某浅埋箱型地铁隧道病害成因分析及治理

Causes Analysis and Treatment of Damage in a Shallow Buried Box Metro Tunnel

研究目的:受侧方深基坑施工扰动影响,某浅埋明挖箱型地铁隧道出现了变形缝部位漏水漏砂、道床脱空与横向开裂、道床冒水涌砂等严重病害。本文通过研究该地铁隧道病害的事故概况,归纳整理主要的隧道病害及分布情况,分析探讨病害产生的原因,为其后的病害治理提供依据。研究结论:(1)隧道纵向不均匀沉降是导致漏水漏砂的主要原因,也是造成道床脱空、道床横向开裂及道床冒水涌砂的重要原因;(2)水位下降诱发隧道下方软弱土层的压缩是导致隧道过大沉降和不均匀沉降的主要原因;(3)隧道的浅埋敷设不利于抵抗侧方基坑施工扰动,基坑施工诱发的地层侧移与隧道结构的侧移不协调导致隧道上方地面裂开,加剧隧道渗漏;(4)针对性地提出了外部跟踪补偿注浆与道床注浆治理方案;(5)该研究成果可为类似箱型地铁隧道工程提供参考。

Research purposes： Some damages such as leakage in deformation joint, disengaging and transverse cracks in ballast, water and sand gushing of ballast, have been found in the shallow buried box metro tunnel, which caused by excavation of adjacent deep foundation pit. In this paper, overview of the metro tunnel disease accident is researched, and then the main disease and distribution are sorted, at last, causes of tunnel disease are deeply investigated which provide reference for damage treatment.Research conclusions： （ 1 ） The structural differential settlement of tunnel is the main reason of leakage in joint. Meanwhile, it is the important reason of disengaging, transverse cracks, water and sand gushing deformation in ballast. （2） The compression of layer leads to huge and uneven settlement of tunnel structure which caused by the decrease of groundwater level. （3） As the shallow buried tunnel is weak to resist the excavation disturbance of adjacent foundation pit, ground fissure occurred above the metro tunnel caused by uncoordinated horizontal deformation between ground and tunnel structure, which will aggravate the tunnel leakage. reinforcement has been proposed. （5）The conclusion could be （4） The reasonable treatment scheme of grouting used for reference of similar engineering of metro tunnel.