Study On Excavation Deformation Of Deep Buried Tunnel With Rich Water Considering Spatial Effect

The tunnel is a kind of underground structure exists in the soil and rock mass,and the study on the stability and deformation of rock mass is an important subject.Tunnel engineering is almost always accompanied by groundwater.With the excavation of the tunnel,initial stress field of surrounding rock is changed,resulting in two redistribution of stress.When groundwater exists in the tunnel,the seepage field points to the hole will be formed around the tunnel,and the permeability of rock mass will be changed.At the same time,the distribution of the stress field of the surrounding rock is also affected by the change of the seepage field,and the two factors influence each other.Especially for the deep buried rock tunnel with rich water,the deformation of the surrounding rock mass induced by tunnel excavation is very large and the deformation speed is very fast under the coupling effect of the stress field and seepage field of the surrounding rock with high stress and high water pressure.In addition,in tunnel excavation,due to the spatial effect of excavation face,the deformation of surrounding rock and its interaction with the support structure will change with the advancement of the excavation.Therefore,the spatial effect is an important part of tunnel excavation deformation.This thesis based on spatial effect carrys out the study on the excavation deformation of deep buried rock tunnel with rich water by means of theoretical analysis,numerical simulation and field monitoring measurement.Based on the basic theory of spatial effect,the displacement release law of surrounding rock of tunnel excavation is analyzed and interaction mechanism between surrounding rock and support when considering the spatial effect of excavation face is studied.In this thesis,the seepage field of fractured rock mass is studied theoretically,the interaction between water and rock mass and the coupling effect of seepage field,displacement field and stress field in fractured rock mass is analyzed.By using the finite element software,the three-dimensional model of deep buried rock tunnel with rich water(i.e.,considering the spatial effect)is used to analyze the influence of surrounding rock grade,support condition,excavation method,groundwater and grouting reinforcement on the deformation of surrounding rock.For the existence of fracture zone in high water level of the 1# tunnel of XiaoBei mountain,through the comparison of numerical simulation and field monitoring data,the influence of broken zone on the deformation of surrounding rock and effect of grouting reinforcement are analyzed.The results show that the deformation of the surrounding rock occurs in the whole process of excavation,and the surrounding rock grade determines the deformation velocity,the total amount of deformation and the convergence time.The application of support can significantly reduce the excavation deformation of low grade surrounding rock,and the selection of construction methods will affect the process of deformation.With the rise of the groundwater level,the consolidation settlement and the surrounding convergence of tunnel caused by seepage flow increases.Grouting consolidation can reduce the consolidation settlement and deformation of surrounding rock,which effect on the broken surrounding rock under high water level is remarkable.The above conclusions have some reference value,which can provide guidance for the construction of deep buried tunnel with rich water.