摘要
程儿山隧道进出口段围岩均为第三系粉细砂岩,地下水较丰富,对照此段施工中出现的问题,分析了其中的原因。并针对第三系粉细砂岩成岩性差,泥质弱胶结,遇水或长时间暴露极易产生结构破坏,很快变成松散的砂状,隧道围岩稳定性迅速变差的特点,采取多级轻型井点真空降水、深孔真空降水和管井降水相结合的系统降水方案,超前旋喷桩预加固及注水泥浆超前预支护等一整套措施,取得了较好的施工效果。对于在此种地层中较易发生的涌水、涌砂等突发事件,采取帷幕注浆+超前大管棚的施工方案也可有效应对。
The surrounding rock of the entry and exit segments of Cheng-er-shan Tunnel is Tertiary fine-silt sandstone with rich groundwater.Analysis was performed to uncover the reasons for the problems occurred during its construction.The tertiary fine-silt sandstone has the characteristics of poor diagenetic performance and muddy weak cement.It is susceptible to structural damage when reacting with water or subjected to prolonged exposure because it can become loose sand quickly and cause the surrounding rock stability to lose its stability.With respect to these characteristics,a comprehensive treatment scheme was adopted including a combined dewatering scheme of multi-level light well vacuum precipitation,deep-hole vacuum dewatering and well dewatering,as well as advanced pre-strengthening with jet grouting pile and advanced pre-support with injecting cement slurry.This scheme acquired good construction effect.The construction scheme of curtain grouting with advanced bassoon studio can be used to effectively deal with emergencies such as water gushing and sand gushing,wich are prone to occur in such conditions.
出处
《施工技术》
CAS
北大核心
2013年第8期65-66,共2页
Construction Technology
关键词
隧道工程
第三系粉细砂岩
降水
涌水
涌砂
tunnels
Teriary fine-silty sandstone
dewatering
water gushing
sand gushing
