强震区隧道工程地震响应特征分析

发布时间：2018-10-12 14:40

【摘要】：随着我国现代化进程的推进,许多地区的隧道及地下工程不可避免地会遇到在活动断层附近或高烈度地震区的问题。因此研究地震带区域隧道稳定性地震响应特征,具有深远的社会意义。为了研究地震对隧道的影响规律,本文首先结合国内外大地震中隧道震害的实例,总结归纳了地震对隧道的破坏形式和影响因素；然后,基于Wells等人的震级与地表的破裂关系的研究,并结合汶川地震中隧道的震害情况对隧道的抗震设计方法进行了分析；其次,利用三维有限元软件ANSYS模拟了地震波入射角对隧道影响的规律；最后,通过分析昆仑山、汶川和阪神地震前后地应力的变化,并利用三维有限元软件3D-sigma模拟了汶川地震前后地应力变化对隧道的影响规律。基于以上几个方面研究,论文的初步结论和进展如下：(1)通过对国内外大地震中的隧道震害实例的研究,结合汶川地震中隧道的震害情况归纳了地震对隧道及地下工程的破坏形式主要是隧道洞身和洞口的破坏,其中洞身的破坏模式主要有：①衬砌的剪切错位,②衬砌纵向开裂,③衬砌环向开裂,④衬砌斜向开裂,⑤底板隆起等。洞口及洞门的破坏模式主要有：①落石崩塌,②滑坡挤压,③端墙开裂等。(2)研究发现,与地下工程和隧道抗震设计直接相关的参数是地表破裂长度SRL(km)、最大同震破裂位移MD(m)、平均同震破裂位移AD(m)。汶川地震发生时,中央断裂和龙门山前山断裂之间的次级断层也会产生一定的活动,因此处在这两个断裂带之间的三座隧道震害非常严重。可见发震断层附近的附属断层在地震时也会产生同震位移,并对穿越的地下结构和隧道产生破坏。(3)从模拟结果来看,在主应力方面,隧道各监测点受到的应力大小各不相同,拱肩部位和拱脚部位受最大最小主应力影响较为显著,拱顶和拱底受的最大最小主应力较小；在位移方面,拱顶的位移变化较大,说明拱肩、拱脚和拱顶受地震的影响较为严重,这与实际中隧道的震害情况较为吻合。(4)通过对比昆仑山、汶川和阪神地震前后地应力的大小,发现地震能够引起震中区地应力大小的降低。利用三维有限元软件3D-sigma模拟了地震前后地应力的变化对隧道稳定性的影响结果发现,地震后隧道断面上的监测点的最大主应力和最小主应力均比地震前的小。隧道的左右拱脚受地震的影响最明显,左右拱肩次之,拱顶和拱底受地震的影响是最小的。
[Abstract]:With the development of modernization in China, tunnels and underground projects in many areas will inevitably encounter problems near active faults or in high-intensity seismic areas. Therefore, it is of profound social significance to study the seismic response characteristics of regional tunnel stability in seismic zone. In order to study the influence of earthquake on tunnel, this paper first summarizes the damage form and influencing factors of tunnel by combining with the examples of tunnel damage caused by large earthquakes at home and abroad, and then summarizes the damage form and influencing factors of tunnel caused by earthquake. Based on the study of the relationship between magnitude and surface rupture of Wells et al., combined with the earthquake damage of tunnel in Wenchuan earthquake, the aseismic design method of tunnel is analyzed. The influence of incident angle of seismic wave on tunnel is simulated by using 3D finite element software ANSYS. Finally, the variation of ground stress before and after Kunlun Mountain, Wenchuan and Hanshin earthquakes is analyzed. The influence law of ground stress change on tunnel before and after Wenchuan earthquake was simulated by using 3D finite element software 3D-sigma. Based on the above studies, the preliminary conclusions and progress of the paper are as follows: (1) through the research of tunnel damage cases in large earthquakes at home and abroad, Combined with the earthquake damage of the tunnel in Wenchuan earthquake, the damage forms of the tunnel and underground engineering are summarized. The main failure modes of the tunnel body are: (1) shear dislocation of lining, (2) longitudinal cracking of lining, Ring cracking of lining, diagonal cracking of lining, uplift of bottom plate, etc. The failure modes of the orifice and portal are as follows: (1) rock collapse, (2) landslide extrusion, (2) crack of the end wall, etc. (2) it is found that, The parameter directly related to the seismic design of underground engineering and tunnel is the surface rupture length SRL (km), the largest coearthquake rupture displacement MD (m), average co-seismic rupture displacement AD (m). At the time of Wenchuan earthquake, the secondary faults between the central fault and Longmenshan fault will also produce certain activities, so the earthquake damage of three tunnels between the two faults is very serious. It can be seen that the subsidiary faults near the seismogenic faults will also produce co-seismic displacement during the earthquake, and will destroy the underground structure and the tunnel. (3) from the simulation results, the magnitude of the stress at the different monitoring points of the tunnel is different in terms of the principal stress. The position of arch shoulder and arch foot are affected by the maximum and minimum principal stress, and the maximum and minimum principal stress of arch top and arch bottom are smaller. The arch foot and arch roof are seriously affected by the earthquake, which is consistent with the actual earthquake damage in the middle tunnel. (4) by comparing the magnitude of the ground stress before and after the Kunlun Mountain, Wenchuan and Hanshin earthquakes, it is found that the earthquake can cause the decrease of the magnitude of the earth stress in the epicenter area. The influence of the variation of ground stress before and after the earthquake on the tunnel stability is simulated by using the three-dimensional finite element software 3D-sigma. The results show that the maximum principal stress and the minimum principal stress at the monitoring point of the tunnel section after the earthquake are smaller than those before the earthquake. The influence of earthquake on the left and right arches of the tunnel is the most obvious, followed by the left and right arches, and the arch roof and the arch bottom are the least affected by the earthquake.
【学位授予单位】：中国地震局地壳应力研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U452.28;P315.9

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