山岭隧道超浅埋段开挖围岩变形分析

随着我国公路、铁路建设的大力发展,山岭隧道洞口段、冲沟段、沟谷等地段的超浅埋问题严重威胁着隧道施工及运营期的安全。本文以某超浅埋山岭隧道为分析对象,采用了数值模拟和现场监测的手段,对超浅埋隧道在开挖条件下围岩的变形进行分析。分析结果表明：当隧道埋深小于2倍隧道直径时,埋深越浅隧道开挖后拱顶下沉位移量越大；超浅埋隧道开挖后围岩的变形可分为三个阶段,即变形急增阶段、变形缓慢阶段和变形平稳阶段；其中,第一阶段围岩产生的变形最大,是隧道开挖过程中重点关注的一个阶段。最后,通过对比分析发现,实际监测数据与模拟结果变化趋势基本吻合,模拟结果的累积变形值略大于实际监测结果,这是因为监测工序晚于开挖工序。因此,掌握超浅埋隧道在开挖过程中的围岩变形规律,并制定科学合理的开挖支护措施对隧道的安全十分重要。本文的研究是基于工程实例开展的,其研究成果对同类工程具有指导意义。

Deformation analysis of surrounding rock in super shallow buried section of mountain tunnel

With the vigorous development of highway and railway construction in China, the super-shallow burial of tunnel portals, gullies and valleys in mountain tunnels seriously threatens the safety of tunnel construction and operation period. Taking a super-shallow mountain tunnel as an analysis object, the deformation of surrounding rock of super-shallow mountain tunnel under excavation condition is analyzed by means of numerical simulation and field monitoring. The analysis results show that when the buried depth of tunnel is less than 2 times the diameter of tunnel, the displacement of vault roof is larger after excavation of shallower tunnel; the deformation of surrounding rock after excavation of super-shallow tunnel can be divided into three stages, i.e., the stage of rapid increase of deformation, the stage of slow deformation and the stage of stable deformation; among them, the deformation of surrounding rock in the first stage is the largest, which is the key step in the process of tunnel excavation. Paragraph. Finally, through comparative analysis, it is found that the actual monitoring data and simulation results are basically consistent, and the cumulative deformation value of simulation results is slightly larger than the actual monitoring results, which is because the monitoring process is later than the excavation process. Therefore, it is very important for tunnel safety to grasp the deformation law of surrounding rock in the process of excavation of super-shallow tunnel and formulate scientific and reasonable excavation support measures. The research of this paper is based on engineering examples, and its research results have guiding significance for similar projects.