【摘要】 高耸构筑物爆破拆除触地振动对周围的影响不容忽视,其塌落体触地与小重锤夯击地面具有一定的相似性,详细介绍了采用小重锤试验进行模拟研究的基本原理、操作方法,利用试验结果对质点峰值振速衰减规律和缓冲垫层减振效果进行了分析。结果表明:当落锤高度和缓冲垫层厚度不变时,随着测点距离的增加,各测点的峰值振速衰减明显;当落锤高度和测点距离不变时,随着缓冲垫层厚度的增加,测点峰值振速也衰减明显。触地振动速度衰减系数Kt随着缓冲垫层厚度的增大而减小,而触地振动速度衰减指数β刚好相反,垂直向地震波衰减比水平向快。缓冲垫层厚度存在一个临界值,一定范围内减振效果明显,大于临界值效果减弱,减振效果呈"小→大→小"的趋势。减振率是一个变数,可以通过改变缓冲垫层厚度进行控制,缓冲垫层厚度与落锤高度之比h/H=0.02~0.04时可以达到80%~93%。试验结论用于实际工程效果良好,对类似工程具有一定的参考价值。更多还原

【Abstract】 Affects of touchdown vibration of towering structures blasting demolition cannot be ignored.Its collapse touchdown has a certain similarity with the small hammer tamping the ground.Details of the basic principle,methods of operation were introduced,the peak particle velocity attenuation law and the effect of cushion damping were analyzed.Results showed that when drop height and cushion layer thickness were constant,the peak velocity of each measuring point was significantly attenuated with the measuring point distance increased.When drop height and measuring point distance were constant,the peak velocity of measurement points also significantly attenuated with the increase of the cushion layer thickness.Touchdown vibration speed attenuation coefficient Ktdecreased with increasing of the cushion layer thickness,while the touchdown vibration speed attenuation indexβwas just the opposite.The vertical attenuation of seismic waves was faster than the horizontal.There existed a critical thickness value of the cushion damping.The damping effect was obvious when the thickness in a certain range,and the effect was weaken when the thickness larger than the critical value.The damping effect showed a "small→large→small" trend.Damping rate was a variable controlled by changing cushion damping thickness.When h/H=0.02~0.04,the damping rate could reach 80% ~93%.The engineering application effect was good,and the conclusion had a certain reference value to the similar projects.更多还原