Abstract The depletion of shallow-buried reserves has been driving the exploitation activities into the deeper crust, and the rising lithostatic stress thus poses substantial challenges to dynamic rock breakage. In this paper, we present new mechanistic insights into the effects of in-situ stresses on blast responses of intact rocks via integrated analytical and numerical analyses. An elastodynamic framework was first developed to characterize the blast wave propagation in pre-stressed rocks. The analytical solution suggests that the rock pressure can essentially promote dynamic compaction by diverting the explosive loading path and suppress fracturing by imposing circumferential compression. Such effects are more pronounced in the minor principal stress (σ3) direction of anisotropic stress fields. The rock responses under the coupled static-dynamic loadings were then simulated using a constitutive framework that was proven valid in this study for broad spectrums of pressures and strain rates. Image processing of the breakage patterns shows that the crushed zone contracts as the rock pressure rises. The crushed zone becomes elliptic in anisotropic stress fields, and its major axis coincides with the major principal stress (σ1) direction and declines more slowly than the minor axis aligned with σ3. The orientation distribution shows quantitatively that fractures get increasingly more clustered around σ1 as stress anisotropy rises, and the fracture density decreases more rapidly in equibiaxial conditions with greater vertical stresses. The consistent insights of the analytical and numerical studies can improve the mechanistic understanding of the evolution of dynamic rock behavior in different in-situ stress conditions.

中文翻译：

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爆炸荷载作用下地应力对动态岩石响应的影响

摘要 浅埋储量的枯竭促使开采活动进入更深的地壳，不断上升的岩石静应力对动态岩石破碎提出了严峻挑战。在本文中，我们通过综合分析和数值分析，对原位应力对完整岩石爆炸响应的影响提出了新的力学见解。首先开发了一个弹性动力学框架来表征预应力岩石中的爆炸波传播。解析解表明，岩石压力可以通过改变爆炸加载路径来促进强夯，并通过施加周向压缩来抑制破裂。这种效应在各向异性应力场的次主应力 (σ3) 方向上更为明显。然后使用本构框架模拟静态-动力耦合载荷下的岩石响应，该框架在本研究中被证明适用于广泛的压力和应变率谱。破碎模式的图像处理表明，破碎区随着岩石压力的升高而收缩。压碎区在各向异性应力场中变为椭圆形，其长轴与主要主应力（σ1）方向重合，并且比与σ3对齐的短轴下降得更慢。取向分布定量表明，随着应力各向异性的增加，裂缝越来越集中在σ1附近，在垂直应力较大的等双轴条件下，裂缝密度下降得更快。