德寨隧道隐伏溶洞对围岩稳定性影响分析

发布时间：2018-04-19 04:21

本文选题：隐伏溶洞 + 围岩　；参考：《成都理工大学》2017年硕士论文

【摘要】：岩溶是西南地区隧道工程建设中常见的地质灾害之一。岩溶地区修建的隧道工程与隐伏溶洞间的影响关系直接影响隧道的安全性,因此,隐伏溶洞对隧道围岩的影响是岩溶地区隧道设计与施工中亟需解决的问题。本文以德寨隧道隐伏溶洞段为研究对象,以FLAC~(3D)数值模拟试验为手段,分析总结了德寨隧道单个和多个隐伏溶洞对围岩稳定性影响规律,并选取典型岩溶断面进行监控量测验证。论文主要工作内容和结论如下:一、结合德寨隧道的工程条件、已揭露溶洞情况和隧道超前地质预报,对隧址区的隐伏溶洞进行归纳,按其特征分为以下几类:与隧道不同距离的隐伏溶洞、距隧道相同距离,相同位置,但高跨比大小不同的隐伏溶洞、位于隧道不同位置的隐伏溶洞、多个隐伏溶洞存在于隧道周围。二、结合岩石力学理论分析隐伏溶洞对隧道围岩影响的因素,并根据德寨隧道隐伏溶洞实际情况,选取不同距离、不同大小、不同高跨比、不同位置为代表因子进行数值模拟分析。三、利用MIDAS GTS和FLAC~(3D)三维数值模拟软件,研究了德寨隧道单个隐伏溶洞和多个组合隐伏溶洞对隧道围岩的影响,主要得出如下结论:1、以不同距离、大小的隐伏溶洞为单因子变量:随着溶洞面积增大,隧道拱顶的x向和z向受力和变形量也相应增加。随着溶洞与隧道的距离增加,围岩受力和变形量都相应减小。2、以不同高跨比(即不同长轴和短轴比值)的隐伏溶洞为单因子变量:隧道拱肩存在x向应力集中区,拱肩部位的x向变形量较大,当高跨比从0.5增加到1时,拱肩的x向变形量也随之增大;当高跨比从1增加到1.5时,拱肩的x向变形量减小,拱肩的z向受力和z向变形量随着高跨比的增加而变大。3、以不同位置的隐伏溶洞为单因子变量:当溶洞处于隧道边墙处时,隧道的x、z向应力图和位移变形图为不对称图形;当溶洞位于隧道拱肩延长线时,隧道拱肩将出现z向受力和z向变形集中区。4、当隧道拱顶上方与边墙一侧同时存在隐伏溶洞时,拱顶和边墙部位将产生较大的z向变形,同时存在z向应力集中区。5、当隧道拱顶上方与底板下方同时存在隐伏溶洞时,拱顶将产生较大的z向变形,同时存在z向应力集中区;底板存在反向z向应力集中区,同时产生向上的z向变形。6、当隧道边墙一侧与底板下方同时存在隐伏溶洞时,边墙处将产生较大的z向变形,同时存在z向应力集中区,减小了底板的z向变形量和z向应力。7、当隧道拱顶上方、边墙一侧与底板下方同时存在隐伏溶洞时,拱顶和边墙将产生较大的z向变形,并存在z向应力集中区;减小了底板向上的变形量和z向应力。四、对德寨隧道典型岩溶K21+145断面进行监控量测,验证了德寨隧道隐伏溶洞对围岩稳定性影响结论的正确性和合理性,说明本文研究成果合理,对岩溶隧道工程具有极高的参考价值。
[Abstract]:Karst is one of the common geological hazards in tunnel construction in southwest China.The influence of the tunnel construction in karst area on the safety of the tunnel directly affects the safety of the tunnel. Therefore, the influence of the hidden karst cave on the surrounding rock of the tunnel is an urgent problem to be solved in the design and construction of the tunnel in karst area.In this paper, taking the hidden karst tunnel section of Dezhai tunnel as the research object, and taking the numerical simulation test of FLACU / 3D as the means, this paper analyzes and sums up the influence law of single or multiple concealed karst caves on the stability of surrounding rock, and selects typical karst sections for monitoring and testing.The main contents and conclusions of this paper are as follows: first, combined with the engineering conditions of Dezhai Tunnel, the situation of the karst cave and the advance geological forecast of the tunnel have been revealed, and the hidden karst cave in the tunnel site has been summarized.According to its characteristics, it can be divided into the following categories: the concealed caverns with different distances from the tunnel, those with the same distance from the tunnel and the same location, but with different height / span ratios, and the concealed caverns located in different locations of the tunnel,Multiple hidden caverns exist around the tunnel.Secondly, according to the theory of rock mechanics, the influence factors of concealed karst cave on the surrounding rock of tunnel are analyzed, and according to the actual situation of hidden karst cave in Dezhai tunnel, different distance, different size and different height / span ratio are selected.The numerical simulation analysis is carried out with the representative factors of different positions.3. Using the software of MIDAS GTS and FLACX 3D, this paper studies the influence of single concealed karst cave and multiple combined concealed karst cave on the surrounding rock of the tunnel. The main conclusions are as follows: 1, at different distances.The size of the concealed cave is a single factor variable: with the increase of the cave area, the x direction and z direction force and deformation of the tunnel dome are increased accordingly.With the increase of the distance between the cave and the tunnel, the stress and deformation of surrounding rock decrease by 0.2. The hidden caverns with different ratio of height to span (that is, different ratio of long axis and short axis) are regarded as single factor variable. The stress concentration zone in the arch shoulder of tunnel exists in x direction.When the ratio of height to span increases from 0.5 to 1, the amount of x direction deformation of arch shoulder increases, and when the ratio of height to span increases from 1 to 1.5, the amount of x direction deformation of arch shoulder decreases.The z direction stress and the z direction deformation of the arch shoulder become larger with the increase of the ratio of height to span, taking the concealed cave in different positions as the single factor variable: when the cave is located at the side wall of the tunnel, the xnz stress diagram and the displacement deformation diagram of the tunnel are asymmetrical;When the cave is located at the extension line of the tunnel arch shoulder, the tunnel arch shoulder will appear Z direction stress and z direction deformation concentration area. When there is a concealed cave above the tunnel arch top and the side of the side wall, the arch roof and the side wall will produce greater z direction deformation.At the same time, there exists Z stress concentration zone. 5. When there are hidden caverns above the tunnel arch top and below the bottom plate, the arch roof will produce larger z direction deformation, and the z direction stress concentration zone will exist, and the bottom plate will have the reverse z direction stress concentration region.At the same time, the upward z direction deformation. 6. When there is a concealed cave at the side of the tunnel wall and under the bottom plate, there will be a larger z direction deformation at the side wall, and there will be a z direction stress concentration area.The z direction deformation and the z direction stress of the bottom plate are reduced. When there is a hidden cave in the side of the side wall and the bottom plate at the top of the tunnel arch, there will be a larger z direction deformation in the arch and the side wall, and there will be a Z direction stress concentration zone.The upward deformation and the z-direction stress of the bottom plate are reduced.Fourthly, the monitoring measurement of typical Karst K21145 section of Dezhai Tunnel verifies the correctness and rationality of the conclusion that the hidden karst cave of Dezhai Tunnel affects the stability of surrounding rock, which indicates that the research results in this paper are reasonable.It has high reference value for karst tunnel engineering.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.11

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