The Temporal And Spatial Effect In Construction And Control Of Large Deformation Of Tunnel In Deep Soft Surrounding Ground

Deformation of deep soft surrounding rock tunnel always correlates with time and space. Based on rheological mechanics, the large deformation mechanics mechanism of deep soft rock surrounding tunnel can be explained, and the theory can guide the tunnel design and construction preferably. According to the rock rheology theory, by the means of a field test experiments and numerical simulation, with the example of Liangjia Yard Tunnel Project, the time-space effect and large deformation control of deep soft rock surrounding tunnel are researched in this dissertation. The main research work and results are as follows:Combined with the field test results of Liangjia Yard Tunnel, the spatial and temporal characteristics and the menchanical characteristic of large deformation of deep soft rock surrounding tunnel are concluded.Furthermore, the mechanism of large deformation mechanics of deep soft rock surrounding tunnel are analyzed.Based on the time-dependent stress-strain behavior of soft clay and the principle of model selection, a model which is compound by the series of Burgers mdel and Mohor-Coulomb model is developed to describe the elastic-viscoplastic mechanical behavior of soft clay. Based on the displacement time series from field monitoring and by the numerical inverse analysis, rheological paramenters of rocks are obtained by numerical inverse analysis.According to the site geological conditions of Liangjia Yard tunnel, three-dimensional elastic-plastic model and numerical model with visco-elastic-visco plastic are established. During the excavation of tunnel, time-space process is investigated. The creep influence of the tunnel deformation and primary support are investigated. Furthermore, temporal and spatial effects of deep soft rock surrounding tunnel are summarized.Based on the mechanical mechanism and time-space effects of large deformation of deep soft rock surrounding tunnel, under the three-step construction engineering methods, the influence to the control of large deformation of deep soft rock surrounding tunnel of the step length, the time of the secondary lining, the parameters of steel and shorcrete, the length of the feet-lock pipe are investigated. The control technologies of large deformation of deep soft rock surrounding tunnel are summarized.