A soil sample is underlying a water column of height h1, as shown in the figure. The vertical effective stresses at point A, B and C are $$\sigma {'_A}$$, $$\sigma {'_B}$$ and $$\sigma {'_C}$$ respectively. Let $$\gamma$$sat and $$\gamma$$' be the saturated and submerged unit weights of the soil sample, respectively and $$\gamma$$w be the unit weight of water. Which one of the following expressions correctly represents the sum ($$\sigma {'_A}$$ + $$\sigma {'_B}$$ + $$\sigma {'_C}$$) ?
Read the following statements :
(P) While designing a shallow footing in sandy soil, monsoon season is considered for critical design in terms of bearing capacity.
(Q) For slope stability of an earthen dam, sudden drawdown is never a critical condition.
(R) In a sandy sea beach, quicksand condition can arise only if the critical hydraulic gradient exceeds the existing hydraulic gradient.
(S) The active earth thrust on a rigid retaining wall supporting homogenous cohesionless backfill will reduce with the lowering of water table in the backfill.
Which one of the following combinations is correct?
The inside diameter of a sampler tube is 50 mm. The inside diameter of the cutting edge is kept such that the Inside Clearance Ratio (ICR) is 1.0% to minimize the friction on the sample as the sampler tube enters into the soil. The inside diameter (in mm) of the cutting edge is _________. (round off to two decimal places)
A group of total 16 piles are arranged in a square grid format. The center-to-center spacing (s) between adjacent piles is 3 m. The diameter (d) and length of embedment of each pile are 1 m and 20 m, respectively. The design capacity of each pile is 1000 kN in the vertical downward direction. The pile group efficiency $${\eta _g}$$ is given by
$${\eta _g} = 1 - {\theta \over {90}}\left[ {{{(n - 1)m + (m - 1)n} \over {mn}}} \right]$$
where m and n are number of rows and columns in the plan grid of pile arrangement and $$\theta = {\tan ^{ - 1}}\left( {{d \over s}} \right)$$.
The design value of the pile group capacity (in kN) in the vertical downward direction is _________. (round off to the nearest integer)