基于等效桁架模型的基坑双排桩结构计算模型研究

Study on Calculation Model of Double-row Piles Retaining Wall based on Equivalent Truss Model

在基坑双排桩支护体系中,由于前、后排桩桩间土的存在,导致其受力及变形机理变得非常复杂,而当前规程及其它常见的双排桩计算模型中,仅采用水平构件等效桩间土的作用不够完善。通过引入等效桁架模型,将前、后排桩桩间土等效为平面桁架结构,进而提出一种基坑双排桩支护结构的改进计算模型。再利用MATLAB自行编制相应的计算程序包,将该计算程序包应用到1个典型的算例分析中,对提出的基坑双排桩改进计算模型的合理性及可行性进行验证。结果表明,引入桩间土等效桁架模型后,由于考虑了桩间土的剪切变形效应和桩侧摩阻力,基坑双排桩计算模型的计算精度和合理性有了进一步提高。

The stress and deformation mechanism of double-row piles retaining system is very complex because of the existing of soil between the two rows of piles.However,the commonly used calculation models for double-row piles system in current technical specifications and practice are sometimes unreasonable for they often equalize the soil between the piles to a horizontal structural member.A modified calculation model for double-row piles supporting structure was presented in this paper by introducing the equivalent truss model and taking the soil between the two rows of piles as a plane truss structure.Then,a computer code package based on the proposed calculation model was compiled using MATLAB.Next,the computer code package was applied in analyzing a typical case.The rationality and feasibility of the presented calculation model were verified.The result shows that the proposed calculation model is more accurate and rational by considering the shear deformation effect of soil between piles and pile-soil interface friction after introducing the equivalent truss model.