Study on dynamic undrained mechanical behavior of saturated soft clay considering temperature effect

Abstract

In order to study the influence of temperature on soil dynamic characteristics, a temperature-controlled triaxial test apparatus was developed, in which a curved heating plate was designed as heating cell. The heating system can achieve the accurate control of the sample temperature within the scope of 10–100 °C. The dynamic undrained characteristics of saturated soft silty clay in Ningbo were studied under different temperatures, dynamic stress amplitude, confining pressure and initial static deviation stress by using the newly developed temperature-controlled triaxial test system. The test results showed that the temperature has great influence on the accumulative plastic strain, pore water pressure, damping ratio and dynamic elastic modulus of soft clay. As temperature increases, the cumulative plastic strain, the dynamic damping ratio and the dynamic pore pressure decrease, while the dynamic elastic modulus increases. Furthermore, the saturated soft clay exhibited a tendency of thermal hardening. Finally, a unified empirical strain model, which can consider the effect of temperature, dynamic stress amplitude, confining pressure and initial static deviator stress on accumulative plastic strain, was proposed. By using the test results, it is confirmed that the proposed empirical model is capable of predicting the undrain cumulative plastic strain of soft clay under different conditions.