土工格栅加筋砂土的变形与破坏机理解析

Numerical analysis of deformation and failure mechanism of geogrid-reinforced sand

利用可考虑局部破坏的非线性弹塑性有限元,对无加筋和加筋砂土的平面应变压缩试验结果进行了从小变形到破坏的全过程数值解析。加筋砂土试验体用土工格栅分6层和11层进行加筋加固。将等价二维有限元解析所得到的解析结果与试验得到的实测值进行了较为全面的比较,结果表明:合理的二维非线性弹塑性有限元解析,不仅可以较为精确的模拟加筋砂土的平均应力-应变特性,而且还可以全面地调查试验体的局部应力-应变分布以及剪切破坏发生状况,从而,对加筋砂土的变形破坏以及加筋材的加固机理有一个更加全面合理的认识。

Numerical analyses of plane strain compression tests for the geogrid-reinforced sand specimens were conducted by the nonlinear elastoplastic FEM considering strain localization. The sand specimens were reinforced with 6 and 11 layers of geogrid respectively. The geogrid reinforcement was modeled as a planar reinforcement in the plane strain finite element analyses. It was found the present finite element analysis could properly simulate the global stress-strain relationships when the equivalent interface friction angle was used together with the measured tensile stiffness. By examining local stress-strain distribution and development of shear band within the specimen obtained from the FEM, the deformation and failure mechanism of reinforced sand and the reinforcing effect of geogrid reinforcement were clearly understood.