关键词: 岩体爆破　, 偏心不耦合装药结构　, 裂隙范围　, 理论模型　, 数值模拟

Abstract: During rock mass blasting excavation,the surrounding rock near the blasthole is highly susceptible to disturb ances,leading to water inrush and surrounding rock collapse.Most existing theories are based on concentric charging,which as sumes that the explosive cartridge is centered within the blasthole.However,due to gravity,the decoupled charge structure often results in an offset of the cartridge center.Continuing to adopt the concentric blasting theory under such conditions deviates from actual engineering practice.The use of concentric charging theory for radially eccentric decoupled charge structures often leads to overbreak or underbreak of the rock mass,and in severe cases,may cause collapse of the peripheral rock mass of the primary support,posing significant safety hazards.Considering the combined effects of radial compressive stress and circumfer ential tensile stress during the crushing and cracking processes of the surrounding rock,the fracture propagation range of the rock mass under eccentric decoupled charging is derived.Furthermore,a comparative analysis and validation are conducted u sing existing theory and a three-dimensional numerical test model for single-hole decoupled blasting,established based on the Johnson-Holmquist-Ⅱ (JH-2) constitutive model for rock materials.The results show that the proposed method agrees well with existing theoretical and numerical simulation results for the fracture radius,thereby validating its effectiveness.The eccen tric fracture distribution effect of eccentric decoupled charging decreases as the cartridge diameter increases.The stress eccen tric distribution follows a trend consistent with that of the fracture eccentric distribution,but it is mainly observed in the early stage of blasting (t≤400 μs),while the stress eccentricity significantly diminishes in the later stage (t>400 μs).The pro posed method can effectively evaluate the eccentric distribution range of rock mass fracturing induced by blasting and provide theoretical guidance for the design of blasthole patterns.