衬砌后空洞对隧道动力稳定性影响规律研究

发布时间：2018-03-27 18:07

  本文选题：衬砌后空洞　切入点：地震响应　出处：《中国矿业大学》2015年硕士论文

【摘要】：隧道衬砌与围岩是一个相互作用的整体,但是相当比例的衬砌后存在空洞现象并对隧道在地震下的稳定性造成威胁。空洞处于隐蔽环境其发现难、成因分析难和处置难,故对衬砌背后空洞对隧道动力稳定性影响规律的研究具有重要的学术价值和现实意义。本文采用理论、数值模拟与工程实例分析相结合的手段,研究了地震作用下有空洞隧道的动力响应规律,探讨了空洞位置、尺寸等因素对衬砌与围岩的受力影响规律,分析了隧道的震害机理,同时还提出了一种简化的地震响应计算方法,主要得出了以下结论:(1)空洞使隧道衬砌向围岩侧凸出变形,衬砌截面安全系数降低,围岩的塑性区域增加,空洞尺寸、隧道所受初始应力越大该趋势越明显。(2)不同方向地震作用下剪切地震反应最大竖向地震最小,隧道等地下结构基本不影响岩土体的整体反应,结构附加内力由围岩的差异变形产生。(3)地震作用下空洞处部分衬砌应力增加并超过材料强度以致破坏,围岩塑性应变不断累积以致围岩压力增大,当地震烈度大于Ⅷ度时破坏明显。(4)剪切地震下拱腰处空洞大于拱顶处影响,隧道初始受力越大则空洞影响程度越大,空洞环向角度与纵向长度的影响明显大于深度,且在隧道纵向有较明显的端部效应。(5)简化的计算方法方便可行,空洞的存在会放大地震的破坏作用。综合认为,在空洞环向角度大于30°,纵向长度大于或等于环向线长度时,隧道在地震作用下更易产生破坏。该论文有图132幅,表35个,参考文献118篇。
[Abstract]:Tunnel lining and surrounding rock are interacted as a whole, but a considerable proportion of the lining has cavities behind the lining, which threaten the stability of the tunnel under earthquake. It is difficult to find the cavities in the hidden environment, to analyze the causes and to deal with them. Therefore, it is of great academic value and practical significance to study the influence of the cavity behind the lining on the dynamic stability of the tunnel. In this paper, the method of combining theory, numerical simulation and engineering example analysis is adopted. In this paper, the dynamic response law of tunnel with holes under earthquake action is studied, and the influence of cavitation position and size on the stress of lining and surrounding rock is discussed, and the earthquake damage mechanism of tunnel is analyzed. At the same time, a simplified method for calculating seismic response is put forward. The main conclusions are as follows: 1) the cavity causes the tunnel lining to protrude and deform toward the surrounding rock side, the safety factor of the lining section decreases, the plastic region of the surrounding rock increases, and the cavity size increases. The larger the initial stress of tunnel is, the more obvious the trend is. (2) under the action of different direction earthquake, the maximum and vertical earthquake response of shear earthquake is minimum, and the underground structure such as tunnel has no effect on the overall response of rock and soil. The additional internal force of the structure is caused by the differential deformation of the surrounding rock. (3) under the action of earthquake, the stress of part of the lining in the cavity increases and exceeds the strength of the material, resulting in the failure, and the plastic strain of the surrounding rock accumulates and the pressure of the surrounding rock increases. When the seismic intensity is greater than 鈪，

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