有限元荷载增量法在判定桩基础极限荷载的应用  

Application of Incremental Load Method of FEM in Determining the Ultimate Load of Pile Foundation

作　　者：刘祥沛 董天文[1,3] 郑颖人[1,3] 

机构地区：[1]后勤工程学院军事土木工程系,重庆400041 [2]岩土力学与地质环境保护重庆重点实验室,重庆401311 [3]重庆市地质灾害防治工程技术研究中心,重庆401311

出　　处：《兵器装备工程学报》2016年第5期144-148,172,共6页Journal of Ordnance Equipment Engineering

基　　金：国家自然科学基金(51178457);重庆市自然科学基金(院士专项cstc2012jjys0001)

摘　　要：针对桩基础极限承载力数值模拟的差异性,以及判定极限荷载时的明显差异,开展了有限元数值极限分析方法的研究。运用荷载增量法对桩基础极限荷载进行数值模拟,得到了3种通过荷载增量法判定极限荷载的方法:P-s曲线判定法,曲线有明显第二个拐点,其后近似平行于s轴,第二拐点对应荷载为极限荷载;数值计算不收敛判定法,即计算刚不收敛时的前一点对应荷载为极限荷载;塑性区贯通判定法,该法只适用于判断计算的正确性。研究表明,遵循判定规则,提高数值极限分析计算精度,可以准确判定极限荷载;并提出临近桩基破坏时减小加载量,在P-s曲线中可以找到陡降的破坏点。Due to difference of numerical simulation of ultimate bearing capacity of pile foundation and difference of determination method of ultimate bearing capacity of pile foundation, finite element numerical limit analysis was developed. Using incremental load method to simulate ultimate load of pile foundation, it can obtain three methods for determining ultimate load： the first is the P-s curve, and there is a second distinct inflection point in the P-s curve, paralleling to s axis approximately after, which can determine the ultimate load. Secondly, the non-convergence of finite element numerical solution is that the load of the point before non-convergence is ultimate load. Thirdly the method of connection of plastic zone is useful to determinate the correctness of solution. The research shows that the ultimate load can be determined accurately by following the rules and improving the calculation accuracy. Meanwhile, if the loading is reduced near the failure, the destruction point of the steep drop can be found in the P-s curve.

关 键 词：有限元 桩基础 荷载增量法 极限荷载 塑性区贯通 

分 类 号：TU473[建筑科学—结构工程]