Soil Mechanics and Foundation Engineering -4th Semester Question Papers(Diploma in civil Engineering)

Program: Diploma in Civil Engineering  Full Marks: 80
Year/Part:II/II (2021) Pass Marks: 32
Subject:Soil Mechanics and Foundation Engineering   Time: 3 hrs.

Candidates are required to give their answers in their own words as far as practicable. The figures in the margin indicate full marks.

Attempt any FIVE questions.

1.a.Define soil mechanics.Write down the importance of soil mechanics. Derive an expression representing the relation between void ratio (e) and porosity (η). [2+3+3]

  b.Derive the following relation:

i. Sr .e = w. G
ii. Yd=Yt / 1+w

2.a.Draw the particle size distribution curve for the following a. data of sieve analysis.

Is Sieve	Mass retained (gm)
20 mm	35
10 mm	40
4.75 mm	80
2 mm	150
1 mm	150
0.6 mm	140
425 meow	115
212 meow	55
150 meow	35
75 meow	25
Pan	7

b.Explain about the MIT system of classification of soil. Also, derive the expression for calculation of coefficient of permeability by constant head method. [4+4]

3.a.Differentiate between compaction and consolidation. List out the factors affecting compaction.[4+2]

  b.At a construction site, a 3 m thick clay layer is followed by a 4 m thick gravel layer which is resting on impervious rock. A surcharge load of 25 KN/m² is applied suddenly at the surface of the ground. The unit weight of soil are 19 KN/m³ and 20 KN/m³ respectively for clay and gravel layers. Calculate the effective stresses and draw the effective stresses, total stresses diagram for various level. [10]

4.a.Write down the different types of consolidation. Explain about the Terzaghi's spring analogy. [2+6]

   b. A direct shear test at failure has a normal stress of 70 KN/m² and shear stress is 45 KN/m². Draw Mohr's circle and determine the principle stresses at failure. [8]

5.a. A retaining wall 4 m high supports a backfill (C = 15 KN/m³, φ = 20°, γ = 18 KN/m³) with horizontal top and flush with the top of the wall. If the wall is pushed towards the backfill, compute the total passive earth pressure and its point of application. [8]

   b.Derive an expression for Terzaghi's bearing capacity theory. [8]

6.Write short notes on: (any FOUR) [4x4]

a.Foundation and its types
b.Soil water and its types
c.Quick sand condition
d.Soil as multiphase material
e.Field identification of soil

                                 Good Luck!