Research On Surrounding Rock Stability And Construction Measures Of Shallow Buried Water-rich Tunne

With the introduction of the new era of high-quality water resources development requirements and the promotion of the "double carbon" strategy,significant progress has been made in the construction of domestic water resources projects.Significant breakthroughs have been made in the construction of hydraulic tunnels,but they still face more complex and difficult risks and challenges.The geological engineering problems and stability influence mechanism of hydraulic tunnel projects through shallow buried water-rich sections have been one of the difficult points in the engineering field.In this paper,taking the Erjia ditch diversion tunnel in Tonghe County,Heilongjiang Province as an example,the whole process of tunnel excavation is simulated by using PLAXIS finite element numerical analysis software and the laws of surrounding rock stress,surrounding rock deformation,groundwater seepage,internal force and deformation of the support structure are analysed.Based on this model,the effect of different rainfall intensities on the stability of the tunnel surrounding rock was also studied,and the mechanism of the surrounding rock stress and deformation was analysed.In addition,based on the numerical analysis,the causes of engineering problems are analysed,the advantages,disadvantages and applicability of different excavation methods are compared and analysed,and targeted disposal measures for the construction of shallow buried water-rich tunnels are proposed.The results of the study show that: during the excavation process,the surrounding rock stress is concentrated at the bottom two bottom corners of the tunnel,and the stress magnitude at the top of the tunnel also needs attention;the large deformation of the tunnel excavation is mainly concentrated near the top of the tunnel;rainfall has a large impact on groundwater seepage and the stability of the surrounding rock,which is an important factor to be considered in the stability analysis;the influence of groundwater,weak rock mass,insufficient initial support strength and rainfall are the main causes of engineering problems.The main reasons for the occurrence of engineering problems.The excavation of shallow buried water-rich tunnels should be carried out using the step method or CD method,taking into account various factors and designing the support structure in a reasonable manner to ensure construction safety.In conclusion,the study of the stability of hydraulic tunnels under shallow buried water-rich conditions is a complex and important topic,which is of great significance in the design,construction and operation management phases of tunnels.Through numerical simulation analysis and actual engineering case studies,this paper discusses in depth the key issues such as stress distribution,rock deformation and groundwater seepage in the tunnel envelope,analyses the causes of engineering problems and proposes solutions,which can provide scientific basis for the design and construction of similar tunnel projects.