Engineering Blasting 

Abstract: Based on the principle of finite-element method,the influence of blasting vibration from excavation of a new tunnel on close-in existed tunnel is studied by use of the ANSYS program.The vibrations of existed tunnels in different country rocks are analyzed at different spacing distances of tunnels.The results of study and analysis show that:(a)the sidewall of the existed tunnel in the face of blasting has a maximum vibration velocity;(b)the solider country rock is,the lower vibration velocity;(c)the vibration velocity of tunnel's lining will exceed the permitted vibration velocity if the spacing distance is less than one-fold of tunnel diameter;(d)the relation between vibration velocity of country rock and the distance to an explosion source is nonlinear.

Abstract: Decoupling charge blasting technique is the main technical measure of pre-splitting blasting and of smooth blasting and is responsible as a technical measure for the formation of a smooth rock and protecting excavation.The present paper established three-dimensional single-arch decoupling charge blasting model by using LS-DYNA and made numerical simulation and dotted cloud picture of decoupling charge blasting stress which presented the development process of blasting stress contours and stress and displacement time-history graph.The stress of hole wall and its damage situation of the air and water decoupling charge blasting were analyzed in the cases of when the decoupling coefficient being at 2,3 and 4 respectively,resulting in an establishment of the function of the stress and hole wall of the decoupling coefficient,and also the differences of the attenuation rate between water and air were compared which offered a theoretical foundation for the calculation of the parameters of presplitting and smooth blasting.

Abstract: The author,regarding the method of predicting collapsing vibration velocity of high chimney or building during blasting demolition,reviewed the formulas for calculating the collapsing vibration velocity given in references and discussed the formula in terms of its physical significance and its parameter selection for clarifying the discrepancy quoted.The paper explained some applicable formulas and discussed the selection of parameters by taking some practical engineering instances for the calculation of collapsing vibration velocity,and with a statement supported by real time data measurement that the intensity of collapsing vibration velocity could be reduced by about 70% when vibration reduction method was adopted.

Abstract: It has been found that the elliptical bipolar linear shaped charge(EBLSC) could concentrate blasting energy and reduce detonation velocity of explosives during blastingAnd the use of an alignment device could ensure the effect that cumulative shooting flow penetrated cracks in rock along the presplit faceAnd furthermore,the combination of effects of the cumulative shooting flow and the blast wave as well as the expansion of high pressure air could interact perfectly at the moment when the crack came into beingIt made the integration of smooth blasting and cumulative blasting and the application of the EBLSC possible in productionThis technology has obtained national patent of invention,which has verified the correctness of the conclusion with the uses of digital analogue and testsThe use of the patent could promise a reduction of the amount of holes and explosive consumption of unit area,with energy consumed by about 50%～65% and cost by about 50%～55%It could also weaken the baleful action of the blasting to the reserved rock and increase the stability of the rock slope,and therefore,expedite the progress and improve the quality of constructionObviously,the application of the technology will create great economic and social benefits