VALLIAMMAI ENGINEERING COLLEGESRM Nagar, Kattankulathur – 603 203 DEPARTMENT OF CIVIL ENGINEERING QUESTION BANK IV SEMESTER CE6405–SOIL MECHANICS Regulation – 2013 Academic Year 2016 – 17 Prepared by Mr. M. MOGANRAJ, Assistant Professor/CIVIL Mr. C. HANUSH PRAVEEN, Assistant Professor/CIVIL Ms. M. SARANYA, Assistant Professor/CIVIL 4. Define plasticity index and flow index.BIS Classification system – Soil compaction – Theory. Find Void ratio and porosity. BT-2 UNDERSTAND 8. Discuss about water content of a soil mass BT-2 UNDERSTAND 9.62kN/m3 has a water content of 15 percent. What do understand from grain size distribution? BT-2 UNDERSTAND 11. Calculate its dry APPLY density. Define compaction. Define Porosity. BT-2 UNDERSTAND 10. Define degree of saturation and shrinkage ratio BT-1 REMEMBER 2. What are the Atterberg limits? List its types. Define plasticity index and flow index.NO QUESTIONS LEVEL COMPETENCE 1.SOIL CLASSIFICATION AND COMPACTION Nature of soil – phase relationships – Soil description and classification for engineering purposes. BT-1 REMEMBER 3. Kattankulathur – 603 203 DEPARTMENT OF CIVIL ENGINEERING QUESTION BANK (As per Anna University 2013 Regulation) SUBJECT CODE/NAME: CE6405.SOIL MECHANICS SEM/YEAR: IV/II UNIT 1. degree of saturation and air content? Assume G = 2. A compacted sample of soil with a bulk unit weight of BT-3 19.65. PART A BT Q. comparison of laboratory and field compaction methods – Factors influencing compaction behavior of soils. BT-1 REMEMBER 7. VALLIAMMAI ENGINEERING COLLEGE SRM Nagar. If the volume of voids is equal to the volume of solids in a given BT-1 REMEMBER soil sample. BT-1 REMEMBER 5. BT-1 REMEMBER 6. Differentiate between plasticity and consistency. . their significance – Index properties of soils . An earth embankment is compacted at a water content of 18% to a bulk density of 1. BT-4 ANALYSE 15. By three phase soil system. Two clay samples A and B have the following properties: Atterberg limits Clay A Clay B Liquid limit 44% 55% Plastic limit 29% 35% BT-6 CREATE Natural water content 30% 50% Which of the clays A or B would experience larger settlement under identical loads? Conclude with your comments.7. A dry clay has a mass of 30g and volume of 15cc. BT-5 EVALUATE 18. 2. Mention the classification of soil system BT-4 ANALYSE 16.65 19. What will be BT-5 the shrinkage EVALUATE limit if the specific gravity of solids is 2. Using phase diagram. Explain the term optimum moisture content of soil. What is a zero air voids line? Draw a compaction curve and show BT-3 the zero air APPLY voids line. void ratio (e). Draw the phase diagram for completely dry and fully saturated BT-6 CREATE soil mass. 13. show that the degree of saturation S (as ratio) in terms of mass unit weight(γ). Describe the procedure for determining water content and specific BT – 1 REMEMBER gravity of a given soil in the laboratory by using a pycnometer.12. BT-4 ANALYSE 17. PART B 1. γw and e. . Write any two engineering classification system of soil. If the specific gravity of the sand is BT – 1 REMEMBER 2.specific gravity of soil grains(G) and unit weight of water (γw) is given by the expression: REMEMBER BT – 1 3. Compose a relation for γsat with G. find the void ratio and degree of saturation of the compacted embankment. 14. 20.92g/cm3. derive the relationship between void ratio BT-3 APPLY and porosity. Do those soils have organic matter? 11. (ii) Better shear strength as function of water content. A soil sample was collected in a sampling tube of internal diameter 50mm. If the volume of the mould BT – 2 UNDERSTAND was 0. Sandy soil in a borrow pit has unit weight of solids as 25. air content and BT. BT – 2 UNDERSTAND ii) sedimentation analysis 6. BT – 4 ANALYSE 9. Determine the degree of saturation. Index Soil A Soil B 1 Plastic limit 16% 19% 2 Liquid limit 30% 52% 3 Flow index 11 06 4 Natural water content 32% 40% BT. Also calculate the change in degree of saturation. The following data on consistency limits are available for two soils A and B. if the required value of porosity in the compacted fill is 30%.67 gave a maximum dry unit weight of 17. void ratio. degree of saturation and percentage of air voids. The water content of the soil was 16%. The mass of wet soil when compacted in a mould was 19. Discuss about the grain size distribution of soil by i) sieve analysis. BT – 2 UNDERSTAND 5. the length of the extracted sample is 313 g. What would be theoretical maximum dry unit weight corresponding to zero air voids at the optimum water content? 10.6 CREATE indicate which soil is (i) Better foundation material on remoulding.4.8 kN/m3. Take G=2.55 kN. (iv) More plastic Classify the soil as per IS classification system. S.95 m3 restate the following dry unit weight.8 KN/m3 and a water content of 15%.4 kN/m3. (iii) Better shear strength at plastic limit. water content equal to11% and bulk unit weight equal to 16.5 EVALUATE percentage air voids at the maximum dry unit weight. Explain the soil classification system. void ratio.4 ANALYSE 8. BT. Explain the factors affecting the compaction of soil.62 . degree of saturation and dry density 12. Summarize with neat sketches of compaction methods. How many cubic meter of compacted fill could be BT -3 APPLY constructed of 3500 m3 of sand excavated from the borrow pit. 7. A laboratory compaction test on soil having G= 2.No. Find BT – 1 REMEMBER porosity. Indicates value of emax BT-2 UNDERSTAND =0. A representative sample of soil taken from it has an initial weight of BT – 4 ANALYSE 18.70 gm and oven dry weight of 16. bulk unit weight.4N consider specific gravity as 2. Weight of oven dried soil sample = 51.7 2.height of core cutter =180 mm.91 gm. compute degree of saturation and relative density . A soil sample consisting of particles of size ranging from 0. Inside diameter of core cutter = 90mm.70.5 in loosest and densest state respectively. 4. specific gravity of soil grains =2.65 and viscosity of water as 0. Weight of BT-1 REMEMBER wet soil sample for moisture content determination = 54.1 mm diameter BT-1 REMEMBER & 76. state the time of settlement of the coarsest and finest particle of the sample BT-2 UNDERSTAND through a depth of 1. The specific gravity of solids is 2.85 and emin=0. Solve (i) voids ratio BT – 3 APPLY (ii) dry density and (iii) unit weight if the soil is completely saturated.688N.01 poise.72.6mm to 0. Determine dry density void ratio degree of saturation. 3. 14. Identify (i) water content (ii) wet density (iii) dry density (iv) void ratio and (v) Degree of saturation of the sample PART-C 1. A moist soil sample compacted in a mould of 1000cm3capacity and weight 3.5 kg and weight 5. the net weight of the sample = 1.84 KN/m3 laboratory test on a dried sample. dry unit weight.2mm height.05gms. void ratio & degree of saturation if the sample size is 38.12 gm.Assume G=2.13.01mm is put on the surface of still water tank. weight of the empty core cutter = 2280gm weight of soil and core cutter = 4950 gm. After oven drying is reduced to 1. Determine water content. A sample of sand above water table was found to have a natural moisture content of 15% and an unit weight of 18.2m.35 kg with the mould. Assume specific gravity of soil particle as 2. A field density test was conducted by core cuter method and the following data were obtained. soil sample has a porosity of 40 per cent.65 . BT-4 Analyze 15. What is meant by total stress. Write down the methods available for determination of permeability BT-1 Remember in the laboratory? 7. neutral stress and effective stress and BT-2 Understand give its relationship. Write down the uses of Flow net. List out the methods of drawing flow net. a flow BT-3 net was constructed and following results were obtained: Number of potential drops= 25. Define capillary rise and surface tension BT-1 Remember 5. State the assumptions in construction of flow net. State and explain Darcy’s law. What are the different types of soil water? BT-1 Remember 4. BT-3 Apply 14.Effective stress concepts in soils – capillary stress – Permeability measurement in the laboratory and field pumping in pumping out tests – factors influencing permeability of soils – Seepage – introduction to flow nets – Simple problems. Apply Number of flow channels =4 Calculate the discharge per metre length of the dam if the co- efficient of permeability of the dam material is3 x 10-5m/sec. For a homogeneous earth dam 52m high and 2m freeboard. Show that effective stress in soil mass is independent of variation in BT-3 Apply water table above the ground surface 12. List the methods of finding field-permeability BT-1 Remember 3. UNIT II. PART A BT Q. BT-1 Remember 6. What is quicksand? How would you calculate the hydraulic gradient BT-2 required to Understand create Quick sand conditions in a sample of sand? 11.SOIL WATER AND WATER FLOW Soil water – static pressure in water . 8. BT-1 Remember 2. BT-2 Understand 9. 13. BT-4 Analyze . What are the factors affecting permeability? BT-2 Understand 10.NO QUESTIONS LEVEL COMPETENCE 1. Define Capillarity and permeability. Differentiate seepage velocity from discharge velocity. (Sheet pile and weir). Above the water table. Find (i) Discharge value and discharge velocities in each layer for horizontal flow and (ii) Hydraulic gradient and loss in head in each layer for vertical flow. The bulk density of sand is BT -3 Apply 19. Calculate the effective pressure at 1m.1. (i) Write a short note on quick sand conditions in soil. Water table is 2m below ground surface. 20. the sand is saturated with capillary water. Determine the BT – 1 Remember ratio of KH and KV. In a constant head permeameter test. Along with the coefficient of permeability of the individual strata. Water table is 2m below BT – 1 Remember ground surface.0m to 0.40m in 20 minutes. The coefficient of permeability of soil is found to be 1 x 10-5 m/s at BT-5 a void ratio of 0. What will be its coefficient of permeability? 19.6. The head fell from 1. 2. 4m. the field determination of BT – 2 Understand permeability 6. 3. The average water content of the clay is 35% and specific gravity of the soil may be assumed to be 2. what is its equivalent permeability in the horizontal and vertical BT-6 Create directions? Derive the formulae used.62kN/m3. Above water table there is capillary rise up to ground surface. (4) (ii) Find the value of the effective stress at 2m.65. Also draw total stress diagram up to 10m. Assuming an average hydraulic gradient of 0. BT-6 Create PART B 1. Above water table there is capillary rise upto ground surface. determine the coefficient of permeability. neutral pressure and effective pressure over the depth of 8m. (i) The falling head permeability test was conducted on a soil sample of 4cm diameter and 18cm length.3 Analyze . Describe in detail with neat sketches. h2 and h3 thick. 18.16. Describe in detail with neat sketches. 6m. Say true or false and justify your answer: In fine-grained soils the BT-5 Evaluate capillary rise is less compared to coarse grained soils. 8m and 10m is a soil mass having γ s =21 KN/m3. 3m and 8m below the ground surface. effective and pore pressure at a depth of 20m BT – 1 Remember below the bottom of a lake 6 m deep. the following observations BT. Also draw total stress diagram up to 10. Explain the terms: seepage pressure and flow net. If the void ratio is 0. If the cross-sectional area of the stand pipe was 1cm2. 5. the laboratory determination of permeability using constant head method and falling head BT – 2 Understand method. (ii) Compute the total. The bottom of lake consists of soft clay with a thickness of more than 20m. 7.4 and the other factors Evaluate remaining same. (12) 4. Hence plot the variation of total pressure. If k1. A stratified soil deposit is shown in Fig. The water table in a deposit of sand 8m thick is at a depth of 3m below the ground surface. What is meant by capillary rise in soil and how it affects the stress BT-4 Analyze level in soils? 17.00 m.3 in both horizontal and vertical seepage. k2 and k3 are the permeability’s of layers h1. 13. effective and pore pressure at a depth of 20 m below the bottom of a lake 6 m deep. the sand is saturated with capillary water.5m below the ground surface. 4m. the following observation were taken. The average water BT -3 Apply content of the clay is 35% and specific gravity of the soil may be assumed to be 2.8and for coarse sand G=2. Calculate the effective stress at 2m. Compute the total.65. Explain briefly about the applications of flow net and (8) BT – 4 Analyze ii. Above the water table. .8m. duration of the test = 900 BT – 2 Understand sec.Diameter of the test sample = 5cm.65. if the thickness and permeability of BT. Quantity of water collected =500ml. If the dry mass of the 15cm long sample is 486g and specific gravity of the solids is 2. duration of the test = 900sec. If the dry mass of the 15cm long sample is 486g and specific gravity of the solids is 2. Under the clay stratum lies a deposit of coarse sand extending to a considerable depth. Also draw total stress diagram up to 10. Difference of water levels in piezometers = 40cm.6m thick.Calculate the effective pressure at 1m. (8) 9.68kN/m3.32kN/m3. Explain any four methods of obtaining flow nets.00 m. if no capillary water is assumed to be present in the fine sand and its bulk unit weight is assumed to be16.The unit weight of clay may be assumed as 19.65.65.4 m and5. diameter of the test sample = 5cm. The water table is 1. The bulk density of sand is 19. The sub soil strata at a site consist of fine sand 1. Determine the coefficient of permeability of the soil. 8. Distance between piezometer tappings =15cm. 11.0m below the BT. e=0. Assume for fine sand G=2. 6m. i. Distance between piezometer tappings = 15cm. and 8m below the ground surface and effective pressure over the depth of 8m. The water table in a deposit of sand 8m thick . calculate the effective pressures at ground surface and at depths of 1. Determine the coefficient of permeability of the soil.e=0. Assuming the top fine sand to be saturated by capillary water. Calculate seepage velocity of water during the test. In a constant head permeameter test.66. quantity of water collected = 500ml.3 Apply surface. were taken.5. What will be the ratio of average permeability in horizontal direction to that in the vertical direction for a soil deposit consisting of three horizontal layers. Determine seepage velocity of water during the test. 3. 12.62 BT – 1 Remember kN/m3. 10.8m thick overlying a stratum of clay1. Above water table there is capillary rise up to ground surface. difference of water levels in piezometers = 40cm.5 Evaluate ground surface. The bottom of lake consists of soft clay with a thickness of more than 20 m. Water table is 2m below ground BT. 14. 3m. 8m and 10m is a soil mass having γ s =21 KN/m3.What will be the change in effective pressure at depth 3.4m.6 Create second layer are twice of those of the first and those of the third layer twice those of second? Derive the equation. is at a depth of 3m below the ground surface. BT-1 Remember 4. PART C 1. What do you understand by the terms immediate settlement and BT-2 Understand compression. List out the component of settlement in soil. Write the Westergaard’s equation for the vertical stress for a point load. 8. BT – 1 Remember Explain the falling head permeability test. Find BT-3 Apply the time taken by the stratum for 90% consolidation and 100 % . 3. BT-1 Remember 2. Define isobar.√t and log t methods– e-log p relationship . PART A BT Q. BT -1 Remember 2. Differentiate between coefficient of consolidation and degree of BT-2 Understand consolidation. Define the terms compression index and coefficient of compressibility. BT-1 Remember 3. 11. Explain the theory of quick sand conditions in soil. . Calculate the ratio of average permeability in horizontal direction to that in the vertical direction for a soil deposit consisting of three horizontal layers.Factors influencing compression behaviour of soils. A Consolidating stratum takes two years for 50% consolidation. if the thickness and permeability of second layer BT-3 Apply are twice of those of the first and those of the third layer twice those of second? UNIT 3-STRESS DISTRIBUTION AND SETTLEMENT Stress distribution . When a soil mass is said to be homogenous? BT-2 Understand 10. BT-1 Remember 6. Discuss about the assumptions made in Terzaghi’s one dimensional BT-2 Understand consolidation theory? 9.NO QUESTIONS LEVEL COMPETENCE 1.soil media – Boussinesq theory . Define primary and secondary consolidation. Name the two theories explaining the stress distribution on soil? BT-1 Remember 7. BT – 2 Understand Classify the various applications of flow net? 4. BT-1 Remember 5.Use of Newmarks influence chart –Components of settlement –– immediate and consolidation settlement – Terzaghi’s one dimensional consolidation theory – computation of rate of settlement. State the Apply of influence chart in soil? BT-3 Apply 12. Determine the intensity of vertical stress at a point 2m below the surface. Where would you use the effective stress analysis and where the total BT-5 Evaluate stress analysis? 19. 13. What will be the vertical pressure at a point at a depth of 5 m and at a radial distance of 2 m from the axis of loading? Use Boussinesq analysis 3. What are the applications of Boussinessq’s equation? BT-3 Apply 14. In a laboratory consolidometer test on a 20 mm thick sample of BT-1 Remember saturated clay taken from a site. directly under the line load and at a distance 2 m perpendicular to the line. 4.(7) 2. 50% consolidation point was reached in10 minutes. What will be the vertical pressure at a point at a depth of 5 m and at a radial distance of 2 m from the axis of loading? Use Boussinesq analysis 6. 20. A concentrated point load of 200 kN acts at the ground surface. Estimate the time required for the clay layer of 5 m thickness at the site for 50% compression if there is drainage only towards the top. Identify the limitations of Terzaghi’s analysis in one dimensional BT-4 Analyze consolidation theory. Discuss the spring analogy for primary consolidation. Draw the Newmark’s chart BT-6 Create PART B 1. (6) (ii) A line load of 100 kN/m run extends to a long distance. Explain with a neat sketch the Terzhaghi’s one dimensional BT-2 Understand consolidation theory. consolidation respectively for the same drainage condition. 15. (i) Explain the assumptions made by Boussinesq in stress BT-1 Remember distribution on soils. . Use Boussinesq’s theory. A concentrated point load of 200 kN acts at the ground surface. 16. Draw a consolidation curve for normally consolidated and over BT-6 Create consolidated clay. What are its BT-1 Remember uses? 5. Find BT-2 Understand the intensity of vertical pressure at a depth of 10 m below the ground surface and situated on the axis of the loading. How is consolidation different from compaction? BT-4 Analyze 17. Compare Boussinessq’s and Westerguard analysis for stress BT-4 Analyze distribution. What is the time required for the clay layer to reach 50% consolidation if the layer has double drainage instead of single drainage. Find BT-1 Remember the intensity of vertical pressure at a depth of 10 m below the ground surface and situated on the axis of the loading. Compare and differentiate geostatic stress and pre-consolidation BT-5 Evaluate pressure? 18. L.5 m.25 to 1. which may be BT-3 Apply considered to be strip load of considerable length. Find how long would the clay take to settle 4. Compute the vertical stress induced at depth of 4 m. Assume e = 0. L. below the centre of ring foundation.5. If the clay layer from which the sample was obtained is 3 m thick in field condition. The load from a continuous footing of width 2 m. Determine the maximum principal stress at 1. If the compression index is 0.5 m depth below the footing.7 cm.10 when the pressure is increased from 200 kN/m2 to 400 kN/m2. the void ratio of the sample BT-4 Analyze decreased from 1. estimate the time it will take to consolidate 50% with double surface drainage and in both cases. if the point lies (i) directly below the centre of the footing.7 and G = 2. 13 In a consolidation test on a soil. Calculate the coefficient of consolidation if the coefficient of permeability is 8 x 10-8 cm/sec 14 A concentrated load of 1000 kN acts vertically at the ground surface. the water table is located 5 m above the top of the clay layer. The sand layer carries a point load of 10 MN.5 m . = 60% and Cv = 25 x 10-4 cm2/sec.0 kg/cm2.8 m away from the edge of the footing (4) 8. Water content is 40% and specific gravity of grains is 2.5 m and a horizontal distance of 4 m (ii) at a depth of 5 m and a radial distance of 2. An undrained soil sample 30 cm thick got 50% consolidation in 20 BT-4 Analyze minutes with drainage allowed at top and bottom in the laboratory.7. (4) (ii) directly below the edge of the footing and (5) (iii) 0. Compute the settlement. 11 (i)A layer of soft clay is 6 m thick and lies under a newly constructed BT-6 Create building. The weight of sand overlying the clay layer produces a pressure of 2.65. using (i) Boussinesq analysis and (ii) Westergaard’s analysis . taking μ= 0.(6) 12 A clay layer of 10 m thickness underlies a sand stratum of 10 m and BT-4 Analyzing overlies a pervious layer.72. The ring foundation transmits uniform load intensity of 160 kN/m2. (7) (ii) Explain in detail the laboratory determination of co-efficient of consolidation. is 200 kN/m2. BT-2 Understand Determine the vertical stress at a point which is at (i) a depth of 2.6 kg/cm2 and the new construction increases the pressureby1. i)How will you determine pre-consolidation pressure?(6) BT-3 Apply ii) How will you determine coefficient of compression index (CC) from an odometer test? (7) 9. consolidation pressure is uniform 10 A water tank is supported by a ring foundation having outer diameter of BT-5 Evaluate 10m and inner diameter of 7. calculate the time required for same degree of consolidation in the field. The water content of the deposit was found to be 50% 4.1 m is perfectly flexible and carries a Analyze load of 300 kN/m2. The overburden pressure over the center of the clay layer is 300 kN/m2. What will be the BT-1 vertical pressure at a point 2 m horizontally away from the axis of loading and at same depth of 3 m? Use Boussinesq’s equation (8) ii) List the Boussinesq’s theory assumptions and limitations (7) 2. G= 2. i) List the different components of settlement? Explain their Create occurrence with respect to the change in soil systems.5. PART C 1. Compute the settlement if there is an increase in pressure BT-4 due to construction of 100 kN/m2. There is a layer of soft clay 4 m thick under a newly constructed Analyze building. A rectangular foundation.7.(7) ii) 20 mm thick undisturbed sample of saturated clay is tested in laboratory with drainage allowed through top and bottom. Take Cc = 0. . Sample BT-6 reaches 50% consolidation in 35 minutes. If clay layer from which sample was obtained is 3 m thick and is free to drain through top and bottom surfaces. i) Find intensity of vertical pressure at a point 3 m directly below 25 Remember kN point load acting on a horizontal ground surface. Determine the vertical pressure at a depth of 5 m BT-4 below a point P at center and corner. 3 x 2. What is the time required if the drainage in the field is only through the top? (8) 3. Write down the coulomb’s expression for shear strength BT-1 Remember 3. PART A BT Q. BT-6 Create 20. What is the effect of pore pressure on shear strength of soil? BT-2 Understand 8. List out the advantages of direct shear test.NO QUESTIONS LEVEL COMPETENCE 1. Explain the shear strength parameters? BT-4 Analyze 17. Evaluate the angle made by failure plane with major principle plane BT-5 Evaluate using Mohr’s circle and strength envelope 19. Explain the effect of pore pressure on shear strength of soil? BT-4 Analyze 16. BT-1 Remember 7. UCC and Vane shear tests – Pore pressure parameters – cyclic mobility – Liquefaction. What is angle of internal friction? BT-2 Understand 11. What are the various methods of determination of shear strength in BT-1 Remember the laboratory? 2. Write down the Mohr’s-Coulomb failure envelope equation. BT-1 Remember 4. UNIT 4. How will you find the shear strength of cohesionless soil? BT-2 Understand 10. What are the different types of shear test based on drainage BT-1 Remember conditions? 5. What is shear strength of soil? BT-2 Understand 9. Explain the Mohr–Coulomb failure theory. . Explain about the Apply of direct shear test. BT-5 Evaluate 18. Discuss about the Apply of UCC of clay soil? BT-3 Apply 14. Sketch the failure envelope for drained triaxial test. When is vane shear test adopted? BT-3 Apply 12.SHEAR STRENGTH Shear strength of cohesive and cohesionless soils – Mohr – Coulomb failure theory – Measurement of shear strength. Define Cohesion and stress path BT-1 Remember 6. Sketch the Mohr’s circle for total and effective stresses for undrained BT-6 Create triaxial test. BT-3 Apply 13. Why triaxial shear test is considered better than direct shear test? BT-4 Analyze 15. direct shear – Triaxial compression. The following data were obtained in a direct sheartest. Tangential pressure =16 kN/m2. The angle of hearing resistance was found to be 360. A particular soil failed under a major principal stress of 300 kN/m2 BT-2 Understand with a corresponding minor principal stress of 100 kN/m2. 3. A saturated specimen of cohesionless and was tested in triaxial BT-2 Understand compression and the sample failed at a deviator stress of 482 kN/m2 when the cell pressure was 100 kN/m2 under the drained conditions. A Cylindrical specimen of dry sand was tested in a triaxial test. (i)Write a brief critical note on unconfined compression test BT-1 Remember (ii)What are the advantages and disadvantages of triaxial compression test. Normal BT-3 Apply pressure 20 kN/m2. with a confining BT-1 Remember pressure of 250 kN/m2. if it is tested under cell pressure of 200 kN/m2. A sample of dry sand was subjected to a triaxial test. the sample is likely to fail? 5. Find the effective angle of shearing resistance of sand. Find (i) Angle of shearing resistance of the soil. Write down a step by step procedure for determination of cohesion of BT-1 Remember a given clayey soil by conducting unconfined compression test. 7. Cohesion = 8 kN/m2. (ii) Normal and shear stresses on the failure plane. What the major principal stress would have been if (i) Φ = 300and (ii) Φ=00. . Explain with neat sketches the procedure of conducting direct shear BT-1 Remember test. Angle of internal friction = 200. Give its advantages over other methods of finding shear strength of soil 2. Use either Mohr’s circle method or analytical method 6. What is Mohr’s strength theory for soils? Sketch typical strength BT-2 Understand envelopes for a clean sand. 4. the minor principal stress had been 200 kN/m2. At what value of the major principal stress. If for the same soil.2 kg/cm2and at a deviator stress of 4. (iii) The angle made by the plane with the minor principal plane. PART B 1. 9.0 kg/cm2. Represent the data. BT-3 Apply Failure occurred under a cell pressure of 1. What would be the deviator stress and the major principal stress at failure for another identical specimen of sand. (iv) The maximum shear stress on any plane in the specimen at the instant of failure. 8. Obtain the relationship between the principal stresses in triaxial BT-6 Create compression test using Mohr-Coulomb failure theory PART C 1. the vane rotated rapidly so as to completely remould the soil. with c’ = 50 kN/m2 and Φ’ = BT-5 Evaluate 200 and unit weight 16 kN/m3. 10 cm long and 8cm in diameter. 11. (8) (ii)Compare the merits and demerits of triaxial compression test. effective stress. Explain the triaxial shear tests based on drainage and their BT-2 Understand applicability 2. disadvantages and limitations of direct shear test 3. (i)By Mohr’s circle and compute the principal stresses and the direction of principal planes. First BT-5 Evaluate specimen failed at a deviator stress of 770 kN/m2 when the cell pressure was 2000 kN/m2. If the same soil is tested in a direct shear apparatus with a normal stress of 600 kN/m2. Two identical soil specimens were tested in a triaxial apparatus. Torque was applied and gradually increased to 45 N-m when failure took place. (8) 10 A vane. the angle of shearing resistance and the inclination of failure plane to the major principal plane. There moulded soil was sheared at a torque of 18 N-m. shear strength of the soil at the base of embankment . 12. 13. Determine the pore water pressure. An embankment is constructed of soil. estimate the shear stress at failure. Derive a relationship between the principal stresses at failure using BT-4 Analyze Mohr-Coulomb failure criterion. Subsequently. was pressed into soft clay BT-4 Analyze at the bottom of a borehole. 14. Analyse the cohesion of the clay in the natural and remoulded states and also the value of the sensitivity. Determine the resultant stress on the plane of failure. Second specimen failed at a deviator stress of 1370 kN/m2 under a cell pressure of 400 kN/m2. the normal and shear BT-4 Analyze stresses are found as 10 kN/m2 and 4 kN/m2. i) What is the shear strength in terms of effective stress on a plane BT-3 Apply within a saturated soil mass at a point where the total normal stress is 295 kN/m2 and the pore water pressure is 120 kN/m2? The effective stress parameters for the soil are c’ = 12 kN/m2 and Φ’ = 300 ii) write the advantages . On a failure plane in a cohesionless soil sample. Determine the value of c and Φ analytically. SLOPE STABILITY Slope failure mechanisms – Types .8. Describe the main cause of slope failure BT-1 Remember 3.slope protection measures. PART A BT Q. 1. Name the different types of slope failure? BT-1 Remember 2. Classify the slope protection measures. and the lateral pressure as on-half of the vertical pressure. 13. 2. BT-6 Create UNIT 5.Friction circle method – Use of stability number . State the basic types of failure occurring in finite slopes BT-1 Remember 7. Sketch any one of the slope protection measures neatly. BT-4 Analyze 17. Explain the different types of FOS used in stability of slopes BT-2 Understand 11. Illustrate critical surface of failure. Show how does tension crack influence stability analysis? BT-5 Evaluate . When and where the circular failure surface is mobilized? Why? BT-2 Understand 10.NO QUESTIONS LEVEL COMPETENCE 1. BT-3 Apply 14. What is a slide? BT-1 Remember 6. Write the expression for FOS of an infinite slope in case of BT-3 Apply cohesionless soil. just after the fill has been raised form 3m to 6 m. BT-4 Analyze 15. BT-2 Understand 8. Analyze briefly about translational slides. Compare stability number and Taylor’s stability number. BT-1 Remember 4. BT-2 Understand 9.infinite slopes – finite slopes – Total stress analysis for saturated clay – Fellenius method .5 and 0. Define finite slope. Take pore pressure coefficients A and B as 0. BT-4 Analyze 16. BT-3 Apply 12. 4. respectively. Distinguish between method of slices and method of friction. Differentiate between finite slope and infinite slope. BT-1 Remember 5. What is Mohr’s circle? Discuss its important characteristics. Define factor of safety and critical depth. (7) 4. Compare and contrast Swedish circle and friction circle method. For this angle of slope what will be the FOS if the water level were to come down well below the surface? The saturated unit weight of the soil is 20 kN/m3. Demonstrate in detail with neat sketches the Bishop’s method of BT-3 Apply stability analysis.20 20. An embankment of 10m high is inclined at 350 to the horizontal.5 BT-1 Remember treating it as an infinite slope. BT-1 Remember 2. If the length of the failure arc is 23 m. There is a thin . Determine the maximum angle of slope for a FOS is 1. Solve. The soil has c= 20kN/m2 and ф = 150 . 11. (7) BT-2 Understand (ii) If the ground water flow could occur parallel to the slope on ground surface. Stability number is 0. A slope of very large extent of soil with properties c’= 0 and ф= 320 is likely to be subjected to seepage parallel to the slope with water level at the surface. BT-2 Understand o 6. (i) An infinitely long slope having an inclination of 26 in an area underlined by firm cohesive soil (G = 2. BT-3 Apply 9.(6) BT-1 Remember (ii) State the use of Taylor’s charts and its applicability.50).ф) by method of slices. Write the maximum depth of soil having undrained cohesion is 50 BT-6 Create kN/m2. (6) 7.72 and e = 0. Explain the Swedish slip circle method in detail BT-1 Remember 3. Stability number is 0. A stability analysis by method of slices gives the following forces: Total normal forces = 900 kN. Outline the FOS of a finite slope possessing both cohesion and BT-2 Understand friction(c . Describe in detail the various methods to protect slopes from failure. Unit weight of soil is 19 kN/m3. 5. what FOS would result. weak layer of soil 6m below and parallel to the slope surface C = 25 kN/m2. BT-6 Create PART B 1. Compute the FOS when the slope is dry. 10.18. (i) Brief Taylor’s stability number . Unit weight of soil is 19 kN/m3. Write in detail about types of slope failure. Write the different modes of failure of finite and infinite slopes. Evaluate the maximum depth of soil having undrained cohesion is BT-5 Evaluate 50kN/m2.20 19. BT-3 Apply Illustrate the technique used to improve the stability of slopes. total neutral BT-4 Analyze force= 200 kN. total tangential force = 420 kN. Ø’=16o. examine the FOS with respect to shear strength. 8. Determine from Taylor’s charts if a 300 BT-4 Analyze slope is Safe.67. A canal is to be excavated to a depth of 6m below ground level through a soil having the following characteristics c = 15kN/m2.The slope of the banks is 1in1.50 is desired. A hard Stratum exists at a depth of 18 m below the ground surface. Analyse the stability of soil using friction circle method. Describe in detail about method of slices. Φ=20°. BT-2 Understand 3.Determine the factor of BT-5 Evaluate safety with respect to cohesion when the canal runs full. Briefly explain about the method of analysis of finite slopes. BT-4 Analyze 13.9and G = 2.12. examine the safe angle of slope? . Explain in general about Fellenius method BT-4 Analyze 4. e = 0. BT-6 Create PART C 1. Write about the analysis of infinite slopes. A cut 9m deep is to be made in clay with a unit weight of 18kN/m3 and cohesion of 27 kN/m2. BT-1 Remember 2. If a factor of safety of 1. Evaluate the factor of safety if the canal is rapidly emptied completely? 14.