应力叠加下的爆破减振效应现场试验研究

Field Experimental Study of Blast Damping Effect under Stress Superposition

地震波振动是造成工程爆破危害的主要原因,使用爆炸能量分配降振原理,采用PFC2D模拟双孔爆破地震波效应,通过现场爆破试验分析单孔、双孔和三孔爆破的三维能量谱和瞬时能量谱,对比验证单孔、双孔、三孔爆破减振效果。研究表明:双孔柱状药包同时起爆的应力波干涉过程为椭球波,干涉中线附近的应力分布较为均匀、集中;爆破振动强度随着时间逐渐衰减,衰减速度逐渐减小,在爆破较近的区域衰减快;振动信号能量基本处在0~75Hz,随水平距离增加而逐渐衰减,50 Hz以下集中存在多个较明显的优势频带,单孔和三孔的能量频率集中分布在30Hz以下,双孔能量分布在较宽的频率范围;双孔实验的瞬时能量分散最明显,在减振效果上明显优于单孔、三孔爆破。

Seismic wave vibration is the main cause of engineering blasting hazards,Using the principle of explosion energy distribution and vibration reduction,PFC2D is used to simulate the seismic wave effect of double-hole blasting.Through on-site blasting experiments,the three-dimensional energy spectrum and instantaneous energy spectrum of single hole,doublehole,and three-hole blasting are analyzed,and the vibration reduction effect of single hole,double-hole,and three-hole blasting is compared and verified.Research shows:The stress wave interference process of simultaneous initiation of double-hole cylindrical charges is an ellipsoidal wave,and the stress distribution near the interference centerline is relatively uniform and concentrated;The intensity of blasting vibration gradually decreases over time,and the attenuation speed gradually decreases,with faster attenuation in the area closer to the blasting;The energy of the vibration signal is basically between 0 and 75 Hz,gradually decreasing with the increase of horizontal distance.There are multiple obvious dominant frequency bands below 50 Hz,with the energy frequency of single hole and three-hole concentrated below 30 Hz,and the energy frequency of double-hole distributed over a wide frequency range;The instantaneous energy dispersion of the double-hole experiment is the most obvious,and its vibration reduction effect is significantly better than that of single hole and three-hole blasting.