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The seismic sliding of rock masses is an important phenomenon that is widely involved in earthquake geological hazards. Practical seismic sliding is a three‐dimensional problem, namely, the seismic loads may act in any direction and the rock masses may move in an arbitrary direction relative to the sliding plane. In the present work, the functions of two different seismic loading methods, that is, loading as body force time histories to the sliders or as displacement time histories to the base, are added to the program of the three‐dimensional discontinuous deformation analysis (3D‐DDA) method that is based on the contact theory to study the seismic sliding of rock blocks. The theoretical solutions of single‐block sliding on an incline under the two seismic loading methods are derived. By comparing the 3D‐DDA results of single‐block seismic sliding with the corresponding theoretical results, and comparing the 3D‐DDA results of seismic sliding of three‐stacked‐blocks under the two seismic loading methods, the correctness of 3D‐DDA for seismic sliding simulations is validated. Thereafter, the influence of three‐dimensional seismic components on single‐block sliding, and the movement of block groups under different seismic load conditions are investigated by 3D‐DDA simulations, which indicate the importance to consider rock mass seismic sliding as a three‐dimensional problem and the capability of 3D‐DDA for its analysis. This work builds a meaningful basis for the further numerical simulation study on the earthquake‐induced rock mass movements by 3D‐DDA. [ABSTRACT FROM AUTHOR]

The crack initiation stress threshold ( σ ci ) is an essential parameter in the brittle failure process of rocks. In this paper, a volumetric strain response method (VSRM) is proposed to determine the σ ci based on two new concepts, i.e., the dilatancy resistance state index ( δ ci ) and the maximum value of the dilatancy resistance state index difference ( Δ δ ci ), which represent the state of dilatancy resistance of the rock and the shear sliding resistance capacity of the crack-like pores during the compressive period, respectively. The deviatoric stress corresponding to the maximum Δ δ ci is taken as the σ ci . We then examine the feasibility and validity of the VSRM using the experimental results. The results from the VSRM are also compared with those calculated by other strain-based methods, including the volumetric strain method (VSM), crack volumetric strain method (CVSM), lateral strain method (LSM) and lateral strain response method (LSRM). Compared with the other methods, the VSRM is effective and reduces subjectivity when determining the σ ci . Finally, with the help of the proposed VSRM, influences from chemical corrosion and confining stress on the σ ci and Δ δ ci of the carbonate rock are analyzed. This study provides a subjective and practical method for determining σ ci . Moreover, it sheds light on the effects of confinement and chemical corrosion on σ ci . Highlights: A volumetric strain response method (VSRM) is proposed to determine the crack initiation stress threshold from the volumetric strain curve. Two novel parameters, i.e., the dilatancy resistance state index and the maximum dilatancy resistance state index difference, are proposed to help the VRSM determine σ ci . Rock's compressive stage is divided into two stages: the interlocking stage and the shear sliding stage. The crack initiation stress threshold divides these two stages. Relationships between the crack initiation stress threshold and rock's mechanical properties (i.e., Young's modulus, Poisson's ratio, mobilized cohesion and friction angle) are analyzed. [ABSTRACT FROM AUTHOR]

Understanding the mechanical behaviour of jointed rock during seismic events is crucial for ensuring the stability of rock engineering. A series of uniaxial compression tests were conducted on granite specimens containing a persistent joint at strain rates (10−5–0.05/s). Acoustic emissions (AEs) were monitored to detect the rock fracturing, and the strain field on the specimen surface was measured by the digital image correlation technique. Three failure patterns of specimens were observed: rock splitting, joint slipping and mixed rock splitting–joint slipping. The shapes of typical strain–stress curves for the three patterns are different, but they are all characterised by multiple stress drops indicating significant rock fractures. When significant fractures occur, the frequency range of AEs expends and the dominant frequency of AEs becomes much larger. The specimen strength is affected by the strain rate, but this effect differs for different failure patterns of specimens. The joint inclination could influence the mode and profile of fractures near the joint, and the specimen strength and joint stiffness significantly decrease with increasing joint angle. This study could help better understand the behaviour of jointed rocks subjected to seismic loads. [ABSTRACT FROM AUTHOR]