富水砂卵石地层深基坑降水成井工艺研究

Study on Dewatering Technology of Deep Foundation Pit in Water Rich Sandy Cobble Stratum

洛阳地铁一号线某车站在深基坑开挖过程中发现地下水位远高于设计阶段勘察地下水位,地处洛河Ⅰ级台地,地层为砂卵石地层。降水管井施工困难,缩颈、塌孔现象严重,结合现场地质状况,分析各类成孔钻机特点,优化降水井成井工艺,选用长螺旋钻机压灌泥浆护壁成孔,成功解决富水卵石地层成井措辞塌孔、缩颈等问题,且具有成井效率高、施工质量可控、施工成本较低等优点,长螺旋钻机成井工艺的成功应用为类似地质情况下基坑降水施工提供借鉴。

The underground water level of a station of Luoyang Metro Line 1 during deep foundation pit excavation is much higher than that of the survey in the design stage.It is located in the class I platform of Luohe River,and the stra⁃tum is sandy pebble stratum.The construction of dewatering pipe well is difficult,necking and hole collapse are seri⁃ous.Combined with the geological conditions of the site,the characteristics of various drilling rigs are analyzed,the well completion technology of dewatering well is optimized,and the long screw drilling rig is selected to fill mud to protect the wall for hole formation,which successfully solves the problems of hole collapse and necking in water rich pebble formation,and has the advantages of high well completion efficiency,controllable construction quality and low construction cost the successful application of rotary drilling well technology provides reference for foundation pit de⁃watering construction under similar geological conditions.