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该文采用颗粒离散元软件PFC2D,研究了不排水条件高频循环剪切作用下饱和松砂与板桩接触面附近的砂土特性,分析了模型参数对饱和松砂孔隙率和体应变的影响,以及剪切过程中超静孔压的变化规律和砂土颗粒的运动轨迹。结果表明:当颗粒摩擦系数、颗粒刚度、剪切振幅和剪切频率越小或边界围压和接触面摩擦系数越大,饱和松砂的剪缩现象越明显。砂土的孔隙率在作用瞬间减少、然后略有增加后呈下降趋势至稳定;随循环次数增加,砂土中的超静孔压总体上呈增长趋势;砂土颗粒的变位随离开接触面距离的增加而减小。
In this paper, we use PFC2D, a discrete element software, to study the characteristics of sand near the contact surface between saturated loose sand and sheet pile under high frequency cyclic shear under undrained condition. The influence of model parameters on the porosity and bulk strain of saturated loose sand , As well as the law of excess pore pressure and the trajectory of sand particles during shearing. The results show that when the coefficient of friction, the stiffness, the shear amplitude and the shear frequency of the particles are smaller or the friction coefficient between the confining pressure and the contact surface is larger, the shear shrinkage phenomenon of saturated sands is more obvious. The porosity of sand decreases at the moment of action, and then decreases slightly to stable after a slight increase. With the increase of circulation times, the excess pore pressure in sand increases with the increasing trend. The displacement of sand particles increases with the distance from the contact surface The distance increases and decreases.