Research On Deformation Of Argillaceous Siltstoue Tunnel And Stability Analysis Of Slope At Tunnel Portal

In recent years,remarkable achievements have been made in the field of tunnel construction at home and abroad.The tunnel with soft surrounding rock is a common phenomenon in mountainous terrain.Due to the particularity of soft surrounding rock,large deformation is commonly occurred during the tunnel excavation and construction period,which have vital impact great influence on safety operation of tunnel and also the surrounding environment.The effective controlling approaches are needed to eliminate the effect of large deformation on tunnel construction and operation.The Taihedong tunnel between Huizhou and Qingyuan of guangdong shantou-zhanjiang expressway is a typical soft rock tunnel,with the surrounding rock of argillaceous siltstone existed.The paper analyzed the tunnel deformation and stability of slop at tunnel portal through the experiment test,site monitoring and measuring and numerical simulation based on the Taihedong tunnel project.The main research content and results are listed as follows;1.Based on the strength reduction method,FLAC3 D numerical simulation software was carried out to analyze the stability of the slope before and after reinforcement treatment.The displacement,shear strain increment,sliding surface and security coefficient of the slip mass were evaluated.The design and results of different reinforcement treatment approach were summarized.Combined with the field monitoring result,the whole process of landslide reinforcing was analyzed detailly.2.The excavation process of the portal of Taihedong tunnel was simulated.The stress and displacement of surrounding rock and initial support at different excavation stages were compared.The numerical simulation results were compared with the site monitoring results to verify the rationality of the numerical simulation.The influence of tunnel excavation on the slope above the portal is also analyzed.3.Argillaceous siltstone site samples were prepared at Taihedong tunnel portal.The uniaxial compression rheological test was completed at the laboratory scale.The stress-strain curves were obtained.The rheological properties of weathered argillaceous siltstone were summarized and analyzed.Based on the burgess rheological model,the rheological parameters and equations could be obtained.Taking the time and rheological effect into consideration,the long-term stability of the tunnel is evaluated.The research results of this paper could provide technical and theoretical reference for the excavation deformation and the tunnel portal's slope stability control for Taihedong tunnel.