深埋式输水隧洞初期支护对二次衬砌结构的受力影响研究

发布时间：2019-06-18 08:13

【摘要】：目前,我国修建了一大批长距离跨流域引调水工程,如南水北调工程、引汉济渭工程以及山西的“大水网工程”等。在这些引调水工程中,深埋式输水隧洞发挥着重要的作用。然而,在大多数水利工程中,二次衬砌结构设计时不考虑隧洞开挖过程中初期支护对二次衬砌的影响,完全将其作为安全储备,和工程实际不符,往往导致二次衬砌结构断面尺寸偏大,设计过于保守。虽然在一定程度上能够保证隧洞的安全,却造成工程量增加和一些不必要的浪费。究其深层次原因是衬砌结构理论和计算方面仍存在许多问题。复合式衬砌中,初期支护在隧洞施工过程中发挥什么作用;初期支护对二次衬砌结构有什么影响,是主要承载结构,承担比例多少,还是安全储备,这些都是困扰设计者的问题。这些问题成为了我国深埋式输水隧洞设计上的瓶颈,严重制约了隧洞设计水平的进步。因此,结合工程实际情况,分析初期支护和二次衬砌结构的承载机理,开展深埋式输水隧洞初期支护对二次衬砌结构受力影响研究是非常必要的。针对以上问题,通过总结初期支护作用机理和二次衬砌的计算方法,分析初期支护和二次衬砌的承载模式,提出基于有限元分析的荷载释放系数分析法。运用该方法,以山西省中部引黄工程典型深埋式输水隧洞为研究对象,建立数值模型,模拟输水隧洞施工过程中不同阶段围岩应力的释放过程,分析初期支护承受不同荷载释放系数时对二次衬砌结构的受力影响和现场监测数据,总结初期支护担荷载比和二次衬砌结构内力变化一般规律,为同类深埋式输水隧洞的衬砌断面设计优化提供借鉴。
[Abstract]:At present, a large number of long-distance cross-basin water diversion projects have been built in China, such as the South-to-North Water transfer Project, the Han to Wei Project and the "Dishui Network Project" in Shanxi Province. Deep buried water diversion tunnel plays an important role in these water diversion projects. However, in most water conservancy projects, the influence of initial support on secondary lining in the process of tunnel excavation is not taken into account in the design of secondary lining structure, and it is completely regarded as a safety reserve, which is inconsistent with the actual project, which often leads to the large section size of secondary lining structure and too conservative design. Although it can ensure the safety of the tunnel to a certain extent, it results in the increase of engineering quantity and some unnecessary waste. The deep reason is that there are still many problems in the theory and calculation of lining structure. In the composite lining, what role the initial support plays in the tunnel construction, what is the influence of the initial support on the secondary lining structure, is the main bearing structure, what is the bearing ratio, or the safety reserve, these are the problems that perplexed the designers. These problems have become the bottleneck in the design of deep buried water transmission tunnel in China, which seriously restricts the progress of tunnel design level. Therefore, combined with the actual situation of the project, it is very necessary to analyze the bearing mechanism of the initial support and the secondary lining structure, and to carry out the research on the influence of the initial support of the deep buried water tunnel on the stress of the secondary lining structure. In view of the above problems, by summing up the mechanism of initial support and the calculation method of secondary lining, the bearing mode of initial support and secondary lining is analyzed, and the load release coefficient analysis method based on finite element analysis is put forward. By using this method, taking the typical deep buried water tunnel of the Yellow River diversion Project in the middle of Shanxi Province as the research object, the numerical model is established to simulate the release process of surrounding rock stress in different stages of the construction of the water diversion tunnel, the influence of the initial support on the secondary lining structure under different load release coefficients and the field monitoring data are analyzed, and the general laws of the load ratio of the initial support load and the internal force of the secondary lining structure are summarized. It provides a reference for the design optimization of lining section of the same kind of deep buried water transmission tunnel.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV31;TV554

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