Electrical resistivity tomography is a non-destructive and efficient geophysical exploration method that can effectively reveal the geological structure and sliding surface characteristics inside landslide bodies. This is crucial for analyzing the stability of landslides and managing associated risks. This study focuses on the Lijiazu landslide in Zhuzhou City, Hunan Province, employing the electrical resistivity tomography method to detect effectively the surrounding area of the landslide. The resistivity data of the deep strata were obtained, and the corresponding geophysical characteristics are inverted. At the same time, combined with the existing drilling data, the electrical structure of the landslide body is discussed in detail. The inversion results reveal significant vertical variations in the landslide body’s resistivity, reflecting changes in rock and soil physical properties. Combined with geological data analysis, it can be concluded that the sliding surface is located in the sandy shale formation. Meanwhile, by integrating various geological data, we can conclude that the landslide is currently in a creeping stage. During the rainy season, with rainfall infiltration, the landslide will further develop, posing a risk of instability. It should be promptly addressed through appropriate remediation measures. Finally, based on the results of two-dimensional inversion, this article constructs a three-dimensional surface morphology of the landslide body, which can more intuitively compare and observe the internal structure and material composition of the landslide body. This also serves as a foundation for the subsequent management and stability assessment of landslides, while also paving the way for exploring new perspectives on the formation mechanisms and theories of landslides.

Rock fractures filled with cementation inevitably lead to rock mass heterogeneity and affect its mechanical properties. The cementation is usually regarded as a defect due to its strength is lower than that of the surrounding rock. To investigate the influence of the defect on fatigue damage and strength of the rock mass under cyclic loading, the defect area ratio was obtained and a series of static and cyclic loading uniaxial tests were carried out. The experimental results reveal that tensile failure with few secondary cracks occurs under static loading. However, microcracks are widely developed in the samples after cyclic loading, especially at the defect interface. The compressive strength decreases with increasing defect area ratio. During cyclic loading, the fatigue damage for samples with small defect area ratios (<10%) is similar to that of intact rock. However, multiple sudden increases in the residual strain and dissipation energy occur when the defect area ratio is greater than 10%. In addition, cumulative residual strain, cumulative acoustic emission (AE) count and cumulative dissipation energy increase with increasing defect area ratio. Cyclic loadings significantly reduce the rock mass strength, and the strength reduction increases with increasing defect area ratio. It is inferred that the incompatible deformation in the heterogeneous rock mass is the main reason for the sample damage and the strength reduction, and the unloading has an essential effect on the initiation, propagation and coalescence of microcracks.

The 2008 Wenchuan Ms 8.0 earthquake triggered the Daguangbao (DGB) landslide, of which the shear surface belongs to a thrust bedding fault 400 m below the carbonate slope. After the landslide, a 1.8 km-long inclined sliding face (0.3 km²) was exposed in the south source area. By using shaking table test, the contributions of the fault to the landslide sliding have been studied in this paper. The bedding fault in the test model is simplified as a weak layer with small elasticity and the carbonate layers as a hard layer with high elastic modulus, which is 296 times the weak one. The test records larger displacement amplitude in the upper hard layer than that in the lower one and larger pressure amplitude in the weak layer than that in the hard ones. We ascribed the stress amplification in the weak layer to time delay of shaking wave as wave velocity in the weak layer is only 1/15 of that in the hard layers. Such time delay gives rise to phase differences between the hard layers during shaking. The compressive stress amplification occurs in the weak layer when the upper hard layer moves downwards relative to the lower one; otherwise, tensile stress amplification occurs. It is suggested that this kind of stress amplification triggered an extensive fragmentation of the bedding fault rock mass during the Wenchuan earthquake, which can be verified by a good deal of gentle-dip and steep-dip cracks observed on site. It is proposed that stress amplification had caused a fast dropping of shear strength in the bedding fault to enhance the suddenness of DGB landslide initiation.