基于PFC3D的筋箍碎石桩直剪试验数值模拟

Numerical Simulation of Direct Shear Test of Reinforced Gravel Pile Based on PFC3D

由于碎石材料具有离散性,因此运用离散元软件PFC3D对筋箍碎石桩复合体进行模拟试验。采用碎石及砂的大型直剪试验的试验结果对其微观力学参数进行标定,通过土工格栅的弯曲及拉伸试验结果对其微观力学参数进行标定。研究分析了筋箍碎石桩复合体的抗剪性能,并讨论了试样在剪切作用下其剪切应力、水平剪切位移及竖向位移之间的关系。研究表明:纯砂试样抗剪性能会随着筋箍碎石桩的加筋作用而有效提高,与此同时试样在剪切过程中均会发生剪切压缩及剪切膨胀现象,且该现象会随着法向应力的不同而发生改变,其法向应力越大,剪缩越容易,剪胀越难。

Because of the discrete nature of gravel,this paper uses discrete element software PFC3D to simulate the reinforced gravel pile composite.The micro-parameter of gravel and sand were calibrated using the test results of the large-scale direct shear test,and the micro-parameter of geogrid were calibrated by the bending and tensile test results.The study analyzes the shear resistance of the reinforced hoop gravel pile composite,and discusses the relationship between the shear stress,horizontal shear displacement and vertical displacement of the specimen under shear.Researches showed The shear resistance of the pure sand sample will be effectively improved with the reinforcement of the hoop crushed stone pile.At the same time,the shear compression and shear expansion phenomena will occur in the specimen during the shearing process,and this phenomenon will change with the difference of normal stress.The larger the normal stress,the easier the shear shrinkage is difficult.