管桩处理软基的圆管涵受力特性离心模型试验  

Centrifuge Modeling on Stress Characteristics of Pipe Culvert Treated by Pipe Pile in Soft Foundation

作　　者：冯忠居[1] 代玉婷 李军 潘放 成圆梦 隆云国 FENG Zhong-ju;DAI Yu-ting;LI Jun;PAN Fang;CHENG Yuan-meng;LONG Yun-guo(School of Highway,Chang’an University,Xi'an 710064,China;Guangdong Province Expressway Company Limited,Guangzhou 510000,China)

机构地区：[1]长安大学公路学院,西安市710064 [2]广东省高速公路有限公司,广州市510000

出　　处：《公路》2021年第10期44-51,共8页Highway

基　　金：国家重点研发计划项目,项目编号2016YFE0111900;陕西省重点研发计划项目,项目编号2018KW-022、2017KW-009。

摘　　要：为探明管桩处理对软基中高填方圆管涵受力特性和填土沉降变形的影响,通过离心模型试验,分析了管桩桩距为1.5、2.0、2.5m和无管桩时的土压力、涵顶垂直土压力集中系数Ks、沉降变形以及涵洞结构应力的变化特征,并提出相关工程技术建议。研究结果表明:土压力、Ks值与管桩桩距呈负相关,土层内外沉降差绝对值与管桩桩距呈正相关,管桩桩距大于2.0m后,管桩处理对涵洞受力和填土沉降变形的影响越来越小;当管桩桩距为1.5m~2.5m时,对应的等沉面高度变化范围为5.7m~6.1m,并且随着桩距的增大,等沉面高度逐渐降低,当管桩桩距为2.0m以上时等沉面高度变化不大,最终保持在5.7m左右;涵管顶上缘受压应力作用,涵管顶下缘受拉应力作用,当管桩桩距不到2.0m时涵管顶混凝土抗拉强度将无法保证安全;在地基承载力得到保证的情况下,管桩桩距以2.0m~2.5m为宜,对于实际工程有一定的参考价值。In order to find out the influence of pipe pile treatment on the mechanical characteristics and fill settlement deformation of high fill circular pipe culvert in soft foundation,through centrifugal model test,the variation characteristics of earth pressure,culvert internal force,settlement deformation and vertical earth pressure concentration factor Ks of culvert top are analyzed when the distance between pipe pile and pipe pile is 1.5 m,2 m,2.5 mand without pipe pile,and the relevant engineering technical suggestions are put forward.The results show that the earth pressure and Ks value are negatively correlated with the distance between pipe pile and pile,and the absolute value of settlement difference between internal and external soil layer is positively correlated with the distance between pipe pile and pipe pile.When the distance between pipe pile is more than 2 m,the influence of pipe pile treatment on culvert force and fill settlement deformation becomes smaller and smaller.Finally,it is close to the value withoutpipe pile treatment.When the pipe pile distance is 1.5 m~2.5 m,the corresponding equal settling plane height varies from 5.7 mto 6.1 m,and with the increase of the pile distance,the equal settling plane height decreases gradually,when the pipe pile distance is more than 2 m,the equal settling plane height changes little,and finally maintains at about 5.7 m;the upper edge of the culvert top is subjected to compressive stress,and the lower edge of the culvert top is subjected to tensile stress,when the pipe pile distance is less than 2 m,the tensile strength of concrete can not be guaranteed.Under the condition that the bearing capacity of the foundation is guaranteed,the distance between pipe piles and piles should be2 m~2.5 m,which has a certain reference value for practical engineering.

关 键 词：软弱地基 高填方圆管涵 土压力集中系数 离心模型试验 

分 类 号：U416.1[交通运输工程—道路与铁道工程] U449.83[建筑科学—桥梁与隧道工程]