四六导洞组合PBA法暗挖车站施工技术

摘要

The PBA method is also called “cavern⁃pile method”, the principle of which is to undertake small pilot tunnel construction in advance, then construct piles, pile⁃top capping beam and arch in it. After the formation of the combined support system of “Pile”,“Beam” and “Arc”, the soil excavation and structural construction could be done in the end. This paper mainly expounded the construction technology of four or six pilot tunnels combination applied in excavation sta⁃tion with PBA technique used in Songjiang Road Station of Dalian Metro first phase project. This new construction method derived and developed from the theory only using“four pilot tunnels”,“six pilot tunnels” or“eight pilot tunnels”. In the same subway station, according to the different geology of different section respectively using four pilot tunnels ( three above and one underneath, for rock basement) or six pilot tunnels ( three above and three underneath, for clay or completely de⁃composed rock basement) . Based on the construction principles mentioned above, this paper carried out on the key tech⁃nology control aiming at different combinations of pilot tunnels.%PBA法又叫“洞桩法”，其原理就是先进行小导洞施工，然后施工洞内桩、桩顶冠梁、扣大拱，“桩（ Pile）、梁（ Beam）、拱（ Arc）”联合支护体系形成后，最后进行土体开挖和结构施工。本文主要介绍了大连地铁一期工程松江路车站四六导洞组合PBA法暗挖车站施工技术，该施工方法将只采用单一的“四导洞”、“六导洞”、“八导洞”等应用理论进行了提升，在同一个车站内，根据不同段落的地质情况，分区段采用四导洞（上三下一，基底为岩石地层）和六导洞（上三下三，基底为黏土或全风化岩石地层）施工，对于不同类型导洞组合有针对性地按照上述工艺原理进行关键技术控制。