The radial (minimum) stress of the near-boundary rockmass in deep excavations plays a key role in inducing rock failures such as spalling and strainbursts. In this study, a strainburst is treated as a structural failure of the near-boundary rockmass. The influence of the radial stress acting asymmetrically on one boundary surface of the burst volume on strainbursts is numerically investigated using a 3D bonded block distinct element method (DEM). The 3D DEM model for simulating the overall process of strainbursts is introduced and its effectiveness is verified by comparing with the analogous true triaxial experiments. Then based on the simulation results, the influence of radial stress on strainbursts is studied from the perspectives of deformation and strength characteristics, fracturing process, crack development, failure mode and energy balance. In addition, discussions of the mechanisms of the influence of radial stress on strainbursts are presented from the perspectives of fracture mechanics and a graphical explanation. Results show that, as the radial stress increases, the strength of the strainburst sample exhibits a quadratic law that increases first and then decreases, the number of shear cracks increases remarkably, the degree of accumulated rock damage precedes burst is getting higher and higher, the failure mode of strainbursts transforms gradually from a tensile-type to a shear-type, and the kinetic energy is getting higher and higher. The fundamental influence of radial stress on strainbursts is concluded as its suppression effect on the tensile failure mechanism of brittle rocks.

深基坑中近边界岩体的径向（最小）应力在引起岩石破裂（例如剥落和应变爆裂）中起关键作用。在这项研究中，应变爆裂被视为近边界岩体的结构破坏。使用3D键合块体离散元方法（DEM）数值研究了径向应力非对称地作用在爆裂体积的一个边界面上对应力爆裂的影响。介绍了用于模拟应变爆炸整个过程的3D DEM模型，并通过与类似的真实三轴实验进行比较验证了其有效性。然后基于模拟结果，从变形和强度特性，断裂过程，裂纹发展，破坏模式和能量平衡的角度研究了径向应力对应变破裂的影响。此外，还从断裂力学和图形解释的角度讨论了径向应力对应变破裂的影响机理。结果表明，随着径向应力的增加，应变爆裂样品的强度呈现出先增大后减小的二次规律，剪切裂纹的数量显着增加，爆破前的累积岩石破坏程度越来越高，应变破裂的破坏模式逐渐从拉伸型转变为剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。从断裂力学和图形解释的角度讨论了径向应力对应变破裂的影响机理。结果表明，随着径向应力的增加，应变爆裂样品的强度呈现出先增大后减小的二次规律，剪切裂纹的数量显着增加，爆破前的累积岩石破坏程度越来越高，应变破裂的破坏模式逐渐从拉伸型转变为剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。从断裂力学和图形解释的角度讨论了径向应力对应变破裂的影响机理。结果表明，随着径向应力的增加，应变爆裂样品的强度呈现出先增大后减小的二次规律，剪切裂纹的数量显着增加，爆破前的累积岩石破坏程度越来越高，应变破裂的破坏模式逐渐从拉伸型转变为剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。随着径向应力的增加，应变爆裂样品的强度呈现出先增大然后减小的二次律，剪切裂纹的数量显着增加，在爆破前累积的岩石损伤程度越来越高，应变爆破的破坏方式从拉伸型逐渐变成剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。随着径向应力的增加，应变爆裂样品的强度呈现出先增大然后减小的二次律，剪切裂纹的数量显着增加，在爆破前累积的岩石损伤程度越来越高，应变爆破的破坏方式从拉伸型逐渐变成剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。应变破裂的破坏模式逐渐由拉伸型转变为剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。应变破裂的破坏模式逐渐由拉伸型转变为剪切型，动能越来越高。径向应力对应变破裂的基本影响可以归结为其对脆性岩石拉伸破坏机理的抑制作用。