多层软土地基中单桩沉降与内力位移分析  

Analysis of settlement and internal force displacement of single pile in multilayer soft soil foundation

作　　者：贺志军[1] 雷皓程 夏张琦 赵炼恒[1] HE Zhi-jun;LEI Hao-cheng;XIA Zhang-qi;ZHAO Lian-heng(School of Civil Engineering,Central South University,Changsha,Hunan 410000,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410000

出　　处：《岩土力学》2020年第2期655-666,共12页Rock and Soil Mechanics

基　　金：湖南省交通运输厅科技进步与创新计划项目(No.201828)。

摘　　要：根据深厚多层软土地区地基土的物理力学性质,考虑桩侧土低荷载水平下的初始极限剪应力和高荷载水平下的应力软化特性以及桩端土承载力分段发挥特性,采用一种新的桩侧和桩端模型模拟单桩荷载传递机制。基于上述模型,利用递推迭代方法可计算单桩桩顶沉降、桩身轴力以及桩侧摩阻力。采取土工参数易于获取且适用于软土地区的经验p-y曲线描述桩-土界面力和位移的非线性关系。基于欧拉-伯努利梁和中心差分理论,考虑桩尖边界条件,采用数值计算方法对桩沿长度方向的转角、剪力、弯矩进行计算,以获取在特定荷载下这些变量的变化特征。最后,结合工程案例,对上述方法进行了验证,其计算简洁且与实际测试结果吻合良好。According to the physical and mechanical properties of foundation soil in the area of deep multilayer soft soil,a new pile-side and pile-end model is adopted to simulate the load transfer mechanism of a single pile by considering the initial ultimate shear stress of pile-side soil at low-load level,the stress softening characteristics at high-load level and the piecewise performance characteristics of pile-end soil bearing capacity.Based on the above model,the iterative method can be applied to calculate the settlement of the single pile top,the axial force of the pile body and the pile side resistance.The p-y curve,which is easy to obtain and suitable for soft soil,is used to describe the nonlinear relationship between pile-soil interface force and displacement.Based on the Euler-Bernoulli beam and centre difference theory,a numerical calculation method is conducted by considering the boundary conditions of the pile tip.The rotation angle,shear force and bending moment of the pile along the length direction are calculated to obtain the variation characteristics of these variables under a specific load.Finally,as verified by an engineering case,the calculation of the above method is simple and in good agreement with the actual testing results.

关 键 词：多层地基 软土 荷载传递法 沉降计算 P-Y曲线法 有限差分法 

分 类 号：TU473.1[建筑科学—结构工程]