四排局部冻结法在上海地铁修复工程中的应用

Application of limited depth freezing method with four-row freeze-tubes to recovering collapse tunnel in Shanghai Metro

上海地铁某修复工程,在完好隧道与破坏隧道连接段采用冻结法施工垂直封水挡土止水墙,取得圆满成功。利用现场监测数据,判别了冻结管是否漏盐水以及隧道内是否充填密实,得出了冻土壁温度场形成规律,计算出积极冻结期结束时间。在浦东隧道清淤排水、浇筑混凝土止水墙阶段,分析了各施工工序对冻土墙温度影响。分析结果表明,冻结法施工质量的好坏可由温度反映出来。通过合理布置温度监测点,采用信息化施工,掌握温度变化规律,可确保复杂工程冻结施工安全。

The limited depth freezing method with four-row freeze-tubes,forming a frozen soil wall to cut off water and resist the soil pressure between the undamaged tunnel and the collapse tunnel,was used in a metro construction in Shanghai.The construction was completed successfully.This paper analyses how to use the monitored data to estimate the situation of leaking brine in freeze-tubes and judge the degree of density of the filling mortar in the tunnel.The temperature field character of the frozen soil wall was analyzed and the time of active freezing was calculated.During the cleaning in the tunnel and casting the concrete wall for water cutoff at the side of Pudong,the variation of the temperature in the frozen wall affected by the construction procedure was analyzed.It can draw a conclusion that temperature can reveal the construction quality of freezing method.Through proper redistribution of the monitoring holes,using informatized construction,studying the law of the temperature variation,the safety of the complex freezing construction can be guaranteed.