大跨度铁路悬索桥隧道锚原位模型试验方案研究

发布时间：2018-03-21 02:42

本文选题：隧道锚　切入点：缩尺模型试验　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文结合金沙江特大桥开展铁路悬索桥隧道式锚碇原位模型试验方案研究。拟采用地质调查、室内岩体常规力学试验、原位岩体力学性质试验、原位缩尺模型试验等综合手段,系统研究隧道锚所在区域工程地质条件、岩体物理力学特性、隧道锚和围岩变形变位特性,流变特征,隧道锚承载能力及潜在破坏特征和隧道锚稳定性等问题。为了准确掌握香格里拉岸试验隧道锚区域围岩力学性质,选取该区域内岩体进行室内常规物理性质试验,并在该区域进行原位力学性质试验,以获得试验区域内岩体准确的物理参数,为后续开展隧道锚原位缩尺模型试验和隧道锚稳定性分析提供依据。原位缩尺模型试验是本次试验方案设计的主体。试验以相似理论为依据并通过对比多个类似原位缩尺模型试验结果,得出不同几何相似比对岩体变形有着巨大的影响,各不相同的地质条件和"尺寸效应"也导致试验结果产生巨大的差异,为尽可能减少因"尺寸效应"带来的影响,真实反映隧道锚及周围岩体在荷载作用下的变形变位特征,确定本次缩尺模型的相似比为1:10。在试验模型尺寸确定的基础上,结合前期针对丽江岸实桥隧道锚有限元数值计算结果,得到试验锚碇及围岩在加载过程中的应力、位移变化规律和极限荷载下的岩体变形范围,确定本次试验的场地及范围。为深入研究锚体及围岩在荷载作用下的变位特征,将本试验测试内容确定为锚体及围岩在荷载作用下的变形和应变等效应量。针对变形和应变等效应量编制采用电感式多点位移计测试锚碇及周围岩体内部变形;采用应变计测试锚碇内部变形;采用智能数码通用位移计测试锚碇及围岩表面变形的测试方案;采用位错计测试锚体与围岩接触面的相对位移。'为了达到试验加载要求,模拟实际隧道锚所处的多种受荷模式,并克服拉拔方式中采用的反力大梁过于笨重等缺点,采用在锚碇后端面布置千斤顶的后推法的加载方式。原位缩尺模型试验是一项系统工程,合适的试验场地,精确的测试仪器,合理的仪器布置方案,有效可行的加载设备和简便高效的采集设备缺一不可,本文就这些方面一一展开讨论,准确把握试验方向,依据试验目的力争制定出一套合理的试验方案,利用地质调查、岩体力学试验、原位缩尺模型试验等综合手段,系统研究隧道锚所在区域工程地质条件、岩体物理力学特性、隧道锚受力变形特性、流变特征、隧道锚承载能力及潜在破坏特征和隧道锚稳定性等问题。验证隧道式锚碇设计成果与计算方法的合理性,并确认这些结果所证实的一般规律与计算理论可推广到实际结构中去,为今后开展类似工程积累经验,提高人们关于各种参数对工程性能影响的认识,并为建立系统的隧道锚设计理论和方法,编制隧道锚相关规程规范提供依据,促进隧道式锚碇设计技术的进步与发展。
[Abstract]:In this paper, combined with Jinsha River Bridge, the research on the in-situ model test scheme of railway suspension bridge tunnel Anchorage is carried out. The comprehensive means of geological investigation, indoor rock mass mechanics test, in-situ rock mass mechanical property test, in-situ scale model test, etc. The engineering geological conditions, physical and mechanical properties of rock mass, deformation and displacement characteristics of tunnel anchors and surrounding rock, rheological characteristics of tunnel anchors in the region of tunnel anchors are systematically studied. The bearing capacity and potential failure characteristics of tunnel anchors and the stability of tunnel anchors are discussed. In order to accurately understand the mechanical properties of surrounding rocks in the Anchorage region of Shangri-La test, the rock mass in this area is selected for indoor routine physical property tests. In order to obtain the accurate physical parameters of rock mass in the test area, the in-situ mechanical property test was carried out in this area. The model test is the main part of the design of the test scheme. The model test is based on the similarity theory and through the comparison of several similar test results, the model test of tunnel anchor in situ scale model test and stability analysis of tunnel anchor in situ is the main part of the design of the test scheme. Results of in-situ scale model test, It is concluded that different geometric similarity ratios have a great influence on rock deformation, and different geological conditions and "size effects" also lead to great differences in test results, in order to minimize the impact of "size effect". The deformation and displacement characteristics of tunnel anchor and surrounding rock mass under load are truly reflected, and the similarity ratio of the scale model is determined to be 1: 10. Based on the determination of the size of the test model, Combined with the numerical results of finite element method for tunnel anchors in Lijiang bank, the stress, displacement and deformation range of test anchorages and surrounding rocks in the course of loading are obtained. Determine the site and scope of this test. In order to study the displacement characteristics of anchor and surrounding rock under load, The content of this test is determined as the deformation and strain of anchor and surrounding rock under load. The inductive multi-point displacement meter is used to test the deformation of Anchorage and surrounding rock mass. The strain gauge is used to test the internal deformation of the Anchorage; the intelligent digital universal displacement meter is used to test the deformation of the Anchorage and surrounding rock surface; the dislocation meter is used to measure the relative displacement of the interface between the anchor and the surrounding rock. It simulates many loading modes of actual tunnel anchors, and overcomes the drawback of reaction beam used in drawing mode. The loading method of setting Jack on the back face of Anchorage is adopted. The in-situ scale model test is a system engineering, a suitable test site, a precise test instrument and a reasonable instrument layout scheme. The effective and feasible loading equipment and the simple and efficient collecting equipment are indispensable. This paper discusses these aspects one by one, grasps the test direction accurately, makes a set of reasonable test plan according to the test purpose, and makes use of the geological survey. By means of comprehensive methods such as rock mass mechanics test, in-situ scaling model test and so on, the engineering geological conditions, rock mass physical and mechanical properties, stress and deformation characteristics and rheological characteristics of tunnel anchors in the region of tunnel anchors are systematically studied. The bearing capacity and potential failure characteristics of tunnel anchors and the stability of tunnel anchors are verified. The rationality of design results and calculation methods of tunnel anchorages is verified, and the general law and calculation theory verified by these results can be extended to practical structures. In order to accumulate experience of similar engineering in the future, improve people's understanding of the influence of various parameters on engineering performance, and provide the basis for the establishment of systematic theory and method of tunnel anchor design and the compilation of relevant specifications for tunnel anchor. To promote the progress and development of tunnel Anchorage design technology.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.25

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