【作者】 曲星；

【导师】 李宁；

【作者基本信息】 西安理工大学 ， 岩土工程， 2009， 硕士

【摘要】 随着我国水利、公路、铁路等工程建设序幕的拉开,隧洞作为工程中重要的一部分得到了广泛的重视,而保证隧洞稳定的重要措施就是支护结构的布置,目前支护结构的设计面临着许多迫切需要解决的问题,因此从不同方面对其展开研究具有重要的理论意义和工程实际意义。隧洞支护结构设计目前主要有以下几个问题：围岩压力的确定、深浅埋深的划分、荷载-结构法计算时的误差以及常规有限元法在计算浅埋松散围岩洞室支护结构受力时的准确性,本文从这几个方面入手,提出了新的深浅埋划分方法,为研究荷载-结构法误差设计了一种拟塌落拱有限元法,在浅埋松散围岩洞室支护结构受力的计算上,推荐采用本文提出的离散化有限元方法。主要研究成果如下：(1)总结并剖析了现有深浅埋洞室下松散岩体围岩压力计算常用公式,得出浅埋洞室围岩压力计算不出现负值的洞型条件及公式在推导假定上的具体差距；通过计算对比松动岩体围岩压力计算方法在不同洞型、不同洞跨以及不同围岩类别下计算值之间的区别。(2)总结并对比了现有深浅埋划分方法,以深浅埋交接处计算围岩压力值不出现突降为依据,建立了修正洞跨的深浅埋划分方法,以此为基础提出了相应的深浅埋隧洞围岩压力计算公式。(3)设计了一种拟塌落拱有限元法,以其计算结果为对比,分析了浅埋洞室不同洞跨、不同洞高、不同埋深及不同围岩类别下的荷载-结构法的计算误差；对比了深埋隧洞下松动荷载与形变荷载计算衬砌受力值之间的差别。(4)提出了一种针对浅埋松散围岩洞室支护结构计算的新方法—离散化有限元法,对比了其与常规有限元法在计算值上的差别；通过对离散块体围岩参数、离散界面参数及离散块体大小对离散化有限元结果的影响研究,证明了离散化有限元在应用上的可行性；通过工程实例证明了本文提出方法的实用性。更多还原

【Abstract】 As an important part of many projects,tunnel have obtained widely attention.and an important measure which ensure tunnel stability is arrangement of support.At present, the design of supporting structure is faced with many crucial problem, Therefore, the research from the different aspects about support has important theoretical significance and practical significance of the project.Design of tunnel support structure mainly has the following several questions at present:the determination of rock stress, the dividing line standard of deep-lying tunnel and shallow-lying tunnel,load-structure method computation error,as well as the accuracy question of result when conventional finite element method calculates supportting force of shallow-lying tunnel in loosen rock mass. This paper obtained from these aspects,to propose a new division method of the depth,designed a FEM to simulate ground arch, recommended the use of the discrete finite element method which this paper proposed to calculate supportting force of shallow-lying tunnel in loosen rock mass.The main research results are as follows:(1) Summed up and analysed commonly used formula of calculation of rock pressure under the loose rock mass,obtained the basic conditions of tunnel size which can ensure calculation do not have a negative in shallow-lying tunnel and the specific gaps that the formula is derived on the assumption;Has contrasted the difference of calculated values of different calculation method under different condition.(2) Summed up and contrasted the division method of existing,established division formula of revision span according to rock pressure does not appear sudden fall,as this foundation to propose corresponding calculation formula of surrounding rock stress.(3) Designed to be a collapsed arch finite element method, take its computed result as the contrast to analyse error of load-structure method under several conditions; Comparison of lining values between deformation load and loosening pressure(4) Proposed the new method of calculation in shallow-lying tunnel under loose rock mass-discrete finite element method,compared with the conventional finite element method;Proved that the method is feasibility of the application by influenceable parameter research;Through project examples prove the practicality of the proposed method in this paper.更多还原