Stability Analysis Of Slope With Tunnel-type Anchorage Of Suspension Bridge Under Seismic Load

The long-span suspension bridge because of its own advantages has been more and more widely used in the mountain and ravine region.The tunnel anchor is an important form of anchoring system,which has the characteristics of reasonable stress distribution,low cost and low environmental damage.The stability of Slope with tunnel-type anchorage in the working period of the suspension bridge,especially the stability under the earthquake action has a very important influence on the bridge structure function.Therefore,the thesis bases on the tunnel anchorage in suspension bridge in Dadu River and makes an in-depth analysis of the stability of Slope with tunnel-type under different earthquake action.The main research work is as follows:1)Based on the geological conditions of Slope engineering with tunnel-type anchorage,the 3D geological model was established with tunnel anchorages,highway tunnels,main pier and mountain body.The FLAC3D finite difference software was used to analyze the stability of Slope on the working condition of 1 times of cable force,the safety factor of tunnel anchorage slope in Dadu River was 2.25,and the failure mode was that the surface of slope moved along the geotechnical interface(the contact surface of clay including gravel and Rock mass)to the temporary surface of the slip;the safety factor of deep rock was 3.75,along the local rock around the anchor?2)Based on the three-dimensional numerical simulation,the stability of the tunnel anchorage slope in Dadu River under the seismic action beyond the probability of 10%in 50 years(El earthquake)was analyzed.The analysis of point safety factor index showed that the slope was stable,but the overburden clay stability was poor.There was a possibility of instability.3)The stability of tunnel anchorage slope in Dadu River was simulated and analyzed under the seismic action beyond the probability of 20%in 50 years(E2 earthquake),and the overall stability of slope was relatively poor.The surface clay would slip along its contact surface with the underlying rock mass.4)Based on the Mindlin solution of elastic theory and the limit equilibrium theory,the quasi-static method was used to simplify the seismic force,and the stability of the tunnel-type anchorage engineering under the action of the E1 and E2 earthquakes was calculated.Under the earthquake of E1 and E2,The safety factor of the shallow surface were 1.13 and 1.06,respectively.The analytical results were basically consistent with the three-dimensional numerical simulation results.The research work of this article can provide guidance and reference for the stability analysis and engineering design of the Slope with tunnel-type anchorage in high intensity mountain under earthquake action,which has important engineering significance.