**Chapter 1: Geo Technical Engineering – Three Phase System **

GATE (Graduate Aptitude Test in Engineering) Civil Engineering is one of the toughest exam in India. Nearly more than 1.50 Lakh students appeared in the exam but 1000 to 3000 people only got benefited by getting good marks. Also 14% of the appeared candidates only cracked the GATE exam.

**In order to crack the GATE exam we need to focus on systematically and well planned manner. The study materials also very important for GATE exam to crack. Below we have shared the very important 15 Civil Engineering solved questions in the topic of Three phase system in Soil Mechanics for GATE exam 2020 preparations. These will really enhance your studying and helps to crack GATE exam with good marks.**

**Question No: 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**

**Question No: 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% **

**Correct Option: (C) 50%**

**Question No: 3**

**Data from a sieve analysis conducted on a given sample of soil showed that 67% of the particles passed through 75m 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**

**Correct Option: (B) MI **

**Question No: 4**

**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 **

**(c) 20 kN/m2 **

**(d) 200 kN/m2**

**Ans = Compressive Strength = 2C = 20 kN/m2**

**Correct Option: (c) 20 kN/m2**

**Question No: 5**

**The ratio of saturated unit weight to dry unit weight of dry unit weight is 1.25. If the specific gravity of solids (Gs) is 2.65, the void ratio of the soil is **

**(a) 0.625 **

**(b) 0.663 **

**(c) 0.944 **

**(d) 1.325**

**Correct Option: (b) 0.663**

**Question No: 6 **

**A saturated soil mass has a total density 22kN/m3 and a water content of 10%. The bulk density and dry density of this soil are**

**(a) 12 kN/m3 and 20 kN/m3 respectively.**

**(b) 22 kN/m3 and 20 kN/m3 respectively.**

**(c) 19.8kN/m3 and19.8 N/m3 respectively.**

**(d) 23.2kN/m3 and19.8kN/m3respectively.**

**Ans:**

**The bulk density is equal to saturated density as the soil is in saturated condition. i.e 22 kN/m3 .**

**Correct Option: (b) 22 kN/m3 and 20 kN/m3 respectively.**

**Question No: 7**

**In its natural condition, a soil sample has a mass of 1.980 Kg and a volume of 0.001 m3 . After being completely dried in an oven, the mass of the sample is 1.800 Kg . Specific gravity G is 2.7. Unit weight of water is 10 kN/m3 . The degree of saturation of the soil is:**

**(A) 0.65 **

**(B) 0.70 **

**(C) 0.54 **

**(D) 0.61**

**Correct Option: (C) 0.54**

**Question No: 8**

**The liquid limit and plastic limit of samples are 65% and 29% respectively. The percentage of soil fraction with grain size finger than 0.002 mm is 24. The activity ratio of the soil sample is**

**(a) 0.05 **

**(b) 1.00 **

**(c) 1.50 **

**(d) 2.00**

**Correct Option: (c) 1.50**

**Question No: 9 **

**Two soil sample A and B have porosities nA=40% and nB=60% respectively. What is the ratio of void ratios eA :eB**

**a) 2:3 **

**b) 3:2 **

**c) 4:9 **

**d) 9:4**

**Correct Option: c) 4:9**

**Question No: 10**

**The natural void ratio of sand sample is 0.6 and its density index is 0.6. If its void ratio in the loosest state is 0.9, then the void ratio in the densest state will be**

**a) 0.2 **

**b) 0.3 **

**c) 0.4 **

**d) 0.5**

**Correct Option: c) 0.4**

**Question No:11**

**Based on grain distribution analysis, The D10, D30 and D60 values of a given soil are 0.23mm, 0.3mm and 0.41mm respectively. As per IS code, the soil classification will be**

**a) SW**

** b) SP**

** c) SM **

**d) SC**

**Correct Option: b) SP**

**Question No: 12**

**A fill having a volume of 1,50,000 cum is to be constructed at a Void ratio of 0.8. The borrow pit soil has a void ratio of 1.4. The volume of soil required (in cubic meters) to be excavated from the borrow pit will be**

**(a) 1,87,500 **

**(b) 2,00,000**

**(c) 2,10,000 **

**(d) 2,50,000**

**Correct Option: (b) 2,00,000**

**Question No: 13**

**The dry density of a soil is 1.5 g/cc. If the saturation water content were 50% then its saturated density and submerged density would, respectively, be**

**(a) 1.5 g/cc and 1.0 g/cc**

**(b) 2.0 g/cc and 1.0 g/cc**

**(c) 2.25 g/cc and 1.25 g/cc**

**(d) 2.50 g/cc and 1.50 g/cc**

**Correct Option: (c) 2.25 g/cc and 1.25 g/cc**

**Question No: 14**

**Match List-I (densities) with List-II (expressions) and select the correct answer using the codes given below the lists: ****(Symbols G, e, γw and S stand for specific gravity of a soil grains , void ratio, 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 **

**Correct Option: a) 2 1 4 3**

**Question No: 15**

**The correct sequence of plasticity of minerals in soil in an increasing order is**

**a) silica, kaolinite, illite, montmorillonite**

**b) silica, kaolinite, montmorillonite, illite**

**c) kaolinite, silica, illite, montmorillonite**

**d) kaolinite,silica, montmorillonite, illite**

**Correct Option:a) silica, kaolinite, illite, montmorillonite**

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