Large-scale field creep tests on moraine soil

The sediment of the Kangding Bank of Xingkkang Bridge of Sichuan-Tibet Expressway is mostly consisted of very thick moraine soil. In order to study the creep characteristics of the moraine soil, the large-scale field creep tests in meters are carried out using the self-developed electric-gas-liquid servo joint control geotechnical mechanics test devices, and the load servo control and the data automatically collected in the whole process are successfully achieved. The peak strength parameters and long-term strength parameters of the moraine soil are obtained by conducting the conventional direct shear tests and shear creep tests in the field. The creep deformation laws and the revelant creep model for settlement deformation under each load are obtained by analyzing the results of the field compression creep test. The study shows that the duration of transient creep is less than 5 min. In addition, the transient creep is characterized by the delayed deformation after loading, and the creep rate fluctuantly decreases in the decelerating creep stage. In addition, the creep rate exhibits a raising curve with fluctuation in the steady creep stage, which indicates the deformation-adjusting effects of soil skeleton particles.