竖向荷载作用下岩溶区单桩承载特性研究

Bearing Characteristics of Single Pile Under Vertical Load in Karst Area

为了研究岩溶地貌对桩基的承载和变形特性的影响,提出相应的简化计算模型,采用非线性有限元分析软件ABAQUS对不同溶洞顶板厚度的单桩承载特性进行数值模拟,分析顶板厚度对单桩极限承载力以及变形的影响规律,探究桩侧与桩端的荷载传递特性。结果表明:溶洞顶板厚度的增大导致桩基的极限承载力增大,并对桩端摩阻力的传递产生影响;随着竖向荷载增大,桩基土体的主要塑性应变区由嵌岩段上部逐渐过渡到溶洞上方的顶板,顶板破坏模式表现为冲切破坏。

To study the influence of karst landform on bearing and deformation characteristics of pile foundation,a corresponding simplified calculation model was proposed.The nonlinear finite element analysis software ABAQUS was used to simulate the bearing characteristics of single pile with different roof thickness.The effect of roof thickness on the ultimate bearing capacity and deformation of the pile was analyzed,and the load transfer characteristics of pile side and end were investigated.The results show that the increase of roof thickness leads to the increase of ultimate bearing capacity of pile foundation and influences the transfer of pile’s end friction resistance.With the increase of vertical load,the main plastic strain zone of pile foundation soil gradually passes from the upper part of rock-socketed section to the roof above the karst cave.The roof failure mode is shown as punching failure.