Sub: Geotechnical Engineering Topic : Three Phase SystemMODULE-43C Origin of soils, soil classification, three-phase system, fundamental definitions, relationship and interrelationships, _________________________________________________________________________ 1. The void ratio and specific gravity of a soil are 0.65 and 2.72 respectively. The degree of saturation (in percent) corresponding to water content of 20% is (A) 65.3 (B) 20.9 (C) 83.7 (D) 54.4 Ans: 0.65 0.544 0.2*2.72 2.72 1 2. The avoid ratios at the densest, loosest and the natural states of a sand deposit are 0.2, 0.6 and 0.4, respectively. The relative density of the deposit is (A) 100% (B) 75% (C) 50% (D) 25% Ans: 3. The following data were obtained from a liquid limit lest conducted on a soil sample. Number 17 22 25 28 34 of blows Water 68.3 63.1 61.9 60.6 60.5 content (%) The liquid limit of the soil is (A) 63.1 % (B) 62.8 % (C) 61.9 % (D) 60.6 % JH ACADEMY Page 1 Sub: Geotechnical Engineering Topic : Three Phase System Ans: The water content at 25 blows is called Liquid limit. i.e. 61.9 4. Data from a sieve analysis conducted on a given sample of soil showed that 67% of the particles passed through 75 micron IS sieve. The liquid limit and plastic limit of the finer fraction was found to be 45 and 33 percents respectively. The group symbol of the given soil as per IS: 1498-1970 is (A) SC (B) MI (C) CH (D) MH Ans: As more than 50 % of the total soil is finer than 75 the given soil is fine grained soil CL CI CH 12 H ML MI MH 20 35 50 on the A-line, =18.25 The soil is below A-line. So the soil is MI 5. The undrained cohesion of a remoulded clay soil is 10 kN/m2. If the sensitivity of the clay is 20, the corresponding remoulded compressive strength is (a) 5 kN/m2 (b) 10 kN/m2 2 (c) 20 kN/m (d) 200 kN/m2 Ans: Compressive strength = 2C =20 kN/m2 6. The ratio of saturated unit weight to dry unit weight of dry unit weight is 1.25. If the specific gravity of solids (G s) is 2.65, the void ratio of the soil is (a) 0.625 (b) 0.663 (c) 0.944 (d) 1.325 Ans: e e 2.65 1 e=0.663 JH ACADEMY Page 2 3 3 (d) 23.8kN/m and19.8kN/m respectively. the soil should be coarse grained. the gravel is only 20 gm and 710 gm is sand. A soil mass contains 40% gravel. The bulk density and dry density of this soil are 3 3 (a) 12 kN/m and 20 kN/m respectively. The percentage of fines is 27 %. CL CI CH H 22 ML MI MH 20 35 50 on the A-line.6 The soil is above A-line. A saturated soil mass has a total density 22kN/m and a water content of 10%. The sand fraction is more than gravel. The liquid limit and plastic limits of the soil fraction passing through 425μ sieves are 40% and 18% respectively. 50% sand and 10% silt.8 N/m respectively. So we need to get information from A-line. So the soil should be sand. The soil may be classified as (a) SC (b) MI (c) CI (d) SM Ans: As 270 gm out of 1000gm pass through 75 sieve. This soil can be classified as (a) silty sandy gravel having coefficient of uniformity less than 60.75 mm and 0. (c) gravelly silty sand having coefficient of uniformity greater than 60. =14. Ans: Soil of higher proportion comes in last 3 8. i.Sub: Geotechnical Engineering Topic : Three Phase System 7. which is more than 12 %.e 22 kN/m .2kN/m and19.075 mm sieve. (b) silty gravelly sand having coefficient of uniformity equal to 10. 9. respectively. Ans: The bulk density is equal to saturated density as the soil is in saturated 3 condition. The classification is SC JH ACADEMY Page 3 . Sieve analysis on a dry soil sample of mass 1000 g showed that 980 g and 270 g of soil pass through 4. So the soil is clayey. The remaining 730 gm of soil. 3 3 (b) 22 kN/m and 20 kN/m respectively. 3 3 (c) 19. (d) gravelly silty sand and its coefficient of uniformity cannot be determined. 0.4.70.81 (b) 18. respectively.45 Ans: 0.75 mm = 60 Percentage finer than 0.075 mm = 30 Liquid Limit = 35% Plastic Limit = 27% The soil classification is (A) GM (B) SM (C) GC (D) ML-MI JH ACADEMY Page 4 . Assuming the unit weight of water to be 10 kN/m3. 0.5.81 27 1 11. 0.3*27 e 0.45 (d) 18.30 (c) 19. plastic limit (PL) and shrinkage limit (SL) of a cohesive soil satisfy the relation (A) LL>PL<SL (B) LL>PL>SL (C) LL<PL<SL (D) LL<PL>SL Ans: volume Semi solid plastic liquid solid Water content 13.Sub: Geotechnical Engineering Topic : Three Phase System 10. Deposit with flocculated structure is formed when (A) Clay particles settle on sea bed (B) Clay particles settle on fresh water lake bed (C) Sand particles settle on river bed (D) Sand particles settle on sea bed Ans: Deposit with flocculated structure is formed when sand particles settle on river bed 14. The liquid limit (LL).4. The water content of a saturated soil and the specific gravity of soil solids were found to be 30% and 2. Group symbols assigned to silty sand and clayey sand are respectively (A) SS and CS (B) SM and CS (C) SM and SC (D) MS and CS Ans: Main soil symbol comes first 12. The laboratory test results of a soil sample are given below: Percentage finer than 4. 0.5. the saturated unit weight (kN/m3) and the void ratio of the soil are (a) 19. S and e represent the specific gravity. w. So the soil is gravel. In a compaction test. G. the soil is represented by the letter symbols (A)CL (B)CI (C) CH (D) CL-ML JH ACADEMY Page 5 . CL CI CH H ML MI MH 20 35 50 on the A-line. the equation for zero air voids line is (A) (B) (C) (D) Ans: wG e wG 1 16. So the soil is silt.Sub: Geotechnical Engineering Topic : Three Phase System Ans: Coarse fraction =70 Fine fraction =30 As coarse fraction is more than fines.95 The soil is above A-line. The classification is GM 15. according to IS classification. As per the plasticity chart. Gravel=40 and sand =30. water content. we need to check A-line. If represents the unit weight of water and represents the dry unit weight of the soil. the soil is coarse grained. As fines are more than 12%. degree of saturation and void ratio of the soil sample. respectively. A fine grained soil has liquid limit of 60 and plastic limit of 20. =10. 6 The soil is above A-line and it is intermediate compressibility. it can be stated that (A) √ (B) (C) (D) Ans: Area under the curve represents fineness modulus. If the fineness modulus values of the three sands are given as . =29. So the soil is clayey. a sample of silty clay with liquid limit of 40% and plasticity index of 28% is classified as (A) CH (B) CI (C) CL (D) CL-ML Ans: A line equation. 18. are given in the adjoining figure.2 The soil is above A-line.Sub: Geotechnical Engineering Topic : Three Phase System Ans: CL CI CH 40 H ML MI MH 20 35 50 on the A-line. =14. The classification is CH 17. P. Q and R. So it is CI JH ACADEMY Page 6 . As per the Indian Standard soil classification system. The results for sieve analysis carried out for three types of sand. 27 0. Marine soils List-II 1. the mass of the sample is 1. Deposited at the bottom of lakes 4.001 .70 (C) 0.1*27 27 1 20. 3 2 1 4 c. In its natural condition. Match list-I (type of soil) with list-II (mode of transportation and deposition) and select the correct answer using the codes given below the lists: List – I A.65 (B) 0. 3 2 4 1 d. Transportation by wind 2.Sub: Geotechnical Engineering Topic : Three Phase System 19. Deposited in sea water Codes: A B C D a.54 (D) 0. Specific gravity is 2. Transportation by running water 3. a soil sample has a mass of 1. Aeolian soils D. Alluvial soils C.61 Ans: e 0. The degree of saturation of the soil is: (A) 0. Lacustrine soils B. 1 3 2 4 JH ACADEMY Page 7 .800 .7. Unit weight of water is 10 . After being completely dried in an oven.980 and a volume of 0. 1 2 3 4 b. 00 (d) 1.8% Ans: 0. In a wet soil mass.1*2. The liquid limit and plastic limit of samples are 65% and 29% respectively. air occupies one-sixth of its volume and water occupies one-third of its volume.5 (c) 1.Sub: Geotechnical Engineering Topic : Three Phase System Ans: (b) 21.50 (d) 2.00 (c) 1. The standard plasticity chart to classify fine grained soils is shown in the given figure JH ACADEMY Page 8 .002 mm is 24.50 Ans: 1/6 1/3 0.212 23. The porosity of the soil at shrinkage limit is (a) 21.00 Ans: 22. A soil sample as shrinkage limit of 10% and specific gravity soils as 2. The percentage of soil fraction with grain size finger than 0.5 24. Lacustrine soils are soils (a) Transported by rivers and streams (b) Transported by glaciers (c) Deposited in sea beds (d) Deposited in lake beds Ans: (d) 25. The activity ratio of the soil sample is (a) 0.7.7 e=0.05 (b) 1. The void ratio of the soil is (a) 0.27 1 =0.25 (b) 0.2% (b) 27% (c) 73% (d) 78. 78 1 = 0.78. If the specific gravity of solids is 2. The water content in percentage required to fully saturate the soil at that void ratio would be (a) 10 (b) 30 (c) 50 (d) 70 Ans: 0.78 e=0.35.0 Ans: e 2.7. A soil sample is having a specific gravity of 2.5 (b) 1. Then the void ratio will be (a) 0.60 and a void ratio of 0.0 (c) 1.3 27.5 (d) 2.Sub: Geotechnical Engineering Topic : Three Phase System The area marked X represents a) Silt of low plasticity b) Clay of high plasticity c) Organic soil of medium plasticity d) Clay of intermediate plasticity Ans: (d) 26. A dry soil has mass specific gravity of 1.7 1 JH ACADEMY Page 9 . 3 and 4 c) 2.7 1 29.5 (b) 1. The liquidity index of soil is (a) 1. 2 and 3 b) 1. Soil is partially saturated at degree of saturation = 60% 2. Void ratio = 40% 3. A soil has liquid limit of 60% plastic limit of 35% and shrinkage limit of 20% and it has a natural moisture content of 50%.5 g/cc Which of these statements is are correct? a) 1.70.5% (d) 22% Ans: Shrinkage limit is nothing but water content at just saturated state. 3 and 4 d) 1.25 (c) 0. Saturated unit weight=1. Water content = 30% 4.50 in dry state and specific gravity of solids = 2.5% (c) 18. 0.60 (d) 0.Sub: Geotechnical Engineering Topic : Three Phase System 28. Consider the following statement in relation to the given sketch 1.40 Ans: volume Water content 30. A clay sample has a void ratio of 0. Its shrinkage limit will be (a) 12% (b) 13.5 e 0.5 2. 2 and 4 JH ACADEMY Page 10 . 5)=2.000 Ans: Mass of solids of fill = Volume of bowwow pit= JH ACADEMY Page 11 .5*(1+0.4. The dry density of a soil is 1. The borrow pit soil has a void ratio of 1.0 g/cc (c) 2.00.87. A fill having a volume of 1. The group symbol of the soil as per IS soil classification is (a) CH (b) CI (c) CL (d) MI Ans: (b) 32.50 g/cc and 1.10.25 g/cc =2.50 g/cc Ans: =1.25 g/cc (d) 2.500 (b) 2.50.25-1=1.50.0 g/cc (b) 2.5 g/cc and 1. respectively.25 33.Sub: Geotechnical Engineering Topic : Three Phase System Ans: 1.25 g/cc and 1. be (a) 1. The volume of soil required (in cubic meters) to be excavated from the borrow pit will be (a) 1.000 cum is to be constructed at a Void ratio of 0.5 g/cc.000 (d) 2. A soil has a liquid limit of 45% and lies above the A-line when plotted on a plasticity chart. If the saturation water content were 50% then its saturated density and submerged density would.0 g/cc and 1.000 (c) 2.8.5 31. for a described PI of 6.2 Ans: (b) 35. Shrinkage limit 2.Sub: Geotechnical Engineering Topic : Three Phase System 34.3 (c) 1.2 (b) 3. Effective size greater than 1mm Which of the statements are correct? (a) 1. The consistency index of the soil is given by – (a) (b) ( – ) ( – ) (c) ) (d) ) Ans: (a) 38.Liquid limit Select the correct answer using the codes given below: (a) 1.3. Coefficient curvature between 1 and 3 3.2. ‘S’ is the degree of saturation of the soil is given by JH ACADEMY Page 12 . unit weight of water= . Plastic limit = and natural moisture content = . What will be the correct sequence of the occurrence of the following limits? 1. Uniformity coefficient greater than 6 2. A Clayey soil has Liquid limit = . 2 and 3 (c) 1 and 2 (b) 1 and 3 (d) 2 and 3 Ans: (c) 37. Given the Plasticity Index (PI) of a local soil =15 and PI of sand=Zero. water content ‘w’ (as ratio).1. the percentage of sand in the mix should be (a) 70 (b) 60 (c) 40 (d) 30 Ans: 36.Plastic limit 3.1 (d) 3. The moisture content of a clayey soil is gradually decreased from a large value. A soil has mass unit weight .2. Consider the following statements: A Well-graded sand should have 1. The specific gravity of soil soilds = G. 18kg having a volume of 10⁻⁴ m³ and dry unit weight of 1600 kg/m³ is mixed with 0. The water content (in percentage) of the soil in the saturated state would be (a) 25 (b) 33.66 Ans: 40. If a soil of sample weight 0. The saturated and dry densities of a soil are respectively 2000kg/m³ and 1500 kg/m³.33 (c) 50 (d) 66.02 kg of water then the water content will be (a) 30% (b) 25% (c) 20% (d) 15% JH ACADEMY Page 13 .Sub: Geotechnical Engineering Topic : Three Phase System (a) S = (b) S = (c) S = (d) S = Ans: e wG wG G 1 39. 16=0.16=0.16 kg Existing water=0. B. If an unconfined compressive strength of 4 kg/cm² in the natural state of clay reduces by four times in the remoulded state.5 (c) 38 (d) 65 Ans: (b) JH ACADEMY Page 14 .18-0. Codes A B C D (a) 4 3 5 1 (b) 5 4 3 1 (c) 4 1 5 2 (d) 5 1 3 2 Ans: (d) 42. Water content 4. If the proportion of soil passing 75 micron sieve is 50% and the liquid limit and plastic limit are 40% and 20% respectively.25 41.8 (b) 6. 5.04/0. D. Porosity 2.02 kg Additional water =0.Sub: Geotechnical Engineering Topic : Three Phase System Ans: Mass of solids=1600*10⁻⁴=0.04kg Water content=0. Degree of saturation 3. C. then the group index of the soil is (a) 3.02 kg Total water = 0. then its sensivity will be (a) 1 (b) 2 (c) 4 (d) 8 Ans: (c) 43. Void ratio 1. Match List-I (terms) with List-II (formulae) and select the correct answer using the codes given below this list List-I List-II A. Silty sand List-II 1. deposits of wind 4. SC 4. Clayey sand C. Deposited from suspension in running water 2. OH 3. SM 2.Sub: Geotechnical Engineering Topic : Three Phase System 44. Match List-I (soils) with List-II (group symbols) and select the correct answer using codes given below the lists List-I A. GC CODES: A B C D a) 3 4 2 1 b) 4 3 1 2 c) 4 3 2 1 d) 3 4 1 2 JH ACADEMY Page 15 . deposits of marine origin 3. Match List-I with List-II and select the correct answer using the codes given below the list List-I A) Loess B) Peat C) Alluvial soil D) Marl List-II 1. Clayey gravel B. Organic clay D. organic soil CODES: A B C D a) 3 4 2 1 b) 4 3 1 2 c) 4 3 2 1 d) 3 4 1 2 Ans: (d) 45. A soil has a liquid limit of 40% and plasticity index of 20% the plastic limit of the soil will be a) 20% b) 30% c) 40% d) 60% Ans: (a) 48.0 100% b) 0. A dry soil sample has equal amounts of soils and voids of volume.3mm and 0. If density of water 10KN/m3.9 Ans: e 27 1 49.6 c) 0.4 d) 0. Its void ratio and porosity will be Void ratio porosity (%) a) 1.5 50% c) 0. As per IS code. the void ratio of the soil sample will be a) 0. 0. A sample of saturated sand has a dry unit weight of 18 KN/m3 and a specific gravity of 2.5 100% d)1. Based on grain distribution analysis. D30 and D60 values of a given soil are 0. the soil classification will be a) SW b) SP c) SM d) SC JH ACADEMY Page 16 .23mm.41mm respectively.5 b) 0.Sub: Geotechnical Engineering Topic : Three Phase System Ans: (c) 46. The D10. The value of porosity of a soil sample in which the total volume of soil grains is equal to twice the total volume of voids would be a) 75% b) 66.66% c) 50% d) 33.33% Ans: (c) 47.0 50% Ans: (d) 50.7. 5 b) 1. the soil is SP 51.2 b) 0.3 c) 0.6.75 mm and more than 75 .67 c) 1.3. water content of 50% and a specific gravity 2.9.5 Ans: 54.6 Ans: 52.6 and its density index is 0. If its void ratio in the loosest state is 0. Which one of the following phase diagrams represents a clay at its shrinkage limit? JH ACADEMY Page 17 . So the soil is sand As is less than 6 and is not in between 1 to 3. The natural void ratio of sand sample is 0.0 d) 0.60 is in a state of a) partial saturation b) full saturation c) over saturation d) under saturation Ans: 53.4 d) 0. Its activity ratio is a) 2.Sub: Geotechnical Engineering Topic : Three Phase System Ans: The given soil is of size less than 4. A soil sample having a void ratio of 1. then the void ratio in the densest state will be a) 0. The plasticity index and the percentage of grain size finer than 2 microns of a clay sample of 25 and 15 respectively. 6? a) 40% b) 50% c) 60% d) 70% Ans: 0. 70% particles are passing through 4.65 0. Which one of the following represents relative density of saturated sand deposit having moisture content of 25% if maximum and minimum void ratio of sand are 0.6mm. this soil will be taken to be a) Uniformly graded sand b) Well-graded sand c) Very fine sand d) Poorly-graded sand Ans: 57.4 D30 = 3mm. Its uniformity JH ACADEMY Page 18 . Given that the coefficient of curvature = 1. based on this information of particle size distribution for use as a sub grade.45 respectively and specific gravity of sand particles is 2. In a soil specimen.65 2.Sub: Geotechnical Engineering Topic : Three Phase System Ans: (b) 55. Which one of the following correctly represents the dry unit weight of a soil sample which has a bulk unit weight of at a moisture content of w%? a) c) b) ] d) Ans: (c) 56.6 1 58.95 and 0.75mm IS sieve and 40% particles are passing through 75 μ IS sieve. D10 = 0. Liquidity index cannot have a negative value and should be taken as zero 2. has a negative value Consider the following comments on this value 1. The soil tested in medium soft state. montmorillonite.Sub: Geotechnical Engineering Topic : Three Phase System coefficient is 8 and coefficient of curvature is 2. kaolinite. silica. Which of these statements are correct? a) 1 and 4 b)1 and 3 b) 2 and 4 d) 2 and 3 JH ACADEMY Page 19 . The correct sequence of plasticity of minerals in soil in an increasing order is a) silica. Consistency as applied to cohesive soils in an indicator of its a) density b) moisture content c) shear strength d) porosity Ans: (b) 62. illite Ans: (a) 60.silica. it is found that liquidity index. The predominant mineral responsible for shrinkage and swelling in black cotton soils is a) illite b) kaolinite c) mica d) montmorillonite Ans: (d) 61. this soil is classified as a) SP b) GP c ) SW d) GW Ans: (c) 59. montmorillonite b) silica. As per IS classification. While computing the values of limits of consistency and consistency indices . illite. illite. The soil tested is in semi solid state and stiff 4. kaolinite. montmorillonite. illite c) kaolinite. montmorillonite d) kaolinite. Liquid index can have a negative value 3. 18. Match List-I (densities) with List-II (expressions) and select the correct answer using the codes given below the lists: (Symbols G.52.6? ( taken density of water has 10KN/ m³). 0.34.52. 1. e.Sub: Geotechnical Engineering Topic : Three Phase System Ans: volume Water content 63.07 b) 0. What is the ratio of void ratios eA :eB? a) 2:3 b) 3:2 c) 4:9 d) 9:4 Ans: 64. void ratio. a) 0. Two soil sample A and B have porosities =40% and =60% respectively. porosity ratio and saturated density (in KN/m³) for a soil sample which has saturation moisture content of 20% and specific gravity of grains has 2.07 JH ACADEMY Page 20 . What are the respective values of void ratio . γw and S stand for specific gravity of a soil grains . unit weight of water and degree of saturation respectively) List-I List-II a) Dry density 1) γw (G+Se)/(1+e) b) Moist density 2) γwG/(1+e) c) Submerged density 3) γw(G+e)/(1+e) d) Saturated density 4) γw(G-1)/(1+e) A B C D a) 2 1 4 3 b) 2 3 4 1 c) 4 1 2 3 d) 4 3 2 1 Ans: (a) 65. 18.08. 5% b) 10.7 1 Water content at just saturation is shrinkage limit. in terms of unit Weight . 1. 20. 0.The soil of the barrow area is at a density of 15 KN/ m³. Mica is a clay mineral 2. 3.52 26 1 66.52.16 Ans: 5. Rock dust particles. Which of these statements are correct? a) 1. 68. 54 2. What is the estimated number of trips of 6 m³ capacity truck for hauling the soil required for compacting 100 m³ fill of the Embankment?(Assume that the soil in the barrow area and that in the Embankment are at the moisture content?) a) 14 b)18 c) 20 d) 23 Ans: 67. water content w (as ratio) and specific gravity of soil solids Gs is unit weight of the water? JH ACADEMY Page 21 . A particle of kaolinte is electrically changed.2 0.54 in dry state.0% c) 17. what is the shrinkage limit of soil? a) 8.08. the specific gravity of soil solids is 2.7. even of clay size are non-plastic.0% Ans: 5.34. A clay sample has a void ratio 0. 16.4 0. 2 and 3 b) only 1and 2 c) Only 2 and 3 d) Only 1 and 3 Ans: (d) 69.Sub: Geotechnical Engineering Topic : Three Phase System c) 0. Embankment fill is to be compacted at density of 18 KN/ m³.77.0% d) 20. Consider the following statements: 1. Which of the following relation gives the value of degree of saturation S.64 d) 0. Sub: Geotechnical Engineering Topic : Three Phase System a) γ b) γ c) γ d) γ Ans: (c) JH ACADEMY Page 22 .