Research on large deformation and control technology of tunnel surrounding rock in jointed carbonaceous shale strata
A high-speed railroad XHS tunnel which crosses through the jointed carbonaceous shale stratum shows significant large deformation and collapse of the surrounding rock.The control effect is not good after adopting measures such as strong support and deepening of the tunnel invert.For the geological conditions of jointed carbonaceous shale stratum in XHS tunnel,the large deformation and damage characteristics of the surrounding rock were analyzed by combining on-site monitoring means and discrete-continuum coupled numerical method.Based on the numerical simulation,the control measures of surrounding rock deformation which mainly focused on pre-reinforcement of stratum were proposed,and the application effect was explored through on-site test.The results show that the rock mass deformation after tunnel excavation is characterized by large volume and fast rate,the crown settlement value is larger than the horizontal convergence value,and the deformation has asymmetric distribution characteristics.Under the influence of multiple excavation disturbances,the unloading area dynamically develops and continuously expands to the whole ring,and the loosening area gradually transfers from the shallow rock mass to the deep and presents asymmetric damage characteristics,which eventually causes the large rock mass deformation.After taking pre-reinforcement measures,the sizes of deformation and loosening areas in the numerical model are obviously reduced,and the asymmetric deformation damage is effectively controlled.With the control measures of pre-reinforcement of the stratum,combined with over-supporting of the pipe shed and three-bench excavation method with temporary invert,the deformation is controlled and the construction effect is good.The tunnel resumes normal construction,and these measures also ensure the tunnel completion.The control measures which are mainly based on pre-reinforcement of the stratum are effective means to control the surrounding rock deformation in this type of jointed carbonaceous shale stratum.
jointed rock masscarbonaceous shalelarge deformationdiscrete-continuum coupled analysispre-reinforcement
万方数据
维普
