堆积体三轴试验及离散元模拟研究

Study on triaxial test and discrete element simulation of remain

对典型地区松散堆积体进行大三轴剪切排水试验,基于细观结构离散元理论,在PFC3D平台嵌入自编程序,引入反映颗粒形状的Clump颗粒,形成与堆积体三轴试验相对应的三维颗粒流数值模型。对比了不同围压下数值模型与三轴试验的应力-应变关系。结果表明:随着围压的增大,堆积体试样强度呈现应变硬化型到应变软化型的过渡,并伴随剪胀现象;数值模拟的应力变形曲线规律与实体三轴剪切试验结果基本一致,颗粒流离散元方法可以较好地模拟堆积体三轴试验的力学特性。

Consolidated-drained triaxial test is conducted for loose remain detritus located in most area of China,based on three dimension particle flow code theory,the numerical model of triaxial test for graded remain detritus is obtained by programming PFC3D( Particle Flow Code of Three Dimension) from the view of mesoscopic scale.Stress-strain and volume-axial strain relationship of particle flow model and triaxial test are compared under different confining pressure.The results show that: with the increase of confining pressure,the type of stress-strain curve became strain-softening from strain hardening accompanied by dilatancy phenomenon.However,the degree of shear dilatancy decreases as the confining pressure of remain detritus.The stress-strain curves from numerical simulation with the selected micro parameters are in agreement well with the results of the laboratory test.Particle flow method can simulate the mechanical properties of the triaxial tests of remain detritus.