寇光明

摘要：随着山区高速公路的大量设计和建设，受地形条件影响，双连拱隧道出现在山区中短公路隧道中。连拱隧道往往处于围岩地质条件差且复杂多变的浅埋地段和偏压地段，尤其是洞口段，几乎都属于严重偏压。隧道洞顶部及周边的围岩多次受到施工扰动，围岩自稳能力差，施工过程中初支变形非常严重，为保证洞身安全，在大变形段可能会设置临时二衬。本文以云南石红大中山3号隧道右洞临时二衬砼拆除为例，对严重偏压地段的隧道临时二衬砼安全拆除技术进行分析研究。

Abstract： With the extensive design and construction of highways in mountainous areas， and affected by topographical conditions， double-arch tunnels appear in medium and short highway tunnels in mountainous areas. Multi-arch tunnels are often located in shallow buried sections and biased sections with poor geological conditions and complex and variable surrounding rock， especially the entrance section， which is almost always under severe bias. The surrounding rock at the top of the tunnel and the surrounding rock has been disturbed many times by the construction， and the surrounding rock has poor self-stability. The deformation of the initial support during the construction process is very serious. To ensure the safety of the tunnel， a temporary secondary lining may be installed in the large deformation section. This paper takes the removal of the temporary second concrete lining of the right tunnel of Dazhongshan No. 3 tunnel in Shihong， Yunnan as an example， analyzes and studies the safety removal technology of the temporary second concrete lining of the tunnel in the severely biased section.

關键词：偏压;隧道临时二衬砼;拆除技术;研究

Key words： bias pressure;temporary secondary concrete lining of tunnel;removal technology;research

中图分类号：U455.4                                     文献标识码：A                                  文章编号：1006-4311（2020）24-0113-04

1  工程概况

云南省石屏县至玉溪市元江县红龙厂高速公路（简称石红公路）为国道323线江西省瑞金至云南省临沧的重要组成部分，路线起于石屏县城南鸡石高速，止于玉溪市元江县红龙厂玉磨高速。四合同段大中山3号隧道为双连拱隧道，全长185m，隧道建筑限界净宽为10.25m，净高为5.0m。所处地表为陡坡“鸡爪”地形，自然陡坡约40～50°，进出口端均属严重偏压，隧道区的上覆地层以第四系残坡积褐色、灰色碎石为主，砂砾质充填，局部夹杂砂岩块石，结构松散;下伏地层为灰白色、紫灰色中厚层状石英砂岩，受区域地质构造影响大，节理裂隙发育，风化破碎严重，设计均为V级围岩，围岩自稳能力差，周围岩体相对容易变形塌方。隧道最大埋深约38m。

2  临时二衬砼

根据双连拱隧道的特性，结合现场的实际情况，施工顺序为：中导洞→中隔墙→先行洞（左洞）→后行洞（右洞）。……