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Calculating rockslide movement and deposit characteristics is challenging due to the complex interactions of various physical factors. This study investigates the effects of rockslide volume, slope angle, and material strength on fragmentation and deposit patterns through laboratory experiments using homogeneous and non-homogeneous specimens. Specimens were tested on sloping chutes at angles of 41.5°, 45.1° and 48.6°. Results showed that increasing the chute angle led to a reduction in specimen completeness. Specifically, as the chute angle increased from 41.5° to 45.1°, the completeness for specimens with heights of 5 cm, 10 cm, and 15 cm decreased by approximately 29.6%, 7.4%, and 32.8%, respectively, with the largest specimen showing the most significant reduction. For non-homogeneous specimens, strength differences between the upper and lower layers significantly influenced fragmentation; a lower-strength bottom layer resulted in increased fragmentation and longer leading-edge distances. A dimensionless parameter Ψ , defined as the ratio of the largest fragment’s travel distance to the farthest debris, to quantify the relationship between fragment travel distance and flow mobility in rockslides. The results demonstrated a positive linear correlation between Ψ and specimen completeness. Greater completeness is associated with larger fragment travel distances. Additionally, a logarithmic correlation was found between Ψ and the apparent friction coefficient, reinforcing the relationship between fragmentation behavior and the potential risk of rockslide events. These findings offer predictive models for assessing rockslide risks based on slope angle, rockslide volume, and apparent friction coefficient. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical effects of vegetation, both root reinforcement and trees’ weight, on slope stability using the Morgenstern–Price method. Root reinforcement was equivalently expressed as root additional cohesion, which varied upon vegetation type and the depth of the root zone. The gravity of trees was simplified as a uniformly distributed load on the slope surface. Three types of variables, including vegetation type, slope geometry, and soil type, were considered. Parametric analysis shows that the response of the factor of safety (FoS) of slopes with different soil textures to the mechanical effects of vegetation significantly differs. The mature forest-covered sand slope with the smallest length and the lowest slope angle exhibits the largest increase in FoS of 34.3% relative to the plain soil slope. With the same configuration, the relative improvement in FoS of silt slopes is only 1/8 to 1/4 of that of sand slopes. The stability enhancement for clay slopes by vegetation is very limited (< 1.5%), and in certain situations, the stability even decreases. Moreover, we find that the Morgenstern–Price method can accurately estimate the additional destabilizing and stabilizing forces due to the mechanical effects, which allows its contribution to the improved FoS to be quantitatively divided into three components: additional cohesion from root system, trees’ surcharge, and variation in depth of slip surface. Generally, the findings of this paper deepen the understanding of the mechanical effects of vegetation on soil slope stability and provide a baseline for future eco-geotechnical engineering design. [ABSTRACT FROM AUTHOR]

Calculating rockslide movement and deposit characteristics is challenging due to the complex interactions of various physical factors. This study investigates the effects of rockslide volume, slope angle, and material strength on fragmentation and deposit patterns through laboratory experiments using homogeneous and non-homogeneous specimens. Specimens were tested on sloping chutes at angles of 41.5°, 45.1° and 48.6°. Results showed that increasing the chute angle led to a reduction in specimen completeness. Specifically, as the chute angle increased from 41.5° to 45.1°, the completeness for specimens with heights of 5 cm, 10 cm, and 15 cm decreased by approximately 29.6%, 7.4%, and 32.8%, respectively, with the largest specimen showing the most significant reduction. For non-homogeneous specimens, strength differences between the upper and lower layers significantly influenced fragmentation; a lower-strength bottom layer resulted in increased fragmentation and longer leading-edge distances. A dimensionless parameter Ψ , defined as the ratio of the largest fragment’s travel distance to the farthest debris, to quantify the relationship between fragment travel distance and flow mobility in rockslides. The results demonstrated a positive linear correlation between Ψ and specimen completeness. Greater completeness is associated with larger fragment travel distances. Additionally, a logarithmic correlation was found between Ψ and the apparent friction coefficient, reinforcing the relationship between fragmentation behavior and the potential risk of rockslide events. These findings offer predictive models for assessing rockslide risks based on slope angle, rockslide volume, and apparent friction coefficient. [ABSTRACT FROM AUTHOR]

Post-landslide high slopes have always been at increased risk for rockfall disasters, posing a considerable threat to the slope toe area and making it very difficult to manage. In this paper, a comprehensive rockfall hazard assessment strategy based on high-resolution terrestrial laser scanning is proposed. A high-resolution digital terrain model was obtained based on terrestrial laser scanning (TLS) and data processing. Combined with a three-dimensional (3D) probabilistic model, the movement of rock blocks is simulated, and the mechanical parameters for simulation are corrected by 3D back analysis. Finally, based on hierarchical analysis process (AHP) and raster calculation, a rockfall hazard map can be obtained. The method was applied to analyze rockfall hazards on the post-landslide rock slope in Ganluo County. It was found that the rockfall hazard of the post-landslide slope is a great threat to the personnel and equipment of the emergency rescue at the site, and its long-term rockfall risk is also a big hidden danger to the railway at the foot of the slope. The planned 3 m high and 1500 kJ energy capacity protection net has 87.22% interception efficiency, but it is difficult to stop the falling rocks with high speed or high bouncing height. According to the characteristics of rockfall hazards, recommendations for rockfall hazard mitigation measures are proposed, including two aspects of rockfall source area remediation and rockfall transport path blocking. The case of rockfall hazard assessment in Ganluo County provides new methods and ideas for the management of rockfall hazard on post-landslide rock slopes. [ABSTRACT FROM AUTHOR]

Landslide dams formed by successive rock slides in the same location may cause severe and long-term destruction to affected areas. However, studies on the formation of landslide dams that result from successive rock slides are still at early stages. In this paper, a flume test that could model rock fragmentation and the flow of fragmentary material is used to study the formation of landslide dams triggered by successive long-runout rock slides. The tests assess the effects of number of blocks, the number of times the blocks are released, and the initial arrangement of blocks before release on the dam geometry. The maximum and minimum landslide dam heights rise with the increasing number of blocks in each series of tests, while there is minimal or even no growth in the dam length for some series. Additionally, more block releases produce larger minimum dam height but smaller maximum dam height. Together, these results indicate that more releases are prone to fully block the flow channel by forming a steep dam. Furthermore, the initial block arrangement is also found to influence the landslide dam formation. In this study, landslide dams caused by successive rock slides are divided into two types: the stable type, namely, the landslide dam(s) already formed by the previous slide event(s) maintains general stability before the next slide lands on the dam surface; the unstable type, namely, the landslide dam(s) by the previous slide episode(s) has failed before the next damming slide occurs. Field investigations showed that slide episodes in both types of successive landslide dams are influential for the dam formation and river morphology. [ABSTRACT FROM AUTHOR]