综合降水技术在胡麻岭隧道富水粉细砂地层中的应用
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摘要
兰渝铁路胡麻岭隧道第三系富水粉细砂地层,具有复杂敏感的水稳特性,开挖后随时间推移受地下水的补给,围岩含水率和稳定性具有显著变化的特点。经过理论分析和现场试验,确定洞内采用分部台阶轻型井点降水、超前水平真空降水、重力深井负压降水,洞外采用地表重力式深井降水。通过含水率现场测定,得到降水时机—围岩含水率的关系,确定了富水粉细砂地层隧道施工的最有利降水时机。实践证明,在富水粉细砂地层开挖支护过程中,洞内超前水平真空降水应在开挖前3d进行,洞内分部台阶轻型井点降水及重力深井真空降水应随时跟进,洞外地表深井降水应超前15d进行,可稳定控制围岩含水率在10%~11%,达到预期降水效果。
The tertiary rich-watered fine sand stratum,where the Humaling Tunnel of the Lan-Yu Railway is located,has the complex and sensitive characteristics of water stability.After excavation begins,with time going on and the underground water made up continuously,the moisture content and the stability of the surrounding rock are remarkably changeable.Upon the basis of theoretical analyses and site tests,it is decided that inside the tunnel the light well-point dewatering by segment steps,dewatering by advanced horizontal vacuum,and the negative pressure dewatering by gravity-type deep wells are performed;outside the tunnel dewatering by ground gravity-type deep wells is carried out.Through testing the water content at the site,the relationship between the dewatering time and the moisture content of the surrounding rock is obtained,and thus the most favorable detwtering time for the tunnel construction in the rich-watered fine sand stratum is determined.Practice shows that in the course of supporting for excavation in the rich-watered fine sand stratum the inside-tunnel dewatering by advanced horizontal vacuum should be started 3 days before the excavation begins,and the inside-tunnel light well-point dewatering by segment steps and the gravity-type deep well and vacuum dewatering should follow at any time as required while the outside-tunnel ground deep-well dewatering should be started 15 days prior to the beginning of the excavation,with the moisture content of the surrounding rock steadily kept to 10%~11% so as to keep it up to the expected dewatering effect.
The tertiary rich-watered fine sand stratum,where the Humaling Tunnel of the Lan-Yu Railway is located,has the complex and sensitive characteristics of water stability.After excavation begins,with time going on and the underground water made up continuously,the moisture content and the stability of the surrounding rock are remarkably changeable.Upon the basis of theoretical analyses and site tests,it is decided that inside the tunnel the light well-point dewatering by segment steps,dewatering by advanced horizontal vacuum,and the negative pressure dewatering by gravity-type deep wells are performed;outside the tunnel dewatering by ground gravity-type deep wells is carried out.Through testing the water content at the site,the relationship between the dewatering time and the moisture content of the surrounding rock is obtained,and thus the most favorable detwtering time for the tunnel construction in the rich-watered fine sand stratum is determined.Practice shows that in the course of supporting for excavation in the rich-watered fine sand stratum the inside-tunnel dewatering by advanced horizontal vacuum should be started 3 days before the excavation begins,and the inside-tunnel light well-point dewatering by segment steps and the gravity-type deep well and vacuum dewatering should follow at any time as required while the outside-tunnel ground deep-well dewatering should be started 15 days prior to the beginning of the excavation,with the moisture content of the surrounding rock steadily kept to 10%~11% so as to keep it up to the expected dewatering effect.
引文
[1]张建法.圆梁山隧道粉细砂充填型溶洞钻孔注浆快速施工技术[J].隧道建设,2009,29(0l):88-92
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[3]刘娟,王海江.水平旋喷桩在酸刺沟隧道拱顶支护中的应用[J].山西建筑,2009,35(28):318-319
[4]毕焕军.胡麻岭隧道水敏性砂岩地下水渗流场模拟研究[J].铁道工程学报,2013(12):64-68
[5]南深,张民庆.饱和动态含水砂层浅埋隧道施工中的注浆技术[J].世界隧道,2000(01):14-18
[6]杨米加,陈明雄,贺永年.注浆理论的研究现状及发展方向[J].岩石力学与工程学报,2001,20(06):839-841
[7]彭振华,闫朝涛,孟庆军.井点降水在富水粉砂地层隧道施工中的应用[J].西部探矿工程,2004(12):118-120
[8]彭斌,攸巧仙.深圳地铁香车区间富水砂层施工[J].山西建筑,2003,29(01):94-95
[9]海军.象山隧道富水围岩段施工方法[J],山西建筑,2009,35(03):316-317
[10]吴生金.厦门翔安海底隧道穿越富水砂层施工技术[J].岩石力学与工程学报,2007,26(02):3816-3821
[11]李芹峰,韩志友.砂性土中的地铁隧道防水治理试验[C]//隧道、地铁工程的结构防水与维护保养.昆明:中国土木工程学会隧道与地下工程分会防水排水专业委员会,2011:124-127,142
[12]王庆林,刘晓翔.桃树坪隧道、胡麻岭隧道第三系富水粉细砂层围岩含水率与稳定性关系浅析[J].现代隧道技术,2012(04):1-5,16
[13]陈德彪.兰渝铁路胡麻岭隧道第三系弱成砂岩蠕变特性试验研究[J].隧道建设,2013(08):659-663
[2]孙国庆,张民庆.圆梁山隧道粉细砂充填型溶洞注浆技术探讨[J].探矿工程(岩土钻掘工程),2005(01):58-65
[3]刘娟,王海江.水平旋喷桩在酸刺沟隧道拱顶支护中的应用[J].山西建筑,2009,35(28):318-319
[4]毕焕军.胡麻岭隧道水敏性砂岩地下水渗流场模拟研究[J].铁道工程学报,2013(12):64-68
[5]南深,张民庆.饱和动态含水砂层浅埋隧道施工中的注浆技术[J].世界隧道,2000(01):14-18
[6]杨米加,陈明雄,贺永年.注浆理论的研究现状及发展方向[J].岩石力学与工程学报,2001,20(06):839-841
[7]彭振华,闫朝涛,孟庆军.井点降水在富水粉砂地层隧道施工中的应用[J].西部探矿工程,2004(12):118-120
[8]彭斌,攸巧仙.深圳地铁香车区间富水砂层施工[J].山西建筑,2003,29(01):94-95
[9]海军.象山隧道富水围岩段施工方法[J],山西建筑,2009,35(03):316-317
[10]吴生金.厦门翔安海底隧道穿越富水砂层施工技术[J].岩石力学与工程学报,2007,26(02):3816-3821
[11]李芹峰,韩志友.砂性土中的地铁隧道防水治理试验[C]//隧道、地铁工程的结构防水与维护保养.昆明:中国土木工程学会隧道与地下工程分会防水排水专业委员会,2011:124-127,142
[12]王庆林,刘晓翔.桃树坪隧道、胡麻岭隧道第三系富水粉细砂层围岩含水率与稳定性关系浅析[J].现代隧道技术,2012(04):1-5,16
[13]陈德彪.兰渝铁路胡麻岭隧道第三系弱成砂岩蠕变特性试验研究[J].隧道建设,2013(08):659-663