岩质高陡边坡关键剖面稳定性分析

Stability Analysis on Key Sections of High and Steep Rock Slope

小江口隧道边坡是灰岩夹泥灰岩的岩质高陡边坡,陡崖处存在两处由多组不规则卸荷裂隙围限出的危岩体,危及拟建隧道及桥梁的安全。为确保隧道施工过程和运营的安全,以小江口隧道为原型,选取关键剖面评价局部危岩体的稳定性。研究表明:隧道出口岸坡与上游侧陡崖边坡的坡体应力状态相同,均呈现坡脚位置应力集中,陡坡面存在受拉区的高山峡谷应力分布特征,易在边坡底部出现剪切破坏以及高位陡岩发生崩塌落石等地质灾害。隧道出口段南侧陡崖的破坏模式为渐进式倾倒破坏,上游侧陡崖的破坏模式是错落式破坏。

Xiaojiangkou tunnel slope is a high and steep rock slope with limestone mixed with marl. There are two dangerous rock masses enclosed by multiple sets of irregular unloading cracks on the steep cliff, which endanger the safety of the proposed tunnel and bridge. In order to ensure the safety of the construction and operation of the tunnel, taking Xiaojiangkou tunnel as a prototype, we select the key section to evaluate the stability of the local dangerous rock mass. The results show that: the stress state of the slope at the exit slope is the same as that of the steep slope at the upper side, all of them show stress concentration at the foot of the slope, and there are stress distribution characteristics of the mountain canyon in the tensile area on steep slope, the geological disasters such as the shear failure and the collapse of the high steep rock are easy to occur at the bottom of the side slope. The failure mode of the steep cliff on the south side of the tunnel exit section is progressive dumping failure, while the upstream side cliff is staggered failure.