Triaxial Testing and Numerical Simulation on High Fill Slopes of Gobi Gravel Soils in Urumchi

Abstract

Gobi gravel soils (GGS), widely distributed in northwestern China, are used as main filling materials in construction of high filling slopes in Urumqi airport. To analyze the stability of slopes, the shear strength of the granular materials should be investigated. To this end, a series of large-scale triaxial tests were performed on GGS to investigate the influencing factors on their mechanical behavior, including coarse content, degree of compaction, and confining pressure. The results show that the stress-strain curves show strain-hardening behavior within 90 % coarse content. The specimens show a transition from shear contraction to shear dilation with increasing coarse fraction and degree of compaction; they show contraction with an increase of confining pressure. The interlocking strength is significantly affected by the degree of compaction and coarse content, whereas the frictional angle changes within a narrow range from 35° to 40°. Based on testing results, the stability of the filling slopes was simulated using limit equilibrium method. The effect of the slope angle and geotextiles on the safety factor is discussed, through which the optimum slope angle and optimum geotextiles reinforcement are determined.