软岩钻孔灌注桩承载力的数值模拟

Numerical simulation of bearing capacity of the bored pile in soft rock

如何确定软岩地区钻孔灌注桩的承载力是一个复杂而又亟待解决的问题。本文以南京长江三桥软岩钻孔灌注桩为例,利用数值模拟法(FLAC3D模拟分析),模拟南京长江三桥软岩钻孔灌注桩逐级加载后的受力性状,根据得到的桩周土岩的应力场、位移场及破坏区的分布和扩展,确定软岩钻孔灌注桩的极限承载力。将数值模拟结果和自平衡测试结果进行比较,笔者发现两者吻合较好。

A method for determining the bearing capacity of bored pries in soft rock areas has been a complex problem that should be solved urgently. Taking the bored pries in soft rock of the third bridge over the Yangtze River in Nanjing as an example and using the numerical simulation method （FLAC3D simulation analysis）, this paper simulated the force behavior of the bored pries in soft rock of the third bridge over the Yangtze River in Nanjing in the case of step stress test. Based on stress field, displacement field and the distribution and expansion of the failure zone obtained in the soil and rock around the pile, the authors determined the ultimate bearing capacity of the bored pile in soft rock. A comparison with the numerical simulation results and the self-balanced load test results shows that the numerical simulation result agrees well with the self-balanced load test result.