超深复杂结构车站基坑开挖施工技术

以南宁市轨道交通3号线青秀山站工程为依托，采用超深群管井综合降水、大直径深长钢管柱成孔及定位技术、非爆破新型双牙高频振动高频破碎锤、抓斗等联合机械开挖、多节点立体交叉隧道施工等技术，解决泥质粉砂岩等地层降水难、大直径深长钢管柱成孔及垂直度控制难度大、基坑开挖效率低、明暗挖工程平面重叠和立体交叉施工难度大、群洞转换节点多等难题。在确保超深基坑、暗挖隧道开挖过程安全的前提下，有效控制了地表下沉，提高了复杂车站基坑开挖施工功效，缩短了工期，取得较明显的经济效益。

Excavation Technology for Super-deep Station Foundation Pit with Complex Structure

Based on the Qingxiushan Station project of Nanning Rail Transit Line 3, it adopts the technologies of comprehensive dewatering of ultra-deep group pipe wells, hole-forming and positioning of deep and long steel pipe column with large diameter, and combined mechanical excavation through new non-blasting double-tooth breaking hammer and grab with high-frequency vibration, multi-node crossing tunnel construction, etc., and it solves the construction obstacles of difficult dewatering in argillaceous siltstone and other strata, difficult control for the hole-forming and verticality of deep and long steel pipe column with large diameter, inefficient excavation of foundation pit, overlapping planes of open and underground excavation projects, troublesome construction of crossing tunnels, and too many conversion nodes of group tunnels. On the premise of ensuring the safety of excavation process of super-deep foundation pits and underground excavation tunnels, these technologies effectively control the surface subsidence, improve the construction efficiency of station foundation pit excavation with complex structure, and shorten the construction period, which achieve obvious economic benefits.