Experimental study on dynamic characteristics of frozen saline silty clay under cyclic loading

In order to investigate the dynamic characteristics of frozen saline silty clay (studied saline soil) under reciprocating loading, a series of cyclic tri -axial experiments have been conducted for studied saline soil with 0.0, 0.5, 1.5, and 2.5 % of Na 2 SO 4 contents under confining pressures 0 MPa -18 MPa at -6 degrees C, respectively. The test results show that as the increase of number of cycle N , the accumulated axial strain e aN continuously increases, and the relationship between e aN and N can be described by an exponential function: e aN = aN b ; As the number of cycle N increasing, dynamic shear modulus G dN and dynamic bulk modulus K dN increase firstly and then decrease slightly; Salt content and confining pressure have great influences on the e aN , G dN and K dN . Within the same loading cycle, G dN and K dN decrease until reaching their minimums when the salt content is 0.5 %, and then G dN and K dN increase as the increase of salt content. With the change of salt content, e aN presents an opposite change law to G dN and K dN . For the studied saline soil with same salt content, during the same loading cycle, e aN and G dN increase until reaching their minimums, and then decrease as the increase of confining pressure, K dN increases with the increase of confining pressure. This study can be applied to evaluate the elasto-plastic properties of frozen soils and saline soils subjected to cyclic dynamic loading.