| Blasting,as an economic, fast, and effective engineering method, has been widely applied in various excavation and demolition blasting projects. The effects on blasting are both favourable and unfavourable. It’s favourable when we use the vibration created by blasting for geological exploration and foundation reinforcement. Explosive wave will certainly spread through the medium around when we blast a structure, which will produce adverse effect on the surrounding buildings. It is an important issue for blasting engineering to reduce and predict the adverse effect.Taking the regulation project of Fengman hydropower dam as the project background, this paper aims to study the blasting vibration effect of the excavation and blasting of the new foundation pits on the old dam and other buildings, and also the vibration effect of the demolition and blasting of the old dam on the new dam and other buildings. Based on the dynamic finite element theory, applying of ANSYS transient dynamics analysis, through the establishment of finite element model of practical engineering, this paper aims to the following several research aspects to carry out the numerical simulation analysis of the regulation project blasting vibration of Fengman hydropower dam.(1) According to analysis of the blasting theory, the blasting safety regulations and the blasting engineering experience of both domestic and international, this paper proposed a safe and permitted standard of the regulation project blasting vibration of Fengman hydropower dam. Proposal of this safe and permitted standard is also a kind of refinement, complement and perfection for the vibration standard matching the national regulation.(2) According to the relevant theory of blasting wave, the blasting load is simplified as a triangular shock wave with reference to the similar engineering blasting vibration tests. Calculate the blasting load peak depending on the hole size, location, explosives and the maximum single sound detonator quantity provided by its design. In the process of calculation, it’s necessary to exert blasting load on the perine of the blast holes and use viscoelastic damping boundary conditions to prevent the reflection of waves.(3) According to the engineering facts, model of the excavation and blasting of the foundation pits are established. Blasting load is exerted in three different blast holes. Study the maximum single sound detonator quantity of the excavation of the proposed new dam through numerical simulation whether meets the blasting safety standard and provide reference to the maximum single sound detonator quantity of similar projects. (4) The old dam demolition blasting model is established according to the actual situation. The water between the new and old dam will produce hydrodynamic pressure in the presence of blasting shock wave as the old dam is demolished. This paper explained the impact of hydrodynamic pressure on blasting vibration effects in a way of added mass. It studied the impact of hydrodynamic pressure on blasting vibration effects through the contrast analysis between added mass and without added mass. And it analyzed blasting maximum explosive single sound detonator quantity of the old dam demolition whether can meet the requirements of the safety operation of the dam and put forward the related proposals. |
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