组合地层渗流对人工地层冻结法及周围工程环境效应的影响  

Effects of seepage in clay-sand composite strata on artificial ground freezing and surrounding engineering environment

作　　者：周洁[1,2] 李泽垚 万鹏 唐益群[1,2] 赵文强 ZHOU Jie;LI Ze-yao;WAN Peng;TANG Yi-qun;ZHAO Wen-qiang(Department of Geotechnical Civil Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education,Shanghai 200092,China;East China Electric Power Design Institute Co.,Ltd.of China Power Engineering Construction Group Survey and Investigation Branch,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]中国电力工程建设集团勘测分公司华东电力设计院有限公司,上海200092

出　　处：《岩土工程学报》2021年第3期471-480,共10页Chinese Journal of Geotechnical Engineering

基　　金：冻土工程国家重点实验室开放基金项目(SKLFSE201916)。

摘　　要：随着沿海地区越来越多大型跨海、越江工程的出现,人工地层冻结法面临着更加复杂的水文地质环境问题及挑战。依托工程背景,通过典型砂黏组合地层的设计,按照严格相似比,建立了组合地层渗流环境下人工地层冻结法的缩尺模型,分析了软黏土下伏较大渗流砂层的工况下,渗流对上覆冻融敏感软黏土的冻结施工及周围工程环境的影响。试验测定了不同渗流速度下各影响区域内的温度、冻胀力、地表沉降量等参数指标。结果表明下伏砂层渗流速度过大会无法完成冻结,存在临界渗流速度。且渗流工况下软黏土上下冻结帷幕边缘的冻结效果也截然不同,尤其是稳定冻结温度和冻胀力发展模式。渗流直接影响的区域,渗流对软黏土潜热效应的削弱明显,随着渗流速度增大相变平衡时间呈线性减小。综合研究成果为冻结方案优化及施工安全提出了理论性指导意见,并对现场工程可能会遇到的施工质量、隧道安全、环境治理等做出预警建议。With the emergence of more and more large-scale cross-sea and river-crossing projects in coastal areas, the artificial ground freezing(AGF) faces more complicated hydrogeological environmental problems and challenges. Based on the engineering background of the large seepage boundary near the frozen soft clay, a scale model is established through strict similarity design to analyze the effects of seepage on the freezing construction of overlying freeze-thaw sensitive soft clay and the surrounding engineering environment under the condition of soft clay with larger seepage sand layer. The temperature, frost-heave force and surface settlement in each affected area under different seepage velocities are measured. The results show that the excessive seepage velocity of the underlying sand layer will make it impossible to complete the freezing, and there is a critical seepage velocity. In addition, the freezing effects of the upper and lower freezing curtain edges of soft clay under seepage conditions are also completely different, especially the stable freezing temperature and the development mode of the frost-heave force. In the area directly affected by seepage, the latent heat effects of seepage on soft clay are significantly weakened, and the phase transition equilibrium time decreases linearly with the increase of seepage velocity. The whole comprehensive research results provide theoretical guidance and valuable advices for the optimization of freezing scheme and construction safety of AGF. The relevant predictions and suggestions are made for construction quality, tunnel safety and environmental management that may be encountered in engineering practice.

关 键 词：组合地层 人工地层冻结法 临界渗流速度 潜热效应 冻胀力发展模式 

分 类 号：TU432[建筑科学—岩土工程]