呼和浩特地铁深基坑夹层水处理施工技术

Construction technology of interlayer water treatment in deep foundation pit of Hohhot Metro

针对呼和浩特东站地层中存在夹层水的情况,采用基坑外和基坑内相互配合进行降水,基坑外侧采用桩外施作降水井以抽水的方式进行降水,基坑内侧采用PVC管桩间引流+桩间内侧盲沟排水+集水井抽水至雨水井、污水井的方法,该技术为首次应用到地铁深基坑施工中,与传统的基坑内+基坑外井点降水相比较,节省施工降水井费用24.5万元,井点维护费用30万元。PVC管侧壁引流+集水坑排水1d便可完成1个施工段的坑内降水且无前期准备时间,相较于基坑外+基坑内井点降水,节约打井时间约3个月,大大节省工期及产生的管理费和设备租赁费,3个月时间共节省150万元。

In view of the existence of interlayer water in the stratum of Hohhot east station,the dewatering was carried out outside the foundation pit and inside the foundation pit,the dewatering well outside the foundation pit was used as the dewatering well to pump water,and the method of drainage between PVC pipe piles and blind ditch drainage inside the pile+water collecting well pumping to the rainwater well and sewage well was used inside the foundation pit.This technology is the first time applied to the construction of subway deep foundation pit.Compared with the traditional dewatering of well points inside and outside the foundation pit,the construction cost of dewatering well is 245000 yuan and the maintenance cost of well points is 300000 yuan.PVC pipe side wall drainage+sump drainage can complete the dewatering in one construction section in one day,and there is no pre preparation time.Compared with the dewatering outside the foundation pit+well point in the foundation pit,which saves about 3 months of drilling time,greatly saves the construction period,management fee and equipment rental fee,a total of 1.5 million yuan in 3 months.