Bedding parallel stepped rock slopes exist widely in nature and are used in slope engineering. They are characterized by complex topography and geological structure and are vulnerable to shattering under strong earthquakes. However, no previous studies have assessed the mechanisms underlying seismic failure in rock slopes. In this study, large-scale shaking table tests and numerical simulations were conducted to delineate the seismic failure mechanism in terms of acceleration, displacement, and earth pressure responses combined with shattering failure phenomena. The results reveal that acceleration response mutations usually occur within weak interlayers owing to their inferior performance, and these mutations may transform into potential sliding surfaces, thereby intensifying the nonlinear seismic response characteristics. Cumulative permanent displacements at the internal corners of the berms can induce quasi-rigid displacements at the external corners, leading to greater permanent displacements at the internal corners. Therefore, the internal corners are identified as the most susceptible parts of the slope. In addition, the concept of baseline offset was utilized to explain the mechanism of earth pressure responses, and the result indicates that residual earth pressures at the internal corners play a dominant role in causing deformation or shattering damage. Four evolutionary deformation phases characterize the processes of seismic responses and shattering failure of the bedding parallel stepped rock slope, i.e. the formation of tensile cracks at the internal corners of the berm, expansion of tensile cracks and bedding surface dislocation, development of vertical tensile cracks at the rear edge, and rock mass slipping leading to slope instability. Overall, this study provides a scientific basis for the seismic design of engineering slopes and offers valuable insights for further studies on preventing seismic disasters in bedding parallel stepped rock slopes. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Earthquakes contribute to the failure of anti-dip bedding rock slopes (ABRSs) in seismically active regions. The pseudo-static method is commonly employed to assess the ABRSs stability. However, simplifying seismic effects as static loads often underestimates rock slope stability. The development of a practical stability analysis approach for ABRSs, particularly in slope engineering design, is imperative. This study proposes a stability evaluation model for ABRSs, incorporating the viscoelastic properties of rock, to quantitatively assess the safety factor and failure surface under seismic conditions. The mathematical description of the pseudo-dynamic method, derived in this study, accounts for the viscoelastic properties of ABRSs and integrates the Hoek-Brown failure criterion with the Kelvin-Voigt stress-strain relationship of rocks. Furthermore, to address concurrent translation-rotation failure in ABRSs, upper bound limit analysis is utilized to quantify the safety factor. Through a comparison with existing literature, the proposed method considers the effect of harmonic vibration on the stability of ABRSs. The obtained safety factor is lower than that of the quasi-static method, with the resulting percentage change exceeding 5%. The critical failure surface demonstrates superior positional accuracy compared to the Aydan and Adhikary basal planes, with minimal error observed between the physical model test and the numerical simulation test. The parameter sensitivity analysis reveals that the inclination of ABRSs exhibits the highest sensitivity (Sk) value across the three levels of horizontal seismic coefficient (kh). The study aims to devise an expeditious calculation approach for assessing the stability of ABRSs during seismic events, intending to offer theoretical guidance for their stability analysis. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

Toppling failure of rock mass/soil slope is an important geological and environmental problem. Clarifying its failure mechanism under different conditions has great significance in engineering. The toppling failure of a cutting slope occurred in a hydropower station in Kyushu, Japan illustrates that the joint characteristic played a significant role in the occurrence of rock slope tipping failure. Thus, in order to consider the mechanical properties of jointed rock mass and the influence of geometric conditions, a simplified analytical approach based on the limit equilibrium method for modeling the flexural toppling of cut rock slopes is proposed to consider the influence of the mechanical properties and geometry condition of jointed rock mass. The theoretical solution is compared with the numerical solution taking Kyushu Hydropower Station in Japan as one case, and it is found that the theoretical solution obtained by the simplified analysis method is consistent with the numerical analytical solution, thus verifying the accuracy of the simplified method. Meanwhile, the Goodman-Bray approach conventionally used in engineering practice is improved according to the analytical results. The results show that the allowable slope angle may be obtained by the improved Goodman-Bray approach considering the joint spacing, the joint frictional angle and the tensile strength of rock mass together.

Reservoir-induced earthquakes (RIEs) occur frequently in the Three Gorges Reservoir Area (TGRA) and the rock mass strength of the hydro-fluctuation belt (HFB) deteriorates severely due to the reservoir-induced seismic loads. Three models of typical bedded rock slopes (BRSs), i.e. gently (GIS), moderately (MIS), and steeply (SIS) inclined slopes, were proposed according to field investigations. The dynamic response mechanism and stability of the BRSs, affected by the rock mass deterioration of the HFB, were investigated by the shaking table test and the universal distinct element code (UDEC) simulation. Specifically, the amplification coefficient of the peak ground acceleration (PGA) of the slope was gradually attenuated under multiple seismic loads, and the acceleration response showed obvious surface effect and elevation effect in the horizontal and vertical directions, respectively. The S-type cubic function and steep-rise type exponential function were used to characterize the cumulative damage evolution of the slope caused by microseismic waves (low seismic waves) and high seismic waves, respectively. According to the dynamic responses of the acceleration, cumulative displacement, rock pressure, pore water pressure, damping ratio, natural frequency, stability coefficient, and sliding velocity of the slope, the typical evolution processes of the dynamic cumulative damage and instability failure of the slope were generalized, and the numerical and experimental results were compared. Considering the dynamic effects of the slope height (SH), slope angle (SA), bedding plane thickness (BPT), dip angle of the bedding plane (DABP), dynamic load amplitude (DLA), dynamic load frequency (DLF), height of water level of the hydro-fluctuation belt (HWLHFB), degradation range of the hydro-fluctuation belt (DRHFB), and degradation shape of the hydro-fluctuation belt (DSHFB), the sensitivity of factors influencing the slope dynamic stability using the orthogonal analysis method (OAM) was DLA > DRHFB > SA > SH > DLF > HWLHFB > DSHFB > DABP > BPT. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Freeze-thaw failure of frozen rock slope often occurs during engineering construction and mining in cold area, which poses a great threat to engineering construction and people's life safety. The properties of rock mass in cold region will change with the periodic change of temperature, which makes it difficult to accurately evaluate the stability of slope under the action of freeze-thaw cycle by conventional methods. Based on field investigation and literature review, this paper discusses the characteristics of frozen rock mass and the failure mechanism of frozen rock slope, and gives the types and failure modes of frozen rock slope. Then, the research status of frozen rock slope is analyzed. It is pointed out that the failure of frozen rock slope is the result of thermo-hydro-mechanical (THM) coupling. It is considered that freeze-thaw cycle, rainfall infiltration and fracture propagation have significant effects on the stability of frozen rock slope, and numerical simulation is used to demonstrate. The research shows that the safety factor of frozen rock slope changes dynamically with the surface temperature, and the safety factor of slope decreases year by year with the increase of freeze-thaw cycles, and the fracture expansion will significantly reduce the safety factor. Based on the above knowledge, a time-varying evaluation method of frozen rock slope stability based on THM coupling theory is proposed. This paper can deepen scholars' understanding of rock fracture slope in cold area and promote related research work.

The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses, as well as the hydrodynamic properties of fractured rock masses. The conventional measurement methods are inadequate for collecting data on high-steep rock slopes in complex mountainous regions. This study establishes a high -resolution three-dimensional model of a rock slope using unmanned aerial vehicle (UAV) multi-angle nap-of-the-object photogrammetry to obtain edge feature points of fractures. Fracture opening morphology is characterized using coordinate projection and transformation. Fracture central axis is determined using vertical measuring lines, allowing for the interpretation of aperture of adaptive fracture shape. The feasibility and reliability of the new method are verified at a construction site of a railway in southeast Tibet, China. The study shows that the fracture aperture has a significant interval effect and size effect. The optimal sampling length for fractures is approximately 0.5-1 m, and the optimal aperture interpretation results can be achieved when the measuring line spacing is 1% of the sampling length. Tensile fractures in the study area generally have larger apertures than shear fractures, and their tendency to increase with slope height is also greater than that of shear fractures. The aperture of tensile fractures is generally positively correlated with their trace length, while the correlation between the aperture of shear fractures and their trace length appears to be weak. Fractures of different orientations exhibit certain differences in their distribution of aperture, but generally follow the forms of normal, log -normal, and gamma distributions. This study provides essential data support for rock and slope stability evaluation, which is of significant practical importance. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

The instability of geological slopes in mining environments poses a significant challenge to the safety and efficiency of operations. Waste Dump#2 at the Ziluoyi Iron Mine in China is a notable case study that highlights the challenges associated with sizable base slopes and large step heights. To address hidden hazards in the mine and the above issues, an inclusive investigation is carried out to examine the physical and mechanical properties of the soil-rock slope through indoor testing and analyze the deformation mechanisms of the slope using numerical simulations, taking various factors into account. The study reveals that the stability of Waste Dump#2 is deeply affected by weight, groundwater conditions, earthquake loading, and rainfall. To this end, the cohesion and internal friction parameters of the soil-rock slope are first determined through direct shear tests, which show a cohesion of 6.215 kPa at the top of the slope and an internal friction angle of 34.12 degrees. By adopting GEO-SLOPE, 3D Mine, and AutoCAD software, stability calculations of the slope are performed, which give stability coefficients of 1.547 under normal conditions, 1.276 in rainfall, and 1.352 in seismic conditions. These results meet safety standards and ensure the safe and efficient operation of the mine.

In deglaciating environments, rock mass weakening and potential formation of rock slope instabilities is driven by long-term and seasonal changes in thermal- and hydraulic- boundary conditions, combined with unloading due to ice melting. However, in-situ observations are rare. In this study, we present new monitoring data from three highly instrumented boreholes, and numerical simulations to investigate rock slope temperature evolution and micrometer-scale deformation during deglaciation. Our results show that the subsurface temperatures are adjusting to a new, warmer surface temperature following ice retreat. Heat conduction is identified as the dominant heat transfer process at sites with intact rock. Observed non-conductive processes are related to groundwater exchange with cold subglacial water, snowmelt infiltration, or creek water infiltration. Our strain data shows that annual surface temperature cycles cause thermoelastic deformation that dominate the strain signals in the shallow thermally active layer at our stable rock slope locations. At deeper sensors, reversible strain signals correlating with pore pressure fluctuations dominate. Irreversible deformation, which we relate with progressive rock mass damage, occurs as short-term (hours to weeks) strain events and as slower, continuous strain trends. The majority of the short-term irreversible strain events coincides with precipitation events or pore pressure changes. Longer-term trends in the strain time series and a minority of short-term strain events cannot directly be related to any of the investigated drivers. We propose that the observed increased damage accumulation close to the glacier margin can significantly contribute to the long-term formation of paraglacial rock slope instabilities during multiple glacial cycles.