Abstract:

Based on the analysis of the characteristics of underground blast induced surface ground motion, the evaluation standard of the effect is discussed. By analytical method, the computational model of surface ground motion and the response spectrum are established. The calculation shows that: There are two wave groups in the surface ground motion, when estimate their effect on above-ground structures, that the periods of the second wave group is 1.5－2.0 times longer must be considered. The response of the above-ground structures are determined by the natural frequency and damping, the frequency and amplitude of the seism. For miniature blast equivalent, the effect of frequency of the surface ground motion could be ignored; but for great blast equivalent, the effect of the frequency could not be ignored. For double layer buildings, the motion of the second layer has the characteristic of big amplitude.

Key words: blast, seismic effect, evaluation standard, dynamic response