爆破作用下低渗砂岩铀储层的岩石损伤范围研究

Research on rock damage range of low permeability sandstone uranium reservoir under blasting

爆破增渗方法可有效提升地浸采铀效率,而爆破范围是影响增渗效果的关键参数。为了研究低渗砂岩铀矿中爆破损伤范围分布特征和裂纹扩展规律,基于LS-DYNA软件,采用RHT材料模型,分析了不耦合系数K和地应力对砂岩爆破损伤区范围和裂纹扩展的影响规律。结果表明:随着不耦合系数K的增大、岩石的粉碎区半径逐渐减小,缩减至同炮孔半径近似;裂隙区裂纹呈现先增大、后稳定的分布规律,在K=1.75时取得了较好的爆破效果。随着地应力的增大,岩石的粉碎区形状和范围基本不发生变化,而裂隙区范围整体呈现先缩小后稳定的分布规律。研究对低渗砂岩铀矿爆破增渗中爆破范围的确定具有理论指导意义。

The blasting permeability enhancement method can effectively improve the efficiency of in-situ leaching and mining uranium,and the blasting range is the key parameter affecting the permeability enhancement effect.In order to study the distribution characteristics of blasting damage range and crack growth law in low-permeability sandstone uranium ore,based on LS-DYNA software and RHT material model,the influence law of uncoupling coefficient K and in-situ stress on blasting damage range and crack growth of sandstone was analyzed.The results show that with the increase of the decoupling coefficient K,the radius of the crushing zone of the rock decreases gradually,which is approximately the same as the radius of the hole.The crack distribution in the crack zone increases first and then stabilizes,and a good blasting effect is obtained at K=1.75.With the increase of ground stress,the shape and scope of the crushed zone of rock do not change basically,while the range of the fractured zone presents a general distribution law of decreasing first and then stabilizing.This study is of theoretical significance to the determination of blasting range in low permeability sandstone uranium mines.