Given below are methods of compaction : 1. Vibration technique 2. Flooding the soil 3. Sheeps-foot roller 4. Tandem roller 5. Heavy weights dropped from a height. The methods suitable for cohesionless soils include

The ratio of torsional moments of resistance of a solid circular shaft of diameter D and a hollow shaft having external diameter D and internal diameter d is given by

Consider the following statements relating to triaxial tests : 1. Change in length of the specimen in a triaxial shear test is required to be accounted for in the calculation of stresses at failure. 2. In 'Drained Triaxial Shear Test', drainage is permitted under a specified all-round pressure until consolidation is complete. The principal stress difference is then applied with no drainage being permitted. 3. Unconfined compression test is a special case of triaxial shear test. Of these statements :