摘要
以小江口隧道边坡为研究对象,利用FLAC3D软件建立了能够精确反映地形地质条件的精细地质力学模型,进而建立三维数值分析模型.在分析过程中,选取4种工况进行模拟分析,其中自重工况和破坏模式分析都与现场实际情况对应.在此基础上模拟环境地质条件恶化时的边坡失稳破坏机理,并进一步分析采空区对坡体的影响,以及隧道开挖时的坡体变形失稳模式.研究结果表明:(1)未来的破坏模式仍然是平行坡面的陡立结构面起控制作用,破坏区域呈片状平行坡面走向位于陡壁表层,在软弱的泥灰岩基座处切断下部岩体,形成楔形错落式滑动破坏,在隧道轴向上,要特别注意裂隙面所切割出来的上游侧三角形体.(2)煤层采空后顶部岩层塌陷明显,变形影响区向外扩展到地表河谷,向内受限于裂隙面,向上接近最临近的泥灰岩夹层,隧道尚在煤层塌落的应力影响区之外.(3)隧道开挖后,围岩变形不明显,但隧道围岩应力改变明显,应力变化明显的区域,受限于裂隙面,局限于裂隙面所界定坡体外侧区域,向坡体内则没有发展.
With Xiaojiangkou Tunnel as the research object,ageo-mechanical model that can accurately reflect the terrain and geological conditions was established by FLAC3 Dsoftware,and then a three-dimensional numerical model was built.Four kinds of working conditions were considered,in which the gravity condition and the failure mode analysis corresponded with the actual situation.Based on this analysis,the mechanism of slope instability,which occurred when the environment geology conditions deteriorated,was simulated,the influence of goaf on the slope was considered,and the slope deformation and instability during tunnel excavation were analyzed.The results showed that the vertical structure parallel to the slope will still control the failure mode in the future.The flaky destruction area,which was parallel to the slope surface and located under the steep wall surface,cut off the lower rock mass in the marlstone base,thus forming a wedge strewn at random sliding failure.On the tunnel axis,special attention should be paid to the upstream side triangular rock which was cut off by fissure-plane.After coal goaf,the collapse of the rock at the top was very obvious,the area of the influence of the deformation extended outward to the earth surface and river valley,its inward extension was limited by the fissure plane,and its upward extension approached the marlstone interlayer.The tunnel remained outside of the influence of the collapse.After the tunnel excavation,the deformation of the surrounding rock was inconspicuous,but the internal stress changed significantly.The area with significant stress change was limited by the fissure plane.The area was only distributed in the outside part of the slope which was cut off by fissure plane,which didn＇t extend to the inside of the slope.
出处
《西南大学学报（自然科学版）》
CAS
CSCD
北大核心
2015年第10期152-161,共10页
Journal of Southwest University(Natural Science Edition)
基金
国家自然科学基金资助项目(41172261)
关键词
边坡失稳
破坏机理
地质模型
采空区
隧道开挖
数值分析
slope instability
failure mechanism
geological model
goaf area
tunnel excavation
numerical analysis
