新意法修建大断面隧道技术介绍

1、新意法修建大断面隧道技术介绍,主要内容,一、前言 二、新意法的理论 三、意大利隧道新意法施工介绍及视频 四、国内首次引进工程实例-兰渝铁路桃树 坪隧道新意法施工实验介绍及视频,一、前言,1、2006年7月铁道部考察团赴意大利考察了意大利软岩隧道的修建技术，认为意大利软岩隧道的修建技术（新意法）对促进中国铁路隧道施工的技术进步具有积极意义。 2、2006年12月意方土力公司组织专业人员来京讲学，推广新意法隧道修建技术。 3、2010年7月铁道部工管中心和鉴定中心主持软岩隧道施工技术研讨会，研讨新意法在中国目前在建的难度较大的铁路隧道实施的可能性，并确定使用该工法进行实际的工程实验。 4、2010年11月中铁一院、中铁21局、中铁瑞威公司组成学习组，赴意大利对软岩隧道修建方法实地学习，为国内实验新意法做准备。 5、2011年2月首次在国内兰渝铁路桃树坪隧道首次实验新意法，并根据国情和现场条件进行优化和创新。,一、前言：隧道技术进步树,二、新意法的理论（本节主要资料由意大利土力公司提供）,Upper section excavation and protection 顶部开挖及保护措施,In

2、 the past, the typical solution when dealing with tunnelling in difficult soils (highly weathered and fissured rocks, soft clays, granular soils etc.) was to operate by dividing the total section in several parts. 过去，当我们在隧道施工时，遇到复杂地层（如强风化和裂隙性岩石，软粘土，颗粒土等）时，典型的施工方法是将隧道断面分成多步施工。,Upper section lining 顶部线,Upper section completed 顶部施工完成,Central section excavation 开挖中间部分,Right side excavation 开挖右侧,Right side lining 右侧线,Left side excavation and lining 开挖左侧及左侧线,Tunnel section completed 完成,6,A full-face e

3、xcavation of the tunnel was almost never considered, mainly because of:隧道全断面开挖几乎不考虑，主要有以下几点原因： the idea that the relevant deformations could be such a magnitude to be uncontrollable;隧道产生的很大的无法控制的相关变形。 the absence on the market of drilling equipment sufficiently big and powerful to cover large tunnel sections. 满足隧道大断面施工要求的大尺寸、大功率钻机的缺乏。,In the last few years, a better knowledge on the failure mechanisms which occur behind and ahead the tunnel face while boring, the introduction of new tunnel desig

4、n approaches and the availability on the market of new generation tunnelling machines, able to cover large tunnel sections, are producing major changes, with unquestionable advantages in terms of tunnel construction: 在过去的几年里，对隧道开挖过程中发生的塌方机理的正确认识，以及新的隧道设计方法和市场上新型隧道设备的高效实用，给隧道施工带来了毋庸置疑的变化和巨大发展。 safety; 安全 quality; 质量 execution time. 施工工期,7,The action of tunnelling may be visualized as a disk (i.e. the tunnel face) proceeding with a certain velocity (V) through the ground, leaving an empty space be

5、hind it. 隧道开挖过程可以想象成一个盘子（也就是掌子面），在地层中以一个某速度（V）向前推进，在其后方流出一段空白的区域。,This action change the original stress-strain equilibrium of the medium, which may respond in different ways. 这样的动作改变了介质（泥土，粘土，岩石）的原拉-压应力平衡，产生不同的响应形态。,8,Tunnelling Response of the ground 隧道开挖-地层的反应,The ground around the tunnel profile can withstand the deviated stress flow around the cavity. An “arch effect” is developed around the cavity and negligible deformations take place. 隧道轮廓线外的地层能够承受洞室外围产生的压应力，在洞室周围产生了“拱形效应”和细微的变形。,The gro

6、und around the cavity cannot withstand the deviated stress flow. The “arch effect” is diverted far from the tunnel profile until a new stress-strain equilibrium is found. Major deformations take place. 隧道轮廓线外的地层不能承受洞室外围产生的压应力。“拱形效应”转移到远离隧道轮廓线的地方，直到找到新的应力平衡。较大的隧道变形产生了。,No portion of the ground around the cavity can withstand the deviated stress flow. The “arch effect” cannot be developed and the cavity collapses. 洞周围没有土体可以承受压力。不会产生“拱形效应”，出现隧道塌方。,9,Tunnelling Response of the ground 隧道开挖-地层的反应,Also

7、 concerning the response of the ground at the tunnel face, we can identify three basic situations, associated to the magnitude of stresses which take place just ahead the tunnel face. 同样联系到隧道掌子面地层的反应，我们定义三种基本形式（挤压，预收敛和收敛），这与隧道掌子面前方的压力大小有关。,10,Tunnelling Response of the ground 隧道开挖-地层的反应,During the progressive decrease in stress at the tunnel face (3 = 0), the ground ahead the face remains in its elastic field. The face will remain stable, showing absolutely negligible deformations (“long term st

8、ability” condition). 隧道掌子面应力不断的减少时(3 = 0), 隧道掌子面前方的地层仍是弹性变形区域。隧道掌子面将保持稳定，出现微小的变形（“长期稳定”情况下）,The progressive decrease in stress at the tunnel face induces elastic-plastic stresses in the ground ahead the face. The face will extrude towards the cavity and, without any intervention, the “arch effect” will be diverted far from the tunnel profile, inducing significant deformations (“short term stability” condition). 隧道掌子面应力不断减少，会使隧道掌子面前方的地层引起弹塑性应力，隧道掌子面会向洞中挤压，在没有任何干涉的情况下，“拱形效应”会转移并远离隧道坡面，引起变形（“短期稳定”情

9、况下）,The progressive decrease in stress at the tunnel face, induces stresses in the failure range in the ground ahead the face. The development of an “arch effect” is impossible and the face will collapse towards the cavity (“unstable face” condition). 隧道掌子面应力不断减少，在隧道掌子面前方“失败范围”的地层上引起应力。 “拱形效应”无法形成，隧道掌子面会向洞中塌方（“不稳定性”情况）,11,“Long term stable face” “长期稳定性掌子面” Max. time without temporary support (if any): 无需临时支撑的最长时间（如果有） - from 1 month to ever 从1个月到任何时候 Max. distance of temporary support (if any) from tunnel face: 临时支撑（如果有）与隧道掌子面的最大间距： - from 1,5 tunnel dia. to - 从隧道掌子面开始1.5倍洞径到无限大 Ground nature:土质情况： “A” - Sound rock (granite, quartzite, gneiss, limestone, sandstone, highly cemented conglomerate, basalt) “A” 硬岩（花岗岩、硅岩片、麻岩、 石灰岩、 沙岩、高度胶结砾岩、玄武岩 ） RQD 95 %Rc 30 Mpa “B” - Firmly bonded clastic rock, schistose rocks (phillites, slates, schists, breccia, cemented mylonite) “B” 牢固结合的碎屑岩，片岩（ phillites 、 板岩、 片岩、 角砾岩、 水泥糜棱岩） RQD 70 %Rc = 4 80 MPa “C” - Compact stratified rocks, schistose

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