List of top Soil Mechanics and Foundation Engineering Questions

The standard plasticity chart for the classification of a fine-grained soil is shown in the figure. As per the Indian standard soil classification system, X represents

A single pile with 450 mm diameter has been driven into a homogeneous clay layer, which has an undrained cohesion (\(c_u\)) of 20 kPa and unit weight of 18 kN/m³. The ground water table is found to be at the surface of the clay layer. The adhesion factor (\(\alpha\)) of the soil is 0.95 and bearing capacity factor (\(N_c\)) is 9. The pile is supporting a column load of 144 kN with a factor of safety of 3.0 against ultimate axial pile capacity in compression. The required embedment depth of the pile (in m) is ......... (rounded off to the nearest integer).

A 60 cm diameter well completely penetrates a confined aquifer of permeability \( 5 \times 10^{-4} \, {m/s} \). The length of the strainer (spanning the entire thickness of the aquifer) is 10 m. The drawdown at the well under steady state pumping is 1.0 m. Assume that the radius of influence for this pumping is 300 m.
The discharge from the well (in litres per minute) is ......... (round off to the nearest integer).

A designer used plate load test to obtain the value of the bearing capacity factor \( N_t \). A circular plate of 1 m diameter was placed on the surface of a dry sand layer extending very deep beneath the ground. The unit weight of the sand is 16.66 kN/m\(^3\). The plate is loaded to failure at a pressure of 1500 kPa.
Considering Terzaghi's bearing capacity theory, the bearing capacity factor \( N_t \) is ......... (round off to the nearest integer).

A square footing is to be designed to carry a column load of 500 kN which is resting on a soil stratum having the following average properties: bulk unit weight = 19 kN/m³; angle of internal friction = 0° and cohesion = 25 kPa. Considering the depth of the footing as 1 m and adopting Meyerhof's bearing capacity theory with a factor of safety of 3, the width of the footing (in m) is \underline{\hspace{2cm} (round off to one decimal place)}

A circular pile of diameter 0.6 m and length 8 m was constructed in a cohesive soil stratum having the following properties: bulk unit weight = 19 kN/m$^3$, angle of internal friction = 0$^\circ$ and cohesion = 25 kPa. The allowable load the pile can carry with a factor of safety of 3 is \underline{\hspace{2cm} kN (round off to one decimal place).}

The figure shows a vertical retaining wall with backfill consisting of cohesive-frictional soil and a failure plane developed due to passive earth pressure. The forces acting on the failure wedge are: \(P\) as the reaction force between the wall and the soil, \(R\) as the reaction force on the failure plane, \(C\) as the cohesive force along the failure plane and \(W\) as the weight of the failure wedge. Assuming that there is no adhesion between the wall and the wedge, identify the most appropriate force polygon for the wedge. \includegraphics[width=0.75\linewidth]{image22.png}

A standard penetration test (SPT) was carried out at a location by using a manually operated hammer dropping system with 50% efficiency. The recorded SPT value at a particular depth is 28. If an automatic hammer dropping system with 70% efficiency is used at the same location, the recorded SPT value will be \underline{\hspace{2cm}.}

Consider that a force \( P \) is acting on the surface of a half-space (Boussinesq's problem). The expression for the vertical stress \( \sigma_z \) at any point \( (r, z) \), within the half-space is given as, \[ \sigma_z = \frac{3P}{2\pi} \frac{z^3}{(r^2 + z^2)^{5/2}}, \] where \( r \) is the radial distance, and \( z \) is the depth with downward direction taken as positive. At any given \( r \), there is a variation of \( \sigma_z \) along \( z \), and at a specific \( z \), the value of \( \sigma_z \) will be maximum. What is the locus of the maximum \( \sigma_z \)?

A square footing of size $2.5\,\text{m\times2.5\,\text{m}$ is placed $1.0\,\text{m}$ below the ground surface on a cohesionless soil. The water table is at the base of the footing. Above and below the water table, $\gamma=18$ and $\gamma_{\text{sat}}=20~\text{kN/m}^3$ (thus $\gamma' = 20-10 = 10~\text{kN/m}^3$). Given $N_q=58$, the net ultimate bearing capacity for the soil is $q_{nu}=1706~\text{kPa}$. Earlier, a plate load test with a circular plate of diameter $0.30$ m was carried out in the same pit during dry season (WT below influence zone). Using Terzaghi's formulation, find the ultimate bearing capacity of the plate (in kPa).}

A sand sample has a bulk density of 20kN/m³ and degree of saturation of 70%. If the specific gravity of soil grain is 2.65, the value of critical hydraulic gradient for the soil will be.

In order to ensure that no scouring take place in the bed of a channel of bed slope 'S' constructed on alluvial soil of particle size 'd' cm, the flow velocity should be restricted.

The discharge unit draw down at the wall is known as.

Relative density of a compacted dense sand is approximately equal to.

Match List I with List II

	LIST I (Deposit)		LIST II (Satl structure)
A.	Coarse grained soil	I.	Flocculated
B.	Silt deposit	II.	Cohesive matrix
C.	Clay deposit	III.	Honey comb
D.	Composite soil	IV.	Single grained

Choose the most appropriate answer from the options given below:

A soil sample has a shrinkage limit of 10% and specific gravity of soil solids as 2.7. The porosity of the soil at shrinkage limit is.

A soil has a liquid limit of 40% and plasticity index of 20% the plastic limit of the soil will be.

A soil has a discharge velocity of 6 × 10 ⁻7 m/s and a void ratio of 0.5, its seepage velocity is.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A: The water content of inorganic soil is determined by heating the soil in an oven at a temperature of 105° to 110°C 
Reason R: The free water absorbed water and structural water are all completely removed from the soil by heating it at 105° to 110°C 
In the light of the above statements, choose the most appropriate answer from the options given below:

Reduction in volume of soil primarily due to squeezing out of water from winds is called.

The change that take place during the process of consolidation of a saturated clay would include.

Match List I with List II

	LIST I (Type of Precipitation)		LIST II (Principle causes)
A.	Lacustrine soil	I.	Transportation by wind
B.	Alluvial soil	II.	Transportation by running water
C.	Aeoline soil	III.	Deposited at the bottom of lakes
D.	Marine soil	IV.	Deposited in sea water

Choose the most appropriate answer from the options given below: