鄂北丘陵岗地区浅埋隧洞劣质围岩支护数值模拟研究

Study on the Numerical Simulation of the Surrounding Rock Support of Shallow-buried Tunnel in Hilly Area of Northern Hubei Province

浅埋隧道工程常遇强度低、风化严重且岩体结构破碎的劣质岩体,严重制约着工程设计与施工。为此,以鄂北地区水资源配置工程第15标唐县-尚市隧洞工程典型的绿泥石片岩为研究对象。采用Hoek-Brown的GSI方法估计围岩力学参数并开展数值研究,揭示开挖过程与支护结构对围岩力学响应和支护结构受力状态的控制作用。结果表明:对于工程区劣质绿泥石片岩采用钢拱架与喷锚支护能够有效控制围岩变形过程;围岩力学参数控制着开挖损伤区的分析规律;锚杆受力状态受围岩力学参数影响成非均匀分布状态,拉应力集中在开挖面附近,充分发挥了锚杆的作用。得出在Ⅴ类围岩设计方案下,支护结构在劣质岩体中的受力行为。可为同类工程支护设计提供研究思路。

The shallow-buried tunnel project often encounters the inferior rock mass with low strength,serious weathering and broken rock mass structure,which seriously restricts the project design and construction.Therefore,the typical chlorite schist used in the 15th standard of water resources allocation project in the Tangxian County Shangshi City Tunnel Project in northern Hubei is studied.Hoek-brown's GSI method was used to estimate the mechanical parameters of surrounding rock and numerical studies were carried out to reveal the control effect of excavation process and supporting structure on the mechanical response of surrounding rock and the stress state of supporting structure.The results show that steel arch support and shotcrete support could effectively control the deformation process of surrounding rock for the inferior chlorite schist in the engineering area;The mechanical parameters of surrounding rock controlled the law of analyzing excavation damage zone;The stress state of the bolt was affected by the mechanical parameters of the surrounding rock into a non-uniform distribution state,and the tensile stress was concentrated near the excavation surface,giving full play to the role of the bolt.The force behavior of the supporting structure in the inferior rock mass under the V-type surrounding rock design scheme was obtained.This study can provide inspiring ideas for similar engineering support design.