Analysis Of Mountain Tunnel Seismic Damage And Study On Dynamic Response Of Tunnel Entrance

All along with legions of infrastructures carrying on in domain and further promotion of Western China's development strategy, tunnels for express, railway and hydro-electric power plant have been built sequentially. "5.12" WenChuan earthquake damaged many tunnels on DuJiangyan-WenChuan highway, which set looming obstacles and extreme challenges to rescue task and reconstruction assignment, And which made us to ignore the vitality of earthquake resistance and disaster mitigation research, especially preeminent importance of earthquake resistance and mitigation analysis on tunnel entrance. Although abundant research works concerning tunnel entrance dynamic response under seismic load carried out and resulted, there is none which study and analogy this issue in using discrete element method.Based on the case of LongXi tunnel post-earthquake restoration, this thesis analyzed procedures both in rescue and repair phase, investigating the pattern of ShaoHuoping tunnel entrance seismic response in comparing the sample of ShaoHuoping tunnel entrance renovation via discrete element method-3DEC.Major content:(1) Concluded the seismic damage features on tunnel portal part, tunnel entrances and bodies of 15 tunnels on Dujiangyan-Wenchuan highway and state pass 213th road after "5.12" Wenchuan earthquake and analyzed repair techniques in rescue and restore phase follow the example of Longxi tunnel post-earthquake renovation.(2) This paper introduced the principle of 3DEC discrete element method, explaining distinguishing test on block contacting in discrete element method. According to 3 DEC standard computing procedure illustrated the accessory method, type selection and implementation procedure of each relevant parameter, respectively describing boundary condition, damp determination, earthquake wave loading approaching, selection of rock and joint mechanical parameter and rock mass disintegration discipline.(3) Fundamentally the slope decomposing progress and the corresponding cause are discussed based on 3DEC transparently stimulating the damage case of entrance slope. Cutting face tunnel portal performed better than end wall, due to the damage of slope basically occurred during crest stage of earthquake wave. Though respectively investigating dynamic response from the influence of joint stiffness, slope height, slope angle and load crest.(4) By studying dynamic response due to earthquake on ShaoHuoping tunnel entrance ideal model we concluded that entrance possess biggest dynamic response and the arch foot, Spandrel, invert is the most dangerous spot in tunnel seismic resistance, which are the focusing area of reinforcement. Since mitigation layer been laid, positive result has been gained owing to slope survived, stress of lining reduced and deformation slightly increased.