The DDA Simulation And Analysis Study Of Blasting Vibration And Stability Of Rock Mass Structure

As an inevitable result of blasting engineering,the occurrence of blasting vibration will have some adverse effects on the adjacent rock masses structures.Decreasing blasting vibration and its influence on the stability of surrounding rock mass structures becomes a major problem faced by scientists and technicians in the filed of blasting engineering.With the development of computer capability and the progress of numerical simulation techniques,using the numerical simulation to study the blasting vibration and its influence on the stability of rock mass structures has become an important way in this research field.In this thesis,the Discontinuous Deformation Analysis(DDA)is used to do numerical simulations of rock blasting under different conditions,including different rock modulus and different peak ratio of explosion-induced stress wave and explosion gas pressure.The curves of velocity-time history that describe the characteristics of blasting vibration are obtained.The wavelet analysis method is applied to analyze the time-frequency characteristics of rock blasting vibration signals under different blasting conditions.Finally,the stability of rock mass structures under the effect of blasting vibrations is simulated by DDA method.The main research work is summarized as follows:(1)In order to get familiar with the DDA method as well as to validate it for rock blasting simulation,simulation models of rock blasting under different geostress conditions are established.The influence of the initial geostress levels and the geostress lateral coefficient on blasting-iuduced rock breakage is simulated and analyzed.(2)The DDA method is further used to simulate rock blasting under different conditions of rock modulus and different peak ratio of explosion-induced stress wave and explosion gas pressure.The curves of velocity-time that describe the characteristics of blasting vibration are obtained.Then,the wavelet analysis program developed in the MATLAB is applied to analyze the time-frequency characteristics of rock blasting vibration signals under different conditions,to explore the influence of different blasting conditions on blasting vibration signals.(3)The blast vibration time histories under different blasting conditions that obtained in(2)are applied as displacement loads to a slope-slider structure.The influence of blasting vibrations under different conditions on the stability of rock mass structures is explored through the displacement of the slider in the slope-slider model.In this thesis,the blasting vibrations under different blasting conditions are obtained by DDA method,and the wavelet analysis is carried out to reveal the characteristics of blasting vibration signals under different peak ratio of explosion-induced stress wave and explosion gas pressure and different elastic modulus of the rock.The influence of blasting vibration on rock mass structure stability under corresponding conditions is also studied by conducting DDA simulations.Generally,an approach is explored for the analysis of the stability of rock mass structure under blasting vibration effects.The conclusions of the study provide a useful reference for the problems related to blasting vibrations.