Characteristics Of Aging Fracture Of Layered Rock Mass And Its Evolution Laws

Layered rock mass is the most common type of rock mass in engineering.Because it has directional stratification,its mechanical characteristics are significantly different from those of general rock mass types.Engineering practice shows that the deformation and failure of caverns or slopes excavated in laminated rock masses is controlled by the surface production,spacing,and the physical and mechanical characteristics of the plane,which shows more obvious aging characteristics.At present,it is not mature to study the characteristics of aging fracture of layered rock mass,especially the laws of mesoscopic deformation and rupture.Therefore,it has important theoretical significance and application value to study the characteristics of aging fracture and the laws of evolution of mesoscopic rock mass.Based on the indoor test of chlorite schist in the Qinling tunnel,a mechanical model of mesoscopic aging fracture of layered rock mass was established by using discrete element method.The characteristics of aging fracture of lamellar rock mass and the evolution laws of meso-view are analyzed.The research work in this paper mainly focuses on the following aspects:1.Based on discrete elements and SJ model,this paper introduces the power function linear parallel bond time-effect mechanics model based on the distribution of Weibull,establishes the laminar rock body time-effect mechanics model,and puts forward the laminar rock body deformation and rupture evolution.The method of calculating the time limitation.2.By analyzing the sensitivity of the meso-mechanical parameters of the meso-time-effect model of layered rock mass,the influence of the meso-time-effect parameters on the evolution of deformation and rupture of rock mass is obtained.On this basis,according to the indoor uniaxial compression test and the uniaxial compression creep test,the mesoscopic mechanical parameters of laminated rock mass are determined,and the mesoscopic aging model of laminated rock mass is constructed.3.Taking the angle of inclination,spacing,encircling pressure,stress intensity ratio,and homogeneity as the main factors,numerical tests on the time-effective mechanical characteristics of layered rock masses were carried out,and the detailed evolution laws of the aging deformation and rupture of layered rock masses were obtained.The plane effect,the effect of stress intensity ratio and the effect of homogenicity on the evolution of mesoscopic deformation and rupture of lamellar rock mass are expounded.