Study On Characteristics And Related Prevention Countermeasures Of Seepage In Fractured Rock Mass

Seepage in fractured rock masses,which is the most common state of groundwater flow,is widespread in various types of projects,such as mining,oil,water conservancy,slope,foundation,underground,etc.A large number of engineering examples show that the stability of engineering structures is seriously affected by groundwater seepage.Therefore,the seepage problem of fractured rock mass must be studied and solved.Due to the complex fracture distribution,the fractured rock mass is a heterogeneous and discontinuous anisotropic body.The uneven distribution and seepage of groundwater in fractured rock mass leads to the study of seepage problems in fractured rock mass is extremely complicated.Therefore,the study is of great significance for practical engineering.Combining Science and Technology Projects of Guangdong Provincial Department of Communications,"Safety Feasibility Study of Deformation Mechanical Behavior and Prevention Measures of Special Formation Tunnels",relying on the Hongtuzhang Tunnel Project,based on the research status at home and abroad,the characteristics and related prevention countermeasures of seepage in fractured rock mass are studied by various means.The following are the main research procedures and achievements:(1)Geometric characteristics of structural plane of fractured rock mass were summarized.The mechanical properties of through and non-through fractured rock mass were expounded.Based on the understanding of permeability coefficient and permeability tensor of fractured rock mass,the physical,chemical and mechanical effects of seepage on fractured rock mass were summarized and analyzed.(2)Based on the engineering geology of the tunnel site,the DIPS software was used to classify the structural plane of the tunnel.Based on the statistical analysis of the occurrence,size and density of the structural plane,the three-dimensional structural plane network model of the rock mass was established,and the permeability tensor was calculated.(3)Based on the three-dimensional discrete network model,the numerical simulation of fractured rock mass was carried out by using 3D EC block discrete element software.Taking intact rock mass,fractured rock mass and fractured rock mass under seepage as research objects,the mechanics and seepage characteristics of fractured rock mass were studied through comparative analysis.(4)The supporting measures and waterproofing measures of water-bearing fractured rock mass in tunnel engineering are summarized.Based on the theory of limited discharge,the influence of grouting on tunnel water inflow and lining external water pressure was analyzed.The corresponding grouting circle parameters were put forward,and the ejection for water plugging measures of Hongtuzhang Tunnel were discussed.