摘要
依托武都水库的导流隧洞工程建设,就既有岩溶溶洞对隧道(洞)稳定性的影响进行了跟踪现场施工的动态监测及数值模拟分析,就不同位置及尺寸的既有溶洞对隧道(洞)围岩受力、变形以及支护结构的受力特性的变化进行了深入研究.既有溶洞影响的数值模拟和现场监测分析表明:受顶部既有岩溶溶洞的影响,隧道(洞)围岩的变形特性明显不同于无溶洞时的变形特性,其围岩超前掌子面的先期变形量增加,即围岩位移具有明显的超前释放性.就变形量而言,当既有溶洞的尺寸大于隧洞最大跨度时,既有顶部溶洞将引起隧道(洞)顶拱沉降位移的减小,而当既有溶洞尺寸大于隧道(洞)的最大尺寸时,隧道(洞)顶拱位移反而增加.同时,既有顶部溶洞将引起隧道(洞)水平收敛位移的增加,且位移的增加量随着既有溶洞尺寸的增加而随之增加.隧道(洞)边墙附近的既有侧边溶洞的出现将引起隧道(洞)水平收敛位移的增加,且位移的增加量随着既有溶洞尺寸的增加而增加.就支护结构受力特性而言,隧道(洞)边墙附近的既有溶洞的存在造成隧道(洞)近溶洞一侧喷层轴力的减小,而远离溶洞一侧喷层轴力的增加.
based on the construction of Wudu reservoir diversion tunnel, this paper make a situ measurement of the tunnel under the impact of concealed cave When the tunnel is under construction, the change of about tunnel＇s surrounding rock stress, displacement, and supporting structural state under the impact of the different cave are analyzed and field observations with numerical results were compared. The analysis showed that： （1） Under the impact of the cave at the top, the deformation of tunnel surrounding rock ahead release. Under the impact of the cave aside, tunnel horizontal convergence displacement increase; and will increase the amount of displacement increases along with the increase of the cave diameter. （2） Under the impact of the cave at the top, the displacement of the top of the tunnel arch settlement will reduce when the cave diameter is larger than the tunnel span, and the displacement of the top of the tunnel arch settlement will increase when diameter ratio is less than 1.0;A affected by the cave at the top ,the horizontal displacement of the tunnel will increase; and the impact of the cave diameter increase in caves also increases. （3） When the tunnel sidewall nearby the cave, tunnel periphery near cave side spray layer axial force will cause the cave side spray layer axial force to increase. （4） The change of the cave tunnel smxounding rock stress and characteristics of displacement with the results of numerical experiments are consistent. Therefore, the results of the theoretical analysis and numerical analysis show that the change about the impact of the cave tunnel surrounding rock displacement and stress become less. But in-situ measurement, the joint fissures of rock mass cave＇s scale and the behavior change have an effect on the result. Due to the impact of the cave, the extent and scope of the cave of the field measurement of tunnel surrounding rock stress and displacement by field measurement is lower than the numerical analysis results by 20% to 30%. The impact of the c
出处
《西安建筑科技大学学报（自然科学版）》
CSCD
北大核心
2014年第4期484-491,共8页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
西部交通项目(200831800030)
关键词
隧道工程
溶洞
稳定性
现场测试
数值分析
tunnel engineering
existing cave
stability
site testing
numerical analysis
