Research Of Underwater Rock Plug Blasting Vibration Respones Spectrum Properties And Sturctural Modal Analysis

Underwater rock plug blasting technique is widely applied in Marine hydraulic engineering construction with its superior quality and efficiently of blasting rock mass. But vibration effect and safety evaluation of the surroundings building that is caused by blasting vibration attracts more and more people's attention. In the past, people considered ground's particle velocity as the criterion of structures' destruction, but this single criterion can't explain the emergence of various phenomena in the blasting Engineering. The studies show that blasting earthquake wave and the dynamic characteristic of structure result of the structures' vibration effect together. According to the dynamics vibration theories, the earthquake harmonic wave frequency contained in blasting earthquake wave and the natural frequency of structure are more closer, vibrating effect is more larger and structure is more easily broken. So we should consider these two kinds of factors comprehensively to analyze dynamics response of structure.The earthquake response spectrum theories comprehensively considers earthquake wave characteristic and structure characteristic, so it is extensively applied in earthquake-proof design of structures in the field of earthquake engineering. The earthquake response spectrum theories are gradually applied in blasting engineering realm because of similarity of blasting vibration and earthquake vibration. Although many researches have been done by making use of response spectrum theories currently, they are subjected to the spot measure data restriction, so a lot of researches all take experiment data as foundation, their actual instruction the function isn't just very mature and didn't become complete norm. Response spectrum theories are applied to engineering dynamic analysis of underwater rock plug blasting much less. This text applies the theories, combining the spot monitor data to analyze the Fen river underwater rock plug blasting dynamic response. It also expands making response spectrum curve by acceleration timing curve to by velocity and displacement timing curve, avoiding inaccuracy caused by cross integral calculus, and makes the corresponding response spectrum curve accurately responses dynamic response regulation and characteristic. By the analysis to the response spectrum curve, we know the structural motive characteristic parameter and blasting characteristic parameter. It carries ANSYS finite element analysis software mode analysis and spectrum analysis on the structure, and proves response spectrum curve and structural motive characteristic parameter,blasting characteristic parameter from response spectrum curve. At the same time, it proves the method that calculating response spectrum curve by velocity and displacement timing curve is correct. It not only fills up the bank of domestic didn't make use of response spectrum theories to analyze actual underwater rock plug blasting engineering, but also put forward the new method of calculating response spectrum curve, pushing response spectrum theories to new development.As the development of computer technology and widely application of fast Fourier transform, digital signal processing technique is gradually applied in engineering construction. In this text, structure is seen as system to study, we make use of the system identification theory and system analysis theory to study the structural characteristic and dynamic response. Mainly it makes use of the frequency-domain analysis method's analytical principle to analyze structure's mode frequency; makes use of related functions to calculate system's delay time, that is reaction time of the system, then calculates the structure 's maximum relative displacement of different height at the same time to verify structure satisfy the request for transforming; it is shown that transfer function is a physical quantity that is determined by quality, stiffness, damping ration of structure ,with structure's output and importation irrelevant, is the function of the inherent property of the structure by expression and characteristic of transfer function. According to characteristics of transfer function, it puts forward to make use of transfer function estimate the structure dynamic response, and make use of Fen river reservoir's rich spot monitor data verify the method's possibility. Transfer function can not only predict the structural dynamic response, but also carry on mold analysis to the structure to beg structural mold frequency and mold shape. This text we made use of that method to beg the mold shape of structure. Also we made use of ANSYS software mold analysis function to verify the mold frequency and mold shape begged by frequency-domain analysis method. Moreover, this text we quoted coherence function that describes the related degree of the importation signal and output signal on the frequency area to help judge credibility of power spectral density function and transfer function.Finally, mold analysis and spectrum analysis software of the ANSYS was introduced. According to the actual size of Fen river reservoir four meters intake tower, finite element model was created ,and accuracy of some conclusions by response spectrum and system analysis method was verified, also the methods by mold analysis and spectrum analysis.