Geotechnical Engineering 2022 Question Paper — Government College of…

Instructions

• 1. Attempt any five questions selecting at least two from each section. All questions carry equal marks.
• 2. Assume missing data if any.
• 3. Use of scientific Calculator is allowed.

Questions

Section-A

• Q1. a) Explain the process of soil formation and discuss the major soil types found in India with examples. b) Describe the Three-phase soil system and derive the phase relationships between its parameters. [15 marks]
• Q2. a) What are the index properties of soils? Describe the methods used to determine specific gravity and water content. b) A soil sample has a water content of 20%, specific gravity 2.65, and dry density of 1.6 g/cc. Calculate void ratio, porosity, degree of saturation, and air content. [15 marks]
• Q3. a) Compare the Unified Soil Classification System (USCS) and IS Soil Classification System. b) A soil sample was tested and gave the following results: Liquid Limit (from flow curve): 48% Plastic Limit (average from 3 trials): 22% Shrinkage Limit: 16% i) Calculate the Plasticity Index (PI), Shrinkage Index (SI), and Liquidity Index (LI), assuming natural water content is 30%. ii) Comment on the consistency and plastic behavior of the soil. [15 marks]
• Q4. a) List and explain the factors affecting the permeability of soil. b) A soil sample shows a discharge of 600 ml in 5 minutes under a hydraulic gradient of 0.25 through a $30\text{ cm}^2$ cross-section and 20 cm long sample. Calculate the coefficient of permeability. [15 marks]

Section-B

• Q5. a) Explain the need for soil compaction. Discuss the mechanism of compaction in cohesionless and cohesive soils. b) A Standard Proctor Test on a soil gave the following results: Trial 1: Water Content (%) = 10.2, Wet Density ($g/cc$) = 1.82 Trial 2: Water Content (%) = 12.5, Wet Density ($g/cc$) = 1.94 Trial 3: Water Content (%) = 14.3, Wet Density ($g/cc$) = 2.02 Trial 4: Water Content (%) = 16.1, Wet Density ($g/cc$) = 2.00 Trial 5: Water Content (%) = 18.4, Wet Density ($g/cc$) = 1.95 i) Compute the dry density for each trial. ii) Plot the compaction curve (dry density vs water content). iii) Determine the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD). iv) Comment on compaction behavior of the soil. [15 marks]
• Q6. a) Explain the types of volume changes in soil. What is the importance of Terzaghi's one-dimensional consolidation theory? b) A normally consolidated clay layer 6 m thick is subjected to an increase in effective stress from 120 kPa to 240 kPa. The compression index Cc=0.28, and the initial void ratio $e_0=0.85$. i) Calculate the consolidation settlement. ii) If the initial layer thickness is 6 m, find the percentage of settlement. iii) Comment on soil behavior under loading. [15 marks]
• Q7. a) Explain with sketches the direct shear test and how shear parameters are determined. b) A consolidated drained (CD) triaxial test was conducted on a normally consolidated clay. The following results were obtained: Cell pressure $(\sigma_3) = 100\text{ kPa}$ Deviator stress at failure $= 160\text{ kPa}$ i) Calculate the major principal stress $(\sigma_1)$. ii) Determine the cohesion ($c$) and angle of internal friction $(\phi)$ if the test is repeated at another cell pressure of 200 kPa and failure occurs at deviator stress of 250 kPa. iv) Plot the Mohr's circles for both tests. [15 marks]
• Q8. a) Differentiate between UU, CU and CD, with neat stress-path diagrams. b) Discuss the effect compaction on the various engineering properties of soils. [15 marks]

Related pages

• Geotechnical Engineering syllabus
• All Geotechnical Engineering papers from 2022

Other years

• Geotechnical Engineering 2022 question paper — end-term
• Geotechnical Engineering 2018 question paper — end-term