摘要
近年来,矿产资源的开采状态由露天转地下,由浅部转深部,在深部岩体的钻爆法施工中,地应力对爆破效果有显著影响。有关掏槽爆破机理和应用的研究主要是针对浅部地层中的巷道爆破施工,没有考虑地应力对爆破效果的作用。采用一种考虑爆破荷载下粉碎区能量耗散的改进型连续-非连续单元法(Continuum-Discontinuum Element Method,CDEM),基于二维平面应变模型,分别研究了普通直眼掏槽爆破和大空孔直眼掏槽爆破在不同地应力条件下的应力演化过程和破裂损伤特征。数值模拟结果表明,大空孔的存在增强了爆炸应力波的反射拉伸作用,削弱了地应力对爆炸裂纹扩展的抑制作用,促进了爆炸主裂纹的扩展,增加了掏槽爆破的分形损伤和损伤面积,提高了掏槽爆破的岩体破碎程度。双向等压地应力对爆炸裂纹的扩展有抑制作用,对径向爆炸裂纹的扩展尤为显著。较大的地应力削弱了孔间爆炸应力波的相互作用,相邻炮孔对爆炸主裂纹扩展的导向效应减弱。随着地应力的增加,爆炸裂纹的分形维数和分形损伤整体上呈逐渐减小的趋势,但是大空孔直眼掏槽爆破的裂隙区分形损伤和损伤面积均显著大于普通直眼掏槽爆破的裂隙区分形损伤和损伤面积。说明在高地应力环境下,大空孔直眼掏槽爆破依然能够显著增加岩石破碎程度和破碎范围,提高爆破效果和破碎效率。
In recent years,the mining state of mineral resources has changed from open air to underground and from shallow to deep.In the drilling and blasting construction of deep rock masses,in-situ stress has a significant impact on the blasting effect.An improved continuum-discontinuum element method(CDEM)considering energy dissipation in the crushing zone under blasting load is used to study the stress evolution process and rupture damage characteristics of ordinary straight hole cut blasting and large empty hole cut blasting under different in-situ stress conditions based on a two-dimensional plane strain model.The numerical results show that the existence of the large empty hole enhances the reflection and stretching effect of the explosion stress wave,weakens the inhibitory effect of the ground stress on the explosion crack expansion,promotes the expansion of the main explosion crack,increases the fractal damage and damage area of the trough blast,and improves the crushing degree of the rock mass of the trough blasting.The bi-directional isobaric in-situ stress has an inhibitory effect on the propagation of blast-induced cracks,especially on the propagation of radial cracks.The larger in-situ stress weakens the interaction of blasting stress waves between holes,and the guiding effect of adjacent holes on the propagation of the main crack is weakened.With the increase of in-situ stress,the fractal dimension and fractal damage of explosion crack decrease gradually on the whole,but the fissure differentiated damage and damage area of large empty hole blasting are significantly greater than the fissure differentiated damage and damage area of ordinary straight hole blasting.It shows that in the high in-situ stress environment,the large empty hole cut blasting can still significantly increase the rock crushing degree and crushing range and improve the blasting effect and crushing efficiency.
作者
丁晨曦
梁欣桐
杨仁树
郭啸
杨阳
周俊
朱心广
DING Chenxi;LIANG Xintong;YANG Renshu;GUO Xiao;YANG Yang;ZHOU Jun;ZHU Xinguang(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Mathematics and Physics,University of Science and Technology Beijing,Beijing 100083,China;Institute of Mechanics,Chinese Academy of Sciences,Beijing 100083,China)
出处
《煤炭科学技术》
EI
CAS
CSCD
北大核心
2024年第7期79-88,共10页
Coal Science and Technology
基金
国家自然科学基金资助项目(52204085)
北京市自然科学基金资助项目(8224086)
北京科技大学青年教师学科交叉研究资助项目(FRFIDRY-21-006)。
