WPŁYW OBCIĄŻEŃ DYNAMICZNYCH NA WYTRZYMAŁOŚĆ GLIN LODOWCOWYCH NA PRZYKŁADZIE GLIN ZLODOWACENIA WARTY REJONU WARSZAWA-SŁUŻEW

Abstract

THE EFFECT OF DYNAMIC LOADINGS ON THE SHEAR STRENGTH OF WARTANIAN GLACIATION TILLS FROM WARSAW-SŁUŻEW AREAAbstract. The paper presents the result of series of laboratory monotonic and cyclic triaxial tests carried out to study the effect of cyclic loading on the shear strength of till deposits from Nowoursynowska testing field in Warsaw. Electromechanical dynamic triaxial testing system (DYNTTS) was used to investigate the undrained shear strength of undisturbed soil samples. The till samples were subjected to two-way cyclic loading with 10 Hz frequency under displacement control condition. An excess pore water pressure, due to low permeability of tills, is likely to be generated under cyclic loading and consequently the post-cyclic shear strength decreases when the effective stress gets reduced. Cyclic loading causes a substantial reduction in shear strength of tills. Post-cyclic shear strength of studied till is equal to 21–76% of its static shear strength.