深大地铁车站基坑机械化组合配套快速开挖技术

Rapid Excavation Technology of Deep and Large Foundation Pit of Metro Station with Mechanization Matching

南宁地铁1号线火车站站点超宽超大、地质及水文条件复杂、周边临近建筑物、施工环境复杂,基坑开挖难度大。为确保深大基坑的快速开挖和安全施工,提出了电动轮胎式起重机与常规履带式挖掘机组合配套开挖技术,即采用多种型号常规履带式挖掘机坑内配合,电动轮胎式起重机地面提升的施工方法。现场实践表明:(1)电动轮胎式起重机首次引入到地铁车站基坑开挖施工,与常规挖机配套施工高效合理,施工组织方便灵活,施工进度提高了1.5倍以上;(2)电动轮胎式起重机能定点开挖、自动行走、取土深度大、作业半径大、机身占地面积小、节能环保;(3)采用该组合配套机械开挖施工,较常规设备机械费节约80万元,动力费节约12万元,取得了较好经济效益,为复杂环境下宽大基坑机械化施工积累了宝贵经验。

The railway station of Nanning Metro Line 1 is very wide and large,with complex geological and hydrological conditions,adjacent buildings and complex construction environment,which causes large difficulty in excavation of foundation pit.In order to ensure the rapid excavation and safe construction of deep and large foundation pit,the combined excavation technology of electric tire crane and conventional crawler excavator is proposed,that is,the construction method of using various types of conventional crawler excavator to cooperate in the pit and electric tire crane to lift the ground.The field practice shows that:(1) the electric tire crane is introduced into the subway station foundation pit excavation construction for the first time,and the construction is efficient and reasonable with the conventional excavator,the construction organization is convenient and flexible,and the construction progress is increased by more than 1.5 times;(2) the electric tire crane can excavate at a fixed point,walk automatically,have large soil-taken depth,large operation radius,small machine body area,energy saving and environmental protection;(3) the electric tire crane can be used in the subway station foundation pit excavation construction.Compared with the conventional equipment,the mechanical cost and power cost of the combined mechanical excavation construction can be saved by RMB 800 000 and RMB 120 000 respectively,which has achieved good economic benefits and accumulated valuable experience for the mechanized construction of wide foundation pit in complex environment.