JNTU
JNTU B.Tech III SOIL MECHANICS Previous Question Paper (February - 2023 - R16)
Question paper consists of Part A, Part B. Part A is compulsory, which carries 25 marks. Answer all questions in Part A. In Part B, Answer any one question from each unit. Each question carries 10 marks.
Part A
Differentiate between ‘residual’ and ‘transported’ soils.
Answer
Residual soils are formed at their original location by the weathering of parent rock, whereas transported soils are formed by the weathering of rock at one location and are subsequently moved and deposited at another location by agents like water, wind, or ice.
Mention the classification system of soil.
Answer
Soils are primarily classified using the Unified Soil Classification System (USCS), the AASHTO Classification System, and the Indian Standard Soil Classification System (ISSCS) based on particle size distribution and plasticity characteristics.
What are the principles of Flow net?
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What is meant by total stresses, neutral stresses and effective stresses?
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Define pressure bulb or stress isobar.
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What is the principle behind the Newmark’s influence chart?
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Draw the consolidation curves for over consolidated clay.
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Briefly explain e-p and e log (p) curves.
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Define Sensitivity of soils.
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What are the different types of shear test based on drainage conditions?
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Part B
Explain Indian standard soil classification system for classifying coarse grained soil.
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Develop a relationship between void ratio, water content, specific gravity of particles and degree of saturation.
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A soil has a porosity of 40%, the specific gravity of solids of 2.65 and water content of 12%. Determine the mass of water required to be added to 100m3 of this soil for full saturation.
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What is relative density? How it is determined? What is its importance for coarse grained soil?
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What is a flow net? Describe its properties and applications.
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Describe pumping-out methods for the determination of the coefficient of permeability in the field. What are their advantages and disadvantages?
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The water table in a deposit of uniform sand is located at 2 m below the ground surface. Assuming the soil above the water table is dry. Determine the effective stress at a depth of 5 m below the ground surface. The void ratio is 0.75 and specific gravity of solids is 2.65, if the soil above the water table is saturated by capillary action, what is the effective stress at that depth?
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What are the limitations of Darcy’s Law?
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A concentrated load of 1000 kN is applied at the ground surface. Determine the vertical stress at a point ‘P’ which is 5m directly below the load. Also calculate the vertical stress at a point ‘R’ which is at a depth of 5 m but at a horizontal distance of 3 m from the axis of the load. Use Westergaard’s theory (Poisson’s ratio=0).
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State the basic requirements to be satisfied for the validity of Boussinesq equation for stress distribution.
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Using Boussinesq’s expression, derive the expression for vertical stress at depth, h, under the centre of a circular area of radius, a, loaded uniformly with a load, q, at the surface of the mass of soil.
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Give the detailed procedure of Usage of Newmark’s Influence Chart.
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A saturated soil stratum 4 m thick lies above an impervious stratum and below a previous stratum. It has a void ratio of 1.50 at an initial pressure of 150kN/m2. Compute the change in void ratio due to an increase of stress of 50kN/m2. Take compression index (Cc) = 0.20. Also compute the final settlement of the soil stratum due to above increase in stress.
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Write short notes on the Log fitting method for evaluation of Cv from laboratory consolidation test.
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Derive the equation for Terzaghi’s theory of one-dimensional consolidation with near sketch.
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In direct shear test, find the angle made by failure plane and major principal plane respectively with respect to horizontal, if the angle of internal friction is 30°.
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Define the Critical void ratio. Compare the behavior of dense sands with that of loose sands under shearing conditions.
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The principal stresses at a point in a material are 80 kN/m2 and 40 kN/m2 determine the normal, shear and resultant stress on a plane inclined at 30° to the major principal plane. Find also, for this plane, the maximum value of obliquity.
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What are the factors affecting the shear strength of cohesive soils?
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