深部岩体爆破开挖围岩动态破坏机理研究

Study on the dynamic failure mechanism of surrounding rock under deep rock blasting excavation

为了揭示高地应力下爆破开挖损伤区(EDZ)形成机理,建立了非均匀应力场条件下深部岩体爆破开挖卸荷数学模型,并利用模态分解和拉普拉斯变换获得不同应力环境中爆破开挖围岩的应力重分布解析解。结合有限元数值模拟,采用Hoek-Brown准则确定岩体强度参数,揭示了爆破加载和初始应力卸载对EDZ形成的定量化贡献。结果表明:爆破加载与初始应力卸载以及产生的次生应力在弹性阶段线性叠加。在浅部较低应力环境下,爆破加载是EDZ形成的主导因素。随着应力的增加,初始应力状态对EDZ的影响更加显著,而爆破加载是高度损伤区(HDZ)形成的主要因素。

To reveal the formation mechanism of the Excavation Damage Zone(EDZ)under high in-situ stress,a mathematical model was established for deep rock blasting excavation unloading under a non-uniform stress field.Modal decomposition and Laplace transform were utilized to obtain the analytical solutions for stress redistribution of surrounding rock under blasting excavation in different stress environments.Combined with finite element numerical simulation,the strength parameters of the rock mass were determined using the Hoek-Brown criterion,and the quantitative contributions of blasting load and initial stress unloading to the formation of the EDZ were further elucidated.The results indicate that the blasting load and the initial stress unloading,along with the secondary stresses they generate,linearly superimpose in the elastic stage.In shallow,lower-stress environments,the blasting load is the dominant factor in the formation of the EDZ.As the stress increases,the initial stress state has a more significant impact on the EDZ,while the blasting load is the primary factor in the formation of the Highly Damaged Zone(HDZ).