冻结法在基坑地下连续墙缺陷处治中的应用分析

Application and Analysis of Freezing Method in Defect Treatment of Diaphragm Wall in Foundation Excavation

地下连续墙出现缺陷时,存在失稳及渗漏水风险,可采用冻结法对缺陷区域进行加固。基于某地铁基坑工程,开展现场监测及数值模拟分析,对比HS模型与MC模型在冻结工法中的适用性,发现HS模型能更好地反映实际冻结效果,适用于研究冻胀问题。基于HS模型,分别讨论冻结区厚度、深度、宽度对基坑变形及支撑内力的影响,建议冻结区采用0.4~0.6倍地下连续墙幅宽、1.5~2倍基坑深度,同时控制冻结区宽度,可保证冻结效果,控制工程规模。

There will be a risk of instability and water leakage when the diaphragm wall has defects.The defect area can be reinforced by using the freezing method.Based on a subway foundation excavation project,in this paper,we carry out on-site monitoring and numerical simulation analysis and compare the applicability of the HS model and the MC model in the freezing method.It is found that the HS model can better reflect the actual freezing effect and is suitable for studying the frost heave problem.Based on the HS model,the influence of the thickness,depth and width of the freezing zone on the deformation of the foundation excavation and the internal force of the support are discussed,respectively.It is suggested that the freezing zone should be 0.4~0.6 times the width of the underground continuous wall,1.5~2 times the depth of the foundation excavation,and the width of the freezing zone should be controlled to ensure the freezing effect and control the scale of the project.