隧道空洞缺陷对衬砌结构的影响及其裂损规律研究

发布时间：2018-07-12 12:02

本文选题：隧道空洞缺陷 + 隧道病害　；参考：《北京交通大学》2017年硕士论文

【摘要】：近年来我国隧道与地下工程建设迅猛发展,受制于诸多不利因素的影响,相当比例的已建或运营隧道存在隧道空洞质量缺陷。隧道空洞缺陷具有隐蔽性特点,它不直接构成衬砌结构的病害实体,但其间接导致衬砌结构发生其他病变,潜在的危害性巨大。因此研究隧道空洞缺陷下衬砌结构的病变对于明晰隧道空洞的致灾机制具有重大的现实意义。有鉴于此,在总结分析前人研究成果的基础上综合运用调查研究、理论分析和数值模拟计算等研究方法,做了以下研究工作:(1)系统的研究分析了隧道空洞的成因与危害,从"围岩—支护"相互作用关系的角度揭示了隧道空洞引发结构坍塌的机理。(2)研究了在自重地应力场与水平地应力场中隧道拱顶空洞横向与竖向尺寸参数对衬砌结构内力的影响规律,并对比分析了两参数对衬砌结构内力影响的强弱。研究认为:1)在两种形式的地应力场中拱顶空洞及其毗邻区域内衬砌结构的弯矩值随着隧道拱顶空洞横向尺寸或竖向尺寸的增大而呈线性增加的趋势;2)两种形式的地应力场中隧道拱顶空洞横向尺寸对衬砌结构内力的影响强于隧道拱顶空洞竖向尺寸对衬砌结构内力的影响。(3)基于"地层—结构"模型,采用模拟材料断裂的新理论—扩展有限单元法(XFEM)研究了自重地应力场与水平地应力场中隧道衬砌背后不同位置存在单一空洞与组合空洞时衬砌结构的裂缝分布规律与隧道结构的破损状况。研究认为1)在自重地应力场中衬砌结构在隧道空洞影响下易发生开裂破坏而不易发生压溃破坏;2)在水平地应力场中衬砌结构在隧道空洞影响下开裂破坏与压溃破坏相伴发生;3)在不同形式的地应力场中隧道空洞对衬砌结构的破坏强度不同,隧道空洞在水平地应力场中对衬砌结构的潜在破坏力更强。(4)通过分析研究认为隧道空洞的致灾机理大致经历以下三个阶段:1)初期阶段—空洞的萌发及结构外挤变形;2)中期阶段—隧道结构变形裂损;3)后期阶段—结构裂缝延伸扩展。
[Abstract]:In recent years, the construction of tunnels and underground projects in our country has developed rapidly. Due to the influence of many unfavorable factors, a considerable proportion of built or operated tunnels have defects in tunnel quality. The defect of tunnel cavity has the characteristics of concealment, which does not directly constitute the diseased entity of the lining structure, but it indirectly leads to other pathological changes of the lining structure, and the potential harm is enormous. Therefore, it is of great practical significance to study the damage of lining structure under tunnel cavity defects for clarifying the mechanism of tunnel cavities. In view of this, on the basis of summing up and analyzing the previous research results, this paper makes comprehensive use of the methods of investigation, theoretical analysis and numerical simulation calculation, and does the following research work: (1) the causes and hazards of tunnel cavities are systematically studied and analyzed. From the angle of the interaction between surrounding rock and support, the collapse mechanism of tunnel cavities induced by cavities is revealed. (2) the lateral and vertical dimension parameters of tunnel arch cavities to lining in the field of gravity stress and horizontal ground stress are studied. The influence law of internal force of structure, The influence of two parameters on the internal force of lining structure is compared and analyzed. It is found that the bending moment of the arch cavities and their adjacent lining structures in two forms of in-situ stress field increases linearly with the increase of the transverse or vertical dimensions of the tunnel arch cavities. In the field of in-situ stress, the influence of the transverse dimension of the tunnel arch roof cavity on the internal force of the lining structure is stronger than that of the vertical dimension of the tunnel vault cavity on the lining structure. (3) based on the "stratigraphic structure" model, In this paper, a new theory of simulating material fracture, extended finite element method (XFEM), is used to study the crack distribution of tunnel lining when there are single cavity and combined cavity behind tunnel lining in the field of gravity ground stress and horizontal field of ground stress. Law and damage condition of tunnel structure. The results are as follows: 1) under the influence of tunnel cavities, the lining structure is liable to crack and destroy but not to be crushed under the influence of tunnel cavity. 2) in horizontal ground stress field, the lining structure is cracked and broken under the influence of tunnel cavity. 2) in horizontal ground stress field, the lining structure is cracked and broken under the influence of tunnel cavity. The failure intensity of tunnel cavity on lining structure is different in different forms of in-situ stress field. (4) through the analysis and research, it is concluded that the mechanism of tunnel cavities has experienced the following three stages: 1: 1) initial stage-cavity germination and structural extrapolation. (4) through analysis and research, it is concluded that the mechanism of tunnel cavities is caused by the following three stages: the initial stage: the germination of cavities and the extrapolation of structures. Form 2) middle stage-tunnel structure deformation and crack damage 3) late stage-structural crack extension and extension.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U451.4

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