向家湾隧道进口段围岩分级及破坏模式研究

Study on Classification and Failure Mode of Surrounding Rock in the Entrance Section of Xiangjiawan Tunnel

为分析郑万高速铁路向家湾隧道围岩稳定性,根据隧道施工过程中编录的围岩地质信息和测定的岩石强度参数,应用铁路隧道设计规范的围岩分级BQ法对隧道进口段围岩进行了亚分级,并使用Geostudio有限元软件对围岩破坏模式进行了数值模拟。结果表明,拱顶拉应力集中明显,可能出现塌落。实际施工中,拱顶围岩局部塌落与数值模拟结果一致,验证了模拟结果的合理性。基于以上分析,考虑地层产状和结构面特征,提出围岩支护措施建议。本研究对类似隧道安全施工具有重要的实践指导意义。

In order to systematically analyze the stability of surrounding rock in Xiangjiawan tunnel of ZhengzhouWanzhou high-speed railway,on the basis of geological information of surrounding rock recorded parameter measured during tunnel,the BQ method as specified in Code for Design of Rai1 way Tunnel is applied to implement sub-level classification for surrounding rock of the tunnel entrance section. And the failure mode of the surrounding rock is simulated numerically by a finite element software-Geostudio. The results show that the rock masses at the vault may collapse induced by tensile stress concentration. In the actual construction process, the partial collapses of the surrounding rock at the vault is consistent with the numerical simulation results,which verifies the rationality of the results. Based on the above analyses,considering the attitude of stratum and the characteristics of the structural planes,the support measures suggestions for the surrounding rock are proposed. This study has important practical guiding significance for the safety construction of similar tunnels.