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在岩土工程中 ,工程的施工力学行为是一个十分重要的 ,具有极大生产实用价值的研究课题。长期以来 ,由于理论、实验、模拟及与施工相结合的难度等各方面的原因 ,系统的研究成果还不多见。论文总结了国内外前人的研究成果之后 ,利用相似模拟、数值计算和理论分析的方法较全面和系统地研究了大跨度扁坦隧道不同开挖方法、支护型式及其力学行为。所获得的研究成果对大跨度扁坦隧道的设计与施工具有特别重要的指导作用。论文的主要贡献和创新之处如下 :(1)以真武山隧道的施工设计为背景 ,在交通部重庆公路科学研究所新研制的“公路隧道结构及围岩综合实验系统”试验平台上进行了多种工法的模拟实验 ,全面测试了开挖过程的位移响应 ,揭示了应力 -变形的时空变化规律 ;利用 3D- σ程序进行的三维弹塑性数值模拟得出了具有一定规律性的施工力学响应图谱。(2 )提出了以模拟实验得出的位移来反推并验证二次衬砌设计尺寸的新思路以及用弹性位移释放系数和当步弹性位移释放系数来描述开挖瞬时弹性释放位移的新见解。(3)研究了锚喷支护与围岩的关系 ,进行了支护层的结构型式及材料受力性能的对比分析 ,提出了隧道地层压力的统一公式。(4 )将灰色建模理论用于隧道施工过程围岩失稳和坍塌是一个新的探索 ,论文所提供的
In geotechnical engineering, the engineering mechanics of construction is a very important research topic with great practical value. For a long time, due to various reasons, such as theory, experiment, simulation and construction, the research results of the system are rare. After summarizing the research achievements of predecessors both at home and abroad, this dissertation comprehensively and systematically studied the different excavation methods, support types and mechanical behaviors of long-span tunnel with similar simulation, numerical calculation and theoretical analysis. The obtained research results have a particularly important guiding role in the design and construction of long-span flat tunnels. The main contributions and innovations of the dissertation are as follows: (1) Taking the construction design of the Zhenwu Mountain Tunnel as the background, the “Highway Tunnel Structure and Surrounding Rock Comprehensive Experimental System” test platform newly developed by Chongqing Highway Science Research Institute of Ministry of Communications A variety of workmanship simulation experiments were carried out to test the displacement response of the excavation process in an all-round way, revealing the temporal and spatial variation of stress-deformation, and the three-dimensional elastoplastic numerical simulation using 3D-σ program resulted in a certain regularity of the construction mechanics response Map. (2) Proposed a new idea of using the displacement obtained from the simulation experiment to inverse and verify the design dimension of the secondary lining, as well as the new opinion of describing the instantaneous elastic release displacement with the elastic displacement release coefficient and the stepwise elastic displacement release coefficient. (3) Studied the relationship between bolt and shotcrete support and surrounding rock, carried out a comparative analysis of the structure type and material force performance of the support layer, and put forward a unified formula of the formation pressure of the tunnel. (4) It is a new exploration that the gray modeling theory is used in the tunnel construction process for the instability and collapse of surrounding rock. The paper provided