基坑悬臂支护桩的双参数有限差分算法研究

FINITE DIFFERENCE METHOD OF BI-PARAMETER ELASTIC FOUNDATION FOR CALCULATIONS OF CANTILEVER RETAINING PILES

在现行基坑规范建议的单参数法的基础上,推导了基坑悬臂支护桩双参数弹性地基有限差分法,将支护桩视为整体,等距离离散化,采用统一的有限差分格式以简化求解格式,并对计算出的土反力超过极限被动土压力的部分进行应力修正,有效地提高了计算精度与效率。以实际工程为例,根据现场监测值反演出地基抗力双参数m和n,将有限差分法的计算值与实测数据进行对比,结果显示吻合良好。从而说明在满足相同精度的条件下,该有限差分法更简便,更具优势。同时讨论了抗剪强度参数及嵌固深度等因素对应力修正的影响,获得了一些有益于工程的结论。

On the basis of the single parameter method recommended by the specification of foundation excavations,the finite difference method of bi-parameter elastic foundation for cantilever retaining piles in excavations was proposed. The cantilever retaining pile was regarded as a whole rather than be divided into two segments-cantilever segment and anchored segment as usual. Meanwhile,the soil reaction which exceeded the limit of passive earth pressure stress was corrected,so the accuracy and efficiency of the calculation was improved.Taking the practical project as an example,the subgrade resistances bi-parameters m and n were obtained through inverting the field data. And the result showed that the calculated value by the method and the measured data were in good agreement. Thus it could be proved that finite difference method has a good advantage under the same condition. At the same time,the effects of shear strength parameters and embedded depth on stress correction were discussed,and some conclusions which were beneficial to the projects were obtained.