季冻区分散性黏土抗剪强度特性研究  

Study on shear strength properties of dispersive clay in seasonal frozen region

作　　者：何影 王理想 宋新江 袁晓铭[3] HE Ying;WANG Lixiang;SONG Xinjiang;YUAN Xiaoming(Anhui and Huaihe River Institute of Hydraulic Research,Hefei 233000,China;Anhui Provincial Construction Engineering Quality Supervision and Inspection Station,Hefei 233000,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)

机构地区：[1]安徽省(水利部淮河水利委员会)水利科学研究院,安徽合肥233000 [2]安徽省建筑工程质量监督检测站,安徽合肥233000 [3]中国地震局工程力学研究所地震工程与工程振动重点实验室,黑龙江哈尔滨150080

出　　处：《自然灾害学报》2023年第4期229-238,共10页Journal of Natural Disasters

基　　金：安徽省自然科学基金“水科学”联合基金项目(2208085US01);国家自然科学基金项目(51378164)。

摘　　要：分散性黏土因遇水呈散凝悬浮状而得名,土中黏土颗粒(主要为胶体颗粒)和可交换钠离子溶解于低盐水中而产生反絮凝现象。季冻区分散性黏土修筑的堤防、渠道出现了滑坡失稳破坏,严重威胁到工程质量和粮食安全。采用现场调研和室内试验相结合的方法,对季冻区分散性黏土的抗剪特性进行研究,结果表明:天然状态下的分散性黏土不排水强度应力-应变曲线呈硬化型且具有剪胀性;初始干密度较小时,冻融对抗剪强度影响较小,浸泡影响较大;初始干密度较大时,冻融对抗剪强度影响较大,而浸泡仅使抗剪强度下降11.25%。经历冻融+浸泡后,抗剪强度下降90%以上且强度值低于10 kPa,黏聚力和内摩擦角仅为天然状态下的1/8~1/5。冻融引起土体劣化,浸泡进一步引起土中可交换钠离子流失是引起季冻区分散性黏土滑坡的主要原因。Dispersive clay is named for its dispersive and suspended state in low salt water.The soil is deflocculation because the clay particles(colloidal particles)and exchangeable sodium ions dissolve in low salt water.Landslides and damage occurred in the embankments and channels built with dispersive clay in the seasonally frozen area,which seriously threatened the project quality and food supply.In this paper,field investigation and laboratory experiments were used to study the shear resistance of dispersive clay in the seasonal frozen area.The results showed the undrained shear strength stress-strain curve of dispersive clay in the natural state was hardening and dilatancy.When the initial dry density was small,the effect of freeze-thaw(F-T)on the shear strength was small,but the effect of soaking was large.When the initial dry density was large,F-T had a greater effect on the shear strength,while the shear strength only reduces by 11.25%in soaking.After F-T and soaking,the shear strength decreased by more than 90%and lower than 10 kPa,and the cohesion and internal friction angle were only 1/8~1/5 of the natural state.The dispersive clay deterioration caused by F-T,and the loss of exchangeable sodium ions caused by soaking was the main reason for the dispersive clay landslide in seasonally frozen areas.

关 键 词：分散性黏土 冻融 浸泡 滑坡 抗剪特性 

分 类 号：TU4[建筑科学—土工工程] X43[环境科学与工程—灾害防治] X9