我国几类特殊地质条件铁路隧道修建问题与对策概述

特殊地质条件隧道处治是隧道修建的主要难题，为总结经验供类似工程借鉴，本文针对几类典型铁路隧道特殊地质条件隧道修建问题与对策进行研究。1）岩溶主要问题为岩溶发育无规律、易产生突水突泥，主要对策为高位选线、畅排、泄压、水文评价与动态设计等； 2）富水破碎带主要问题为围岩稳定性差、易产生突水突泥，主要对策为超前排水泄压、超前支护与加固地层； 3）高地应力软岩主要问题为易产生大变形，主要对策为主动控制围岩变形、支护宁补勿拆、快挖、快支、快封闭等； 4）岩爆主要问题为无规律性和随机性，主要对策为改善围岩物理力学性能、围岩应力条件、加固围岩； 5）第三系含水砂层主要问题为水稳性差、降水和注浆困难，主要对策为地表和洞内联合降水、扰动置换压密型注浆加固、超前支护等； 6）高地温主要问题为恶化作业环境、降低生产率，主要对策为洒水、通风、放置冰块、机械制冷和劳动保护等； 7）瓦斯等有害气体主要问题为存在气体燃烧、爆突、爆炸风险，主要对策为通风、监测与检测、防爆设备配备、安全生产管理等。

Problems of Railway Tunnel Construction under Some Special Geological Conditions in China and Their Countermeasures

The treatment for tunnels under special geological conditions is the main problem for tunnel construction. In this paper, the main difficulties and their countermeasures for tunnel construction under special geological conditions are summarized and studied. They include: (1) For the problems caused by karst, i.e. irregular karst development and be prone to water and mud gushing, the countermeasures include selecting lines in high position, draining as soon as possible, releasing pressure, making hydrogeologic evaluation and dynamical design. (2) For the problems caused by water rich fracture zone, i.e. unstable surrounding rock and be prone to water and mud gushing, the countermeasures include draining and releasing pressure in advance, supporting and reinforcing the ground in advance. (3) For the problem, be prone to large deferment, caused by soft rocks with high crustal stress, the countermeasures include controlling the deformation of surrounding rock actively, carrying out supplementary support rather than dismantling, and carrying out rapid excavation, supporting and closing as early as possible. (4) For the irregularity and randomicity of rockburst, the countermeasures include improving the physico mechanical properties of surrounding rocks, adjusting stress conditions and reinforcing the surrounding rock. (5) For the problems caused by Tertiary water bearing sand, i.e. unstable water condition and be difficult to dewater and grout, the countermeasures include dewatering both on ground surface and in tunnel, disturbing the ground and then grouting to reinforce the ground, and supporting in advance. (6) For the problems caused by high ground temperature, i.e. deteriorated environment and lower working efficiency, the countermeasures include sprinkling water, ventilating, laying ice cakes, mechanically cooling, and personnel protecting. (7) For the problems caused by harmful gas, i.e. risks of burning, outburst and exploring, countermeasures include ventilating, monitoring and inspecting, equipping explosion proof equipment, and implementing safety production management.