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The construction of major hydropower projects globally is challenged by slope deformation in reservoir areas. The deformation and failure mechanisms of large rock slopes are complex and poorly understood, making prevention and management extremely challenging. In order to explore the influence mechanism of the water level variation on the deformation of steep toppling bedding rock slopes, this paper takes the right bank slope near the dam area of the Longtou Hydropower Station as an example, and field investigations, deformation monitoring, physical simulation tests and numerical analyses are carried out. It is found that the slope deformation response is obvious under the influence of the reservoir water level variation, which is mainly reflected in the change in the slope groundwater level, rock mechanical parameters and seepage field in the slope body. The toe of the slope produces plastic deformation and maximum displacement. With the increase in the reservoir water level, the plastic zone expands and the displacement increases, which leads to the intensification of the slope deformation. This paper puts forward that the deformation and failure modes of the steep and toppling bedding rock slope caused by water level variation are due to shear dislocation, bending deformation and toppling fracture. This study reveals the influence mechanism of the water level variation on the deformation of steep and toppling bedding rock slopes, which can provide theoretical support for the construction of major hydropower projects. [ABSTRACT FROM AUTHOR]

Three-section landslides are renowned for their immense size, concealed development process, and devastating impact. This study conducted physical model tests to simulate one special geological structure called a three-section-within landslide. The failure process and precursory characteristics of the tested samples were meticulously analyzed using video imagery, micro-seismic (MS) signals, and acoustic emission (AE) signals, with a focus on event activity, intensity, and frequency. A novel classification method based on AE waveform characteristics was proposed, categorizing AE signals into burst signals and continuous signals. The findings reveal distinct differences in the evolution of these signals. Burst signals appeared exclusively during the crack propagation and failure stages. During these stages, the cumulative AE hits of burst signals increased gradually, with amplitude rising and then declining. High-amplitude burst signals were predominantly distributed in the middle- and high-frequency bands. In contrast, cumulative AE hits of continuous signals escalated rapidly, with amplitude monotonously increasing, and high-amplitude continuous signals were primarily distributed in the low-frequency band. The emergence of burst signals and high-frequency AE signals indicated the generation of microcracks, serving as early-warning indicators. Notably, the early-warning points of AE signals were detected earlier than those of video imagery and MS signals. Furthermore, the early-warning point of burst signals occurred earlier than those of continuous signals, and the early-warning point of the classification method preceded that of overall AE signals. [ABSTRACT FROM AUTHOR]

ABSTRACT Investigating the effect of wet‐dry (W‐D) cycling on loading–unloading damage is crucial for ensuring the stability of granite slopes in mountainous areas prone to strong earthquakes. This study conducted a series of W‐D cycling and loading–unloading tests on granite samples, complemented by weight measurements, wave velocity assessments, and nuclear magnetic resonance (NMR) tests on samples subjected to W‐D cycling. The results indicated that W‐D cycling reduced the mechanical properties of granite and increased the irreversible strain, dissipated energy, and number of acoustic emission (AE) counts during loading–unloading. The increase in the number of W‐D cycles led to a significant rise in the number of small‐scale, intergranular, and transgranular microcracks and the gradual formation of middle‐scale and large‐scale microcracks. W‐D cycling weakened the granite because of crystal expansion and contraction as well as mineral dissolution, whereas loading–unloading damaged the granite through inconsistent deformation resulting from the varying hardness of different minerals. This study provides a foundation for understanding the formation mechanism of seismically cracked slopes under the combined effects of rainfall and earthquakes. [ABSTRACT FROM AUTHOR]