Geography

Soil and Foundation Engineering

584 Questions

Soil and foundation engineering questions address the physical and mechanical properties of soil critical for construction and stability. The topics include shear strength, soil compaction, void ratios, and subsurface investigation techniques. These advanced geotechnical concepts are typically evaluated in civil engineering and specialized recruitment examinations.

Soil compactionShear strengthBearing capacityVoid ratio analysisSubsurface exploration

Soil and Foundation Engineering Questions

Multiple choice

It is proposed to widen and strengthen an existing 2-lane NH section as a divided highway. The existing traffic in one direction is 2500 commercial vehicles (CV) per day. The construction will take 1 year. The design CBR of soil subgrade is found to be 5 percent. Given: traffic growth rate for CV = 8 percent, vehicle damage factor = 3.5 (standard axles per CV), design life = 10 years and traffic distribution factor = 0.75. The cumulative standard axles (msa) computed are

  1. 35

  2. 37

  3. 65

  4. 70
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice

An R.C. square footing of side length 2 m and uniform effective depth 200 mm is provided for a 300 mm x 300 mm column. The line of action of the vertical compressive load passes through the centroid of the footing as well as of the column. If the magnitude of the load is 320 kN, the nominal transverse (one way) shear stress in the footing is

  1. 0.26 N/mm2

  2. 0.30 N/mm2

  3. 0.34 N/mm2

  4. 0.75 N/mm2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One-way shear is checked at a distance 'd' from the face of the column. The shear force is the load on the footing area outside this critical section. Dividing this force by the perimeter (b * d) gives the nominal shear stress.

Multiple choice

The figure given below represents the contact pressure distribution underneath a

  1. rigid footing on saturated clay

  2. rigid footing on sand

  3. flexible footing on saturated clay

  4. flexible footing on sand
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Rigid footings on clay exhibit a uniform settlement profile, which results in higher contact pressure at the edges compared to the center. This is characteristic of rigid footings on cohesive soils.

Multiple choice

An infinite soil slope with an inclination of 35o is subjected to seepage parallel to its surface. The soil has c' = 100 kN/m2 = f' = 30o. Using the concept of mobilised cohesion and friction, at a factor of safety of 1.5 with respect to shear strength, the mobilised friction angle is

  1. 20.02o

  2. 21.05o

  3. 23.33o

  4. 30.00o
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The factor of safety is defined as the ratio of available shear strength to mobilized shear stress. Given the slope angle and seepage conditions, the mobilized friction angle can be derived from the equilibrium equation.

Multiple choice

In the context of collecting undisturbed soil samples of high quality using a spoon sampler, the following statements are made. (I) Area ratio should be less than 10%. (II) Clearance ratio should be less than 1%. With reference to above statements, which of the following applies?

  1. Both the statements are true.

  2. Statement II is true but I is false.

  3. Statement I is true but II is false.

  4. Both the statement are false.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For high-quality undisturbed samples, the area ratio (Ar) must be low to minimize soil disturbance, typically < 10%. The clearance ratio (Cr) should be small (0.5-3%) to reduce friction, but the statement provided is standard practice.

Multiple choice

A retaining wall of height 8 m retains dry sand. In the initial state, the soil is loose and has a void ratio of 0.5, $\gamma d$= 17.8 kN/m3 and $psi$ = 30o. Subsequently, the backfill is compacted to a state where void ratio is 0.4, $\gamma d$= 18.8 kN/m3 and $psi$= 35o. The ratio of initial passive thrust to the final passive thrust, according to Rankine’s earth pressure theory, is

  1. 0.38

  2. 0.64

  3. 0.77

  4. 1.55
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Passive thrust Pp = 0.5*gamma*H^2*Kp. Calculate Kp for both states using Rankine's theory (Kp = tan^2(45 + phi/2)) and find the ratio of the thrusts.