Analysis On The Damage Failure Mechanism Of Fractured Rockmass Under High Seepage Pressure And Its Application

Jointed rock mass is rich inavariety of intenral defects such as micro-cracks,pores, fissures and other discontinuous maero-joints etc. the exist and change of seepage in the fissures is a important reasons for the instability of rock masses engineering. the high seepage pressure in fractures will aggravat the branch cracks seeding, propagation and coalescence, this process will lead to the damage of rock mass strength, enve causeing large-scale geological disasters. on the other hand, the change of rock mass stress field and the damage propagation of rock fractures cause the change of seepage properties and accordingly change seepage field distribution. the coupling effect of seepage-stess-damage in fractured rock masses has a good prospect of engineering application in the field of hydropower engineering, civil engineering,mining engineering etc.The studied title is come from National Science Foundation Project (grant number:10972238-Study on the damage failure mechanism of fractured rockmass under high gradient seepage pressure and its application) and Master Innovation Project of CSU(grant number:2010ssxt240-analysis on the damage failure mechanism of fractured rockmass under high seepage pressure and its application in the deep). has researched the fracture mechanic property of fractured rock masses, and damage deformation of fractured rock masses under the action of high seepage-stress, the research work involving several aspects as follows:(1)The fracture mechanical properties of jointed rockmass and the law of initiation and propagation of the crack discussed under the tension pressure or shear stress and the high water pressure water pressure are studied by the fracture mechanics and damage mechanies.,have established The wing cracks model subjected to compress shear stress under the high water pressure,the damage fracture mechanics model and the fracture failure criterion of rock multi-crack body has also been established.which revealed the crack propagation rules of hydraulic fracture about the rock mass at theoretically.(2) basing on micromechanics theory,the paper has studied the laws of seepage properties of singel cracks. established the permeability tensor evolution equation, considering initial damage and damage evolution of fractured rock under the coupling effect of tensile or shear stress and the high seepage water pressure derived the damage constitutive equations of elasto-plastic fracture and the damage evolution equations.(3)From the aspect of rocks structure mechanics, using the seepage theory of fissured rock,derived the equivalent continuous model of the jointed rockmass,then applied to a unlined pressure tunnels for the coupling analysis, The results show that the coupling effect has important theoretical significance and practical value in the rock engineering.