软弱围岩下浅埋隧道稳定性的能量分析

基于能量的角度,采用极限分析理论中的上限定理对软弱围岩下浅埋隧道的稳定性进行分析,得到了围岩压力的理论公式。研究表明:埋深、土体容重越大及黏聚力、内摩擦角越小,浅埋隧道的围岩压力越大,破坏范围也越大;当埋深较大、围岩较好时,浅埋隧道由于自稳能力有可能不会发生破坏,而对于比较差的围岩,在施工过程中应采取更为安全可靠的支护措施,以防止发生垮塌破坏。

Energy analysis of stability of shallow tunnel in weak surrounding rock

From the viewpoint of energy, the stability of shallow tunnel is analyzed based on the upper bound theorem of limit analysis. The expression of surrounding rock pressure and the position of failure surface are obtained by calculating. Result shows that the surrounding rock pressure and the region of the collapsing block increases with the increasing of buried depth and unit weight of soil mass, however it decreases with the increasing of cohesion and internal friction angle. Moreover, it can also be found that the tunnel with a higher buried depth and a better characteristic of surrounding rock mass is not easy to collapse. While a more reliable supporting measure should be taken in the excavating tunnel in poor surrounding rock so as to keep from collapsing.