冻结暗挖法在普天基地地下车库中的数值分析

Numerical analysis of freezing underground excavation method in Putian base underground garage

为解决在工程实践应用中保证工程质量问题,采用理论分析和数值模拟的方法进行验算求证方案设计的可靠性,以上海轨道交通15号线与9号线换乘通道下穿普天基地地下车库为背景,研究了因地质条件比较复杂,传统施工工艺已无法满足设计要求,利用ANSYS有限元软件,选取合适的物理参数对冻结壁的温度场进行数值模拟,利用有限元法进行冻土帷幕的受力分析与变形计算的问题.研究结果表明:45 d、60 d、90 d时冻土帷幕内侧局部存在应力集中但是范围很小,且冻土帷幕角部是圆弧过渡的并且冻土帷幕中间尚有土体或支撑,位移变化很小满足施工设计要求.研究结论水平冻结法克服了传统工艺无法满足设计要求的缺陷,解决了冻土帷幕中温度场变形问题.

In order to solve the problem of ensuring the engineering quality in engineering practice,theoretical analysis and numerical simulation were adopted to check and verify the reliability of the scheme design.This paper took the underground garage of Putian base under the transfer passage of Shanghai rail transit line 15 and line 9 as the background,and studied the traditional construction technology which cannot meet the design requirements due to the complicated geological conditions.Using ANSYS finite element software,the temperature field of frozen wall was numerically simulated by selecting appropriate physical parameters,and the stress analysis and deformation calculation of frozen soil curtain were carried out by using finite element method.The results show that the stress concentration exists locally on the inner side of the frozen soil curtain at 45 d,60 d and 90 d,but the range is very small,the corners of the frozen soil curtain are in arc transition,and there is still soil or support in the middle of the frozen soil curtain,so the displacement change is very small to meet the construction design requirements.The horizontal freezing method overcomes the defect that the traditional technology cannot meet the design requirements,and solves the problem of temperature field deformation in frozen soil curtain.