电爆炸破碎岩石类脆性材料实验方法与应用

Experimental method and application of electrical explosion for breaking rock-like brittle materials

炸药使用受到严格管控,限制了岩石等脆性材料在爆炸动载荷下破坏机理的研究。为了建立安全有效模拟炸药爆炸动载荷的实验手段,进而深入精细开展岩石等脆性材料在爆炸冲击载荷作用下的破坏机理等研究,提出了利用金属丝电爆炸模拟炸药爆炸进行破碎岩石与脆性材料的实验方法。设计并开展了金属丝电爆炸模拟球状药包和柱状药包破碎水泥砂浆试件实验,论述了试件模型的制作方法与实验流程。采用高速相机拍摄试件表面裂纹的形成与扩展过程,采用罗氏线圈测量金属丝电爆炸过程电流。研究了充电电压对试件破坏过程与破坏效果的影响,对比分析了电爆炸载荷与炸药爆炸载荷的异同点,以及金属丝电爆炸实验方法的优势。结果表明:随着充电电压升高,金属丝电爆炸的峰值电流越大,但是上升沿时间不变;金属丝电爆炸可有效破碎岩石类脆性材料,是模拟炸药爆炸破碎岩石类脆性材料的有效方法,具有安全、无污染、能量可控、使用方便、可重复性高等优势;在模拟球状药包与柱状药包爆破实验中,随着电压逐渐增大,试件表面裂纹出现的时间越早、数量越多,破碎块度越小;与炸药爆炸相比,金属丝电爆炸以冲击波作用为主,气体的作用可忽略不计;在电压为50 kV(能量5.0 kJ)条件下,直径0.4 mm、长100 mm的直线型铜丝电爆炸峰值压力约为49.05 GPa;金属丝具有细长的特点,通过改变电极直径与金属丝的长径比,可开展与现场爆破参数高度几何相似的小型化的球状与柱状药包爆破模型实验。

The use of explosives is tightly regulated,limiting the research on the failure mechanism of brittle materials such as rocks under dynamic explosive loads.In order to establish a safe and effective experimental method to simulate the dynamic load of explosive explosion,and to carry out further research on the failure mechanism of brittle materials such as rocks under the explosion load,an experimental method of breaking rock and brittle materials by using wire electrical explosion to simulate explosive explosion is proposed.Experiments of metal wire electrical explosion simulating spherical charge and cylindrical charge breaking cement mortar specimens are designed and carried out.A description of the model and experimental procedures is presented.A high-speed camera is used to photograph the formation and propagation of cracks on the surface of the specimen,and a Rogowski coil is used to measure the electrical explosion current of the wire.The influence of charging voltage on the failure process of cement mortar specimens is investigated.The similarities and differences between electrical explosion load and explosive explosion load are analyzed,and the advantages of wire electrical explosion experimental method are also discussed.The results show that with the charge voltage increases,the peak current of the wire explosion increases,but the rising edge time of current remains the same.The wire electrical explosion can effectively break cement mortar specimens,and is an effective method to simulate the explosive explosion to break rock-like brittle materials with the advantages of safety,non-pollution,energy control,and repeatability.Meanwhile,the experimental results of simulating spherical charge and cylindrical charge show that compared with explosive explosion,the wire electrical explosion is dominated by shock wave,and the effect of blasting gas is negligible.At a voltage of 50 kV(energy 5.0 kJ),the peak electrical explosion pressure of a linear copper wire of 0.4 mm diameter and 100 mm length is 49.05 GPa.The metal wire has the characteristics of slender.By changing electrode diameter and length-diameter ratio of wire,the miniaturized spherical charge and cylindrical charge blasting model experiments with high geometric similarity to in situ blasting parameters can be conducted.