顶部隐伏溶洞对隧洞位移影响特征分析

Influence of displacement characteristic of tunnel with concealed cave upside

【目的】探究顶部隐伏溶洞对隧洞施工过程中隧洞结构位移特征的影响,给岩溶区隧洞的施工提供一定的依据.【方法】采用数值模拟的方法,运用大型通用有限元软件ANSYS,建立溶洞距隧洞顶部不同距离和不同大小时的有限元模型,分析隧洞结构上的位移变化特征.【结果】当溶洞与隧洞距离大于20m时,溶洞对隧洞各特征点竖向位移的影响变得很小;当溶洞长轴小于1.5m时,溶洞的存在对隧道各特征点竖向位移影响变得很小.【结论】溶洞与隧洞之间的围岩是施工中的最危险区域;随着溶洞与隧洞距离的增大,隧洞各特征点的竖向位移呈增大的趋势,而水平位移呈减小的趋势;随着溶洞由小变大,隧洞各特征点竖向位移呈减小的趋势而水平位移呈增大的趋势.

【Objective】To explore the influence of the hidden cave in the top of the tunnel on the displacement characteristics of the tunnel structure during the tunnel construction,and to provide a certain basis for the construction of tunnel in Karst Area.【Method】Numerical simulation method was adopted,finite element models were established with different distances and scales of cave in the top of the tunnel using ANSYS,and the change characteristics of the displacement were analyzed in the tunnel structure.【Result】When the distance between the cave and the tunnel was greater than 20 m,the effect of the cave become small on the vertical displacement of each characteristic point of the tunnel.When the long axis of the cave was less than 1.5 m,the existence of the cave had little effect on the vertical displacement of the tunnel characteristic points.【Conclusion】The surrounding rock between the cave and the tunnel is the most dangerous area in the construction.With the increase of the distance between the cave and the tunnel,the vertical displacement of each characteristic point of the tunnel increases and the horizontal displacement decreases.As the caverns become larger,the vertical displacement of each characteristic point of the tunnel decreases and the horizontal displacement tends to increase.