兰渝铁路木寨岭隧道典型工程区地应力测量及工程地质意义

发布时间：2018-09-17 15:55

【摘要】：兰渝铁路是我国正在建设的连接西北、西南地区重要的大型交通线路。木寨岭隧道地处甘肃省定西市岷县,是兰渝铁路目前尚未完工的路段之一。隧道走向近SN,隧道全长近19km,地质条件差、施工难度高,被称为全国铁路高风险隧道之最。木寨岭隧道工程区主要为板岩、炭质板岩等软岩地层及砂岩等坚硬岩地层。受构造活动影响强烈,断裂、褶皱发育,岩体破碎。隧道开挖过程中出现较大的围岩变形,导致衬砌变形乃至破坏,工程进度缓慢。急需查明当前工程区地应力状态,对工程区所遇到的软岩大变形及其他可能存在的工程地质问题进行分析预测,以保证隧道顺利施工。本文以中国地质科学院地质力学研究所项目“兰渝铁路木寨岭隧道地应力测量研究”为依托,通过开展现场地应力测量工作获取当前木寨岭地区地应力状态,进而结合木寨岭隧道未贯通段地层岩性,对隧道当前所遇到的围岩变形及其他可能存在的问题进行分析预测,得出相应的结论。主要进行了以下分析和研究工作:(1)系统归纳、整理现有的关于木寨岭地区地应力状态的相关文献;(2)采用水压致裂法在隧道内开展了地应力测量试验,查明了木寨岭地区地应力大小和方向;(3)对隧道内围岩大变形、岩爆等工程地质问题进行分析。获得了以下主要成果:(1)分析试验结果得出:当前木寨岭隧道工程区最大水平主应力平均值是32.03MPa,最小水平主应力平均值是18.73MPa,地应力随深度的增大总体呈递增变化,地应力方向N35°~55°E,为高应力区;(2)结合隧道走向和当前地应力方向分析得出:木寨岭隧道工程区当前最大水平主应力方向与隧道走向基本一致,夹角不大,对隧道安全施工是有利的;(3)隧道未贯通段在开挖后,板岩区可能发生中高等强度的挤压变形;砂岩区存在发生中高等强度岩爆的可能。
[Abstract]:Lanyu Railway is an important transportation line connecting northwest and southwest China. Located in Minxian, Dingxi City, Gansu Province, Muzhailing Tunnel is one of the unfinished sections of Lanzhou-Chongqing Railway. The length of tunnel near SN, tunnel is about 19 km, the geological condition is poor, the construction difficulty is high, and it is called the most high risk tunnel of railway in China. The engineering area of Muzhailing Tunnel is mainly composed of slate, carbonaceous slate and hard rock such as sandstone. Strongly affected by tectonic activity, fault, fold development, rock mass fragmentation. Large surrounding rock deformation occurs during tunnel excavation, resulting in lining deformation and even destruction, and the progress of the project is slow. In order to ensure the smooth construction of the tunnel, it is urgent to find out the in-situ stress state of the project area and analyze and predict the large deformation of soft rock and other possible engineering geological problems encountered in the project area. Based on the project of Institute of Geomechanics of the Chinese Academy of Geology, "study on in-situ stress measurement of Muzhai Mountain Tunnel on Lanzhou-Chongqing Railway", the present in-situ stress state in Muzhai Mountain area is obtained by carrying out in-situ stress measurement work. Combined with the stratum lithology of the unconnected section of Muzhailing tunnel, the deformation of surrounding rock and other possible problems encountered in the tunnel are analyzed and forecasted, and the corresponding conclusions are drawn. The main work is as follows: (1) systematical induction and collation of the existing literature on the stress state in Muzhailing region; (2) using hydraulic fracturing method to carry out the in-situ stress measurement test in the tunnel. The magnitude and direction of geostress in Muzhailing area are found out. (3) the engineering geological problems such as large deformation of surrounding rock and rock burst in tunnel are analyzed. The main results are as follows: (1) the experimental results show that the average value of the maximum horizontal principal stress and the minimum horizontal principal stress are 32.03 MPA and 18.73 MPA respectively, and the in-situ stress increases with the increase of depth. The direction of in-situ stress is N35 掳~ 55 掳E, which is a high stress area. (2) combined with the analysis of tunnel direction and current direction of in-situ stress, it is concluded that the direction of maximum horizontal principal stress in Muzhailing tunnel project area is basically the same as that of tunnel direction, and the angle between them is not large. It is beneficial to the safe construction of the tunnel; (3) after the tunnel is excavated, the compression deformation of the middle and high strength may occur in the slate area, and the rock burst of the middle and high strength may occur in the sandstone area.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.11

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