钻孔爆破过程中炮孔远区爆炸荷载的实验研究

Experimental Study on Explosive Load far from Boreholes during Engineering Blasting

为了研究钻孔爆破过程中炮孔远区的爆炸荷载作用特征,以高层建筑物钢筋混凝土立柱为原型,建立了1∶1物理模型,采用圆柱形乳化炸药进行钻孔爆破试验,并对立柱的钻孔爆破过程进行高速摄影及应变监测。监测结果表明:采用延期雷管起爆时炮孔存在明显的起爆时间的不一致现象,这导致炸药爆炸荷载作用下立柱破坏过程的渐进性,同时立柱保留区爆炸荷载具有显著的多峰性及互相叠加现象。采用空气间隔装药药包长度为10~30cm时,爆炸荷载作用时间在0.1~1ms之间,且加载应变率大于卸载应变率。基于试验结果,构建了爆炸荷载的三角形荷载函数,并通过一维直杆波动力学模型,对炮孔远区的应变时程曲线进行了模拟。与监测结果对比表明:采用三角形爆炸荷载函数可较准确的模拟炮孔远区的爆炸荷载。同时,对于采用延期雷管的多炮孔爆破的模拟,多峰值三角形爆炸荷载函数更为适用。

In order to study the characteristics of explosive loading far from the boreholes during the blasting process,taking the reinforced concrete column of high-rise building as the objective,a 1∶ 1 physical model was established,the cylindrical emulsified explosive was used for the drilling and blasting tests,and the high-speed photography and strain monitoring of the blasting process of the column were carried out.The monitoring results showed that there was an inconsistency in the detonation time of the boreholes when the detonators were initiated,which lead to the column rupture step by step under the explosive load.The explosion load on the retaining part of the column had significant multimodality and superposition.When the length of the charge was 10~30 cm,the time of explosion load was about 0.1~1 ms,and the loading strain rate was greater than the unloading strain rate.Based on the experimental results,a triangular load function of the explosion load was proposed,and the strain time history curve of the straight rod under explosive load was simulated by a one-dimensional dynamic model.Compared with the monitoring results,it showed that the triangular explosive load function could accurately simulate the explosive load in the retaining part of the column far from the boreholes.At the same time,the multi-peak triangular blast load function was more suitable for the simulation of multi-bore blasting with delay detonators.