极高地应力软岩隧道双层支护技术  

Technologies for Double-shell Support of Tunnels in Soft Rock with Extra-high Ground Stress

作　　者：司剑钧[1] 

机构地区：[1]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《隧道建设》2014年第7期685-690,共6页Tunnel Construction

摘　　要：兰渝铁路两水隧道洞身主要通过炭质千枚岩软岩地层，隧道为极高地应力状态，最大水平主应力值为6．5～11．3 MPa。施工前期，隧道初期支护结构变形较大，部分钢拱架扭曲、断裂，支护结构失稳，初期支护结构侵入衬砌净空，拆换拱情况频繁发生，局部地段二次衬砌开裂。针对前期施工中出现的问题，分别开展双层初期支护和双层衬砌试验，对试验段初期支护变形、围岩压力、接触压力、钢架应力、钢筋应力、混凝土应力等进行现场试验研究，掌握试验段设计及施工参数条件下，隧道支护和衬砌结构受力和变形规律。主要研究结果如下：1）双层初期支护变形相对较小，喷混凝土应力、钢架应力、二次衬砌混凝土应力及二次衬砌钢筋应力均未超过材料的容许应力，工作状态良好；2）双层初期支护可减少绑扎钢筋的工序，不需要再另增衬砌台车，在工序组织上更加便利，工效性相对较高。Liangshui tunnel on Lanzhou-Chongqing railway is located in soft rock of carbon phyllite.The rock has extra-high ground stress,with the maximum horizontal principal stress ranging from 6.5 MPa to 11.3 MPa.In the early stage of the tunnel construction,serious deformation occurred to the primary support structure,which resulted in distorted and fractured steel arches,instability of the support structure and interference of the primary support structure into the lining clearance.Therefore,the distorted primary support structure had to be dismantled and even cracks occurred to the secondary lining at local positions.In the paper,double-shell primary support experiment and double-shell secondary lining experiment are made,so as to solve the above-mentioned problems.In the experiments,the primary support deformation,the surrounding rock pressure,the contact pressure,the steel arch stress,the steel bar stress and the concrete stress are studied.Conclusions drawn are as follows：1 ）The deformation of the double-shell primary support is relatively small,the stress of the shotcrete,steel arches,secondary lining concrete and secondary lining steel bars have not exceeded the allowable stresses of these materials,and the double-shell primary support works well;2 ）Due to the adoption of the double-shell primary support,the steel bar binding process can be reduced,no additional lining formwork jumbos are needed,the construction organization is more convenient,and construction efficiency is relatively high.

关 键 词：兰渝铁路 两水隧道 双层初期支护 双层二次衬砌 现场试验 极高地应力 软岩 

分 类 号：U45[建筑科学—桥梁与隧道工程]