COMPARISON OF LIQUEFACTION POTENTIAL FROM DYNAMIC TRIAXIAL AND SHAKE TABLE TEST DATA

Abstract

For prediction of liquefaction possibility two types of laboratory tests are in practice, namely, (i) Dynamic triaxial test on small size samples and (ii) Vibration table test on large size samples. Both the tests have their limitations and it can not be said conclusively as which can predict the soil behaviour in the field better. Also the results frot the two may be at variant. In this study attempt has been made to have a comparison of the results of the two tests for the same soil. Thus, the comparison of vibration table tests results with dynamic triaxial test results has been done by comparing the variations of liquefaction potential, cyclic stress ratio strength ratio, safety factors by the two tests as varying with relative density and different levels of horizontal acceleration. The vibration table tests were performed on Solani river sand by preparing the samples in the vibration table container of size 105x59x39cm having relative density within the range of 40% to 60%. The triaxial test data from Seed(1970) has been used for shake table test conditions to evaluate the parameters mentioned above. Results, obtained from the tests performed and calculations done for triaxial test conditions to see the variations in different parameters, are studied with respect to relative densities of the sand and acceleration levels of vibrations. Lv These results show that numerical values of safety factors (FOS) against liquefaction observed in shake table tests are far greater than the corresponding FOSs calculated from triaxial data for the same soil conditions. In the range of relative density values considered, it is seen from the results that triaxial data indicate liquefaction at all relative density and acceleration levels considered while vibration table test results show liquefaction occurring only in lower range of relative density