大跨度浅埋隧道岩体的工程地质研究

Engineering Geological Investigation of Rock Masses for a Tunnel with Large-scan Buried Shallowly

目的以我国跨度最大的公路隧道韩家岭浅埋隧道为背景,讨论通过不连续面网络图模拟真实岩体的几何特征,建立工程适用的计算模型问题,探讨地表不连续面研究成果对于隧道稳定性分析和设计的意义.方法采用蒙特卡洛方法建立不连续面模拟的数学模型,应用计算机随机绘制拟开挖岩体不连续面三维网络图.结果介绍了隧道岩体相关工程地质工作,给出了基于统计原理的岩体不连续面三维计算机模拟方法.结论应用“岩体不连续面数据处理系统”进行数据的计算机处理,可以随机模拟不同不连续面产状参数,绘制出拟开挖岩体不连续面三维网络图,建立工程适用的计算模型.设计初期由拟开挖隧道附近公路路堑边坡得到的工程地质研究结果与隧道施工期间得到的隧道围岩工程地质研究结果基本一致,表明采用地表不连续面工程地质工作研究结果进行隧道设计的可能性.

The engineering geological characteristics of surrounding rock masses of a tunnel have a significant effect on its stability, excavating plan and decision of excavation and supporting. Geometric distribution of the discontinuities and physics and mechanics properties of the surrounding rock masses are the basic data for tunnel excavation method and stability analysis. In this paper, the project of the Hanjialing tunnel which is one of the tunnels with the largest-span in China has been described in detail, with the introduction of tunnel rock mass and related engineering geological investigation. The principle of three-dimension simulation for the discontinuities in rock mass by computer based on statistics has been introduced. By using the data processing system for discontinuities in rock masses, the geometric distribution of the discontinuities in surrounding rock masses and the computing model can be simulated. The engineering geological investigation on the road slopes surrounding the tunnel has been conducted at the beginning of the design, of the projects of the principal discontinuities and their features, the outcome of which is mostly the same with those acquired by engineering geological investigation on the surrounding rock masses of the Hanjialing tunnel during excavating, which indicates that the possibility for tunnel programming of the discontinuities data is obtained through the engineering geological investigation by surface surveying.