中文摘要：

考虑桩土界面初始剪切刚度的深度效应,把接触面剪切应力和剪切应变沿接触面厚度均匀化,提出基于统计损伤本构模型的无厚度单元接触面本构模型,根据剪切实验的数据对改进的本构模型参数进行拟合,得到了不同法向应力下的模拟曲线。计算结果表明：本文提出的无厚度单元接触面本构模型是正确的,能够合理地模拟桩土界面的力学行为,可以描述接触面剪切刚度的非线性变化,适用性强,有较高的理论和实际应用价值。

英文摘要：

Considering the initial shear stiffness depth effect of the pile-soil interface and keeping the uniformityalong the contact surface thickness direction of the shear stress and shear strain, the paper put forward the zerothicknesszone contact surface constitutive model based on the statistical damage constitutive model. According tothe shear experiment data , we obtained the simulation curves fitting parameters of the improved constitutive modelunder different normal stresses .Calculation results indicated that the zero-thickness zone contact surface constitutivemodel developed was correct , which could simulate reasonably the mechanical behavior of the pile-soilinterface and describe the nonlinearity of the pile -soil contact surface shear stiffness. It also has strong applicability,relatively high theoretical and practical application value.