持续浸泡下硬黏土强度劣化试验研究  

Experimental research on strength deterioration of stiff clay under continuous immersion

作　　者：张骏 郭杨[1] 陈小川 乐腾胜 高坤[1] 柯宅邦[1] 奚邦禄 ZHANG Jun;GUO Yang;CHEN Xiaochuan;YUE Tengsheng;GAO Kun;KE Zhaibang;XI Banglu(Anhui Province Key Laboratory of Green Building and Assembly Construction,Anhui Institute of Building Research&Design,Hefei 230031,China;College of Civil Engineering,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]安徽省建筑科学研究设计院绿色建筑与装配式建造安徽省重点实验室,安徽合肥230031 [2]合肥工业大学土木与水利工程学院,安徽合肥230009

出　　处：《水利水运工程学报》2023年第4期130-137,共8页Hydro-Science and Engineering

基　　金：住房和城乡建设部科学技术研究项目(2017-K5-013);安徽省住房城乡建设科学技术计划项目(2021-YF27);绿色建筑与装配式建造安徽省重点实验室开放基金(2021-JKYL-003)。

摘　　要：引江济淮工程岸坡广泛分布的硬黏土,经历河水持续浸泡后,会对岸坡稳定造成重大影响。为了探究硬黏土在持续浸泡下的强度劣化机制,以引江济淮合肥段岸坡硬黏土为研究对象,设计持续浸泡试验,结合三轴压缩试验、矿物成分分析试验、微观结构试验和浸泡液离子含量试验,研究持续浸泡下硬黏土的强度劣化机制。结果表明:持续浸泡下硬黏土强度会发生劣化,30d内劣化明显,30d后劣化减弱且趋于平缓;硬黏土中的方解石质量分数随浸泡时长的增加,呈指数降低趋势,浸泡液中Ca2+质量体积分数呈对数增加趋势;随浸泡时长的增加,试样表面微孔隙数量增多,尺寸增大,30d内增加速度较快,30d后增加速度减缓趋于平稳。硬黏土持续浸泡后强度劣化是由亲水性黏土矿物吸水膨胀和土体内部充当“骨架”的方解石发生溶蚀共同导致的。The stiff clay widely distributed on the bank slope of the project of“Diversion of water from Changjiang River to Huaihe River”is bound to cause a series of engineering problems under the continuous soaking of river water,which will have a great impact on the stability of the bank slope.In order to explore the stiff clay under continuous soaking strength degradation mechanism,taking the stiff clay of the bank slope of the Hefei section of the project of“Diversion of water from Changjiang River to Huaihe River”as the research object,and based on the continuous soaking test,triaxial compression test,mineral composition analysis test,microstructure test and ion concentration of soaking solution test,the strength of stiff clay under continuous soaking degradation mechanism was studied.The results show that the strength of stiff clay will deteriorate under continuous soaking,and the deterioration is obvious within 30 days,and the deterioration is weak and tends to be gentle after 30 days.The mass fraction of calcite in stiff clay decreases exponentially with the increase of continuous soaking time,and the Ca2+concentration in soaking solution increases logarithmically.With the increase of continuous soaking time,the number and size of micropores on the sample surface increase,and the increase rate is fast within 30 days.After 30 days,the increase rate slows down and gradually stabilizes.The strength deterioration of stiff clay after continuous soaking is caused by water absorption and expansion of hydrophilic clay minerals and dissolution of calcite,which acts as the“skeleton”in the soil.

关 键 词：硬黏土 持续浸泡 强度 劣化机制 

分 类 号：TU442[建筑科学—岩土工程]