富水浅埋全风化花岗岩地层隧道施工降排水技术研究
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摘要
某高铁隧道段处于富水浅埋全风化花岗岩地层,全风化花岗岩遇水迅速崩解,隧道无自稳性,且开挖极易造成塌方冒顶,施工风险极高,基于以上工程背景,论文开展了富水浅埋全风化花岗岩地层隧道施工降排水技术研究。通过研究得到:浅埋富水全风化花岗岩隧道采用地表截排水、井点降水、洞内掌子面引排水技术可有效降低地下水位,降低地层含水率,实现掌子面稳定并方便施工;井点降水作业需提前隧道开挖掌子面40m或提前掌子面开挖20d实施,隧道仰拱施工完成后停止;浅埋隧道可采用在隧道初期支护顶部预埋波纹管方法,将隧道内积水直接抽排至洞顶排水系统,从而减少洞内反坡排水设备投入,节省电力。现场实践证明,本文形成的研究成果可为浅埋富水长大隧道的反坡排水施工提供一定的借鉴作用。
A high-speed railway tunnel is situated in shallow water-rich and fully weathered granite stratum. The fully weathered granite collapses rapidly when it meets water. The tunnel has no self-stability, and it is extremely easy to cause collapse and roof fall during the excavation. The construction risk is very high. Based on the above engineering background,this paper studies the dewatering and drainage technology for shallow tunnel construction in water-rich fully weathered granite stratum. The results are as follows: The surface interception and drainage, well points dewatering and drainage technology of the face for shallow tunnel in water-rich fully weathered granite can effectively lower the groundwater level, reduce the water content, realize the stability of the face and facilitate construction. The well points dewatering operation should be carried out 40 meters ahead of the face of tunnel or 20 days ahead of the excavation time of face, and stopped after the tunnel inverted arch construction is completed. Shallow tunnels can adopt the method of embedding bellows at the top of the primary support of the tunnel to directly drain the accumulated water into the drainage system at the top of the tunnel, thus reducing the investment of drainage equipment on the back slope of the tunnel and saving electricity. Field practice has proved that the research results in this paper can provide some reference for the construction of backslope drainage in shallow and long tunnels with abundant water.
A high-speed railway tunnel is situated in shallow water-rich and fully weathered granite stratum. The fully weathered granite collapses rapidly when it meets water. The tunnel has no self-stability, and it is extremely easy to cause collapse and roof fall during the excavation. The construction risk is very high. Based on the above engineering background,this paper studies the dewatering and drainage technology for shallow tunnel construction in water-rich fully weathered granite stratum. The results are as follows: The surface interception and drainage, well points dewatering and drainage technology of the face for shallow tunnel in water-rich fully weathered granite can effectively lower the groundwater level, reduce the water content, realize the stability of the face and facilitate construction. The well points dewatering operation should be carried out 40 meters ahead of the face of tunnel or 20 days ahead of the excavation time of face, and stopped after the tunnel inverted arch construction is completed. Shallow tunnels can adopt the method of embedding bellows at the top of the primary support of the tunnel to directly drain the accumulated water into the drainage system at the top of the tunnel, thus reducing the investment of drainage equipment on the back slope of the tunnel and saving electricity. Field practice has proved that the research results in this paper can provide some reference for the construction of backslope drainage in shallow and long tunnels with abundant water.
引文
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[3]雷刚,刘涛,苏秀婷.富水砂层中地铁隧道施工降水现场试验研究[J].现代隧道技术,2016,53(2):173-181.
[4]刘楠,田英.井点降水在铁路隧道病害整治中的应用研究[J].铁道建筑技术,2014(7):120-123.
[5]王广宏,罗利彬.富水未成岩粉细砂层隧道降水技术探讨[J].隧道建设(中英文),2018,38(Z1):142-147.
[2]周立.京张高铁东花园隧道降水及排水施工方案研究[J].石家庄铁路职业技术学院学报,2018,17(2):12-16.
[3]雷刚,刘涛,苏秀婷.富水砂层中地铁隧道施工降水现场试验研究[J].现代隧道技术,2016,53(2):173-181.
[4]刘楠,田英.井点降水在铁路隧道病害整治中的应用研究[J].铁道建筑技术,2014(7):120-123.
[5]王广宏,罗利彬.富水未成岩粉细砂层隧道降水技术探讨[J].隧道建设(中英文),2018,38(Z1):142-147.