港珠澳大桥珠海连接线拱北隧道曲线管幕9号管脱困方案研究

港珠澳大桥拱北隧道曲线管幕施工阶段,由于始发端深基坑突发涌水、涌砂,造成顶管施工区域地层严重失水和管周润滑泥浆流失,9号管顶进被困。根据顶管施工区域工程环境、地质条件和地层变形情况,以及9号管被困位置和施工装备条件因素,按照"不危及施工安全和避免发生次生灾害,可操作性强,处置费用低"的原则,提出了增加后背顶力、中继套管顶推、逆向开挖拉拔、顶部开窗等4种递进脱困方案。经比选,首先采用了增加后背顶力方案未果,后采用中继套管推进方案,取得了成功。9号管成功脱困为本工程后续顶管施工积累了经验,也为类似工程施工提供了借鉴。

Solution to 9 # Pipe Jacking Problem on the Connecting Curve Line of Gongbei Tunnel

During Gongbei tunnel curve pipe curtain construction,9#pipe jacking was trapped due to sudden inflow of water and sand in the originating deep foundation pit,causing local serious dehydration and lubricating mud loss. In view of the local engineering environment,geological conditions and strata deformation,the location where the pipe is trapped and construction equipment,four schemes are proposed:( 1) increasing back jacking force,( 2) relay casing pushing,( 3) reverse excavation,and( 4) top opening,following the principle of construction without jeopardizing safety and causing secondary disaster,strong operability and low disposal cost. The first scheme was applied and failed,then the application of the second succeeded,which has accumulated experiences for follow-up projects and provided references for similar engineering.