Effect of sample preparation on strength of sands

Juneja, A., and Raghunandan, M.E. (2010)., Proceedings of Indian Geotechnical Conference, Mumbai, India, Vol. 1, 327-330, 2010

Selection of the most suitable method of sand sample preparation becomes difficult because all available methods affect the fabric and dry density of samples, and none of the available methods are shown to be unique. The objective of this paper is to address some of these issues. A series of consolidated drained (CD) and consolidated undrained (CU) triaxial compression tests were conducted on sand samples prepared using pluviation and tamping techniques, under both dry and moist conditions. The standard triaxial test setup at IITB is described first. Stress strain behaviour for samples prepared with different sample preparation methods showed considerable difference in the peak stress and dilation, whilst all sample reached the peak stress at 5 to 10% axial strains. Results showed that samples prepared using tamping technique usually strain softens, whilst samples prepared by pluviation technique may harden or soften with strain depending up on the sample relative density and confining pressures applied during testing. Hence, pluviation technique proves to be the more reliable technique to prepare samples for triaxial testing.