【作者】 杜鑫；

【导师】 刘小兵；

【作者基本信息】 西华大学 ， 水利水电工程， 2010， 硕士

【摘要】 随着我国水电站装机巨型化,隧洞大型化的发展,特大断面隧洞的出现对“地下工作者”提出了严峻的考验。隧洞作为水电站的关键部位,对水电站的导流、泄洪起着尤为重要的作用。但是国内外有关特大断面、大跨度隧洞的施工研究成果并不多,可借鉴的施工经验较少,大跨度的隧洞施工带有一定的盲目性。通过对大型隧洞开挖过程及开挖方法的分析,可以了解大型隧洞的位移场分布,这对保障施工安全、加快施工进度均具有十分重要的意义。本研究以一个具体水电站的导流洞为参考,建立其隧洞的几何模型,并应用ANSYS软件对其开挖过程进行了数值模拟,通过不同工况下的计算结果对大型隧洞开挖方法进行了分析。本文完成的主要研究工作如下:1、根据所选水电站导流洞的实际地质条件、断面大小,对隧洞开挖部位、隧洞周围岩体建立了三维几何模型,并将建好的三维模型进行了计算网格划分;2、利用ANSYS软件对隧洞周围进行了边界设定、参数选择、求解器选择等,对其计算网格模型进行了边界条件设置;3、对隧洞开挖过程进行了数值计算,并对求解收敛的结果进行后处理,得到了各个工况下隧洞开挖过程中岩体竖直方向和水平方向的位移场以及位移等值线分布,并分析了不同工况下隧洞周围位移的变化;4、通过对比和分析各开挖工况下隧洞的特征,获取隧洞关键部位的收敛变化信息,从而选择合理的施工方法。更多还原

【Abstract】 With the development of huge-capacity units of hydroelectric power stations and large-scale tunnels in China, the issues of the large section tunnels render a challenge for "underground workers". As a key part of the station, tunnel plays a particularly important role for diversion and flood-discharge. However, there are few research results of large section tunnels both at home and abroad, hence the corresponding construction experience is few to reference, as a matter of which, at present large-span tunnels are constructed with a certain degree of blindness. Through the analysis of excavation process and methods of large-scale tunnels, the distribution of the displacement field of large-scale tunnels can be obtained. And the analysis results have a significant importance in ensuring the construction safety and accelerating the construction speed.In this paper, a specific hydropower diversion tunnel is taken as a reference. The geometrical models of the tunnel are established. And the ANSYS software is employed to simulate the excavation process. The excavation methods of large-scale tunnels are analyzed according to the calculation results under different operating conditions. The specific works completed in this paper are as following:Firstly, according to the actual geological conditions and the cross section size of the selected diversion tunnel, three-dimensional geometric models of the tunnel excavation and tunnel rock mass are established, and the mesh of the models are generated.Secondly, ANSYS software is used in setting boundaries around the tunnels, selecting parameters, selecting calculation solvers, and so on. Boundary conditions of the meshed models are set, and calculation is started.Thirdly, the numerical calculation of the excavation process of tunnels is conducted. Through post-processing of the convergence results, vertical and horizontal displacement fields and displacement contours of rock mass during tunnel excavation under different conditions are obtained. And the changes of displacement under different conditions are analyzed.Finally, by comparing and analyzing the characteristics of tunnel excavation under different working conditions, the convergence change information of key parts of the tunnel is obtained, thus the rational construction method is selected.更多还原