高速公路隧道穿越浅埋段地层联合快速施工法研究

Study on Joint Rapid Construction Method of Expressway Tunnel Crossing Shallow Buried Section

隧道穿越前方浅埋段施工一直是山岭隧道施工领域的难点问题。本文以2022年北京冬奥会重大交通保障工程玉渡山隧道为背景,基于FLAC3D软件模拟隧道开挖作用下隧道穿越浅埋破碎区域的力学效应,提出一种"地表注浆为主,超前小导管为辅,预留核心土"的联合快速施工法,分析施工后隧道拱顶沉降、水平收敛与塑性区范围,并给出合理的支护方案。研究表明:(1)提出的联合快速施工法对浅埋破碎区域的扰动较小,在施工过程中隧道上覆土层基本不会出现破坏;(2)隧道前进方向存在浅埋破碎区域,若不进行及时有效的治理,将会发生塌方、隧道变形过大等灾害事故;(3)所提出的联合快速施工法具有经济合理性,可为相关的浅埋破碎带施工工程提供一定的理论指导。

The construction of shallow buried section of tunnel crossing the front is always a difficult problem in the field of mountain tunnel construction.This paper was based on the background of Yudushan tunnel,a major traffic support project for the 2022 Beijing Winter Olympic Games.Based on FLAC3 Dto simulate tunnel excavation under the action of tunnel through the mechanical effect of shallow buried and broken area,a joint rapid construction method of"surface grouting as the main part,advance small pipe as the auxiliary,reserve core soil"is put forward,and the tunnel vault settlement,horizontal convergence and plastic zone range after construction is analyzed.What is more,the reasonable supporting scheme is given.The results show that:(1)the proposed combined rapid construction method has little disturbance to the shallow buried broken area,and the overlying soil layer of the tunnel will not be damaged during the construction process;(2)there is a shallow buried crushing area in the forward direction of the tunnel.If no timely and effective treatment is carried out,disaster accidents such as collapse and excessive deformation of the tunnel will occur;(3)the proposed joint rapid construction method has economic rationality,which can provide certain theoretical guidance for the relevant shallow buried crushing zone construction projects.