Conjugate flaws widely exist in rock masses and play a significant role in their deformation and strength properties. Understanding the mechanical behaviors of rock masses containing conjugate flaws is conducive to rock engineering stability assessment and the related supporting design. This study experimentally investigates the mechanical properties of conjugate-flawed sandstone specimens under coupled static–dynamic compression, thereby providing insight into how conjugate fractures interact to produce tracing tensional joints. Results indicate that the coupled compressive strength and the dynamic elastic modulus of conjugate-flawed rock specimens show remarkable loading rate dependence. For a fixed strain rate, the specimen with a static pre-stress equal to 60% of its uniaxial compressive strength has the highest coupled strength. Besides, both higher static pre-stress and strain rate can induce smaller mean fragment size and greater fractal dimension of the specimen, corresponding to a more uniform distribution of the broken fragments with smaller sizes. When the static pre-stress is lower than 80%UCS, the flawed specimen under a higher strain rate is characterized by higher absorbed energy. However, when the pre-stress equals 80%UCS, the value of the energy absorbed by the specimen in the dynamic loading process is negative due to the release of the preexisting considerable elastic strain energy input from the static pre-loading. As for the failure modes, cracks always penetrate the preexisting ipsilateral flaw tips to form anti-wing cracks. Under dynamic loading, the conjugate-flawed specimen generally shows tensile failure at a low strain rate, while the shear failure dominates at a high strain rate. In addition, based on progressive failure processes of the conjugate-flawed rock specimens, the evolution of tracing tensional joints in the field is discussed.

共轭缺陷广泛存在于岩体中，对岩体的变形和强度特性起着重要作用。了解含共轭缺陷岩体的力学行为，有利于岩石工程稳定性评估及相关支护设计。本研究通过实验研究了在静态-动态耦合压缩下共轭缺陷砂岩试样的力学性能，从而深入了解共轭裂缝如何相互作用以产生跟踪拉伸接头。结果表明，共轭缺陷岩石试样的压缩强度和动态弹性模量的耦合表现出显着的加载速率依赖性。对于固定应变率，静态预应力等于其单轴抗压强度 60% 的试样具有最高的耦合强度。除了，较高的静态预应力和应变率都可以导致试样的平均碎片尺寸更小，分形维数更大，对应于尺寸更小的破碎碎片更均匀的分布。当静态预应力低于 80%UCS 时，在较高应变率下的缺陷试样具有较高的吸收能。然而，当预应力等于 80%UCS 时，由于静态预加载释放了预先存在的相当大的弹性应变能输入，试件在动态加载过程中吸收的能量值为负。至于失效模式，裂纹总是穿透先前存在的同侧裂纹尖端形成反翼裂纹。在动态载荷下，共轭缺陷试样通常在低应变率下表现出拉伸破坏，而剪切破坏在高应变率下占主导地位。此外，基于共轭缺陷岩石试样的渐进破坏过程，讨论了现场跟踪拉伸节理的演变。