北京地铁区间联络通道冻结法施工技术

北京地铁一区间联络通道兼泵房采取冻结法施工,冻土帷幕是冻结法施工的关键所在。施工前对盐水温度、冻土温度、泄压孔压力进行现场监测,分析冻土帷幕发展规律,判定冻土帷幕各参数是否达到施工指标。通道开挖时获得冻土帷幕信息,以此来验证监测数据的准确性。结果表明:温度随着时间的变化先是急剧下降,之后缓慢下降趋于稳定;冻结壁交圈发生在泄压孔压力开始增大时,泄压孔压力稳定表明冻土帷幕基本形成。开挖施工获得的冻土帷幕信息证实了监测数据的准确性。

Freezing Construction Technology of Cross Passage in Beijing Subway

The freezing method was adopted in the construction of the cross passage and pump house in a section ofBeijing Subway.The freezing curtain formed is the key to the freezing method construction.Before construction,realtime monitoring of brine temperature,frozen soil temperature and pressure relief hole pressure was carried out.Thedevelopment laws of frozen soil curtain were analyzed to determine whether the parameters of frozen soil curtain meet theconstruction index.The information of frozen wall was obtained from actual excavation,and the accuracy of monitoringdata was verified.The results show that the change of temperature with time show firstly a sharp drop,and then a slowdecline to stability.The frozen wall intersection occurs at the time when the pressure relief hole pressure begins toincrease,and the stable pressure of pressure relief hole indicates the formation of frozen soil curtain.The information offrozen soil curtain obtained from excavation construction proved the accuracy of monitoring data.