In such a distribution, smaller particles fill the voids between larger particles. This results in a denser packing arrangement, higher interlocking between grains, and a higher shear strength. Consequently, well-graded soils are more stable and less compressible under loading.
2. **Uniformly graded soil**: These soils consist of particles of nearly the same size. This leads to larger void spaces and less interlocking between particles, making them more susceptible to settlement and instability compared to well-graded soils.
3. **Higher void ratio**: A higher void ratio implies more empty space and less solid material per unit volume. This generally leads to higher compressibility and lower stability.
4. **Plastic soil**: Plasticity is a characteristic of fine-grained soils (like clays). While they have cohesive strength, they are generally more prone to long-term consolidation settlement and volume changes (shrink-swell) compared to well-graded granular soils, making them less 'stable' in the context of immediate loading and settlement control.
Since both soils in the question have the same dry density, the deciding factor for stability is the grain size distribution. The well-graded soil provides superior mechanical interlocking and stability.
A retaining wall fails mainly due to-
A)
Wind pressure
B)
Overturning or sliding
C)
Snow accumulation
D)
Thermal expansion
A retaining wall is designed to resist the lateral earth pressure exerted by the soil it retains. The primary stability checks for any retaining wall involve ensuring it does not fail due to the following modes: 1. Overturning: This occurs when the lateral pressure causes the wall to rotate about its toe. 2. Sliding: This occurs when the lateral force exceeds the frictional resistance between the base of the wall and the foundation soil. 3. Bearing Capacity Failure: When the pressure exerted by the wall exceeds the allowable bearing capacity of the soil.
Analyzing the options:
- Option (a) Wind pressure: While wind acts on structures, it is negligible compared to the lateral earth pressure for a retaining wall.
- Option (b) Overturning or sliding: These are the fundamental failure modes analyzed in geotechnical and structural engineering for retaining walls.
- Option (c) Snow accumulation: This may add a surcharge load, but it is not a primary cause of failure for the structure itself.
- Option (d) Thermal expansion: This can cause cracking in concrete but does not lead to the overall structural failure (collapse) of the wall in the way sliding or overturning does.
Compaction differs from consolidation in that compaction is-
A)
A long-term process
B)
Due to expulsion of air under mechanical effort
C)
Due to drainage of water
D)
Due to increase in permeability
To understand why option (b) is correct, we must distinguish between the two fundamental processes of volume reduction in soil mechanics: Compaction and Consolidation.
1. **Compaction**: This is an instantaneous process where soil is densified by applying mechanical energy (such as rolling, tamping, or vibration). The primary mechanism is the expulsion of **air** from the void spaces between soil particles. It is typically performed on unsaturated soils.
2. **Consolidation**: This is a time-dependent (long-term) process that occurs in saturated cohesive soils (like clay). It involves the gradual expulsion of **pore water** from the soil voids under a sustained static load, leading to a decrease in volume.
Evaluating the options:
- **Option (a)**: Incorrect. Compaction is an instantaneous process, whereas consolidation is a long-term process.
- **Option (b)**: Correct. Compaction occurs due to the expulsion of air under mechanical effort.
- **Option (c)**: Incorrect. The drainage of water is the defining characteristic of consolidation, not compaction.
- **Option (d)**: Incorrect. Both processes generally lead to a decrease in void ratio, which typically results in a decrease in permeability, not an increase.
The partial safety factor for concrete in LSM is typically taken as-
A)
1.0
B)
1.5
C)
1.25
D)
2.0
In Limit State Method (LSM) for reinforced concrete design, the partial safety factor for concrete is typically taken as 1.5 (for concrete strength in design). Hence option b is correct. Option c (1.25) is not the standard value for concrete in LSM; it is sometimes associated with other materials or specific code contexts, but not the usual concrete factor. Option a (1.0) would mean no safety reduction, which is not used for design strength. Option d (2.0) is too high and not the prescribed partial safety factor for concrete in standard LSM design.
A road has a width of 6m and an average thickness of 20 cm. The length of the road is 1 km. What is the total volume of material required?
A)
1000 m3
B)
1200 m3
C)
1500 m3
D)
1800 m3
To find the total volume of material required for the road, we use the formula for the volume of a rectangular prism: Volume = Length × Width × Thickness.
1. **Identify and Convert Units to Meters (m):**
- Width = 6 m
- Thickness = 20 cm = 20 / 100 = 0.2 m
- Length = 1 km = 1000 m
2. **Calculate the Volume:**
- Volume = 1000 m (Length) × 6 m (Width) × 0.2 m (Thickness)
- Volume = 6000 × 0.2
- Volume = 1200 m³
Comparing this result to the given options:
- Option (a) 1000 m³ is incorrect.
- Option (b) 1200 m³ matches our calculation.
- Option (c) 1500 m³ is incorrect.
- Option (d) 1800 m³ is incorrect.
What is the function of coarse aggregates in concrete?
A)
Reduce shrinkage
B)
Increase workability
C)
Increase strength and durability
D)
Reduce cost
In concrete technology, coarse aggregates (such as crushed stone or gravel) act as the primary structural filler. Their main functions are: 1) To provide strength and stability to the concrete matrix, as they are generally stronger and stiffer than the cement paste. 2) To improve durability by reducing the overall permeability and resisting wear and tear. 3) To provide dimensional stability. While aggregates do indirectly help in reducing shrinkage (by reducing the volume of cement paste) and reducing cost (by replacing expensive cement), their primary engineering function in the mix design is to provide the necessary strength and durability to the hardened concrete. Option (b) is incorrect because coarse aggregates generally decrease workability compared to fine aggregates or paste alone.
How does increasing water content affect soil compaction?
A)
Increases dry density beyond a limit
B)
Increases soil strength indefinitely
C)
Reduces shear strength permanently
D)
Does not affect soil properties
In soil mechanics, compaction is the process of increasing the dry density of soil by removing air voids using mechanical energy. The relationship between water content and dry density is described by the Compaction Curve.
1. **Lubrication Effect**: Initially, as water is added to a dry soil, it acts as a lubricant between soil particles, allowing them to slide over each other more easily and pack more closely under a given compactive effort. This leads to an increase in dry density.
2. **Optimum Moisture Content (OMC)**: The dry density continues to increase until it reaches a peak value known as the Maximum Dry Density (MDD). The water content at which this occurs is the Optimum Moisture Content (OMC).
3. **Beyond the Limit**: Once the OMC is exceeded, the water begins to occupy the space that would otherwise be occupied by soil particles. Since water cannot be compressed, it pushes the particles apart, causing the dry density to decrease.
Analysis of other options:
- Option (b) is incorrect because increasing water content beyond the OMC actually decreases soil strength.
- Option (c) is incorrect because while water affects shear strength, the question specifically asks about 'compaction' (density), and the reduction in strength is not necessarily 'permanent' as it depends on the current saturation level.
- Option (d) is incorrect because water content is the primary variable affecting the compaction characteristics of soil.
Which of the following is the primary binding material in concrete?
A)
Sand
B)
Cement
C)
Water
D)
Aggregates
Concrete is a composite material consisting of a binding medium and filler materials.
1. **Cement (The Binder):** Cement is a hydraulic binder. When mixed with water, it undergoes a chemical reaction called hydration, forming a calcium silicate hydrate (C-S-H) gel. This gel acts as the 'glue' that binds the aggregates together into a solid, rock-like mass.
2. **Sand (Fine Aggregate):** Sand acts as a filler material to occupy the voids between coarse aggregates and reduce shrinkage. It does not possess binding properties.
3. **Water:** Water is a reactant required to initiate the hydration of cement. While essential for the process, it is not the binding material itself; rather, it is the medium in which the binder reacts.
4. **Aggregates (Coarse Aggregate):** These provide the structural bulk and strength to the concrete but are inert and cannot bind to one another without a binder.
Therefore, cement is the primary binding material in concrete.
Why do earthen dams require more maintenance compared to concrete dams?
A)
Because they are expensive to construct
B)
Because they are susceptible to seepage and erosion
C)
Because they do not store water efficiently
D)
Because they cannot withstand high pressure
Earthen dams are constructed using compacted soil, sand, and clay. Unlike concrete dams, which are rigid and impermeable, earthen dams are porous and subject to several natural degradation processes.
1. Seepage: Water naturally permeates through the soil body. If not properly controlled (via cores or filters), this can lead to 'piping,' where internal erosion creates tunnels through the dam, potentially leading to failure.
2. Erosion: The surface of an earthen dam is vulnerable to erosion from rainfall, wind, and wave action (overtopping). This requires constant maintenance of grass cover or rip-rap protection.
3. Biological Factors: Burrowing animals and vegetation growth can create pathways for water, further increasing seepage risks.
Comparing other options:
- Option (a) is incorrect because earthen dams are generally cheaper to construct than concrete dams due to the use of local materials.
- Option (c) is incorrect because earthen dams are highly efficient at storing water if designed correctly.
- Option (d) is incorrect because earthen dams are specifically designed to withstand high hydrostatic pressure through their wide base and massive weight (gravity principle).
What is the primary purpose of an abstract estimate?
A)
To provide a quick, approximate cost of the project
B)
To determine the detailed breakdown of each item
C)
To estimate only the labor cost
D)
To calculate the total area of the site
In civil engineering estimation and costing, an 'Abstract Estimate' (often associated with preliminary or rough cost estimates) is prepared to obtain a quick and approximate idea of the total expenditure required for a project. It is typically used during the initial planning stages to secure administrative approval or budget allocation before detailed drawings and specifications are finalized.
Reasoning for other options:
- Option (b) is incorrect because the detailed breakdown of each item is the purpose of a 'Detailed Estimate', which involves a complete quantity takeoff (Bill of Quantities).
- Option (c) is incorrect because an estimate covers all costs, including materials, labor, plant, and overheads, not just labor.
- Option (d) is incorrect because calculating the total area of the site is a surveying or measurement task, which is a prerequisite for estimation, not the purpose of the abstract estimate itself.
A rectangular plot of land is to be excavated 20m long, 10m wide, and 3m deep. What is the total excavation volume?
A)
500m3
B)
600 m3
C)
700 m3
D)
800 m3
To find the total excavation volume of a rectangular plot, we use the formula for the volume of a rectangular prism (cuboid): Volume = Length × Width × Depth.
Given values:
Length (L) = 20 m
Width (W) = 10 m
Depth (D) = 3 m
Calculation:
Volume = 20 m × 10 m × 3 m
Volume = 200 m² × 3 m
Volume = 600 m³
Therefore, the total excavation volume is 600 cubic meters.
- Option (a) 500m³ is incorrect as it does not match the product of the dimensions.
- Option (c) 700m³ is incorrect.
- Option (d) 800m³ is incorrect.
Under-sluices are usually provided:
A)
At the extreme left of the barrage
B)
At the extreme right of the barrage
C)
Just adjacent to the canal head regulator
D)
In the middle of the barrage
Under-sluices are gated openings provided in a barrage or weir to maintain a clear channel for water and sediment to pass through. Their primary purpose is to prevent the deposition of silt and debris in front of the canal head regulator. By placing the under-sluices just adjacent to the canal head regulator, the high-velocity flow created by opening these sluices 'scours' the riverbed and flushes the accumulated silt downstream, ensuring that only clear water (free of heavy sediment) enters the canal system.
- Option (a) and (b) are incorrect because placing them at the extremes would not effectively clear the area immediately in front of the canal intake.
- Option (d) is incorrect because the middle of the barrage is typically used for main spillway bays to handle flood discharge, not for the specific purpose of sediment exclusion for the canal.
Why is soil exploration necessary before foundation design?
A)
To determine the best location for underground utilities
B)
To study soil strength and bearing capacity
C)
To find the water table depth only
D)
To identify topsoil fertility
Soil exploration (also known as site investigation) is a critical preliminary step in geotechnical engineering. The primary objective is to determine the physical and engineering properties of the soil beneath the proposed structure. Specifically, it is necessary to: 1) Determine the bearing capacity of the soil to ensure the foundation can support the structural load without shear failure. 2) Assess the settlement characteristics to prevent excessive or differential settlement. 3) Identify the stratification of soil layers. While finding the water table depth (option c) is part of soil exploration, it is not the sole purpose. Options a and d are irrelevant to foundation design; underground utility location is a surveying/planning task, and topsoil fertility is an agricultural concern, not a structural one.
What is the main difference between a gravity dam and an arch dam?
A)
Gravity dams rely on their weight, while arch dams transfer forces to the valley walls
B)
Gravity dams require strong abutments, while arch dams do not
C)
Gravity dams are more suitable for narrow valleys than arch dams
D)
Gravity dams require less construction material than arch dams
Step-by-step reasoning:
1. **Gravity Dam Analysis**: A gravity dam is a structure designed to resist the external forces (primarily the hydrostatic pressure of the water) by using its own massive weight. The stability is maintained by the friction between the dam base and the foundation, ensuring it does not slide or overturn.
2. **Arch Dam Analysis**: An arch dam is a curved structure that utilizes the 'arch effect.' Instead of relying solely on weight, it transfers the water pressure horizontally to the canyon walls (abutments) through compressive stress.
3. **Evaluating Option (a)**: This correctly identifies the fundamental structural difference: weight-based stability for gravity dams vs. load-transfer (arch action) for arch dams.
4. **Evaluating Option (b)**: This is incorrect. Arch dams require extremely strong, stable rock abutments to support the transferred load; gravity dams do not rely on abutments for stability in the same way.
5. **Evaluating Option (c)**: This is incorrect. Arch dams are specifically suited for narrow, deep valleys with strong walls, whereas gravity dams can be used in wider valleys.
6. **Evaluating Option (d)**: This is incorrect. Because arch dams use structural geometry rather than mass, they typically require significantly less concrete/material than gravity dams.
What is the major factor affecting the shear strength of soil?
A)
Permeability
B)
Cohesion and internal friction angle
C)
Soil color
D)
Moisture content only
The shear strength of soil is defined as the internal resistance per unit area that a soil mass can offer to resist failure along a plane. According to the Mohr-Coulomb failure criterion, the shear strength (τ) is expressed by the equation: τ = c + σ tan(φ), where 'c' represents cohesion and 'φ' represents the angle of internal friction.
1. Cohesion (c): This is the component of shear strength that is independent of the normal stress. It is dominant in cohesive soils like clays due to chemical bonding and electrostatic forces between particles.
2. Internal Friction Angle (φ): This represents the resistance due to the interlocking of soil grains and friction between them. It is the dominant factor in cohesionless soils like sands and gravels.
Analysis of other options:
- Permeability (a): This refers to the ease with which water flows through soil; while it affects the rate of consolidation, it is not a primary component of the shear strength formula.
- Soil color (c): This is a physical characteristic used for classification but has no direct impact on the mechanical strength of the soil.
- Moisture content only (d): While moisture content significantly influences cohesion and effective stress (and thus affects shear strength), it is not the 'major factor' in the sense of the fundamental parameters (c and φ) that define the strength of the soil matrix.