岳家沟隧道塌方机制与数值模拟

Collapse mechanism and numerical simulation of Yuejiagou Tunnel

过对岳家沟隧道RK74+010处塌方前超前地质预报结果与塌方后揭示的实际围岩情况相比较得出:塌方前的掌子面的地质超前预报结果存在一定的局限性,而与实际塌方后揭示的围岩状况存在偏差,并未发现隐藏在隧道上方的软弱破碎围岩,从而导致施工中人们对该处围岩施加了较低的支护强度,致使在掌子面向前推进的过程中,隧道发生塌方.通过3DEC离散元数值模拟,从塌方处围岩受力及位移特征上分析了岳家沟隧道的塌方机制。

Based on the comparison between the results of the geological prediction before the landslip and the actual surrounding rock condition after the landslip at the RK74+010 in the Yuejiagou Tunnel,the results show that there are some limitations in the geological prediction of the excavation face before the landslip.There is some deviation from the surrounding rock condition revealed after the landslip,and no soft rocky surroundings are found at the top of the tunnel,and thus a lower support strength was exerted in the construction of the surrounding rock,and causes the collapse of the tunnel during the forward advancement of the excavation face.Through the 3DEC discrete element numerical simulation,the collapse mechanism of Yuejiagou Tunnel is analyzed from the stress and displacement characteristics of surrounding rock.