TEST PAPER OF GEOTECH1.docx

Sub: Geotechnical Engineering

Topic : Soil Mechanics

TEST PAPER OF GEOTECH ___________________________________________________________________________ 1.

In a liquid limit test, the moisture content at 10 blows was 70% and that at 100 blows was 20%. The liquid limit of the soil is a) 35% b) 50% c) 65% d) 45%

2.

The active earth pressure of a soil is proportional to a)

(

7.

A compacted soil sample using 10% moisture content has a weight of 200g and mass unit weight of 2.0g/cc. if the specific gravity of soil particles and water are 2.7 and 1.0, the degree of saturation of the soil is a) 11.1% b) 55.6% c) 69.6% d) 80%

8.

Sieve analysis was carried out on a soil sample of 400gms. Out of 400gms, of soil 160gm retained on 4.75mm sieve, 120gm retained on 2mm sieve and 80gm retained on 600 sieve. The value of will be a) 7.4, 1.7 b) 1.7, 7.4 c) 7.92, 1.4 d) 1.4, 7.92

9.

Degree of saturation of a natural soil deposit having content 15% specific gravity 2.50 and void ratio 0.5 is a) 50% b) 60% c) 75% d) 80%

)

b)

(

)

c)

(

)

d)

having permeabilities 3 and 1 before and after deflection. According to the law of deflection of flow lines at the interface of the dissimilar soils, the is a) b) c) d)

(

)

3.

The quantity of seepage of water through soil is proportional to a) Coefficient of permeability of soil b) Total head loss through the soil c) Neither “a” nor “b” d) Both “a” and “b”

4.

The maximum value of effective stress in the past divided by the present value is defined as over consolidation ratio (OCR). The OCR of an over consolidated clay is a) Less than 1 b) 1 c) More than 1 d) None

5.

If number of flow channels are 10, number of drops are 6, the total hydraulic head difference is 4m, the length of dam is 50m and the coefficient of permeability is 2 , the total loss of water per day in is a) 576 b) 5760 c) 57600 d) 576000

6.

A flow line makes angles and with the normal to the interface of the soils

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10. The liquidity index is defined as a ratio expressed as percentage of a) Plastic limit minus natural water content, to its plasticity index b) Natural water content minus its plastic limit to its plasticity index c) Natural water content plus in elastic limit, to its plasticity index d) Liquid limit minus natural water content to the plasticity index.

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Sub: Geotechnical Engineering 11. A coarse grained soil has a void ratio 0.75 and specific gravity is 2.75. the critical gradient at which quick sand condition occurs is a) 0.25 b) 0.50 c) 0.75 d) 1.00 12. The weight of a Pycnometer containing 400g sand and water full to the top is 2150gr. The weight of Pycnometer full of clean water is 1950g. if specific gravity of the soil is 2.5, the water content is a) 5% b) 10% c) 15% d) 20% 13. A permeameter of 82.5mm diameter contains a column of the fine sand 460mm long. When water flows through it under a constant head at a rate of 191 , the loss of head between two points 250mm apart is 380mm. calculate the coefficient of permeability? If the falling head test is made on the same sample using a stand pipe of diameter 30mm, in what time the water level in stand pipe fall from 1560mm to 1066mm above out flow level? 14. A 10m thick layer of clay is under lained by a 4m thick layer of sand. The water table is at a depth of 4m from the ground level. The void ratio of clay is 0.65 and specific gravity is 2.67 water content above the saturated soil is 17% and void ratio of the sand is 0.567 and G= 2.65. Determine total and effective stress. 15. A borrow area soil has a natural water content of 10% and the bulk density of 1.8Mg/ . The soil is used for an embankment to be compacted at 18% moisture content to a dry density of 1.85Mg/ . Determine the amount of water to be added to 1 of borrow soil. How many of excavated soil required for embankment. 16. A new canal is excavated to a depth of 5m below ground level through a soil having the following characteristics. C=14KN/ the slope of banks is . Calculate the factor of safety with respect to cohesion when the canal runs full. If it is suddenly and

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Topic : Soil Mechanics completely emptied, what will be the factor of safety? 17. A saturated specimen of cohesion less sand tested in tri axial compression and the ample failed at a deviator stress of 482KN/ when the cell pressure was 100KN/ under drained conditions. Find the effective angle of shearing resistance of sand. What would be the deviator stress and the major principal stress at failure for another identical specimen of sand it is tested under cell pressure of 200KN/ . 18. A concentrated point load of 200KN acts at the ground surface. Find the intensity of vertical pressure at a depth of 10m below the ground surface and situated on the axis of the loading. What will be the vertical pressure at a point at a depth of 5m and at a radial distance of 2m from the axis of loading? 19. Compute the total, effective and pore water pressure at a depth of 20m below the bottom of a lake 6m deep. The bottom of lake consists of soft clay with a thickness of more than 20m. The average water content of the clay is 35% and specific gravity of the soil may be assumed as 2.65. 20. The subsoil strata at a site consist of fine sand 1.8m thick overlaying a stratum of clay 1.6m thick. Under the clay stratum lies a deposit of coarse extending to a considerable depth. The water table is 1.5m below the ground surface. Assuming the top fine sand to be saturated by capillary water, calculate the effective pressure at ground surface an at depth of 1.8m, 3.4m and 5m below the ground surface. Assume for find sand a=2.65, e=0.8 and for coarse sand a=2.66, e=0.5. what will be the change in effective pressure at depth 3.4m if no capillary water is assumed to be present in the fine sand and its bulk unit weight is assumed to be 16.68KN/ The unit weight of clay is 19.32KN/ .

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Sub: Geotechnical Engineering 21. The load from a continuous footing of width 2m, which may be considered to be strip load of considerable length, is 200KN/ . Determine the maximum principal stress at 1.5m depth below the footing, if the point lies (i) directly below the centre of the footing (ii) directly below the edge of the footing, (iii) 0.8m away from the edge of the footing. 22. In a laboratory consolidometer test on a 20mm thick sample of saturated clay taken from a site, 50% consolidation point was reached in 10min. Estimate the time required for the clay layer of 5m thickness at the site for 50% compression if there drainage only towards the top. What is the time required for the clay layer to reach 50% consolidation if the layer has double drainage instead of single drainage. 23. A layer of soft clay is 6m thick and lies under a newly constructed building. The weight of sand overlying a clay layer produces a pressure of 2.6Kg/ and the new construction increases the pressure by 1.0kg/ . If the compression index is 0.5. Compute settlement. Water content is 40% and specific gravity of grains is 2.65. 24. A vane, 10cm long and 8cm in diameter, was pressed into soft clay at the bottom of a bore hole. Torque was applied and gradually increased to 45N-m when failure took place. Subsequently, the vane rotated rapidly so as to completely remould the soil. The remoulded soil was sheared at a torque 18N-m. Calculate the cohesion of clay in the natural and remoulded states and also the value of the sensitivity. 25. A cut 9m deep is to be made in clay with a unit weight of 18KN/ and cohesion of 27KN/ . A hard stratum exists at a depth of 18m below the ground surface. Determine from Taylor’s stability number of factor of safety is 1.5. 26. In a consolidation test the following results were obtained. When the load was changed from 50KN/ to 100KN/ ,

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Topic : Soil Mechanics the void ratio changed from 0.7 to 0.65. Determine the coefficient of volume decrease and the compression index. 27. A cylindrical specimen of a saturated soil fails under an axial stress of 150KN/ in an unconfined compression test. The failure plane makes an angle of with the horizontal. Calculate the cohesion and angle of internal friction of soil. 28. Size of an isolated footing is to be limited to 1.5m square. Calculate the depth at which the footing should be placed to take a load of 200KN with a factor of safety 3. The soil is having angle of internal friction= . The weight of soil is 21KN/ . Bearing capacity factors for

29. A footing rests at a depth of 1m has a size of 3m and it causes a pressure increment of 200KN/ at its base. The soil profile at the site consists of sand for the top 3m, which is underlained by a clay layer of 3m. Water table is at a depth of 2.5m from the ground surface. The units weight of sand layer above and below water table are 16KN/ respectively. The unit weight of clay is 15KN/ the initial void ratio is 0.8 and compression index is 0.3. Determine the consolidation settlement at the middle of the clay layer. Assume 2:1 pressure distribution and consider the variation of pressure across the depth of the clay layer. 30. A group of 16 Piles of 50cm diameter is arranged with a centre to centre spacing of 1.0m. The piles are 9m long and are embedded in soft clay with cohesion 30KN/m. bearing resistance may be neglected for the piles. Adhesion factor is 0.6. Determine the ultimate load capacity of the pile group. 31. A pile group consists of a piles 30cm diameter and 10m length driven in clay. Unconfined compressive strength of soil is 200KN/ . And insitu density of soil is 200KN/ determine the safe load for the pile group.

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32. A building 10m in plan is built on a raft foundation resting on the surface. The soil profile consists of 4m dense sand over 3m thick silty clay resting on rock. The water table is at 2m below ground level. Consolidation test conducted on UDS of clay layer gave the following results. Initial and final void ratios and corresponding stresses are , =1.0, ̅ KN/ . If the weight of the building is 1000KN. What is the settlement? 33. Calculate the ultimate bearing capacity per unit area of (i) strip footing 2.5m wide (ii) square footing 4.75 (iii) circular footing 5.2m dia. The footing is supported on a soil for which the following data is available. KN/ .c=17KN/ , depth=1.75m,

34. An embankment of 10m height is constructed in a soil having c= 0.02N/ KN/ . Find the factor of safety with respect to cohesion and also the critical height of embankment. Assume stability number=0.05 35. Find the factor of safety against sliding along the interface for infinite slope with slope of . =16KN/ , c=10KN/ , Also find the height z that will give F.S of 2 against sliding along the interface. 36. A pile is driven with a single acting steam hammer of weight 15KN with a free fall of 900mm. The final set, the average of the last three blows is 27.5mm. Find the safe load using the engineering news formula. 37. A retaining wall is 4m high. Its back is vertical and it has got sandy backfill up to its top. The top of the fill is horizontal carries a uniform surcharge of 85KN/ . Determine the active earth pressure on the wall per meter length of wall. Water table is 1m below the top of the fill. Dry density

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Topic : Soil Mechanics of soil =18.5KN/ . Moisture content of soil above water table=12%. Angle of internal friction of soil = specific gravity of soil particles=2.65, porosity of backfill= . The wall friction may be neglected. 38. Compute the safe bearing capacity of square footing 1.5m 1.5m located at a depth of 1m below the ground level in a soil of average density 20KN/ . , . Assume a factor of safety of 2.5 and that the water table is very deep. Also compute the reduction in safe bearing capacity of the footing if the water table rises to the ground level. 39. Plate load test was performed on dense sand. Size of plate is 0.2 . find the settlement of a footing of size 3m under the pressure of 20KN/ if the plate settles by 5mm under this pressure. 40. A smooth retaining wall of 9m high retains for a top 4.5m soil with cohesion 0 and internal friction . KN/ . For the bottom 4.5m, the soil has cohesion of 0 and internal friction , KN/ . Top surface of soil is horizontal. Find resultant pressure and its point of application. 41. The field N value in a deposit of fully submerged find sand was 40 at a depth of 6m. The average saturated unit weight of soil is 19KN/ .calculate the corrected N value. 42. A reinforced concrete pile weighing 30KN (inclusive of helmet and dolly) is driven by a drop hammer weighing 40KN and having an effective fall of 0.8m. The average set per blow is 1.4cm. The total temporary elastic compression is 1.8cm. Assuming the co-efficient of restitution as 0.25 and factor of safety of 2, determine the ultimate bearing capacity and the allowable load for the pile. 43. A 450mm wide, square in section concrete pile, 15m long is driven in a deep deposit

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Sub: Geotechnical Engineering of uniform clay laboratory unconfined compression tests on undistributed samples indicates an average unconfined compressive strength of 75KN/ . Calculate the ultimate load capacity of the pile. Take adhesion factor as 0.8 and as 9. 44. A group of 4 4 piles is driven to bear in a dense sand layer 2.5m thick. Pile spacing is 1.0m c/c, diameter is 0.4m. the total load on top is 3000KN. A compressible layer of clay, 2m thick exists below dense sand. Clay is underlained by rock. Find the settlement of pile group if co-efficient of volume compressibility of clay layer is 1.5 /KN. 45. A smooth vertical wall of 4.5m high, retains a soil with c= 25KN/ , The horizontal backfill surface carries a uniform surcharge load 50KN/ . The retaining wall is tend to move towards the soil. What is the magnitude and point of application of total pressure? 46. Determine the safe load carrying of pile group consists of 9 friction pile of 30cm diameter and 12m lengths driven in soft clay. F.S=3, 0.6. 47. A square pile group of 16 piles penetrates through a filled up soil of 3m depth. The pile diameter of 250mm and file spacing is 0.75m. The unit cohesion of the material is 18KN/ . And the unit weight of soil is 15KN/ compute the negative skin friction on the group.

Topic : Soil Mechanics foundation 18KN/ .

soil

has

c=9KN/

r=

50. A footing 3m 2m in plan transmits a pressure of 160KN/ on a cohesive soil having E= 9 KN/ and =0.46. Determine the immediate settlement of the centre. 51. A saturated sand has a dry unit weight of 18KN/ and a specific gravity of 2.65. If =10KN/ , the water content of the soil is . 52. The void ratio of sample is 1 the corresponding porosity of the sample is 53. The total unit of soil is 18.8KN/ , the specific gravity (G) of the solid particles of the soil is 2.67 and water content of the soil is 12% calculate dry unit weight, void ratio and degree of saturation. 54. The unit weight of a soil at zero air voids depends on a) Specific gravity b) Water content c) Unit wt. of water d) All 55. Which one of the following relations is not correct? a) b) c) d) 56. If the porosity of soil sample is 20%, the void ratio is a) 0.20 b) 0.80 c) 1.00 d) 0.25

48. The load carrying capacity (against shear failure) of a surface square footing founded on sandy soil is 800 KN. If the size of the square footing is reduced by one half, what will be its load carrying capacity against shear failure?

57. Principle involved in relationship between submerged unit weight and saturated unit weight of soil is based on a) Equilibrium of floating bodies b) Archemedes principle c) Stokes’s law d) Darcy’s law

49. Determine the depth at which a circular footing of 3.3m diameter be found to be provided to carry a safe load of 1500KN with a factor of safety of 2.40. the

58. A soil sample has a void ratio 0.5 and porosity will be close to a) 50% b) 66% c) 100% d) 33%

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Sub: Geotechnical Engineering 59. A barrow pit soil has a dry density of 17KN/ . How many cubic meters of this soil will be required to construct an embankment of 100 volume with a dry density of 16KN/ a) 94 b) 106 c) 100

d) 90

60. The void ratio and specific gravity of a soil are 0.65 & 2.72 respectively. The degree of saturation (%) corresponding to water content of 20% is a) 65.3 b) 20.9 c) 83.7 d) 54.4 61.

A saturated soil mass has a total density 22KN/ and water of 10%. The bulk density and dry density of the soil are a) 12KN/ and 20KN/ b) 22 &20KN/ c) 19.8 &19.8KN/ d) 23.2 & 19.8KN/

62. The water content of saturated soil and the specific gravity of soil solids were found to be 30% and 2.7 respectively. Assuming the unit of water to be 10KN/ , the saturated unit weight (KN/ ) and the void ratio of the soil are a) 19.4, 0.81 b) 18.5, 0.30 c) 19.4, 0.45 d) 18.5, 0.45 63. The saturated unit weight of the sand (KN/ ) is to be find for water content= 20%, G= 2.7 and =10KN/ a) 15 b) 18 c) 21 d) 24 64. A saturated undistributed sample from a clay stratum has moisture content of 22.22% and specific weight is 2.7. assuming =10KN/ , the void ratio and saturated unit weight of clay respectively are a) 0.6 and 16.875KN/ b) 0.3 and 20.625KN/ c) 0.6 and 20.625KN/ d) 0.3 and 16.975KN/ 65. In a compaction test, G, W, S, and e represent the specific gravity, water content, degree of saturation and void ratio of the soil sample respectively. If represents unit weight of water and represents the dry unit weight of the soil, the equation for zero-air voids line is a)

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Topic : Soil Mechanics b) c)

=

d) 66. In this natural condition, a soil sample has a mass of 1-980kg and a volume of 0.001 . After being completely dried in an oven, the mass of sample is 1.8kg. Specific gravity G is 2.7. Unit weight of water is 10KN/ . The degree of saturation of the soil is a) 0.65 b) 0.70 c) 0.54 d) 0.61 67. The maximum possible value of group index for a soil is . 68. The description sandy silty clay signifies that a) The soil contains unequal proportions of the three constituents in the order sand > silt > clay b) The soil contains equal proportions of sand, silt and clay c) The soil contains unequal proportions of three constituents such that clay>silt>sand d) There is no information regarding the relative proportions of the three 69. The Atterberg limits of clay are 38%, 27% and 24.5%. Its natural water content is 30%. The clay is in state. 70. A soil having particles of nearly the same size is known as a) Well graded b) Uniformly graded c) Poorly graded d) Gap graded 71. The consistency of saturated cohesive soil is affected by a) Water content b) Particle size distribution c) Density index d) Co-efficient of permeability 72. The equation of A-line in the plasticity chary is . 73. The particle size distribution curves are extremely useful for the classification of a) Fine grained soils b) Coarse grained soils c) Both fine and coarse grained soils d) Silts and clays

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Sub: Geotechnical Engineering 74. Consistency index for a clay soil is a) b) c) LL-PL d) 0.5w 75. Some of the structural strength of a clayey material is lost by remolding is slowly recovered with time. This property of soils to undergo an isothermal gel-to-sol-to-gel transformation upon agitation and subsequent rest is termed a) Isotropy b) Anisotropy c) Thixotropy d) Allotropy 76. The values of liquid limit and plasticity index for soils having common geological origin in a restricted locality usually define a) A zone above A-line b) A straight line parallel to A-line c) A straight line perpendicular to A-line d) Points may be anywhere in the plasticity chart 77. The toughness index of a clayey soils is given by a) Plasticity index/flow index b) Liquid limit/plastic limit c) Liquidity index/plastic limit d) Plastic limit/ liquidity index 78. Soil has been compacted in an embankment at bulk density of 2.15Mg/ and a water content of 12%. The value of specific gravity of soil solids is 2.65. The water table is well below the foundation level. Estimate the dry density, void ratio, degree of saturation and air content of compacted soil. 79. The un drained cohesion of a remoulded clay soil is 10KN/ . If the sensivity of the clay is 20, the corresponding remoulded compressive strength is a) 5KN/ b) 10KN/ c)

20KN/

d) 200KN/

80. A soil mass contains 40% gravel, 50%sand & 10% silt. The soil can be classified as a) Silty sandy gravel having co-efficient of uniformity less than 60

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Topic : Soil Mechanics b) Silty gravelly sand having co-efficient of uniformity equal to 10 c) Gravelly silty sand having coefficient of uniformity greater than 60 d) Gravelly silty sand and its coefficient of uniformity cannot be determined. 81. In a standard proctor test, 1.8kg of moist soil was filling the mould (volume=944Cc) after compaction. A soil sample weighing 23g was taken from mould and over dried for 24 hours at a temperature of C weight of the dry sample was found to be 20g. Specific gravity of soil solids is a=2.7. the theoretical maximum value of the dry unit weight of the soil at that water content is equal to a) 4.67KN/ b) 11.5KN/ c) 16.26KN/

d) 18.85KN/

82. Laboratory sieve analysis was carried out on a soil sample using complete set of standard IS sieves. Out of 500gr. Of soil used in the test, 200g was retained on IS600 size, 250g was retained on IS-500 sieve and remaining 50g was retained on IS-425 sieve a) The Coefficient of uniformity of soil is a. 0.9 b. 1.0 c. 1.1 d. 1.2 b) The classification of soil is a. SP b. SW c. CI d. GW 83. Sieve analysis on a dry soil sample of mass 1000g showed that 980g and 270g of soil pass through 4.75mm and 0.075mm sieve, respectively. The liquid limit and plastic limit of the soil fraction pass through 425 sieves are 40% and 18% respectively. The soil may be classified as a) SC b) MI c) CI d) SM 84. Group symbols to silty sand and clayey sand are respectively a) SS and CS b) SM and CS c) SM and SC d) MS and CS

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Sub: Geotechnical Engineering 85. The liquid limit (LL), plastic limit (PL) and shrinkage limit (SL) of a cohesive soil satisfy the relation a) LL>PL>SL b) LL>PL>SL c) LL>PLSL 86. The laboratory test results of a soil sample are given be Percentage finer than 4.75mm=60 Percentage finer than 0.075mm=30 Liquid limit=35% plastic limit=27% The soil classification is a) GM b) SM c) GC d) ML-MI 87. A fine grained soil has liquid limit of 60 and plastic limit of 20. AS per the plasticity chart, according to IS classification the soil is represented by the letter symbols a) CL b) CJ c) CH CL-ML 88. A construction site is 3m thick clay layer is followed by a 4m thick gravel layer, which is resting on impervious rock. A load of 25KN/ is applied suddenly at the surface. The saturated unit weights of the soil are 19KN/ and 20KN/ for the clay and gravel layers, respectively. The water table is at the surface draw diagrams showing variation with depth of total neutral and effective stresses in the layers. 89. The soil profile at the bottom of the valley comprises 2m of and overlying 10m of clay. The clay layer itself is resting on highly permeable weathered sand stone. The unit wt. of sand above water table, which is 1m below the water table it is 20KN/ . The saturated unit wt. of clay is 22KN/ . If the water table in the sand stone layer is under artesian condition, corresponding to a stand pipe level at 5m above the ground plot the variation of (i) total stress (ii) pore water pressure (iii) effective stress with depth. 90. State true or false: effective stresses in a sand layer below a lake do not alter as level fluctuates.

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Topic : Soil Mechanics 91. A sheet of water thickness 1m is available to the voids of cohesion- less soil to a degree of saturation of 80%. The void ratio of the soil is 0.5. Determine the thickness of the layer required to accommodate this amount of water. 92. A cohesion less soil with a void ratio e=0.6 and G=2.65 exists at a site where the water table is located at a depth of 2m below the ground surface. Calculate effective stress at a depth 5m below the ground surface. 93. For the subsoil condition shown in Fig. calculate the total neutral and effective stress at 1m, 3m & 6m below ground level. =10KN/

94. The total unit weight of the glacial outwash is 16KN/ =10KN/ . The specific gravity of the solids is 2.67. the water content of the soil is 17% calculate a) b) c) e d) S 95. A layer of saturated clay 5m thick is over laid by sand 4.0m deep. The water table is 3m below the top surface. The saturated unit weight of sand is 18KN/ and 20KN/ respectively. Above the water table, the unit weight of sand is 17KN/ . Calculate the effective pressures on a horizontal plane at a depth of 9mbelow the ground surface. What will be the increase in the effective pressure at 9m if the soil gets saturated by capillary, up to height of 1m above the water table? =9.81KN/

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Sub: Geotechnical Engineering 96. A 5m thick clay layer lies between two layers of sand each 4m thick, the top of the upper layer of sand being at ground level. The water table is 2m below the ground level but the lower layer of sand is under artesian pressure the piezometric surface being 4m above ground level. Of clay is 20KN/ & of sand is 19KN/ . Above water table of sand is 16.5KN/ . Calculate the effective stresses at top and bottom of the clay layer.

Topic : Soil Mechanics 99. A 10m thick clay layer is underlain by a sand layer of 20m depth. The water table is 5m below the surface of clay layer. The soil above the water table is capillary saturated. =19KN/ . If now the water table rises to the surface, the effective stress at a point P on the interface will (a) Increase by 5 (b) Remain unchanged (c) Decrease by 5 (d) Decrease by 10

97. Data from a sieve analysis conducted on a given sample of soil showed that 67% of the particles passed through 75 . The and of the finer fraction was found to be 45% and 33% respectively. The group symbol is a) SC b) MI c) CH d) MH 98. For the soil strata shown in fig. the water table is lowered by drainage by 2m and if the top 2m thick silty sand stratum remains saturated by capillary action even after lowering of water table. The increase in effective vertical pressure in KPa at mid height of clay layer will be

100. Assuming that a river bed level does not change and the depth of water in river was 10m, 15m and 8m during the months of February, July and December. Respectively of a particular year. =20KN/ . 10KN/ . The effective stress at a depth of 10m below river bed during these months would be Feb July dec a) 300 350 320 b) 100 100 100 c) 200 250 180 d) 300 350 280 101. The coefficient of permeability of a soil is 5 cm/sec for a certain pore fluid. If the viscosity of the pore fluid is reduced to half, the co-efficient of permeability will be a) 5 cm/sec b) 10 cm/sec c) 2.5 cm/sec d) 1.25 cm/sec 102. The piezometric head at point C, in the experimental set up shown in fig. when

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Sub: Geotechnical Engineering the flow takes under constant head through the soils A and B is a) 0 cm b) 40 cm c) 80 cm d) 120 cm

103. According to Darcy’s law for flow through porous media, the velocity is proportional to a) Effective stress b) Hydraulic gradient c) Cohesion d) Stability number

Topic : Soil Mechanics c) (i) AD (ii) AF d) (i) AB (ii) AB

106. Estimate the flow quantity (in liters/ sec) through the soil the pipe shown below. The pressure heads at two locations shown in figure. The internal diameter of pipe is 1m and coefficient of permeability is 1 m/sec

104. In a falling head permeameter test on a silty clay sample, the following results were obtained: sample length 120mm; sample diameter;80mm; initial head 1200 mm, final head 400mm, time for fall in head 6 minutes, stand pipe diameter 4mm, find the coefficient of permeability of the soil in mm/sec 105. The two tubes shown in fig. may be considered to be permeameter. Dimensions of the sample in Fig (i) & (ii) are alike, and the elevations of head water and tail water are the same for both the figures. A, B. . . etc. indicate points and AB,AE. . .etc. indicate heads loss through these samples are a) (i) BD (ii) FB b) (i) AC (ii) AE

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107. In filling head permeability test the initial head of 1.0m dropped to 0.35m in 3 hours, the diameter of stand pipe 5mm. the soil specimen was 200mm long and 100mm diameter. The coefficient of permeability of the soil is a) 4.86 cm/sec b) 4.86 cm/sec c) 4.86 cm/sec

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Sub: Geotechnical Engineering d) 4.86

cm/sec

108. In a constant head permeameter with cross section area of , when the flow was taking place under a hydraulic gradient of 0.5, the amount of water collected in 60 section is 600 cc. the permeability of the soil is a) 0.002 cm/s b) 0.02 cm/s c) 0.2 cm/s d) 2.0 cm/s 109. The soil profile below a lake with water level at elevation =0 m and lake bottom at elevation =-10 m is shown in fig. where k is permeability co-efficient. A piezometer installed in sand layer shows a reading of +10 m elevation. Assume that the piezometric head is uniform in the sand layer. The quantity of water (in ) flowing into the lake from the sand layer through the silt layer per unit area of lake bed is a) 1.5 b) 2.0 c) 1.0 d) 0.5

Topic : Soil Mechanics a) b) c) d)

relationship is linear is linear is linear is linear

111. A sampling tube has inner diameter of 72mm and an outer of 75mm. The area ratio is . 112. A saturated clay layer of 5m thickness takes 1.5 year for 50% primary consolidation when drained on both sides. Its coefficient of volume change /KN. Determine coefficient of compressibility (in ) and the coefficient of permeability (in m/yr.) Assume KN/ 113. The coefficient of consolidation is used for a) Establishing the duration of primary consolidation b) Establishing the amount of settlement for a load increment c) Determining the depth to which the soil is stressed when loads are applied on the surface of a soil deposit d) Determining the pre-consolidation pressure for soil deposits known to be over-consolidated. 114. A standard Oedometer test in the laboratory indicated that 0.02 m thick clay specimen took 0.5 day to undergo 90% primary consolidation. How many days will a 2m thick layer of identical clay sandwiched between sand layers and subjected to an identical stress increment take to undergo the same? 115. The number of flow channels and head drops is 4 and 12 respectively. If the difference in the U/s and d/s water levels is 3 m, what is the discharge per m width of a sheet pile wall, if K=0.1 m/s?

110. Terzaghi’s one dimensional consolidation theory assumes that

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116. A footing 1.5 m square is located 1.5 m below the surface of a uniform soil deposit of density 20 KN/ . If the total thickness of the deposit, which is underlain by rock strata, is 3.5 m, compute the primary

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Sub: Geotechnical Engineering consolidation settlement of footing when it carries a load of 225 KN. 2:1 distribution is to be used. Consider 2 layers. 117. A homogeneous anisotropic earth dam which is 20m high constructed on an impermeable foundation. m/s and m/s. the water level on reservoir side is at 18m from the base of the dam. Downstream side is dry. It is seen that there are 4 flow channels and 18 equi potential drop in a square flow net drawn in the transformed dam section. Estimate the quantity of seepage per unit length. 118. In the laboratory test on a clay sample of thickness 25mm drained at top only, 50% consolidation occurred in 11 minutes. Find the time required for the corresponding clay layer in the field 3m thick and drained at top and bottom, to undergo 70% consolidation. Assume

119. A 20 mm diameter well fully penetrates a confined aquifer of 30m depth. For a pumpage of 35 lit/sec the steady draw downs at 100 m and 300m distances from the well are observed as 3.2m and 2.5m respectively. Estimate the K in m/day and transmissibility of the aquifer in / day. Estimate also the draw down at the well. (Transmissibility= permeability depth of aqifer) 120. A clay layer 8m thick is subjected to a pressure of 70 KN/ . If the layer has a double drainage and undergoes 50% consolidation ( ) in one year. Determine the coefficient of consolidation? If the K is 0.04 m/year find settlement in one year. Use KN/ 121. A soil mass has co-efficient of horizontal and vertical permeability as cm/s and 4 cm/s respectively. The transformed permeability of an equivalent isotropic soil mass is

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Topic : Soil Mechanics a) b) c) d)

cm/s cm/s cm/s cm/s

122. In a compaction test, as the compaction effort is increased, the optimum moisture content a) Decreases b) Remain same c) Increases d) Increases first there after decreases 123. The slope of the e-log P curve for a soil mass gives a) Co-efficient of permeability b) Coefficient of consolidation c) Compression index d) Coefficient of volume compressibility

124. A settlement analysis carried out proposed structure indicates that 9 cm of settlement will occur in 5 years and the final settlement will occur in 50 year and final settlement will be 45 cm based on double drainage exists. Estimate the settlement at the end of 5 years for the changed condition. 125. The time for a clay layer to achieve 90% consolidation is 15 years. The time required to achieve 90% consolidation, if the layer were twice as thick, 3 times more permeable and 4 times more compressible would be a) 70 years b) 75 years c) 80 years d) 85 years 126. Consolidation in soils a) Is a function of effective stress b) Does not depend on the present stress c) Is a function of the pore water pressure d) Is a function of the total stress 127. For an isotropic soil, permeabilities in x and y directions are respectively in a two dimensional flow.

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Sub: Geotechnical Engineering The effective permeability soil is given by a)

Topic : Soil Mechanics for the

b) c)

(

d)

(

) )

⁄

⁄

128. A building is constructed on the ground surface beneath which there is a 2m thick saturated clay layer sand witched between two highly pervious layers. The building starts setting with time if =2.5 cm/s. in how many days will the building reach half of its final settlement?

129. In an Oedometer test, a specimen of saturated clay 19 mm reaches 50% consolidation in 20 minutes. How long it would take a layer of this clay 5m thick to reach the same degree of consolidation under the same stress and drainage conditions? How long would it take for the clay layer to reach 30% consolidation? 130. A well of 300mm diameter is located in a confined aquifer of 40m thick. The aquifer has a hydraulic conductivity of 25 m/day. And the radius of influence is 300 m. determine the discharge if the diameter in / hr. from the well if the draw down is 3m. also determine the % increase in discharge if the diameter is made to 450mm, with other conditions remains same. 131. The time for a clay layer to achieve 85% consolidation is 10 years. If the layer was half as thick, 10 times more permeable and 4 times more compressible. The time that would be required to achieve the same degree of consolidation is a) 1 year b) 5 years c) 12 years d) 16 years

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132. At a reclamation site for which the soil strata is shown in Fig. a 3m thick layer of a full material is to be laid instaneous on the top surface. If the coefficient of volume compressibility for clay is 2.2 /KN, the consolidation settlement of the clay layer due to placing of fill material will be a) 69.5mm b) 139mm c) 228mm d) 278mm 133. A 6m thick clay layer under goes 90% consolidation four times faster under two way drainage as compared to one drainage in an identical clay of 15m thick, two way drainage will be faster as compared to one way drainage by a) 8 times b) 4 times c) 2.5 times d) 2 times

134. A 6m thick clay layer under goes 90% consolidation four times faster under two way drainage as compared to one drainage in an identical clay of 15m thick, two way drainage will be faster as compared to one way drainage by e) 8 times f) 4 times g) 2.5 times h) 2 times 135. The average effective over burden pressure on 10 m thick homogeneous saturated clay layer is 150 KPa. Consolidation test on an undisturbed soil sample taken from the clay layer showed that the void ratio decreased from 0.6 to 0.5 by increasing the stress intensity from 100 KPa to 300KPa (a=2.65) a) The initial void ratio of clay layer is a. 0.209 b. 0.563 c. 0.746

d. 1.000

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b) The total consolidation settlement of the clay layer due to the construction of a structure imposing an additional stress intensity of 200 KPa is a. 0.1 m b. 0.25 m c.

0.35

d. 0.5m

136. The equation transformed

can be to

by

substituting a) b) c)

√

d)

√

e) 137. A saturated clay stratum draining both at the top and bottom undergoes 50% consolidation in 16 years under an applied load. If additional drainage layer were present at the middle of the clay stratum, 50% consolidation would occur in a) 2 years b) 4 years c) 8 years d) 16 years 138. A well of diameter 20 cm fully penetrates a confined aquifer. After a long period of pumping at rate of 2720 lit/min. The observations of draw down taken at 10 m and 100 m distances from the centre of the well are found to be 3m and 0.5m respectively. The transmissibility of the aquifer is a) 676 day b) 576 day c) 526 day d) 249 day 139. In a consolidated drained tri axial test, a specimen of clay fails at a cell pressure of 60 KN/ . The effective shear strength parameters are KN/ and determine the compressive strength.

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140. and strength.

determine the compressive

141. An un-confined compression test yielded strength of 0-1N . If the failure plane is inclined at to the horizontal, what are the values of the shear strength parameters. 142. In a drained tri axial compression test conducted on dry sand, failure occurred when deviator stress was 218 KN at a confining pressure of 61 KN . What is the effective angle of shearing resistance and inclination of failure plane to major principle plane? a) b) c) d) 143. The average friction angle ( ) for a homogeneous sand deposit is . The ratio of the major and minor principal stresses at any point in the soil medium, at failure will be .

144. The appropriate field test to determine the undrained shear strength of soft clay is a) Plate load test b) Static cone penetration test c) Standard penetration test d) Vane shear test 145. A given saturated clay is known to have effective strength parameters of KPa and = . A sample of this clay was brought to failure quickly so that no dissipation of the pore water pressures could occur. At failure it was known that , = 10KPa and =20 KPa a) Estimate the values of at failure b) What was the effective normal stress on the failure plane? c) What was the value of un drained shear strength ?

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Sub: Geotechnical Engineering 146. Vane test is normally used determining in situ shear strength of a) Soft clays b) Sand c) Stiff clays d) Gravel

Topic : Soil Mechanics for

147. What is the shear strength in terms of effective stress on a plane within a saturated soil mass at a point where the total normal stress is 295 KPa and the pore water pressure 120KPa? The effective shear strength parameters are 12 KPa And = 148. If an element of a stressed body is in a state of pure shear with a magnitude of 80N/ , the magnitude of maximum principal stress at that location is a) 80 N/ b) 113.14 N/ c) 120 N/ d) 56.57N/ 149. In a drained tri axial compression test conducted on dry sand, failure occurred when deviator stress was 218 KN at a confining pressure of 61 KN . What is the effective angle of shearing resistance and inclination of failure plane to major principle plane? e) f) g) h) a) 150. If the effective stress parameters of a soil are =10 KPa and = , the shear strength on a plane within the saturated soil mass at a point where the total normal stress is 300 KPa and pore water pressure is 150 KPa will be a) 90.5 KPa b) 96.6KPa c) 101.5KPa d) 105.5KPa

MPa respectively, then maximum shear stress at the point is a) 10 MPa b) 15 MPa c) 20 MPa d) 30 MPa

151. A direct shear test was conducted on a cohesion less soil (c=0). Specimen under a normal stress of 200KN/ . The specimen failed at a shear stress of 100KN/ . The angle of internal friction of soil is a) 26.6 b) 29.5 c)

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d) 32.6

152. An infinite slope, with a slope angle of , is made up of a cohesion less soil having and KN/ . It experiences seepage with the water table at the surface. If the unit weight of water is 10 KN/ , the factor of safety against failure, without seepage and with seepage will be and Respectively. .

153. A slope is to be constructed in a soil for which 0 and . It is to be assumed that the water level may occasionally reach the surface of slope with seepage taking place parallel to slope. Determine the maximum slope angle for a factor of safety of 1.5. Assuming a potential failure surface parallel to the slope. What would be the factor of safety of the slope, constructed at this angle, if the water table should be well below the surface? The saturated unit weight is 19 KN/ . 154. The vertical stress at depth. Z directly below the point load P is (K is constant) a) b) c)

151. If the principal stresses in a two dimensional case are -10 MPa and 20

30.0

d)

√

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Sub: Geotechnical Engineering 155. A slope is excavated to a depth of 10m in a deep of 10m in a deep layer of saturated clay of unit weight 20 KN/ . The relevant shear strength parameters are KN/ and . The rock edge is at a great depth. The Taylor stability coefficient coefficient for and slope angle is 0.18. the factor of safety of the load is a) 2.0 b) 2.1 c) 2.2 d) 2.3 156. A point load of 700 KN is applied on the surface of thick layer of saturated clay. Using Boussinesq’s elastic analysis, the estimated vertical stress ( ). At a depth of 2m and radial distance of 1.0m from the point of application of the load is a) 47.5 KPa b) 47.6 KPa c) 47.7 KPa d) 47.8 KPa 157. An infinite slope is to be constructed in a soil. The effective stress strength parameters of the soil are . The saturated unit weight of the slope is 20 KN/ . And the KN/ . Assuming that seepage is occurring parallel to the slope, the maximum slope angle for a factor of safety of 1.5 would be a) 10. b) 11. c) 12. 14. 158. A canal having side slopes 1:1 is proposed to be constructed in a cohesive soil to a depth of 10m below the ground surface. The soil properties are KPa, e= 1.0, G= 2.65 a) If Taylor’s stability number, and if the canal flows fall, the factor of safety with respect to cohesion against failure of the canal bank slopes will be a. 3.7 b. 1.85 c. 1.0 d. None

Topic : Soil Mechanics 159. For two infinite slopes (one in dry condition and other in submerged condition) in a sand deposit having the angle of shearing resistance , factor of safety was determined as 1.5 (for both slopes). The slope angles would have been a) For dry and for submerged. b) c) , d) , 160. The factor of safety of an infinite soil slope shown in fig having properties e=0, KN/ and KN/ is approximately equal to a) 0.70 b) 0.8 c) 1.0 d) 1.2

161. The vertical stress at point due to the point load Q on the ground surface as shown in fig. is . According to Boussinesq’s eqn, the vertical stress at will be a) b) c) d)

b) If there is a sudden draw down of water in the canal and if Taylor’s stability number for the reduced value of is 0.126, the factor of safety with respect to cohesion against the failure of bank slopes will be a. 1.85 b. 1.18 c. 0.84 d. 0.53

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167. Soils transported by wind are known as soil. 162. An unsupported excavation is to be made in a clay layer. If KN/ , c= 30KN/ and a. Calculate depth of tension cracks b. Calculate the maximum possible unsupported depth c. Draw the active pressure distribution diagram

168. Plot the active earth pressure distribution on the retaining wall shown by Rankine’s theory for data given below 10 KN/ KN/ C=15 KN/

163. Two consolidated drained shear tests on silt yielded the following data: 0.2 0.46 0.4 0.88 If this material is used as a backfill for a smooth vertical retaining wall of 10m height, what is the active earth pressure at the base of the wall? Density of the fill is 1.6g/cc.

164. A large scale bearing capacity test on a footing of size 1.05 m at a depth of 1.5 m yielding on ultimate value of 141 KN unconfined compressive tests on the soft saturated clay yielded a strength of 0.03 N/ . =1.6g/cc. How much does the test value differ from that obtained using Terzaghi’s bearing capacity equation? 165. For the trial slip circle shown in fig. calculate the factor of safety W= 346 KN/m KN/ 20 KN/ radius = 9 m

169. The total active thrust on a vertical wall 3m high retaining a horizontal sand backfill KN/ , when the water table is at the bottom of the wall, will be a) 30 KN/m b) 35 KN/m c) 40 KN/m d) 45 KN/m 170. Compute the intensity of passive earth pressure at a depth of 8 m in cohesion less sand with an angle of internal friction of when water rises to the ground level. KN/ , KN/

171. A vertical excavation was made in a clay deposit having unit weight of 22 KN/ . It caved in after the digging reached 4 m depth. Assuming . Calculate the magnitude of cohesion

166. A vertical wall 6 m high above the water table, retains a soil slope, 18 KN/ c=0, Ka= ?

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172. Two footings, one circular and the other square, are founded on the surface of a purely cohesion less soil. The diameter of the circular footing is same as that of the side of the square

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footing. The ratio of their ultimate bearing capacities is a)

⁄

b)

⁄

c) 1.0 d) 1.3 173. To have zero active pressure intensity at the tip of a wall in cohesive soil one should apply a uniform surcharge intensity of a) tan b) cot c) tan d) tan 174. 1. Find active earth pressure per meter of wall 2. find location of the resultant line of action.

177. Soils that have been deposited from suspension in running water are called . 178. A sample of sand with G=2.65 has a porosity of 40%. Find out the . When fully saturated when the degree of saturation is 50% 179. A clay sample has a liquid limit of 42.5%, plastic limit of 22.4% and natural moisture content as 30%. Determine its plasticity index and liquidity index. 180. In a shrinkage limit test a 9.6 cc container was filled with soil slurry. The weight of the saturated soil was 17.46 g. The slurry was then gradually dried first in atmosphere and then in an oven at a constant temperature of C. The weight and volume of the dried soil were 11.58 g and 5.22 cc respectively. Determine the shrinkage limit of the soil.

175. A plate load test was conducted in sand on a 300 mm diameter plate. If the plate settlement was 5 mm at a pressure of 100 KPa, the settlement of a5m rectangular footing at the same pressure will be a) 9.4 b) 18.6 c) 12.7 d) 17.8 176. Estimate the resultant thrust and its location.

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181. A sample of sand taken from a natural deposit has a porosity of 35%. For a volume of 495 cc the dry weights in the densest and loosest states are 1100 g and 800g respectively. Compute the relative density of sand assuming the specific gravity of solids to be 2.65 182. Laboratory sieve analysis was carried out on a soil sample using complete set of sieves. Out of 1200 gm of sample, 480 gm retained on 4.75mm sieve, 360 gm retained on 2 mm sieve and 240 gm retained on 75 sieve. Limit and plastic limit of soil are 40%

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Sub: Geotechnical Engineering and 20% respectively. Find cc, classify the soil according to IS.

Topic : Soil Mechanics and

183. A barrow pit density is 18 KN/ . How many soil required to construct an embankment of 200 with KN/ . 184. A compaction of an embankment is carried out in 300mm thick horizontal layers. The rammer used for compaction has the foot of area 0.05 sq.m. The energy developed per drop of the hammer is 40 kg-m. Assuming 50% more energy I each pass due to overlap, calculate the number of passes required to develop compactive energy equivalent to Indian standard (light compaction for each layer). 185. The end of a clean glass tube is inserted in pure water. What is the height of capillary rise, if the tube is a) 0.1 mm b) 0.001 mm in diameter. 186. A sample of soil for a constant head permeability test yields following data: dia of permeameter= 7.6 cm. length of soil sample = 20 cm, head causing flow = 15 cm, quantity of water collected in 10 min = 150 cc. , KN/ . Determine a) Coefficient of permeability in cm/s b) Superficial velocity flow c) Seepage velocity 187. For the cases 1 and 2 of fig determine the pressure head, elevation head, total head and head loss at the entering end, exit end and point X of the sample.

188. a) What is the quantity of water flowing per minute? b) To what height above xx would the water rise in a piezometer inserted at points 1, 2 & 3? c) What is the effective stress at mid height of soil A? Soil A: K= cm/s = 18 KN/ Soil B: K= cm/s = 20 KN/

189. An deposit of fine sand the water table is 3m below the ground surface but the sand up to a height of 1 m above the water table is saturated by capillary water. The sand above this height may be considered dry. For the sand = 2.68 and 𝛈=40% calculate the effective stress at a depth of 8m 190. A falling head permeability test was performed on a sand sample and the following data were recorded. c/s area of permeameter=100 . Length of soil sample is 15 cm. area of stand

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Sub: Geotechnical Engineering pipe =1 , time taken for the head to fall from 150 cm to 50 cm =8min. temperature of water= C dry mass of the soil specimen =2.2 kg and compute coefficient of permeability of the soil for a void ratio of 0.70 and temperature of C 8.95 mill poises 10.09 mill poises 191. Two rows of sheet piles are driven to a depth of 4.4 m below the bed of a river to form a coffer dam. Excavation is then carried out within the coffer Dam up to a depth of 3.3m below water level by keeping the area free from water by pumping. The river bed is sand with K=3 cm/s and is under lain by an impermeable stratum at a depth of 6.0m below the river bed. What is the quantity of flow into the coffer dam per hour per m. Length of the sheet pile walls? Is there any danger of quick condition developing at the bottom of excavation?

Topic : Soil Mechanics increment due to this loading at a point 7 m beneath the centre of the structure. 194. Representative samples of a layer of silty clay 5 m thick, were tested in a consolidometer and the following results were obtained. Initial void ratio pre consolidation stress ̅ =120 KN/ re-compression index, , compression index =0.27. estimate the consolidation settlement if the present average over burden stress of the layer ̅̅̅ is 70 KN/ and increase in average stress in the layer is 80 KN/ 195. A normally consolidated clay layer settled by 20 mm when the effective stress was increased from 25 KN/ to 50 KN/ . What will be the settlement when the effective stress is increased from 50 KN/ to 100 KN/ 196. Certain clay has a thickness of 5 m. after 1 year when the clay was 50% consolidated, 8cm of settlement had occurred. For similar clay and loading conditions, how much settlement would occur at the end of 1 year and 4 years respectively, if the thickness of this new layer were 25 m. 197. On a reclamination site where the water table is at the ground surface, a layer of silty sand, 4 m thick, over lies a layer of soft clay, 10m thick underlying the clay layer is sandy gravel. A 3 m thick layer of fill is to be laid over the site. Unit wt of fill =21 KN/ , of silty sand=20 KN/ , of clay=18 KN/ . of clay= 2.2 /KN. of the clay= 0.8 year. Calculate the consolidation settlement of the clay layer due to the placing of the fill

192. An excavated structure with a total weight of 10,000 KN is supported on a tower with 4 legs rest on piers located at the corners of a square 6 m on a side. What is the vertical stress

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198. The effective stress shear strength parameters of a soil are = 25 KN/ and . Determine the shearing resistance on a plane within

Page 20

Sub: Geotechnical Engineering a submerged soil mass where the total normal stress is 328 KN/ and pore water pressure is 114 KN/ . 199. A symmetrical 16 pile group in soft clay, with unconfined compressive strength of 40 KN/ is to be used as foundation for a column. The piles are 300 mm in diameter and 10 m long. Determine the maximum load the group can carry with piles failing (i) individually and (ii) as a block.

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200. A precast pile is driven with a drop hammer weighing 50 KN with a fall of 1.5m. the average penetration of the load carrying capacity of pile according to engineering news formula.

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TEST PAPER OF GEOTECH1.docx

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