基于PFC^(3D)的路基土细观特征数值模拟研究

Numerical simulation of subgrade soil mesoscopic features based on PFC^(3D)

为研究围压作用对路基土细观特征的影响,本文以辽宁某在建高速公路为工程背景,采用颗粒流软件PFC^(3D)对该公路路基土进行不同围压下的三轴压缩数值模拟试验,分析试样内部裂隙及颗粒间接触力随围压的分布规律。结果表明:在宏观上,随着围压的增大,峰后曲线逐渐由应变软化向应变硬化过渡;在细观上,随着围压的逐渐增大,试样内部裂隙逐渐增多,且拉伸裂隙明显多于剪切裂隙;颗粒间法向接触力和切向接触力均随围压逐渐增大,土样的各向异性在围压的作用下逐渐增强。

In order to study the influence of confining pressure on the subgrade soil mesoscopic features,this paper took an expressway under construction in Liaoning as the engineering example,and used particle flow software PFC^(3D) to carry out triaxial compression numerical simulation tests of the subgrade soil under different confining pressure,and analyzed the distribution law of cracks and contact forces in samples between particles with confining pressure.The results showed that the post-peak curve gradually changed from strain softening to strain hardening with the increase of confining pressure.In meso-scale,with the increasing of confining pressure,the number of cracks in the sample increased gradually,and the number of tensile crack was obviously more than that of shear crack.The normal and tangential contact forces between particles increased gradually with the confining pressure,and the anisotropy of soil samples increased gradually under the confining pressure.