控制型结构面几何参数对隧道围岩稳定性的控制效应——以郑万高铁向家湾隧道为例

Control Effect of Controlling Structural Plane’s Geometric Parameterson Stability of Tunnel’s Surrounding Rock--Case Study onXiangjiawan Tunnel of Zhengzhou-Wanzhou High-speed Railway

隧道围岩变形破坏与岩石强度、结构面特征、地下水和地应力等因素关系密切,其中控制性结构面的几何参数(间距和倾角)影响着隧道围岩的宏观完整性和开挖后的应力分布,进而控制着围岩塑性变形和结构面剪切滑移。为研究结构面几何参数对隧道围岩稳定性的控制效应,以郑万高铁向家湾隧道为例,在区域地质环境调查、隧道掌子面地质素描和岩石物理力学参数测定的基础上,使用UDEC离散元软件分析了不同几何参数结构面的隧道围岩变形破坏特征。研究表明隧道结构面间距和倾角对围岩变形破坏影响显著,当结构面间距>1/10洞直径,倾角位于0°~30°范围内时,隧道施工过程中围岩稳定性相对较好。本研究对类似隧道安全施工具有实践指导意义。

The deformation and failure of tunnel’s surrounding rock is closely related to factors such as rock strength,characteristics of structural plane,groundwater and geostress.The geometric parameters(spacing and inclination)of the controlling structural plane affect the macro-integrity of the surrounding rock and the stress distribution after excavation,and furthermore,control the plastic deformation of the surrounding rock and the shear-slipping of structural plane.In order to study the control effect of structural plane’s geometric parameters on the stability of tunnel’s surrounding rock,we analyzed the deformation and failure of surrounding rock of Xiangjiawan tunnel in Zhengzhou-Wanzhou high-speed railway as a case study using UDEC based on regional geo-environmental investigation,geologic sketch of tunnel face,and test of the rock physical and mechanic parameters.Results demonstrated that the spacing and inclination of structural plane have a significant influence on the deformation and failure of surrounding rock.The stability of surrounding rock should be relatively superior during the tunnelling construction when the spacing of the structural plane was greater than 1/10 diameter and the inclination of the structural plane was in the range from 0°to 30°.The research finding has practical guiding significance for the safety construction of similar tunnels.