基于模型试验的预裂孔爆破参数优选

Parameter Optimization of Presplitting Blasting Based on Model Test

为了有效地降低预裂爆破振动对边坡岩体和周边建构筑物的扰动,除了关注预裂缝的减振效应外,还需对预裂孔本身的爆破参数和起爆方式进行优化。为此,采用正交试验法,选用C30混凝土为爆破对象的相似模拟材料,开展预裂孔爆破成缝过程的相似模型试验,选取不耦合系数、延期时间、最大单响药量3个因素,每个因素设置4个水平,以有效半孔率、预裂缝宽度和原岩损伤率为评价指标,通过极差与方差计算分析各因素对评价指标的敏感度,确定了本次模型试验达到最佳爆破效果的预裂孔爆破参数:不耦合系数为1.33,延期时间为12 ms,最大单响药量为1.8 g。研究结果可为现场预裂孔爆破参数选择和精确延期时间设计提供指导。

In order to effectively reduce the disturbance derived from the vibration of the presplitting blasting in the slope rock mass and surrounding structures,it is important not only to pay attention to the vibration damping effect of the presplitting,but also to optimize the blasting parameters and initiation modes of the presplitting hole.The study adopts the orthogonal experimental method,which selects the C30 concrete as the similar simulation material of the blasting object to carry out the similar model test of the blasting process with presplitting hole.In this model test,three factors are considered as the non-coupling coefficient,which are delay time,and maximum single-shot charge,and four levels are set for each factor,taking effective half porosity,pre-fracture width and original rock damage rate as evaluation indicators.After the analysis of the sensitivity of each factor to evaluation indicators through range and variance calculations,the best blasting effect with the blasting parameters of the presplitting hole are finally achieved in this model test:non-coupling coefficient is 1.33,delay time is 12 ms,and maximum single-shot charge is 1.8 g.The research results provide guidance for the design of the parameters of on-site blasting with presplitting hole and precise delay time.