大断面公路隧道进洞段围岩稳定性分析  

Stability Analysis of Surrounding Rock in Tunnel Entrance Section of Large Section Highway

作　　者：林波 邝健驹 黄丽霞 Lin Bo;Kuang Jianju;Huang Lixia(Poly Changda Overseas Engineering Co.,Ltd.,Guangzhou 510623,China)

机构地区：[1]保利长大海外工程有限公司,广东广州510623

出　　处：《市政技术》2022年第4期111-117,共7页Journal of Municipal Technology

基　　金：国家自然科学基金项目(51908168)。

摘　　要：隧道进洞段围岩的稳定性是隧道工程领域重点关注的问题。以某大断面公路隧道进洞段作为研究对象,采用Midas GTS NX有限元软件建立了隧道进洞段三维数值模型,利用监测的变形数据和压力数据对模型参数进行标定,获取了一组可真实反映围岩特性的模型参数。并进一步对进洞施工工法进行了模拟,通过分析开挖过程中围岩变形和应力的变化规律,分析大断面隧道进洞段围岩的稳定性。结果表明:采用三台阶法开挖进洞,大断面隧道掌子面开挖所引起的围岩沉降量占总沉降量的75%以上;围岩完成应力重分布之后的应力水平约为开挖之前的25%;隧道边墙的围岩应力和变形规律呈现出明显的四阶段演化特征,且在前3个阶段表现出相反的增减趋势,最后均趋于平缓。整体而言,采用三台阶法开挖可保证大断面隧道进洞段围岩的稳定性。The stability of surrounding rock in the tunnel entrance section is a key engineering problem. Taking a large section highway tunnel as the research object, a three-dimensional numerical model of the tunnel was established by MIDAS GTS NX finite element software. The model parameters were calibrated by the monitored deformation and pressure data and obtained a set of model parameters which could truly reflect the characteristics of surrounding rock. Furthermore, the excavation method was simulated. The stability is analyzed by analysis of the deformation and stress variation of the surrounding rock during the excavation. The results show that the settlement of surrounding rock caused by the excavation of the tunnel face by three-step method occupies more than 75% of the total settlement;The surrounding rock stress after stress redistribution is about 25% of that before excavation;The surrounding rock stress and deformation of the tunnel side wall show an obvious four-stage evolution characteristic,and an opposite trend of increase and decrease appears at the first three stages, and finally all evolutions tend to stability. In general, the three-step excavation method can ensure the stability of surrounding rock in large section tunnel.

关 键 词：隧道进洞段 围岩稳定性 模型参数标定 三台阶法 数值分析 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]