基于大三轴试验的粗粒土应力剪胀方程

Study on Stress-dilatancy Equation of Coarse-grained Soils Based on Large-scale Triaxial Test

采用大三轴剪切仪对3种不同相对密度的双江口心墙坝覆盖层料,进行各向等压固结条件下的排水剪切试验。对试验成果进行了深入分析,寻找剪胀率与应力状态之间的关系,提出一个适用于粗粒土的经验型应力剪胀方程。通过分析剪胀方程参数与围压之间的关系,给出剪胀方程参数的确定方法。该方程反映了剪胀率与当前应力比、破坏应力比及围压之间的关系。采用本文剪胀方程和Rowe剪胀方程分别对多种粗粒土三轴试验结果进行预测,结果初步表明,和Rowe剪胀方程相比,此剪胀方程能更好地模拟粗粒土的剪胀性。

Using large-scale shearing device,isotropic consolidated-drained triaxial tests under different confining pressures were carried out for three relative density overburden materials of Shuangjiangkou earth dam. Based on the analysis of test and the relationship between shear dilatancy ratio and stress state,a new stress-dilatancy equation,which is available for coarse-grained soils,was set forward,and the mothed to determine the parameters of dilatancy equation was given through analyzing the relationship of the parameters of dilatancy equation and confining pressure. The new dilatancy equation reflected the relationship between the shear dilatancy ratio and current stress ratio and the relationship between failure stress ratio and confining pressure. Using the present dilatancy equation and Rowe＇s dilatancy law,the triaxial compression test results of several kinds of coarse-grained soils were predicted. The results showed that the effect of simulating the dilatancy characteristics of coarse-grained soil by the present dilatancy equation is better than Rowe＇s dilatancy law.