大面积堆载作用下桩板结构负摩阻力特性研究  

Study on Negative Skin Friction Characteristics of Pile-plate Structure under Large-area Surcharge

作　　者：袁宇 YUAN Yu(China Railway Design Corporation,Tianjin 300308,China)

机构地区：[1]中国铁路设计集团有限公司,天津300308

出　　处：《高速铁路技术》2025年第2期29-38,共10页High Speed Railway Technology

基　　金：中国铁路设计集团有限公司科技开发课题(2022B03406015)。

摘　　要：为研究桩板结构在大面积堆载作用下的负摩阻力特性,基于修正剑桥模型与有限元方法,建立大面积堆载作用下桩板结构与土体三维有效应力模型,研究不同桩长和桩土界面摩擦系数条件下桩基负摩阻力的发展规律。结果表明,(1)桩板结构存在明显的群桩遮蔽效应,中心桩和边桩的中性点高度和负摩阻力均小于单桩,且以中心桩的减小最为明显;(2)无量纲中性点位置和归一化下拉荷载可采用负指数公式予以表征;(3)对比规范结果,明确了规范对于无量纲中性点高度和负摩阻力系数的适用范围,给出了两者随桩土摩擦系数变化的计算公式;(4)基于中性点计算公式、负摩阻力系数计算公式和群桩效应系数建议表,可计算出任意时刻的桩板结构负摩阻力。To investigate the negative skin friction characteristics of pile-plate structures under large-area surcharge,a three-dimensional effective stress model for pile-plate structures and soil under such loading conditions was established based on the modified Cam-Clay model and finite element method.This study examined the development patterns of negative friction resistance in pile foundations under varying pile lengths and pile-soil interface friction coefficients.The results indicate that:(1)There is a significant pile group shielding effect in pile-plate structures,where the neutral point heights and negative friction resistance of both central and perimeter piles are less than those of a single pile,with the most pronounced reduction observed in central piles.(2)The dimensionless neutral point position and normalized downdrag can be characterized using a negative exponential formula.(3)By comparing with standard results,the applicable scope of standards for the dimensionless neutral point height and negative friction resistance coefficient is clarified,and formulas for calculating these two parameters as functions of the pile-soil friction coefficient are provided.(4)Based on the neutral point calculation formula,the negative friction resistance coefficient formula,and a proposed table of pile group effect coefficients,the negative friction resistance of pile-plate structures at any given time can be calculated.

关 键 词：大面积堆载 桩板结构 负摩阻力 下拉荷载 中性点 

分 类 号：TU43[建筑科学—岩土工程] U213.1[建筑科学—土工工程]