粗粒土大型静止侧压力系数测定试验的颗粒流模拟

Particle Flow Simulation of Large-size Static Lateral Pressure Coefficient Tests for Coarse Grained Soil

静止侧压力系数K0是粗粒土重要的力学参数。采用基于离散元理论的颗粒流数值分析和室内试验相结合的方法,建立了粗粒土大型静止侧压力系数试验的三维颗粒流模型,模拟结果与室内试验具有良好的一致性。在总结数值试验结果的基础上,分析了粗粒土的位移和力链的细观变化过程,并研究了不同竖向应力下细观参数与K0的关系曲线,探讨孔隙率、颗粒摩擦因数、切向刚度、法向刚度等参数对粗粒土K0的影响规律,并建立了细观参数和粗粒土K0的函数关系。结果表明:相同竖向应力下试样K0随着孔隙率的增大逐渐增大,但增大趋势趋于平缓;试样K0与摩擦因数存在线性负相关关系;在相同竖向应力下,试样法向接触刚度越大或切向接触刚度的越大时,K0越小。

The coefficient of static lateral pressure(K0)is an important mechanical parameter of coarse-grained soil.A three-dimensional particle flow analysis model of large-scale K0 test was established by combining the numerical analysis of discrete element method(DEM)with laboratory test.On the basis of summarizing a large number of numerical test results,the relationship curves of meso-parameters and K0 under different confining pressures were analyzed,and the effects of porosity,grain friction coefficient,tangential stiffness and normal stiffness on K0 of coarse-grained soil were also discussed.Furthermore,the functional relationship between meso-parameters and K0 of coarse-grained soil was presented.The results show that under the same confining pressure,the K0 of the specimen increases gradually with the increasing of porosity,but the trend tends increases slowly.Besides,the K0 of the specimen has a linear negative correlation with the friction coefficient.And for larger value of the normal contact stiffness or tangential contact stiffness of the specimen,K0 is smaller.