小净距公路隧道施工力学效应研究

Mechanical Effect of Neighborhood Highway Tunnel Construction

通过有限元数值模拟，分析了小净距公路隧道中夹岩柱的受力特性、围岩屈服接近度、锚杆轴力、二次衬砌混凝土内力特征等。研究结果表明：净距较小为B／3时，研究区中夹岩柱围岩会受到左右双洞开挖应力场重叠作用的严重影响，受力状态十分不利，屈服区也贯通中夹岩柱，中夹岩柱两侧的隧道支护衬砌结构都应有所加强；当净距为（0．85～1．5）B时，中夹岩柱受力状态受净距的影响已很小。

Adopting the FEM numerical simulation, the mechanical characteristics of middle rock pillar, the approach degree of surrounding rock yielding,the bolt axial force and the internal force of secondary lining structure, etc. are elaborated. The results demonstrate as follows： when the clear distance equals B/3, the mechanical behavior of middle rock pillar is adverse, because it is severely affected by the overlapping effect of the excavation stress field from left and right holes;the yielding district can cut across middle rock pillar, and the supporting-lining structures around the middle rock pillar should be strengthened. With the clear distance at the range from 0. 85B to 1.5B,the mechanic state of middle rock pillar is little influenced by the clear distance.