近地表爆炸地震的地面竖向振动速度的随机特性

Random Property of Ground Vertical Vibration Velocity Induced by Near Ground Explosion Seismic Effect

引入了将爆炸地震的地面运动速度分解为一个确定性的幅值衰减函数和一个随机振动响应函数的乘积进行描述的基本方法 ,对近地表爆炸地震引起的地面竖向振动速度的实验测试结果进行了简要的分析。分析结果表明 :近地表爆炸地震的地面竖向振动速度随机波动分量的双对数功率谱在 10～ 70 0Hz的频率范围内满足近似的线性关系 ,功率谱指数介于 2 .5 1～ 2 .85之间 ,由此得到非平稳地震地面振动速度的演变谱密度方程。此外 ,还给出了地面竖向振动速度的理论模拟结果 。

A general method to describe the ground velocity induced by explosion seismic is introduced,which resolves the velocity into a product of a determined amplitude attenuation function and a random response function.A brief analysis is presented on the measurements of the random velocity fluctuation caused by the near ground explosion seismic effect.The analyses of the experimental results show that the log log power spectrum of the random velocity fluctuation follows the linear relation with the spectral exponent between 2.51～2.85 within the frequency range 10～700Hz approximately,and then an evolutionary power spectrum equation of the non stationary ground vibration velocity is yielded.Otherwise,the theoretical modeling results of the ground vertical velocity are obtained,which agree with the experimental results statistically.