利用旁压试验分析设计横向受荷桩

Analysis and Design of Laterally Loaded Piles by Pressuremeter Test

本文从理论上导出如何通过旁压曲线确定桩的P-y曲线。对地基土的反力函数提出双曲线模型P(z,y)=y/[a(z)y+b(z)]的假设,并考虑其系数a(z),b(z)随深度z成线性变化。以这一模型拟合桩的P-y曲线族,求出系数a(z),b(z),得到地基土反力P(z,y)的数学表达式。对横向受荷桩的求解问题则采用弹性地基梁的微分方程,用有限差分法,并考虑边界条件进行求解,编制了单桩受横向静荷载作用下的分析求解程序,供饱和粘性土中的单桩计算应用,并通过一个实例进行计算对比,表明理论结果与实测结果相当吻合。

In this paper a theoretical approach is provided for getting a series of P-y curves of laterally loaded piles from the expansion curves of selfboring pressuremeter. A hyperbolic model is used to describe the nonlinear behavior of subsoil, where the parameters of a(z) and b(z) are assumed to vary linearly with depth z. Using the above model, a mathematical expression of the subsoil reaction P (z, y ) is obtained by fitting the P-y curves from the pressuremeter. A differential equation of elastic subgrade beam is used to solve the problems of laterally loaded piles. The solution of the differential equation is obtained by using the method of finite differences with the given boundary conditions of the pile. A program for the analysis and the design of laterally loaded piles is compiled. The computation results are fairly comparable with the observations of a practical example.