隧道顶部溶洞影响围岩稳定性的模型试验研究

利用公路隧道结构与围岩综合实验系统 ,对石灰岩地区大断面隧道开挖过程中 ,隧道顶部不同距离上的溶洞对围岩稳定性的影响进行相似模型实验研究 ,实验结果表明 ,开挖引起的总释放位移随溶洞的距离呈现减函数变化 ;在有溶洞的断面开挖瞬间释放位移增量随溶洞离隧道的距离增大而减小 ;开挖后的流变位移也随溶洞的距离增大而减小。开挖瞬间的位移释放率随溶洞距离而呈现减小的趋势 ,约为 2 3%- 2 5 %。开挖后的流变位移释放率与溶洞距离没有明显的关系

A Model Test Study on Influence of Top Karst Cave on Stability of the Surrounding Rockmass during Tunnel Construction

Based on the comprehensive testing system for structure and surrounding rockmass of highway tunnel, taking Chaodongyan Tunnel as an example, a test concerning the influence of top Karst cave on stability of surrounding rock mass during tunnel construction is carried out with physical similarity modeling. The results of physical similarity modeling show that the total releasing displacement of the surrounding rock mass of tunnel decreased with increase of the distance between Karst cave and edge of tunnel during excavation. The instant released displacement during excavation is decreased with distance between Karst cave and edge of the tunnel and the rheological displacement decreased as well. The instant releasing displacement rate is reduced with distance between Karst cave and edge of the tunnel. The rheological displacement releasing rate is independent on the distance.