复杂条件下地铁隧道马头门施工技术与监测分析

 地铁隧道马头门是整个隧道结构的薄弱环节，在复杂条件下施工时容易发生拱顶坍塌或引起地表及周围构筑物的过大沉降。以深圳地铁5号线怡景路站～黄贝岭站区间隧道的马头门工程为例，介绍马头门工程的施工技术和监测方法。施工经验及监测分析表明：(1) 采用二重管注浆、中空锚杆注浆、大管棚支护、小导管注浆相结合的支护方法并根据监测结果进行动态施工，能有效地控制地表及周围构筑物的沉降；(2) 二重管注浆对地下构筑物及周围土体的加固具有明显作用；(3) 管棚施工法简便快速，能防止拱顶大面积坍塌，但可能导致土层失水，引起地表沉降；(4) 开挖时快速封闭支护结构是控制马头门洞内水平收敛的有效途径。

CONSTRUCTION TECHNOLOGY AND MONITORING ANALYSIS OF SUBWAY TUNNEL INGATE UNDER COMPLEX CONDITION

Subway tunnel ingate is the weak links of the tunnel structure. The construction under complex conditions easily leads to the collapse of vault and the settlement of ground and surrounding structures. Taking the Yijing road station to Huangbeiling station tunnel ingate project of Shenzhen Metro Line 5 for example，the construction techniques and monitoring methods are described. Construction experience and monitoring analysis show that：(1) because of using double-pipe grouting，hollow anchor grouting，big pipe shed and ductile grouting support methods，and constructing in accordance with monitoring results，the settlements of the ground and surrounding structures are controlled effectively；(2) double-pipe grouting reinforces the underground structures and the surrounding soil obviously；(3) big pipe shed construction is simple and rapid，and it can prevent the large area collapse of the vault，but the construction may lead to the water loss and ground settlement；(4) and the enclosure of lining structure is an effective method to control the horizontal convergence of the ingate section.