Creep Damage Model And Finite Element Analysis Of Closed Tunnel Collapse

During the process of tunnel construction,complex geological conditions and construction conditions,easy to cause the tunnel collapse,water gushing and other geological disasters,tunnel" close type" landslides is tunnel in construction process is one of the most common disasters,and often cause serious safety accidents.Combined with the creep damage constitutive model,start from the creep properties of rock,study the tunnel surrounding rock deformation behavior,the long-term stability and instability problems;established nine tunnel models Under the different supporting and buried depth,which conclude longitudinal anchor supporting spacing rely on 0.8 meters,1.0 meters,1.0 meters and conclude tunnel buried depth rely on 40 meters,60 meters,100 meters.Analysising the creep deformation of tunnel surrounding and the influence of creep on closed type landslide when consider for surrounding rock elastic-plastic body and sticky elastic-plastic body.Finally the main conclusions are:(1)Based on damage theory and irreversible thermodynamics,considering the influence of damage factor on the material,the introduction of Rabotonv injury body,established a new generalized kelvin creep damage model;using the parameters of experiment results of carbonaceous mudstone,mudstone,Qiao Hou salt rock and long salt rock,to match the new generalized kelvin creep damage model.It is concluded that the generalized kelvin also can be a very good description of rock damage model accelerated creep process.(2)Under elastic-plastic model and creep model calculation:along the tunnel axis,tunnel surrounding rock deformation law are showing that increases with the increase of distance from constraints.Under the same material model,with the tunnel buried depth and the anchor support spacing increased,the tunnel peripheral deformation also increases.(3)Same support circumstances,the two kinds of model calculation results show that with the increase of buried depth,the space effect of the tunnel vault and arch shoulder also increase.Same case depth,vertical anchor supporting spacing increases,the space effect is not obvious.A little space influence when buried depth and supporting of inverted arch and arch waist location changed.Equivalent depth and supporting conditions,compared with the results of the analysis of elastic-plastic model,rock creep property of the space effect have different degrees of weakening effect on the tunnel each location.(4)Creep deformation of tunnel surrounding stabilized,three types of supporting method from the model and calculating data from three kinds of tunnel buried depth,tunnel in the vault,spandrel,hance maximum for each position of the creep deformation relative to total deformation of tunnel were more than 85%,more than 50%in inverted arch position.Therefore,the impact of the surrounding rock in the process of creep deformation can not be underestimated,even in a certain period of time may occur instability damage,and resulting in tunnel "closed" landslide.