土-膨润土隔离墙应力状态与固结行为的现场试验研究  

Field test on the stress state and consolidation behavior of soil-bentonite cutoff walls

作　　者：童星[1,2] 李育超[1,2] 柯瀚[1,2] 文一多 潘倩[1,2] TONG Xing;LI Yu-chao;KE Han;WEN Yi-duo;PAN Qian(Key Laboratory of Sott Soils and Geoenvironmental Engineering of Ministry of Education, Zhejiang University, Hangzhou, Zhejiang 310058, China;Institute of Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China)

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058 [2]浙江大学岩土工程研究所,浙江杭州310058

出　　处：《岩土力学》2018年第6期2131-2138,共8页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.41672284);浙江省科技计划项目(No.2015C03021)~~

摘　　要：土-膨润土竖向隔离墙被广泛应用于污染场地治理,其服役性能受应力状态和固结变形影响较大。通过建造两段不同尺寸的土-膨润土隔离墙试验段,并利用土压力盒、孔压计、测斜管等分别对墙体现场应力状态和变形进行了为期15个月的监测,获得了土-膨润土隔离墙固结行为的基本特征。监测结果表明:墙体主固结阶段需要数月;墙体固结变形以侧向变形为主;大部分深度内总应力在前1个月显著减小,并在随后基本保持稳定,有效应力随超孔压消散而不断增加;水平应变与最大水平有效应力均与墙深呈显著正相关;然而在主固结期间,墙体底部总应力和孔压均一直减小直至等于静水压力,有效应力始终很小。根据实测墙体变形及应力分布的特点,指出在相邻土体中可能形成滑动楔形体,对填料产生整体挤压,从而对隔离墙的现场固结行为特征作出了合理解释。最后,针对土-膨润土隔离墙的设计施工提出了相关建议。Soil-bentonite（SB） cutoff wall has been widely applied in contaminated soil remediation. Its service performance is largely influenced by stress state and consolidation deformation. Two test sections of soil-bentonite cutoff wall were built for the investigation on the consolidation behavior of SB cutoff walls. The stress state and deformation of the walls were monitored for 15 months using earth pressure load cells, piezometers and inclinometer. Results show that the major consolidation process of SB cutoff wall lasts several months. The dominant form of the wall deformation is lateral deformation. The total stress decreases in the first month, and barely changes thereafter, while the effective stress increases with the dissipation of excess pore pressure. The horizontal strain and the maximum horizontal effective stress are both correlated with the depth of the wall. At the bottom of the wall, both the total stress and pore pressure decrease to the hydrostatic pressure. The effective stress stays low during the major consolidation process. According to the deformation and stress distribution, it is suggested that there may be sliding wedges forming in the adjacent ground, squeezing the backfills integrally, which makes a reasonable explanation of the consolidation behavior of the cutoff walls. At last, recommendations on design and construction of SB cutoff walls have been proposed.

关 键 词：土-膨润土 隔离墙 固结 应力状态 变形 

分 类 号：TU413[建筑科学—岩土工程]