| Blasting is used for excavating rock in many geotechnical engineerings, which brings convenience while some disaster effects ,such as blasting vibration is created. Using blasting to excavate rock in the city,blasting vibration not only damages architectural structures but also harms people psychologically, therefore it must be controlled.In view of this, blasting vibration effect ,safety criterion and blasting vibration effect safety controlling are researched deeply by combining theoretical study and field test in this paper, the following specific aspects are researched:①The mechanism and characteristics of blasting seismic wave are analyzed,the difference between blasting vibration and natural earthquake are discussed and the methods of calculating the maximum pressure on hole wall in different charging structures are analyzed.②The vibration effect caused by a single cylindrical charge and spherical charge explosion in rock are analyzed, for the lack of previous blasting vibration models,the dynamic pressure on the wall of hole is changed and rock is simplified as single DOF system,then the rock vibration models caused by a cylindrical charge and spherical charge explosion in rock are established by using structural dynamics. The distribution of blasting vibration intensity are obtained through the study on vibration that is caused by charges simultaneous blasting empirically and theoretically.③The blasting seismic wave's reflection and transmission in high-intensity structural plane and low-intensity structural plane are researched,through the examples, the displacement amplitude's variation of reflected and transmitted wave with the incident angle,and the variation of blasting seismic wave propagation effect with the incident angle are analyzed.And the expressions of critical displacement amplitude of incident wave and critical safety vibration velocity in structural plane are deduced,also the formula that can calculate sliding displacement difference of the rock in the both sides of low-intensity structural plane is established, and the variation of mutual dislocation's degree of the rock in the both sides of low-intensity structural plane with incident angle is analyzed. The stress attenuation model of blasting seismic wave through soft interlayer is established, and then the relationship between the stress and energy attenuation of blasting seismic wave and thickness of soft interlayer and distance from soft interlayer to explosion source are obtained with example - calculating. ④With field monitoring tests of rock blasting vibration velocity and the established rock vibration models caused by a single cylindrical charge and spherical charge explosion in rock are verified.And one method of arranging measurement points is proposed in doing the predicting– peak - velocity experiments. The experiments that how soft interlayer impacts on blasting signal were did, the law about soft interlayer affects blasting vibration signal is obtained,according to the law,the approximate and simple method that soft interlayer can be identify by blasting vibration signal is proposed.⑤The damage mechanism of architectural structures under blasting vibration influenced by three factors of blasting vibration, accumulated vibration effects and physical characteristics of architectural structures itself are analyzed, the existing blasting safety criterion are evaluated. Towards the inadequacies of these safety criterion, a new one is established based on the damage mechanism of architectural structures under blasting vibration, and which is verified by field tests.⑥Taking the rock mass completeness modulus as a standard, quantifying the geological conditions that the blasting seismic wave passes through and making it as a related factor,the importance order of the factors that affect blasting effect are obtained by using grey relation method.According to the importance order of these factors,six measures for safety controlling are brought forward and their effectiveness are verified by field tests.
|
PDF Full Text Request