水泥浆封堵深孔预裂爆破合理封堵长度

针对深孔预裂爆破装药量大,传统炮泥封堵易发生“冲孔”的问题,提出以水泥浆为封堵材料,并对其合理封堵长度进行研究。基于水泥浆性能,假设凝固后的水泥浆与岩石为同一材料,阐述水泥浆封堵炮孔的作用机理；根据Starfield迭加法的基本思想,建立柱状药包等效多个球状药包计算模型,探究球状药包应力波衰减规律,计算球状药包在自由面的迭加拉应力；基于减弱爆破漏斗理论,以迭加拉应力与岩石抗拉强度相等为原则,推导封堵长度取值公式；利用数值模拟,分析了不同封堵长度下爆破后应力波的扩散范围与岩石的破碎范围；以新巨龙煤矿2302N工作面爆破法过大落差断层为背景,进行现场试验,借助钻孔成像仪观测炮孔周边岩层破碎情况。结合理论计算、数值模拟及现场试验确定水泥浆封堵长度为2.5 m。

Study on Reasonable Plugging Length of Cement Slurry for Deep Hole Pre-splitting Blasting

Aiming at the problem of large charge in deep hole pre-splitting blasting and easy punching in traditional gun mud, the cement slurry is proposed as the sealing material, and the reasonable sealing length is studied. Based on the properties of cement slurry, it is assumed that cement slurry and rock are the same material after solidification, and the mechanism of cement slurry sealing gun hole is expounded. Based on the basic idea of superposition in Starfield, the calculation model of cylindrical charge packages equivalent to multiple spherical charge packages is established, the attenuation rule of stress wave of spherical charge packages is explored, and the stress of spherical charge packages on free surface is calculated. Based on the theory of weakening blasting funnel, the formula for determining the sealing length is derived based on the principle that the stress of jiajara is equal to the tensile strength of rock. Using numerical simulation, the propagation of stress wave after blasting is analyzed, and the fracture range of rock in the inwards area of the orifice is analyzed. Taking the oversized drop fault of 2302N working face blasting method in xinjulong coal mine as the background, combining with theoretical calculation, numerical simulation and field test, the cement slurry sealing length is determined to be 2.5m.