厦门地区嵌岩桩单桩轴向受压容许承载力分析计算

Analysis &Calculation on Axial Compression Allowable Bearing Capacity of Rock-Socketed Pile in Xiamen City

依照厦门市疏港路下穿仙岳路通道工程地质勘测资料,根据公路规范、建筑规范和福建省当地规范对基坑开挖过程中单排围护桩的单桩轴向受压容许承载力进行计算,并对各规范计算值进行分析比较.同时结合大型有限元软件ANSYS建立桩基础三维弹塑性模型分析桩土共同工作机理,将规范计算值以面荷载的形式在模型中施加于桩顶,对此荷载下的桩体位移和桩底反力进行计算分析,同时对门机轴向荷载作用下的桩顶位移实测值和模型计算值进行对比分析,得出在规范计算值范围内,桩体未发生破坏.结果表明各个规范公式在计算桩基轴向受压容许承载力时对岩土参数取值各异,采用的计算模式存在差异,因此规范计算值差别较大,ANSYS模型数值分析结果与现场实测结果吻合良好,可为该地区桩基础设计提供参考.

According to the channel construction engineering geology survey material of Xianyue Road and Shugang Road in Xiamen,the axial compression allowable bearing capacity of fender pile in the process of excavation is calculated by highway criterion, building code and local regulations in Fujian Province and all standard calculation values are compared. With the large finite element software ANSYS, the pile founda- tion three-dimensional elastic-plastic model is established to analyze the pile and soil common working mechanism. The model uses the standard calculation value as the surface load applied to the pile and gets the displacement of the pile and the reaction at the bottom of pile. The displacement of pile under the axial load of the crane is also measured and analyzed. It is found that the pile foundation is not destroyed in the range of standard calculation values. The results show that all codes adopt different geotechnical parame- ters and the calculation method is different, so the difference of standard calculation values is big. The nu- merical analysis result of ANSYS model is similar to the actual engineering measurement result and can provide a reference for the design of pile foundation in the region.