**SOIL MECHANICS LAB VIVA Questions with Answers :-**

**PERMEABILITY TEST**

1) List ‘k’ values for different types of soils.

2) How permeability test is done in the field?

3) Mention other permeability tests that can be done in the lab.

4) What is the application of permeability of soils?

5) Derive the expression for ‘k’ by falling head method.

6) Is hydraulic gradient constant in variable head test? Why?

7) How will you reduce observed permeability to permeability at standard temperature?

8) What is the necessity of two methods for determination of ‘k’ in lab?

9) Estimate discharge velocity in constant head test conducted. What is seepage velocity?

10) Time interval for flow from h1 to h0 should be same as that from h0 to h2. Why?

**FIELD DENSITY –SAND REPLACEMENT METHOD (IS 2720 PART XXVIII-1974)**

11) Depth of hole made in field is limited to 15 cm.Why?

12) Explain core cutter method for determination of in-situ density of soil.

13) Explain the significance of in-situ density soil density determination.

**COMPACTION TEST (IS 2720 PART VII-1974)**

14) What is the approximate value of degree of saturation at OMC?

15) How does amount of compaction affect maximum dry density and OMC?

16) What is the procedure for conducting modified proctor test?

17) What is the use of proctor’s needle? How is it used for compaction control in the field?

18) Explain how soil compaction is achieved?

**CALIFORNIA BEARING RATIO TEST**

19) How correction for initial concavity is done in load-penetration curve?

20) What is the application of CBR test results?

21) Write the procedure to find expansion ratios for a soaked test.

22) What is the need for adding surcharge weights?

**CONSISTENCY LIMITS (IS 2720 PART V-1972, IS 9259-1979)**

23) Draw plasticity chart and mark the soil tested and classify soil.

24) What is activity number?

25) Why clay exhibit plasticity while silt does not?

26) Indicate engineering uses of IP , IT , IL and IC

27) Is soil fully saturated at shrinkage limit?

28) Explain the one point method for liquid limit determination.

29) If the plastic limit is greater than or equal to liquid limit, how will you report IP of the soil?

30) If plastic limit can’t be determined for sandy soil, how will you report plasticity index?

31) Whether oven drying of sample before test is permitted? If not why?

32) Find compression index of given normally sensitive clay. What is the use of it?

33) How will you differentiate organic and inorganic soil using liquid limit test?