Research On Calculation Method Of Three-dimensional Stability Of Unstable Rock

Rockfall is a kind of natural geological disasters all over the world,and it has great scientific value for the study of the prevention and control of the collapse of the dangerous rock.The first task of the prevention and control of the geological disaster of the rock collapse is the identification of the critical rock and the analysis of the stability of the critical rock.The calculation of dangerous rock stability is the key to prevent and control geological hazards in dangerous rock collapse.Reasonable and accurate calculation method is of great significance for disaster prediction of dangerous rock collapse.At present,the theory of stability analysis for dangerous rock includes limit equilibrium theory,structural theory,fracture propagation theory,energy theory,dynamic time history analysis,wave theory,catastrophe theory and geometry theory.Generally speaking,the development of stability calculation of dangerous rock has gone through the process of material mechanics method and fracture mechanics analysis.It involves mechanical analysis,graphic analysis and numerical analysis.Study on calculation method of dangerous rock stability is still under the assumption that the rock surface is composed of main control structure through section and non through section structure and surface morphology with the length direction of rock under changing conditions,focusing on the main control of dangerous rock mass structural plane two-dimensional expansion of the problem,not involved in dangerous rock control fissure distribution is through regional and non through rock controlling structural surface area of the combination of three dimensional stability problems.The essence of instability and failure of dangerous rock is the development of complex cracks in the rock mass in space.Its development direction,scale and speed(abrupt)are uncertain.Therefore,it is of little significance to analyze dangerous rock stability from microscopic perspective.The stability of dangerous rock is regarded as macroscopic crack and the knowledge of micro fracture mechanics is used to calculate and analyze the stability of dangerous rock mass.The rationality of the method is worth further proving from the essence of fracture mechanics.It is worth noting that the design specification of geological disaster prevention project implementation of the current disaster survey and design specification "(DB50/5029-2004)on the stability of rock body calculation of this piece is used in two-dimensional equilibrium theory of mechanics of rigid body,the calculation method is simple and practical,but it ignores the three-dimensional characteristics of dangerous rock.Given the lack of current research and engineering application to the Chongqing Wanzhou first mountain rock based on typical examples,based on three-dimensional space,considering three-dimensional morphological characteristics of rock and the main control structure of the distribution,the calculation method of three dimensional stability of the middle region surrounding rock through bonding were studied using the limit equilibrium theory and rock strength theory,research the results can be summarized as follows:1)analyses the advantages and disadvantages at present rock stability calculation method,found that the current calculation methods are mostly focusing on the dangerous rock stability control fissure extended two-dimensional problems and ignore the essence of rock body is three-dimensional,and the analysis model is designed through segment and non linear model through sections,the lack of research on the middle area through the method of calculating bond surrounding the rock stability.2)Chongqing Wanzhou first instance of in-depth and systematic analysis of the rock mountain area surrounding rock through intermediate bond formation and evolution mechanism based on fracture mechanics,and based on the theory of rock mechanics,rock mass was analyzed from microcosmic angle cut breaking mechanism.3)the relationship between the failure mode of the critical rock and the shape of the rock body is analyzed by the example of the slide block movement on the slope.4)considering the three-dimensional shape characteristics of dangerous rock mass and the adhesion of main control structure surface,based on the three-dimensional space,based on the limit equilibrium theory and strength theory,the three-dimensional stability calculation method of three kinds of dangerous rocks,such as slump,dump and falling type,has been derived.5)rock three-dimensional calculation method proposed in this paper combined with the Chongqing Wanzhou mountain rock W53 W51,the first case analysis,comparison and practical monitoring results analysis showed that the 3D steady rock which is put forward in this paper to calculate and analyze the stability of rock is more close to the actual judgment method.