The Method Of Surrounding Rock Control And Stability Of Calcilutite In Large Section Tunnel And Application

In recent years,with the national strategy of infrastructure construction to the depth development of the western region,the number of tunnel which pass through the unfavorable geological area is increasing.But some disasters such as collapse,rock bursting and large deformation will happen,which could cause significant property damage and casualties.To deal these disasters,the first thing is to forecast when these disasters happen,which is an effective way to prevent and control them.Secondly,the normal support cannot satisfy the need,therefore,the new support structure system should to be developed.(1)Choosing the calcareous mudstone from a tunnel in Chongqing Province,the homotaxial and triaxial instantaneous mechanical character were conducted.From the aspect of stress-strain curve's character,strength and deformation index and damage pattern,the paper analyses instantaneous mechanical character of calcareous mudstone and its damage regular under the condition of homotaxial and traiaxial with diverse confining pressure,which also discussed the instantaneous damage mechanism of calcareous mudstone when in different stress state.(2)Construction process of the tunnel in tectonic region is numerically simulated with elasto-plastic FEM by using ABAQUS software.Then the deformation and stress of the tunnel is analyzed.(3)The new support structure system is constituted with grid steel frame-concrete core tube supporting structure,high toughness sprayed concrete and strong adhesion sprayed applied membranes.The settlement of surrounding rock,internal displacement of surrounding rock,pressure between surrounding rock and primary support,internal force of support arch,axial force of rock bolts,were all measured and analyzed.(4)Choosing the region of high possibility disasters,measuring the surrounding rock displacement,rock stress and osmotic pressure.And develop the tunnel safety construction management platform,with geological prediction,monitoring measurement,excavation schedule and major disaster monitoring.