Abstract:

In order to study the dynamic characteristics of warm and ice-rich frozen soil with the instability, a series of dynamic triaxial compressive tests on frozen clay of Qinghai-Tibet Railway, with the corresponding volumetric water content 50%, were conducted. Confining pressures are 0.3, 0.5, 1.0, 3.0, 5.0 MPa and temperatures are -0.5, -1.0, -2.0, -4.0℃. According to the tests results, the general hyperbolic model is proposed to describe the stress-strain relationships; and the prediction relationships of their parameters are provided. Based on the nonlinear relationship between dynamic elastic modulus and axial strain, the critical confining stress is figured out. The dynamic modulus decreases as the dynamic strain increases when the confining pressure is larger than 0.5 MPa. The dynamic modulus increases at first and then decreases as the dynamic strain increases when the confining pressure is below 0.5 MPa. Moreover, the damping ratio increases with increasing of shear strain amplitude or confining pressure; and with the decrease of temperature, the damping ratio becomes small.

Key words: warm and ice-rich frozen clay, dynamic stress-strain relationships, dynamic elastic modulus, dynamic damping ratio