大埋深裂隙岩层中土压平衡盾构下穿水道施工安全性分析

广州-佛山环线沙堤隧道在大埋深裂隙岩层中采用土压平衡盾构法下穿佛山水道,采用FLAC 3D软件建立流固耦合数值模型,分析隧道下穿水道施工安全性。研究结果表明:下穿施工时引起地下水渗流,其中横断面方向影响范围约为隧道洞径的3. 6倍,纵断面方向影响范围约为隧道洞径的2. 4倍;在一定支护压力下开挖面具有一定的自稳能力,支护压力较小时在水压力的作用下开挖面易发生失稳破坏;在大埋深裂隙岩层中采用土压平衡盾构法施工时,应保证土仓的止水能力。

Construction Safety Analysis of Earth Pressure Balanced Shield Tunnel Under-crossing Waterway in Deep Buried Fractured Rock Stratum

The Shadi tunnel of Guangzhou-Foshan loop line under-crosses the Foshan waterway by the earth pressure balanced shield tunneling method in the deep buried fractured rock stratum.FLAC 3D software was used to establish a f luid-solid coupling numerical model to analyze the construction safety of tunnel under-crossing the waterway.Research results show that groundwater seepage is caused by under-crossing construction,the inf luence range of cross-section direction is about 3.6 times the tunnel diameter,and the inf luence range of longitudinal section direction is about 2.4 times the tunnel diameter.The excavation face has certain self-stabilization ability under certain support pressure,the excavation face is prone to destabilization under the action of water pressure when the support pressure is low.When the earth pressure balanced shield tunneling method is used in the deep buried fractured rock stratum,the sealing capacity of the earth silo should be guaranteed.