低应力条件下高液限红黏土湿化变形特性研究  

Wetting deformation characteristics of high liquid limit red clay under low stress condition

作　　者：邱祥 李锦鸿[1] 曾波 付宏渊 罗震宇 陈镜丞 刘忠伟 QIU Xiang;LI Jin-hong;ZENG Bo;FU Hong-yuan;LUO Zhen-yu;CHEN Jing-cheng;LIU Zhong-wei(School of Civil Engineering,Changsha University of Science&Technology,Changsha,Hunan 410114,China;Key Laboratory of Road Structure and Materials Transportation Industry,Changsha University of Science&Technology,Changsha,Hunan 410114,China;The Third Construction Co.,Ltd.,China Construction No.5 Engineering Bureau,Changsha,Hunan 410011,China;Changsha Highway and Bridge Construction Co.,Ltd.,Changsha,Hunan 410007,China)

机构地区：[1]长沙理工大学土木工程学院,湖南长沙410114 [2]长沙理工大学道路结构与材料交通行业重点实验室,湖南长沙410114 [3]中建五局第三建设有限公司,湖南长沙410011 [4]长沙市公路桥梁建设有限责任公司,湖南长沙410007

出　　处：《岩土力学》2023年第7期2028-2040,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.51908073,No.51838001);湖南省自然科学基金项目(No.2020JJ5581);湖南省教育厅自然科学研究项目(No.21B0317);长沙理工大学道路结构与材料交通行业重点实验室开放基金项目(No.kfj170302);长沙理工大学专业学位研究生“实践创新与创业能力提升计划”项目(No.SJCX2021114)。

摘　　要：针对我国南方地区高液限红黏土低路堤存在工后沉降变形的问题,采用自主设计可测试低应力条件下岩土体湿化变形的试验装置,研究了不同围压、轴压与围压之比和压实度条件下高液限红黏土竖向湿化应变、侧向湿化应变的变化规律,建立了可以考虑围压、轴压与围压之比、压实度影响的高液限红黏土竖向湿化应变峰值预估模型,并对预估模型进行了验证。研究得到的主要结论为:渗流与应力耦合作用下,高液限红黏土侧向湿化应变与竖向变形均先增大、后趋于稳定,高液限红黏土试样在湿化变形稳定后呈现上部大、下部小的特点;高液限红黏土侧向湿化应变开始响应至达到峰值所需时间、侧向湿化应变峰值、竖向变形量峰值与围压、轴压与围压之比呈正相关;高液限红黏土侧向湿化应变峰值、竖向变形量峰值与压实度呈负相关,侧向湿化应变开始响应至达到峰值所需时间与压实度呈正相关;高液限红黏土侧向湿化应变可以分成由增湿引起的侧向湿化应变和由膨胀性矿物吸水引起的侧向湿化应变两部分;不同因素对高液限红黏土竖向湿化应变峰值的影响程度为:压实度>轴压与围压之比>围压;本研究对高液限红黏土低路堤工后沉降变形预测与控制具有重要的工程意义。Given the problems of post-construction settlement deformation of high liquid limit red clay low embankment in Southern China,the variation laws of vertical and lateral wetting strain of high liquid limit red clay under different confining pressures,ratios of axial pressure to confining pressure and compactness were studied using a self-designed test device which can test the wetting deformation of rock and soil under low stress conditions.A peak prediction model of vertical wetting strain of high liquid limit red clay considering the influence of confining pressure,ratio of axial pressure to confining pressure and compactness is further established,and the prediction model is validated.The primary conclusions are as follows:under the coupling action of seepage and stress,the lateral wetting strain and vertical deformation of high liquid limit red clay first increase and then tend to be stable.When the wetting deformation is stable,the high liquid limit red clay sample shows the characteristics of large upper part and small lower part.The duration of lateral wetting strain,peak value of lateral wetting strain and peak value of vertical deformation of high liquid limit red clay are positively correlated with confining pressure and ratio of axial pressure to confining pressure.The peak value of lateral wetting strain and peak value of vertical deformation of high liquid limit red clay are negatively correlated with the degree of compaction,and the duration of lateral wetting strain is positively correlated with the degree of compaction.The lateral wetting strain of high liquid limit red clay can be divided into two parts:the lateral wetting strain caused by humidification and the one caused by water absorption of expansive minerals.The importance of different factors on the vertical wetting strain peak of high liquid limit red clay is:compactness>ratio of axial pressure to confining pressure>confining pressure.This study has an important engineering significance for the prediction and control of post-construction s

关 键 词：道路工程 高液限红黏土 低应力 侧向湿化应变 竖向湿化应变 预估模型 

分 类 号：U416.12[交通运输工程—道路与铁道工程]