DYNAMIC STRENGTH OF C4 SOILS UNDER COMBINED SUSTAINED AND PULSATING STRESSES

Abstract

An attempt has been made to study the behaviour of C-Ø soils under combined oscillatory and sasta ned shearing Stresses. Test results contain qualitative and quantitative data on behaviour of artificial C_Ø soils under abovementioned loading condition. The apparatus used was the one developed at School of Research and Training in Earthquake Engineering, University of Roorkee, Roorkee, with little modification for applying sustained loads. Various parameters studied during testing include, sustained shear stress, pulsating shear stress, normal stress, frequency and type 'of soil. In all, 81 test results were analysed on three different artificial C_r- soils made up of locally available Solani Sand and Bentonite mixed in different proportions. Frequency throughout the test pro-gramme was 0.70 Hz. Results indicate that (1) Strength of soils is reduced in dynamic tests for sustained stress less than 50% of the normal strength. For sustained stresses more than 50% of the normal strengtt dynamic strength remains almost equal to the normal strength.