在对地下爆炸地表震动特性进行分析的基础上,对地下爆炸地震效应的评价标准进行了分析与探讨,通过解析的方法,建立了地下爆炸地表运动计算模型和震动反应谱。计算结果表明:地下爆炸地表运动存在两组波群,在评价波对于建筑物的作用时应当考虑到第2波群中粒子运动的周期比第1波群的粒子运动周期长1.5~2.0倍;地面建筑物的响应取决于建筑物的固有频率、阻尼和地震的频率、振幅;对于小当量一次性爆破,震动频率高而震动时间短,可以忽略地表震动频率对结构的影响;但是对丁大当量爆炸地震安全问题,不应当忽略频率的影响;对于双层建筑物,第2层结构的不稳定运动有大振幅的特点。
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.