论文部分内容阅读
德江隧道穿越石朝向斜轴部,上覆岩溶地下水发育,顶板最小厚度45 m,隧道开挖可能会导致隧道顶板裂隙扩张及渗透性增大,将对隧道顶板隔水能力及隧道涌突水产生巨大影响,采用二维离散元数值模拟软件UDEC模拟德江隧道开挖裂隙扩张规律、渗流场分布及涌突水特征。研究得到:(1)德江隧道开挖将导致隧道拱顶以上50 m内裂隙扩张,渗透性增大;(2)数值模拟得到隧道开挖后最大涌水压力为0.25 MPa,最大流量为0.035 m~3/s,最大值均出现在拱顶,但远小于2.1 MPa汛季水头值,所以顶板仍然具有隔水能力,不会发生突水;(3)隧道开挖将经历应力重分布及裂隙扩张阶段、流固耦合作用阶段、隧道涌水3个阶段;(4)耦合算法模拟汛季开挖、枯季开挖隧道的拱顶位移值均比不考虑地下水的非耦合算法模拟位移值3.2cm大,说明渗流对围岩稳定性具有很大影响。
The tunnel passes through the inclined shaft and the overlying karst groundwater develops. The minimum thickness of the roof is 45 m. Tunnel excavation may lead to the expansion of the tunnel roof cracks and permeability increase. The tunnel roof waterbreaking capacity and inrush water burst A huge influence, using two-dimensional discrete element numerical simulation software UDEC simulate the expansion of Dejiang tunnel fissures, seepage field distribution and water inrush characteristics. The results are as follows: (1) Excavation of Dejiang tunnel will cause the fracture expansion and permeability increase within 50 m above tunnel vault. (2) The maximum gushing pressure after tunnel excavation is 0.25 MPa and the maximum flow rate is 0.035 m ~ 3 / s, the maximum appears in the vault, but much less than 2.1 MPa flood season head value, so the roof still has a water barrier, water inrush will not occur; (3) tunneling will experience stress redistribution and crack expansion (4) The coupling algorithm simulates the excavation in the flood season, the displacement of vaults in tunnels in dry seasons is 3.2cm larger than the uncoupling algorithm that does not consider groundwater , Indicating that seepage has a great impact on the stability of surrounding rock.