On May 1, 2024, a small embankment collapse occurred in the early hours of the morning on the Meida Highway in Meizhou City, Guangdong Province, resulting in 48 fatalities. The small-scale collapse caused massive casualties and garnered widespread attention. In detail, there is a significant lack of precipitation at the time of the 51 Meida collapse disaster, lagging 10 h behind the peak precipitation. The collapse occurs on a mountainous slope, with a hollow catchment area located above the embankment. Multiple potential streams converge in the area, contributing to the water flow towards the slope. Within the western zone of the Lianhua Mountain fault, the collapse area is crossed by fault lines at approximately 800 m on the upper side and 650 m on the lower side. Bedrock fractures formed by faults act as water conduits. The combination of catchment topography and potential faults enriches the water around the embankment slope, contributing to its instability. The disaster site is situated within granite formations. The refilling soil, composed of weathered granite, exhibits poor hydro-mechanical properties, making the slope particularly susceptible to failure due to the effects of multi-source water infiltration. A key insight from this research is that potentially unstable embankment slopes should be identified by considering the interaction between multi-source water and soil/rock. Greater emphasis should be placed on factors such as fault development and hollow topography above the slope, which influence the effects of multi-source water. These factors should be quantified in future studies to improve the assessment of unstable highway slopes in mountainous regions. The findings and strategies outlined in this study can serve as a valuable reference for assessing both embankment and natural slopes in mountainous areas.

Understanding the effects of seawater on solidified soil is crucial for its application in ocean engineering, especially when using marine dredged clay as raw material. In this study, Comparative experiments, comprising unconfined compressive strength (UCS) tests and scanning electron microscopy (SEM) analyses, were conducted under both seawater and standard curing conditions to investigate the combined effects of additives, curing environments, and seawater on soil properties. Results show that seawater significantly weakens the mechanical performance of solidified soil. Compared to standard curing, solidified soil with ordinary Portland cement (OPC) showed an average strength reduction of 38.65 % after 7 days and over 29.28 % after 28 days. In contrast, solidified soil prepared with sulphoaluminate cement (SAC) exhibited greater resistance to seawater, with strength reductions of 28.69 % after 7 days and 20.19 % after 28 days. Polyacrylamide (PAM) can enhance the early strength of solidified soil in seawater by forming a composite structure with hydration products. An increase of 0.5 % in PAM content leads to an average strength improvement of 27.03 % at 7 days and 34.61 % at 14 days. In contrast, for every 1 % increase in superplasticizer (SP) content, the soil strength in seawater decreases by 17.78 %, 11.20 %, and 9.24 % at 7, 14, and 28 days, respectively. These findings provide important insights for improving solidified soil performance in marine environments.

The reactivation events of old landslides in the Three Gorges Reservoir area occur frequently, making it imperative to study the water softening characteristics and reactivation mechanism. An old clay landslide was selected as the focus of the research, and a segmented water injection permeable sliding surface was designed to simulate the formation and evolution of the old sliding zone during the process of groundwater rise. Volumetric water content sensors, pore water pressure gauges, high-speed camera devices, and Geopiv-RG digital image processing technology were used to obtain data on multiple physical fields. The analysis results indicated that the decrease in shear strength of the sliding zone soil and the sudden increase in pore water pressure on the sliding surface were important factors in the reactivation of old landslides. The surface deformation exhibited prominent zoning characteristics, primarily categorized into zones of strong deformation, weak deformation, and traction deformation. The failure mechanism involved shear sliding at the front edge, tensile cracking and failure at the trailing edge, and shear creep in the middle section. The development of multi-stage secondary sliding zones in old landslides can be categorized into three types: parallel to the original old sliding zone, partially overlapping with the original sliding zone to form a layered landslide, and completely overlapping with the original sliding zone, indicating overall reactivated deformation.

Failure of important supporting structural systems such as pipelines carrying water from the faraway source may be disastrous to the site environment and lead to public clamor. Such events resulting from blasts (intentional/unintentional) do not give any warning of impending failure as their duration is very short and intensity is very high as compared to other loadings excited by the earthquake. Therefore, the investigations for the response of buried pipelines under explosive loading are of considerable interest. This study is executed for numerical analyses using an advanced coupled Eulerian-Lagrangian finite-element (CEL-FE) approach to predict the anti-blast performance of a buried steel pipeline loaded by on- and below-ground blast loading. A 3D numerical model of the buried pipeline is first created in the ABAQUS software and analyses are performed with ABAQUS built-in explicit module to investigate the role of carried liquid (e.g., water) on the anti-blast response of the pipeline. The considered pipeline is seamless and has an outer diameter of 1e+03 mm, a wall thickness of 1e+01 mm, and a total length of 12000 mm; typical dimensions for water, gas, and oil transmission pipelines. It is buried in a brown clayey soil medium at a depth of 2000 mm (= 2 x pipe diameter) below ground level. Simplified Johnson-Cook plasticity (JCP), Jones-Wilkins-Lee (JWL)-Equation-of-State (EOS), ideal gas EOS, Us Up Hugoniot EOS, and Mohr-Coulomb plasticity (MCP) constitutive models, respectively, are considered to define material properties for the pipeline, TNT, air, water, and soil medium. Responses are compared and discussed. Significant improvement in the blast performance of the pipeline carrying 50% water has been observed in terms of dynamic response and damage compared to the empty pipeline showing that the water proactively contributes to protecting the pipeline from getting severely damaged by the blastwaves.