Length of tunnels comprises 68.1％ of the length of Lanzhou-Chonqing railway. In tunnels there exist four high risk resources such as, water-rich immature sandstone and large deformations of soft rock with high ground stresses; gas (natural gases); mud and water outburst in karst (worked-out area of coal mine). that seriousIy affect construction safety, progress and investment control. By means of on-site survey. expert consultation,construction testing and continuous optimization of design and construction, the main influential factors were verified and relative regulations were mastered, and the measures of experimental construction were established. In this paper the characteristics and harzards of four high risks are presented and the countermeasures and construction options for large deformations are analyzed in detail.%兰渝铁路隧线比达68.1%,存在富水未成砂岩、高地应力软岩大变形、瓦斯(天然气)、岩溶(煤矿采空区)突泥突水四大高风险源,严重影响施工安全、进度和投资控制.通过现场调研、专家会诊、施工试验,以及不断地优化设计和施工方法,初步探明了主要影响因素,基本掌握了一定的规律,制定了继续试验性施工的针对措施.目前,兰渝铁路隧道施工总体处于受控状态.文章重点介绍了兰渝铁路隧道的四大高风险的特点及危害,较详细地分析了应对大变形的措施和施工方案.
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