基于有限杆单元法的陡坡段桥梁基桩受力分析  

Mechanical Analysis of Bridge Pile Foundation in High and Steep Slopes Based on Finite Bar Element Method

作　　者：赵明华[1] 杨超炜[1] 杨明辉[1] 尹平保[1] 张锐[1] 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《中国公路学报》2014年第6期51-58,108,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(50878083);交通运输部西部交通建设科技项目(2008 318 785 31);湖南省研究生科研创新项目(CX2011B160)

摘　　要：为了对山区高陡边坡桥梁桩基进行合理分析,提出了一种改进有限杆单元法。首先,对通用杆系有限单元法的单元刚度矩阵进行修正,以综合考虑"P-Δ"效应及桩土相互作用对桩身内力和位移的影响。在此基础上,根据陡坡段基桩不同特征段的受力变形特点,将基桩划分为自由段、受荷段和嵌固段,并对桩身荷载及边界条件进行处理,建立了适用于高陡边坡桥梁桩基内力位移分析的改进有限杆单元法,并以MATLAB为平台编制了相应的计算程序。最后,结合某工程实例,重点分析了剩余下滑力大小、桩顶荷载形式等因素对基桩内力及位移的影响。研究结果表明:理论计算值与室内模型试验的实测结果吻合较好,最大相对误差在10%以内,表明该方法正确、可行;高陡边坡条件下桥梁基桩桩顶荷载对桩身内力有显著影响,"P-Δ"效应明显,在实际工程中应对其予以考虑。An improved finite bar element method was developed to reasonably analyze the pile foundation in high and steep slopes of mountainous region. Firstly, the influences of the ＂P-△＂effect and the pile-soil interaction on the internal force and displacement were taken into account by amending the element stiffness matrix of finite element method of general bar system. Based on the deformation characteristics of different typical segments of pile, the pile was divided into free segment, loaded segment and build-in segment and the load on pile body and the boundary conditions were refined to establish the improved finite bar element method that was appropriate for the internal force and displacement analysis of pile foundation in high and steep slopes. Computation program was developed on the platform of MATLAB. Finally, the influences of residual sliding force, the load on the pile top and other factors on the internal force and displacement of the pile were analyzed with respect to a practical case. The results show that the computed results are in good agreement with the measured data in laboratory model test with the maximum error less than ten percent, which verifies the correctness and applicability of this approach in the engineering practice. The load on the pile top has a significant influence on the internal force of the pile and ＂P-△＂ effect is obvious in high and steep slopes which needs to be considered in engineering practice,

关 键 词：桥梁工程 桩基础 有限杆单元法 高陡斜坡 “P-△”效应 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]