Subject 2018 Question Paper — Government College of Engineering and T…

The 2018 Subject previous year question paper (Government College of Engineering and Technology, Jammu), with every question and its marks.

Instructions

Q1a. Explain Cullman's graphical method for determining active earth pressure? Draw neat sketches? [10 marks]
Q1b. A retaining wall 6m high, has a smooth vertical back. The backfill has a horizontal surface in level with the top of the wall. There is uniform surcharge load of 48kN/m³ intensity over the backfill. The unit weight of the backfill is 20kN/m³; its angle of shearing resistance is 30° and cohesion is zero. If the water table rises behind the wall to an elevation of 2m below the top, determine active earth pressure and its point of application. Take submerged weight of sand as 12 kN/m³. Also assume that there is no change in the angle of shearing resistance due to the submergence. [10 marks]
Q2a. An embankment is inclined at an angle of 35° and its height is 15 m. The angle of shearing resistance is 15° and the cohesion intercept is 200 kN/m². The unit weight of soil is 18.0 kN/m³. If Taylor's stability number is 0.06, find the factor of safety with respect to cohesion. [10 marks]
Q2b. Elaborate different methods to improve stability of slopes? And also write about different factors of safety used? [10 marks]

Q3. A strip footing 2m wide carries a load intensity of 560 kN/m² at a depth of 1.2 m in sand. The saturated unit weight of sand is 18 kN/m³ and unit weight have water table is 16.8 kN/m³. The shear strength parameters are C=0 and $\phi=35^{\circ}$. Determine the factor of safety with respect to shear failure for the following cases of location of water table. i) water table 3m below the ground surface ii) water table is at ground level iii) water table is 4m below the ground level iv) water table is 0.5m below ground level [20 marks]
Q4a. Discuss the assumptions made by Terzaghi and derive the Terzaghi's bearing capacity equation for shallow foundation? [10 marks]
Q4b. How Plate load test is used to calculate bearing capacity of soil. Explain the process involved. [10 marks]

Q5a. Explain the function of pile foundations. Also classify different types of piles. [10 marks]
Q5b. A precast concrete pile 25cm X 25 cm is driven by a single acting steam hammer. Estimate the allowable load using (a) Engineering News record Formula (F.S.=6) (b) Hiley Formula(F.S.=4). Use the following data: i) maximum rated energy = 3500 kN-cm v) coeff. Of restitution = 0.5 ii) weight of hammer = 35 kN vi) weight of pile = 3 kN iii) length of pile= 15m vii) no. of blows for last 25.4 mm = 6 iv) efficiency of hammer= 0.8 viii) modulus of elasticity of concrete = 2 X 10⁷ kN/m² assume any other missing data, if required. Take the weight of pile as 73.5 kN. [10 marks]
Q6a. What is tilt and shift? How can it be rectified? [10 marks]
Q6b. A circular well has an external diameter of 7.5m and is sunk into a sandy soil to a depth of 20 m below the maximum scour level. The resultant horizontal force is 1800kN. The well is subjected to a moment of 36000 kN.m about the maximum scour level due to the lateral force. Determine whether the well is safe against lateral forces, assuming $\gamma = 10 \text{ kN/m}^3$ and $\varphi = 36^{\circ}$. Use Terzaghi's analysis, and a factor of safety of 2 against passive resistance. [10 marks]

Q7a. Discuss about "N-value" of standard penetration test. Explain the various corrections to be applied to observe the value of N. [10 marks]
Q7b. Give critical notes on disturbed and undisturbed samples? Explain briefly with the help of a sketch the construction and use of split spoon sampler. [10 marks]
Q8a. A 25 kN point load acts on the surface of a horizontal ground. Find the intensity of vertical pressure at 6m directly below the load. Use Boussinesq's theory. [10 marks]
Q8b. What do you understand by pressure bulb? Illustrate with sketches [10 marks]