【作者】 周捷；

【导师】 漆泰岳；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2010， 硕士

【摘要】 客运专线上的隧道基本采用双线铁路隧道设计,这些隧道轨面以上的净空面积在100m2以上,开挖断面积都很大。随着断面的增大,掌子面的稳定成为了开挖稳定的控制性因素之一。论文以武广高速浏阳河隧道下穿河底段为工程背景,主要进行了以下几个方面的工作：1.总结国外大跨隧道超前预加固的研究经验,简要阐述了岩土控制变形分析(ADECO-RS)方法(新意法)的基本理念。2.通过数值模拟计算了Ⅱ～Ⅵ级围岩条件下4种不同尺寸大断面隧道的开挖情况,研究了相应各种情况下掌子面的变形、塑性区分布、破坏特征以及拱顶位移及地层变形情况。对掌子面的塑性破坏特征进行了总结归纳,以围岩条件和隧道尺寸为主要参考因素对大断面隧道掌子面稳定性提出了参考的分类标准。3.计算表明,在软岩大断面隧道开挖过程中,如果没有初期支护以及对超前核心围岩进行加固,只采用大管棚预加固时,其梁拱效应不明显,超前核心围岩的变形仍然较大,掌子面不能保持稳定。超前玻璃锚杆及注浆均能显著提高核心土自身的强度和刚度,大大减小塑性区的深度。中空玻璃锚杆注浆由于对岩体的改良效果,比单设锚杆时更能控制掌子面的挤出位移,更有效的减小超前核心围岩塑性区的深度和范围。4.提出适合浏阳河隧道的超前预加固方式。运用FLAC3D有限差分软件,模拟经超前预加固后对掌子面变形、隧道收敛、塑性区分布、地表沉降的影响,在此基础上,应用模型试验对所选施工方法进行验证,证明所采用的超前预加固参数是合理有效的。在客运专线建设中会遇到较多的大断面隧道,在软弱围岩等不良地质条件下,通过对掌子面前方核心土进行预加固以及掌子面外的预支护,可以明显的提高核心土的强度并改善其受力情况,显著的减少掌子面的变形和缩小塑性区范围,减小了隧道的预收敛,提高了施工过程中工作面的稳定性。更多还原

【Abstract】 The tunnels in the Passenger Dedicated Lines offen are double track tunnels in order to solve the aerodynamics problems,the clearance area of these tunnels is above 100 square meters.The stability of the cutting face has rised to the most important factor of the security with the dimension increasing.This article has done following work based on Liuyang River Tunnel:1.It summarizes the experience of domestic and foreign tunnels with large section, and introduce the theory of the ADECO-RS approach.2. The research dicusses the face extrusion、plastic area、characteristic of collapse、surface settlement based on the numerical simulation with four types of dimension in the ground condition from II class to VI class,then summarizes the collapse types of the cutting face and offer a classification of the stability of the shallow tunnel with large cross section.3. The pipe-roof can not reduce the pre-convergence evidently without primary support or pre-reinforcing the advance core,so the cutting face is still not stabile.The fiberglass reinforced rock bolt and grouting could improve the strength and stiffness of the advance core,cut down the depth of the plastic area. The fiberglass bolt with grouting has much better effect than bolt used only to control the extrusion and plastic area.4. Suggest the pre-reinforcement method and parameters which is suitable for the large span Liuyang River Tunnel preliminary by contrasting the result before. Find the influence of the pre-reinforcement method on the face extrusion、convergence、surface settlement and the prime support by three-dimensional numerical simulation, then verify the previous result by model test to ensure the method and parameters is effective.It will meet many tunnels with large section in the Passenger Dedicated Lines, the stiffness of the advance core will increase evidently by the pre-reinforcement, and the face extrusion and convergence can be reduced,so enhance the security of construction.更多还原