考虑施工过程影响的桩基础承载力的非线性数值模拟

Non-linear Numerical Simulation of Pile Bearing Capacity Considering Construction Process

在全面考虑钻孔灌注桩施工过程的基础上,应用大型非线性有限元软件Marc建立了考虑单桩施工全过程的空间轴对称有限元模型;对Marc软件功能进行了二次开发,研编了在钻孔中考虑土体初始应力的子程序。模型由多个工况组成,包括初始应力施加、桩位分段钻孔、泥浆护壁、混凝土分段浇注成桩、混凝土凝固及分级施加荷载等,并系统分析了以上各工况中地基应力变化过程,最后得到了考虑施工过程影响的桩的承载力。通过与不考虑施工过程的模拟结果对比,证明此种数值模拟方法更合理。

On the basis of construction property of bored cast-iwsitu pile, the spatial axisymmetry finite element model considering construction process is established by the large nonlinear finite element MARC program. And the MARC program＇s function has been secondarily developed, with subroutines for soil initial stress analysis. The model comprises many different loadcases, including initial stress, subsection bore, shaft wall protection by drilling mud, pile subsection concreting and imposing grading load, etc.In addition, foundation stress changes of different loadcases have been systematically analyzed. Finally pile bearing capacity considering construction process is obtained. It is proved that the model considering construction process is more feasible than the model without the consideration.