桩土界面荷载传递模型的改进及其数值实现

Improvement on the Load Transfer Model of Pile-Soil Interface and its Numerical Simulation

目前,在数值模拟中,桩土界面的刚度缺乏简便可靠的确定方法。针对这一问题,本文提出了桩土界面改进双曲线模型,该模型中初始刚度由极限剪应力和极限相对位移的比值来确定,可考虑桩土相对滑移和土体深度效应的影响,并以有限差分软件FLAC3D为平台,利用其内嵌的FISH汇编语言编程,将改进双曲线模型应用到FLAC3D的桩土相互作用的模型中。最后,通过实例验证,将本文方法的计算值、FLAC3D内嵌理想弹塑性模型的计算值与相关文献中的结果进行对比。结果表明:本文提出的改进双曲线模型及数值实现是合理的,能够更为合理地模拟桩土共同作用。

At present, in the numerical simulation, there lacks a simple and reliable method to determine the stiffness of the pile-soil interface. This paper proposed an improved hyperbolic model for the pile-soil interface, in which the stiffness of the interface is determined by the ratio of the ultimate shear stress to the ultimate relative displacement. Based on the finite difference code FLAC3D, the built-in assembly language, FISH, was then used to compile the improved hyperbolic model, which was later used in the simulation of the pile-soil interaction in FLAG3D. Finally, the validity and accuracy of the proposed hyperbolic model was verified by comparing the calculation results with those of relevant cases. The comparison shows that the proposed hyperbolic model and its application in numerical simulation are reasonable and reliable, and the model can be used to simulate the pile-soil interaction with a higher accuracy.