Theory Study And Numerical Simulation On Rock Blasting Of Tunnel

With the rapid development of economy, rock blasting technology is widely applied in the field of slope excavation,tunnel driving and mineral exploitation,how to reduce the amount of explosive and rock damage and blast effectively have become the urgent program. By using LS-DYNA finite element program,single column charge blasting and blasting vibration of tunnel excavation are simulated numerically and the rules on blasting of explosive in the rock are studiedy deeply in this paper. The contents in this paper are concluded as follows:1 .The mechanism of rock blasting is performed. Started with the development history of rock blasting model,a systematic discussion of the advantages and disadvantages of elastic model,fracture model,damage model and fractal damage model is given and some theoretical formulas are derived. Blasting broking mechanism of rock is discusssed and its proximal development. is introduced. On the basis of the previous researches,the theory of rock fragmentation by blasting of continuous charge and all kinds of decoupling charge is studied and different initiation modes of continuous charge structure are researched on theoretically.2.Calculation principle of dynamic finite element program LS-DYNA isstudied. Control equation,time integral,gaussian single point integral,hourglasscontrol,stress calculation, artificial bulk viscosity,time-step control andnon-reflecting boundary etc of LS-DYNA in theory and constitutive relation of rockmodel, yield criterion and numerical calculation model of explosive are introduced.The differences between the three method of Lagrange Eluer and ALE arediscussed,which provide theoretical basis for the subsequent work in the dissertation.3.Through the software of LS-DYNA,single column charge blasting processunder decoupling and explosion in downward and upward conditions issimulated,the change process of pressure,horizontal velocity and acceleration inrock by blasting is studied, simulation results are compared,which verifythe theoryand promote the application of computer simulation in rock blasting.4. As for blasting vibration,the effect from blasting excavation of Yunding tunnel on surrounding rock are simulated numerically,some rules are concluded. A comlarative analysis among the different length of explosive dynamite column,millisecond delay interval and direction of initiation is done,the optimum parameters are obtained. The interaction of parallel tunnel blasting are simulated and analyzed, some conlusions are received. These things give reference for engineering construction.