偏压小净距公路隧道施工围岩变形破坏规律研究  

Study on Deformation and Failure Law of Surrounding Rock of Highway Tunnel with Small Clear Distance under Bias Pressure

作　　者：潘子叶 PAN Ziye(Henan Transportation Development Group Co.,Ltd.,Zhengzhou 450000,China)

机构地区：[1]河南省交通运输发展集团有限公司,河南郑州450000

出　　处：《粉煤灰综合利用》2022年第6期22-27,34,共7页Fly Ash Comprehensive Utilization

基　　金：国家自然科学基金(51808508)。

摘　　要：为了研究偏压小净距公路隧道施工对围岩变形的影响规律,以黄家夼隧道为研究背景,利用FLAC 3D建立数值模拟模型,对比分析先内后外、先外后内和同时施工三种施工方案的内外侧隧道位移、中间岩柱最大竖向应力和坡面最大位移,找出了最优的施工顺序;研究不同施工步骤下,隧道围岩的位移、塑性区、中间岩柱竖向应力以及边坡稳定性变化规律。结果表明:偏压小净距隧道选择先内后外的施工顺序对保证隧道安全最为有利;围岩稳定控制的要点在于减小隧道上方的围岩位移,必要的情况下可以对其进行超前注浆加固;中间岩柱的应力和塑性区随岩柱宽度的减小而增大,且易在施工过程中发生破坏,应进行喷射混凝土、打锚杆、注浆等加固处理;隧道施工前后,边坡的安全稳定系数分别为1.86和1.91,这表明在足够支护强度条件下,隧道施工有利于山体边坡的安全。In order to study the influence of the construction of highway tunnel with small clear distance under bias pressure on surrounding rock deformation,a numerical simulation model is established based on FLAC 3D. The optimal construction sequence is found by comparing and analyzing the internal and external tunnel displacement,the maximum vertical stress of middle rock pillar and the maximum slope displacement of three construction schemes: “first inside and then outside”,“first outside and then inside”and“at the same time”. The displacement of surrounding rock,plastic zone,vertical stress of middle rock pillar and slope stability under different construction steps are studied. The results show that the construction sequence of “first inside and then outside”is the most beneficial to ensure the safety of the tunnel with small bias net distance. The key point of surrounding rock stability control is to reduce the displacement of surrounding rock above the tunnel,and advance grouting reinforcement can be carried out if necessary. The stress and plastic zone of the middle rock pillar increase with the decrease of the width of the rock pillar,and it is easy to be destroyed in the construction process,so it should be reinforced with shotcrete,anchor rod,grouting and so on. The safety and stability coefficients of slope before and after tunnel construction are 1. 86 and 1. 91 respectively,which indicates that tunnel construction is beneficial to the safety of mountain slope under the condition of sufficient support strength.

关 键 词：公路隧道 围岩变形 偏压 小净距 中间岩柱 

分 类 号：TU457[建筑科学—岩土工程]