基于地应力和二次损伤的预留光爆层爆破参数研究

对于地下开采，预留光爆层进行二次爆破可以保证巷道掘进面轮廓成形效果,减少围岩损伤。基于地应力、应力波和爆生气体等共同作用理论，对预留光爆层二次爆破进行参数优化。分析预留光爆层厚度对地应力重分布的影响以及二次应力对爆生裂纹扩展的影响，可知二次应力会抑制爆生裂纹扩展，且预留光爆层厚度与二次应力大小呈正相关；分析在不考虑损伤、考虑一次损伤和考虑二次损伤条件下，轴向不耦合系数及炮孔间距大小的变化，可知考虑损伤可以适当增大轴向不耦合系数和炮孔间距。以焦家金矿深部开采工程为背景，对比爆破参数优化前后爆破效果，可知在深部开采时考虑地应力和损伤，能提高半孔率和节约成本。研究结果为地下开采爆破标准化提供了理论依据。

Study on Blasting Parameters of Pre-reserved Smooth Blasting Layer Under In-situ Stress and Double Damage

For underground mining，the reserved blasting layer for secondary blasting can ensure the contouring effect of the roadway face and reduce the surrounding rock damage.When using the reserved photo-explosive layer for roadway blasting，the influence of the initial stress field redistribution on the blasting crack propagation，the damage of the inner ring blasting to the reserved photo-explosive layer，and the stress wave during the blasting of the photo-explosive layer should be considered.Based on the interaction theory of ground stress，stress wave and explosive gas，the parameters of the secondary blasting of the reserved photo-explosive layer are optimized.The influence of the thickness of the reserved photo-explosive layer on the redistribution of ground stress and the influence of the secondary stress on the crack propagation of the explosion are analyzed.It is known that the secondary stress will inhibit the crack propagation and the thickness of the photo-explosive layer and the secondary stress are positive correlation，therefore，in the construction of the project，the thickness of the photoburst layer should be reserved for the secondary blasting.The thickness of the blast layer should not be too large.The analysis should not consider the damage，consider one damage and consider the double damage conditions，the axial non-coupling coefficient and the blasthole.The change in the size of the gap makes it possible to appropriately increase the axial uncoupling coefficient and the blast hole spacing in consideration of the damage.Taking the deep mining project of Jiaojia gold mine as the background，compared with the blasting effect before and after the optimization of blasting parameters，it can be seen that considering the ground stress and damage in deep mining，the porosity and cost can be improved.The research results provide a theoretical basis for the standardization of underground mining blasting，which can provide reference for similar projects.