人工冻结水泥改良软黏土冻融及强度特性研究  

Experimental Study on Freeze-thaw and Strength Characteristics ofArtificially Frozen Cement-improved Soft Clay

作　　者：王升福 张祥荣 周彪 吕亮 嵇晓雷[2] WANG Shengfu;ZHANG Xiangrong;ZHOU Biao;LYU Liang;JI Xiaolei(School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China;School of Architecture and Civil Engineering,Jiangsu Open University,Nanjing 210036,China)

机构地区：[1]东华理工大学土木与建筑工程学院,江西南昌330013 [2]江苏开放大学建筑工程学院,江苏南京210036

出　　处：《东华理工大学学报（自然科学版）》2024年第4期370-380,共11页Journal of East China University of Technology(Natural Science)

基　　金：国家自然科学基金项目(42167024,52168043);江西省自然科学基金项目(20224BAB204068);江西省地质环境与地下空间工程研究中心开放基金项目(JXDHJJ2022-002);东华理工大学研究生创新项目(DHYC-202332)。

摘　　要：为探究人工冻结水泥改良软黏土冻胀融沉特性及冻融前后强度变化规律,通过室内冻胀融沉试验和单轴抗压强度试验,揭示不同冻融状态、不同影响因素等条件下水泥改良软黏土冻胀融沉及强度特性。研究结果表明,软黏土冻胀率和融沉系数随冻结冷端温度降低而减小,且融沉系数大于冻胀率;掺入水泥后融沉系数均小于冻胀率,且随水泥掺量增加而降低,当水泥掺量超过5%时,融沉系数小于2%。水泥土起始冻结温度随水泥掺量增加而降低,当水泥掺量为9%时,起始冻结温度最低达到-1.53℃;冻融过程沿试样不同高度温度场变化分为积极冻结、维护冻结和融化三个阶段;冻融后水泥改良软黏土强度降低,25组试样平均降低56%,冻融后强度折减最大达76%。研究指出,改良土强度分别随水泥掺量增加而增大,随含水率增大而减小,随龄期增长而增大。To investigate the frost heave and thaw settlement characteristics of artificially frozen cement-improved soft clay as well as the variation of strength before and after freeze-thaw cycles,laboratory experiments including frost heave and thaw settlement tests,and uniaxial compression tests were conducted to reveal the frost heave,thaw settlement,and strength properties of cement-improved soft clay under different freeze-thaw conditions and influencing factors.The results show that the freeze-thaw ratio and settlement coefficient of soft clay decrease with decreasing freezing cold end temperature,and the settlement coefficient is greater than the freeze-thaw ratio.After adding cement,the settlement coefficient is smaller than the freeze-thaw ratio,and decreases with increasing cement content.When the cement content exceeds 5%,the settlement coefficient is less than 2%.The initial freezing temperature of cement-treated soil decreases with increasing cement content,reaching a minimum of-1.53℃when the cement content is 9%.The freeze-thaw process is divided into three stages:active freezing,maintenance freezing,and melting,with temperature field changes at different heights of the sample.The strength of cement-improved soft clay decreases after freezing and thawing,with an average reduction of 56%in 25 sets of samples,and the maximum strength reduction after freezing and thawing reaches 76%.The study indicates that the strength of improved soil increases with increasing cement content,decreases with increasing moisture content,and increases with age.

关 键 词：人工地层冻结法 水泥改良土 冻胀融沉 冻结温度场 强度 

分 类 号：TU446[建筑科学—岩土工程]