【作者】 王晓形；

【导师】 丁文其；

【作者基本信息】 同济大学 ， 结构工程， 2006， 硕士

【摘要】 随着能源、交通、国防、市政,采矿业等国民经济建设的迅速发展和全球性环境保护及人类生存可持续发展的需求,地下工程的建设越来越多。近年来,我国交通基础设施建设规模逐步扩大,在西部山区修建大量的高速公路,不可避免地带来公路隧道的快速发展。但是在设计与施工中存在一些问题,一方面造成洞室塌方、衬砌开裂等事故,一方面过于保守,导致人力、物力、财力的巨大浪费与损失。这些存在的问题需要进一步研究: (1)连拱隧道作为一种新型的结构,在中短隧道设计中有较为明显的优势,其荷载模型一直是设计人员关心的问题; (2)公路隧道设计规范(JTG D70-2004)将地层结构法引入到Ⅰ～Ⅳ级深埋隧道的围岩压力计算中,但是浅埋隧道围岩压力仍以松散荷载进行确定,事实上,即使是浅埋洞室,仍有很大部分的洞室围岩发挥了一定的自承载能力;如何对这部分围岩承担的荷载进行确定是目前设计中面临的一大难题,也是优化设计的关键; (3)有限元法在地下工程设计中研究存在主观和客观上的不确定性,如计算模型、计算参数的选取、计算的假定以及设计施工数据与信息不足等,目前在地下工程设计中一般只能作定性分析,无法给出定量的设计值。 其他诸如在浅埋地下洞室开挖过程中,存在地表植被、保护性建筑等得不到保护;支护参数设计过大或发生整体塌陷;隧道运营之后出现仰拱鼓起、路面开裂等一系列问题。 本文结合西部交通建设科技项目《连拱隧道建设关键技术的研究》,通过广泛的设计与施工调查、数值方法以及对监测数据的详细分析,取得了一些成果。本文完成的研究工作和取得的创新成果主要包括: (1)提出了小隧道棚支护的浅埋洞室开挖方法,小隧道棚支护的浅埋洞室开挖方法为保护地表植被、建筑,避免大开挖提供了一种新颖且有效的途径,并比较了暗挖条件下各种施工方法对围岩压力的影响。 (2)考虑连拱隧道中墙支护的作用,提出双塌落拱假定,确定了连拱隧道的围岩压力模式及其大小,双塌落拱假定为多拱结构施工期围岩压力的研究奠定了基础; (3)在广泛现场调查的基础上,通过监测数据的详细分析以及数值模拟,提出了各级围岩条件下浅埋洞室围岩压力的分配比例。Ⅰ～Ⅱ级围岩,压力完全由围岩与初衬承担;Ⅲ级围岩,压力由围岩与初衬承担50～60%;Ⅳ级围岩,更多还原

【Abstract】 With the rapid development of national economy such as the energy sources, communication, national defense municipal engineering,and mine engineering etc,and global environmental protection and the need of sustainable development for the human being, the constructions of underground engineering have got more and more. Recently years, with the development of communication infrastructure has been increased sharply. And there appear more and more tunnels inevitably with the expansion of highways. But there exist some problems in the design and construction in underground project. These problems cause landslide, lining crack or excessive safety, which leads to the large waste of human and material resources. The existing problems which need further research are listed as follow.(1) The twin tunnel, as a new structure style, has obvious dominance in middle and short length tunnel. And its rational load mode is what the designer focuses on.(2) The Code for Design of Road Tunnel (JTG D70-2004) introduce the rock-structure method to the rock pressure calculation of deep seated tunnel for rock class I~IV. But the rock pressure of shallow tunnel are still calculates as loosening load. In fact, the rock displays self-bearing capacity in some shallow buried caverns. How to determine the load ratio beared by the rock itself is the key to optimize design, which is still a puzzle we face today.(3) There are subjective and objective indeterminacies in design by FEM. They are the calculation mode, the calculation parameters, calculation assumption, data and information shortage in design and construction, and etc. The FEM can not give us quantitative designing parameters, but qualitative analysis.And the other problems such as the protection of the plant cover and historic buildings while excavating, integral collapse of the shallow-seated cavern, blow up of the inverted arch also exist.The research is carried on combined with the Key Technologies In The Construction of Twin Tunnel, which is Western Communications Infrastructure Science Project of Ministry of Communications. Through extensive investigation of caverns design and construction, detailed analysis of the measuring data, some achievements are obtained. The research contents and achieved creative work are listed as follow.(1) Presenting a new design and construction method named as multi-arcade tunnels shed method for shallow buried and large span cavern. The new method has many merits such as good stability, minimum excavating quantity, low costs, especially reservation of rock appearance of cavern all around, and protection of plantcover and historical buildings of ground surface, it provides us a useful and new way to escape open excavation.(2) Presenting a new assumption of two slumping arches considering the supporting effects of the middle wall, then establishes the load model of twin tunnel based on the assumption, it settles the groundwork for the further study on th rock pressure of mutil-arch structure in construction process.(3) Giving the distribution ratio of rock pressure under different rock in shallow-seated cavern through analysis of the measured data from mode test and field minitoring in details.(4) Discussing the response of the supporting structure to the excavation under different constrtuction schemes. Some typical construction process is compared on internal force of the lining and the shotconcrete. The time effects with the rock pressure based on long-term measured data is analysised, the mechanical behaviors of the inverted arch are also discussed.更多还原