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Study On Theory And Application Of Blasting Vibration Cumulative Effects

Posted on:2003-01-08Degree:DoctorType:Dissertation
Country:ChinaCandidate:S Q YangFull Text:PDF
GTID:1100360125958083Subject:Mining engineering
Abstract/Summary:PDF Full Text Request
Firstly, the present information of the blasting vibration effects is described in three aspects, which is respectively wave propagation characteristic & effect theory, prediction & controlling of blasting vibration, and safety criterion. Following, some former preparing research work of blasting vibration cumulative effects is listed. It is pointed out that some different studying methods and content need to be developed after analyzing the present achievement and problems. Therefore the blasting vibration cumulative effects is to be explored for the first time, which is mainly for cycling blasting in underground engineering and mines.The characteristic of blasting seismic wave in propagation, energy, frequency and altitude, and damage, is illustrated that there are randomicity and unpredictability of wave, wide-band and frequency concentration, great damage and unobvious, and changeability and variety of blasting seismic waves. And the rock mass dynamic characteristic analysis shows that the cumulative damage will be taken place in rock mass under the dynamic loads of blasting seismic waves. The phenomena of blasting vibration cumulative effects of ground buildings and underground structures is explained respectively , which is confirmed by theoretical and practical analysis. There are two aspects of blasting vibration cumulative effects in rock mass, which is damaging-effects and alterable-effects differently. The damaging-effects is weaken-effects in intensity and the alterable effects is strengthen-effects in intensity.The blasting vibration cumulative effect mechanism is discussed and explained based on the theories of fracture mechanics and damage mechanics: crack propagation will be taken place under dynamic loads of blasting seismic waves, the same as faults such as joint, crack, fracture, and interface etc. Developing of these fault cause damage of rock mass, which is more obvious in jointed rock mass relatively. There are two kinds of effects theories which are single-wave theory and multi-waves theory respectively. The single-wave theory is defined as cumulative effect of single blasting seismic wave, in same wave in rock mass, and the past state of wave affects the present state. The multi-waves theory is defined as cumulative effect of several waves, which is independent each another. The general outline of multi-waves is that there is cumulative damage in media mass under dynamic loads of blasting seismic waves.On the other hand, there are two effects of blasting vibration cumulative effects, which is step effects and memory effects respectively. Here, the absonant damage theory is also explored and discussed, which means re-distribution of blasting vibration energy cause crack propagation.It is pointed out that the faults in rock mass and the blasting seismic waves propagation affect each other. And there are some decline that different faults affect mainly different wave propagation. At the same time, fracture series in rock mass can be treated as a some size fault interface.Through research and theoretical analysis, it is confirmed that the surface ofvibration velocity wave in rock mass can be used to explain and comment energy of blasting vibration in rock mass. The magnitude of surface of vibration velocity wave changed with charges of explosives and distance correspond to the change of blasting vibration energy. Furthermore, it is also used to illustrate the change of characteristic of rock mass and attenuation of the blasting vibration energy in rock mass. Similarly, the effect unit surface of vibration velocity on unit charges and distance can be used to comment unit blasting vibration energy in rock mass. Here, the calculation methods of the unit effect surface have been put forward. And the information of faults and its' developing state in rock mass can also be illustrated through comparing the magnitude of the unit effect surface of the same point vibration velocity.In the last chapter, the affect factors of blasting vibration effects and its contr...
Keywords/Search Tags:seismic wave, blasting vibration, cumulative effects, cumulative effect mechanism, surface of vibration velocity, unit effect surface, safety criterion
PDF Full Text Request
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