复杂条件下大断面小净距隧道施工方法及荷载分布力学机制研究

【作者】 杨德升；

【导师】 杨小礼；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 小净距隧道中夹岩柱较薄,双洞净距较小,是介于普通分离式隧道和连拱隧道之间的一种隧道型式。小净距隧道能很好地满足特定地质、地形条件和线桥隧衔接方式,有利于线路整体线型规划和线型优化,具有明显的技术经济效果,从而得到了越来越广泛地应用。本文以广深沿江高速公路单拱四车道小净距宴岗隧道为工程背景,通过数值模拟和理论分析,对大断面小净距隧道的施工方法和力学机制作了详尽的研究,主要工作如下：(1)本文首先总结了小净距隧道的研究现状,结合宴岗隧道工程参数,利用三维快速有限差分法建立隧道模型进行数值模拟。对大断面小净距双孔隧道在不同围岩级别(Ⅲ级、Ⅳ级、V级)、不同埋深(浅埋、浅埋偏压、深埋)和不同施工方法(全断面法、台阶法、CD法、CRD法、双侧壁导坑法)下,对其拱顶沉降、仰拱隆起、洞内收敛、地表沉降及中隔墙应力位移、围岩塑性区分别进行对比分析,以求得到大断面小净距隧道在不同地质地貌条件下的最优施工方案。另外,针对小净距隧道在浅埋偏压情况下对其施工顺序及坡度变化下小净距隧道应力位移变化规律也作了相应的研究。(2)简要总结了近几年国内众多学者对单洞隧道及小净距双洞隧道围岩压力的探索研究,归纳了浅埋隧道、浅埋偏压隧道和深埋隧道不同的计算模型及计算方法,在前人研究的基础上寻找出新的计算小净距隧道(深埋隧道)围岩压力的方法。更多还原

【Abstract】 Neighborhood tunnels stand between separated tunnels and double-arch tunnels, which have thin middle rocky column and small clear distance. They can easily satisfy the specific geological, terrain and line, bridge and tunnel cohesion, and they are conducive to the overall line programming and line optimization, they have obvious technology and economic effects, so they are more and more widely used.Yan Gang tunnel is a single-arch four-lane neighborhood tunnel along the Guangzhou-Shenzhen Expressway. In this paper, we have taken it as our engineering background. By numerical simulation and theoretical analysis, the author has done detailed research on the construction methods and mechanical mechanism of the large cross-section neighborhood tunnel. Main tasks are as follows:Firstly, this paper summarizes the status of neighborhood tunnel study, and adopts three-dimensional fast finite difference method to simulate the tunnel model according to Yan Gang tunnel parameters. When it comes to the large cross-section neighborhood tunnel at different surrounding rock grades (Ⅲgrade,Ⅳgrade,Ⅴgrades), at different buried depth (shallow, shallow bias, deep) and under the different construction methods (entire section method, the bench method, CD method, CRD method, both side heading method), the values of its crown settlement, inverted arch uplift, inside convergence, ground settlement, the middle wall stress and displacement, plastic zone of surrounding rock are analyzed separately in order for us to obtain the optimal construction plan for the neighborhood tunnel in different geological features. Besides, corresponding research has been carried out concerning the construction sequence of the shallow bias neighborhood tunnel as well as the variation of its stress and displacement with the gradient changes.Secondly, we’ve done a brief summary of the research on rock pressure in a single-hole tunnel or double-hole neighborhood tunnel by many domestic scholars in recent years, and summarized the different calculation models and calculation methods of the tunnels at different buried depth (shallow, shallow bias, deep). Based on previous research, we are to find out a new calculation method about rock pressure in a neighborhood tunnel (deep tunnel).更多还原