Simulation And Analysis Of Factors Of Seismic Response Of Cross-section Of Rock Tunel

After Wenchuan "5.12" earthquake, a rock tunnel that located in the earthquakezone had suffered some serious damages, such as the large area of the lining cracking,squeezed of the side wall,floor uplift,vault bending deformation etc.It has veryimportant meanings for understanding and prevention the earthquakedamage of rocktunnel to research the seismic response and failure mechanism.In this paper, the mainly job had done was tosimulate the seismic response oftwo-dimensional cross-section of rock tunnelbased on ABAQUAS and analyse someinfluencing factors.The main job:1) Through consulting literature, the article summarizes the history and currentsituation of the seismic research of tunnels or other underground structures; summarizesthe seismic methods of tunnels or other underground structures;simply summarizes thedamage mechanism of rock tunnels; simply describes the earthquake damagephenomena of a rock tunnel.2) Introduce several important issues when use the finite element software toanalyze the seismic response of rock tunnels; choose lining and a thin layer of rock nearthe tunnel as the objects of the seismic response analysis of rock tunnels.3) Using ABAQUS software to simulate the seismic response of rock tunnels;tosimple explain thedamage phenomenon of rock tunnel damage;to analyze the effect ofthree factors that the surrounding rock stress release, the rock parametersand thedepthon the seismic response of rock tunnel lining and a thin layer of rock near thetunnel.The results showed that:1) The damage mechanism of rock tunnel are the large deformation of lining or theexpansion of jointed and fractured which lead the rock broken and slip that cause thelining be destroyed.It is likely to occurtensile failure in the hance,to occurcompressionfailure in the spandrel.The rock outside the side wall is likey to occurshear failure, thefailure is eayse to lead the expansion of jointed and fractured, which may lead the rockbroken and slip, that cause the lining be destroyed. The plastic deformation of the rockthat outside of the inverted archisasymmetric, which may cause that a side of the rocktunnel floor uplift.2) Surrounding rock stress release rate has a significant effect on the seismicresponse of rock tunnellining and thin layer of rock near the tunnel.While the surrounding rock stress release rate ismedium,the horizontal directiondeformation of theside wall, the first principal stress of the hance,the third principal stress of the spandrelis larger;the vertical directiondeformation of the vault is smaller; the vertical dislocationof rock tunnel floorchanged obviously;the vertical directiondeformation of sidewallchanged obviously;While the surrounding rock stress release rate islarge or small, theseismic response of rock tunnels are not very different.When rock stress release rate ismedium, the equivalent plastic strain of the thin rock layer outside of the lining changedobviously.While the surrounding rock stress release rate islarge or small,the equivalentplastic strain of the thin rock layer outside of the liningare not very different.3) The rock level has a complex influence on the seismic response of rock tunnellining and the thin layer of rock near the tunnel. In those models that the depth is40m,while the rock level is Ⅲ, the lining has the largest earthquake response, and thenⅣ,and then Ⅱ or Ⅴ.The rock level has an influence on the distribution of theequivalent plastic strain of the thin layer of rock near the tunnel.4) Depth has a great influence on the seismic response ofrock tunnel lining and thethin layer of rock near the tunnel.When the depth is30m, the seismic response of rocktunnel lining is the smallest; when the depth is larger than30m, the seismic response ofrock tunnel lining will increase with the increase of the depth. For surface seismicreflection, when the depth is20m, the seismic response of rock tunnel lining is largerthan30m;the deeper of the depth, the lager response of the thin layer of rock near thetunnel is similar;depthhas an influence on the distribution of the equivalent plastic strainof the thin layer of rock near the tunnel.