考虑主应力偏转的桩承式路堤土拱效应分析  

Soil arch effect of pile-supported embankment considering principal stress deflection

作　　者：张玲[1,2,3] 林炜 周帅 周杰[1,2,3] ZHANG Ling;LIN Wei;ZHOU Shuai;ZHOU Jie(College of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education,Hunan University,Changsha 410082,China;National International Joint Research Center for Building Safety and Environment,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学建筑安全与节能教育部重点实验室,湖南长沙410082 [3]湖南大学国家级建筑安全与环境国际联合研究中心,湖南长沙410082

出　　处：《铁道科学与工程学报》2025年第3期1064-1073,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52378340,52108317)。

摘　　要：土拱效应是桩承式路堤荷载传递的主要机理之一。基于Terzaghi土柱土拱模型,考虑小主应力偏转对桩承式路堤土拱效应的影响,假定应力偏转角随土拱高度的增加呈线性变化,且小主应力线轨迹为圆弧形,引入小主应力形状系数来表征同一深度处桩间土平均竖向应力与滑移面竖向应力的关系;然后通过分析等沉面以下桩间土上方路堤填土单元体,建立竖向应力平衡方程,同时利用Winkler地基模型表征桩间土和桩,建立等沉面至桩底的桩-土位移协调方程,解得随桩土差异沉降变化的桩承式路堤土拱高度,以及随土拱高度变化的桩土应力比;最后,结合2个实际工程案例,对比本文方法计算值、实测值以及其他已有理论方法计算值,验证本文方法的合理性。在此基础上,分析路堤高度、桩土刚度比、桩间净距等参数变化时主应力偏转对桩土应力比的影响。研究结果表明:本文方法考虑了主应力偏转,优化了滑移面应力分布;与传统Terzaghi法相比,本文方法土拱高度能随剪应力动态调整;桩土应力比与Terzaghi法趋势一致,但数值更低;桩土应力比和土拱高度随桩土刚度比和路堤高度的增加而增大,桩土应力比随桩间净距的增大而减小,而土拱高度随桩间净距的增加而增大;3个影响因素中,桩间净距对桩土应力比和土拱高度的影响最为显著,路堤填土高度的影响则相对较小。Soil arching effect is one of the main load transfer mechanisms within pile-supported embankment.Based on the soil-column arching model by Terzaghi,this paper considered the influence of minor principal stress deflection on the soil arching effect of pile-supported embankment assuming that the stress deflection angle changes linearly with the increase of the soil arch height,and the trajectory of the minor principal stress line was circular.A shape coefficient of minor principal stress was introduced to characterize the relationship between the average vertical stress of soil between piles and the vertical stress of the slip plane at the same depth.Then,the vertical stress equilibrium equation was established by analyzing the unit layer of embankment fill above the soil between piles under the equal settlement plane.Simultaneously,utilizing the Winkler foundation model to characterize the soft soil and piles,the pile-soil displacement compatibility equation was established from the equal settlement plane to the bottom of the piles.The soil arch height of the pile-supported embankment,which varied with the differential settlement between the piles and the soil,was determined,along with the pile-soil stress ratio,which varied with the soil arch height.Finally,the proposed method was verified by comparing the calculated values using the proposed method in this study with the measured values and the calculated values using other existing theoretical methods in two actual engineering cases.On this basis,the influence of principal stress deflection on pile-soil stress ratio was analyzed when varying embankment height,pile-soil stiffness ratio,and clear pile spacing.The results show that the stress distribution on the slip surface is optimized when considering the principal stress deflection.Compared with the traditional Terzaghi method,the proposed method reveals that the soil arch height can be dynamically adjusted with the shear stress.The trend of the pile-soil stress ratio is consistent with that of the Terzaghi me

关 键 词：桩承式路堤 土拱效应 主应力偏转 桩土应力比 土拱高度 桩土刚度比 

分 类 号：TU432[建筑科学—岩土工程]