小净距双洞隧道穿越断层影响带的空间效应研究

Study on Spatial Effect Neighborhood Twin Tunnel Crossing the Influence Belt of Faults

隧道及地下工程在近接施工过程中会产生空间效应的影响,主要表现为先行洞室对后行洞室开挖前的卸荷和后行洞室通过后对先行洞室的二次扰动,如不能有效控制空间效应对洞室开挖稳定性的影响,极有可能导致洞室支护结构的失稳破坏,引发工程事故。以在建成兰铁路柿子园隧道小净距双洞段为研究对象,通过对现场地应力、围岩强度和隧道变形的实测,并用FLAC3D对隧道施工过程进行模拟,计算隧道变形及锚杆、衬砌的受力,分析仰拱开裂及小净距隧道施工的空间效应影响,并形成相应的处理措施。

The spatial effect would be produced during adjacent construction for tunnel and underground engineering. It was mainly presented that existing tunnel unloaded the surrounding rock stress before following tunnel arrived and following tunnel made the secondary disturbance to existing tunnel. If the influence of space effect to the stability of cavern excavation could not be controlled,the supporting structure of tunnel will be damaged and even induce project accident. The neighborhood twin tunnel of Shiziyuan tunnel belong to the railway from Chengdu to Lanzhou was made as the research object in this paper. In order to analyze the cause of invert cracking and the space effect by neighborhood tunnel construction,the authors tested the ground stress, strengthened of surrounding rock and tunnel deformation. Then the authors simulated the tunnel construction process by FLAC3 Dto calculate the tunnel deformation and the force of the bolts and lining. In the end,the corresponding treatment measures were put forward.