分配特殊群桩空间作用效应的双向m法  

A bidirectional m-method for allocating spatial effects of special pile groups

作　　者：廖立坚 苏伟 杨新安[2] 王雨权 LIAO Lijian;SU Wei;YANG Xinan;WANG Yuquan(China Railway Design Corporation,Tianjin 300308,China;College of Transportation Engineering,Tongji University,Shanghai 201804,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308 [2]同济大学交通运输工程学院,上海201804

出　　处：《岩土工程学报》2024年第6期1197-1205,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划项目(2022YFB2603400);中国国家铁路集团有限公司科技研究开发计划项目(K2022G009);中国国家铁路集团有限公司科技研究开发计划项目(N2022G064)。

摘　　要：群桩到单桩的作用分配是桩基计算的关键问题,针对规范中的单向m法只适用于平面作用的局限性,从单桩刚度、群桩刚度、受力平衡方程3个层面进行公式推导,建立了变形协调的群桩刚度矩阵和空间受力平衡方程,形成了适用于空间作用的双向m法,并以对称等长直桩、双向斜桩、不对称桩为计算实例,对比分析了单向m法和双向m法的计算结果。结果表明:单向m法计算对称等长直桩时,结果准确,计算双向斜桩时,单桩的弯矩和剪力波动较大,最大值偏小20%左右,计算不对称桩时,单桩外力之和与总外力不闭合,可信度低;而双向m法的理论解可覆盖这些桩基类型,结果更接近有限元数值解。研究成果为特殊桩基提供了一种快速且简便的计算方法,扩展了公路和铁路桥梁桩基设计规范的适用范围。The load distribution from a pile group to a single pile is the key issue in calculation of pile foundations.Aiming at the limitation that the one-way m-method in the Chinese specifications and codes is only applicable to plane action,the formulas are derived from three levels:stiffness of a single pile,stiffness of pile groups and equation for force balance,and the stiffness matrix for a deformation-coordinated pile group and the equation for spatial force balance are established,forming a bidirectional m-method suitable for spatial loads.Based on the examples of symmetric straight piles with equal length,bidirectional inclined piles and asymmetric piles,the calculated results by the one-way m-method and the bidirectional m-method are compared and analyzed.The results show that when using the one-way m-method to calculate the symmetric straight piles with equal length,the results are accurate.When calculating the bidirectional inclined piles,the bending moment and shear force of a single pile fluctuate greatly,with the maximum value being about 20% smaller.When calculating the asymmetric piles,the sum of external forces of a single pile is not closed to the total external force,and the reliability is low.The theoretical solutions for the bidirectional m-method can cover these pile foundation types,and the results are closer to the finite element numerical solutions.The research results provide a fast and simple method for special pile foundations,expanding the scope of application of the Chinese design specifications and codes for pile foundations of highway and railway bridges.

关 键 词：群桩 作用分配 空间作用 M法 双向斜桩 不对称桩 

分 类 号：TU43[建筑科学—岩土工程]