Safety Analysis Of Hydropower Station Under Blasting Vibration Loads

In the continuation of hydraulic and hydroelectric projects, blasting often happens nearby some primary constructions.During the process of blasting excavation, blasting also bring with some unfavorable effects.Especially in the safety of primary constructions and electromechanical deivces around the source of blasting will be affected.The safety measure and the safety criterion are different in some continuation project at home and abroad.Because of difference destroy mode between constructions and electromechanical deivces, only the vibration velocity can not be used as the safety criterion. Under blasting vibration loads, the safety of constructions and electromechanical deivces of hydropower station is an important problem.Aiming at the above-mentioned problems, the works of this thesis include two parts as followed:(1) At the present time, in numerical simulation of the constructions vibration response under blasting vibration loads, considering it mainly make research by means of the two-dimension FEM ,and now the commercial FEM analysis software LS-DYNA3D can solve the three-dimension non-linear structure's dynamic questions.In this thesis, three-dimensional dynamic FEM are used to analysis the different vibration response of electrical machine floor and control center floor under blasting vibration loads which are produced in different blasting mode and different blasting source. Through the comparisons with practical blasting project, the result shows that the method is reasonable and feasible.(2)Based on the vibration response of electrical machine floor and control center floor and the uncertainties of blasting vibration and the uncertainties of material intensity, probability model can be used to calculate the reliability of electromechanical deivces. The destroy degree of electromechanical deivces in the blasting vibration need to be measured by reliability index and destroy probability.By means of calculation and analysis, some conclusions are reached as follows:(Dthe safety criterion of blasting for powerhouse is mainly determined by earthquake-resistant behavior of electromechanical deivces.(2)Vibration isolation measures is important for the safety of the electromechanical deivces.(3)There is a definite relation between variance of invalidation velocity and failure probability of the electromechanical deivces. That is, the greater is the variance of invalidation velocity, the greater is the failure probability of electromechanical deivces.(4)Natural frequency have exerted a major influence on the reliability of the electromechanical deivces. The less is the ratio of the natural frequency of electromechanical deivces to the frequency of blasting vibration wave, the less is the failure probability of electromechanical deivces.