Prioritizing safety management and operational maintenance within hydropower stations proves imperative for both economic development and environmental protection. This study analyzed the joint effects of differential ground settlement and machinery vibration on the superstructure damages through a real case that happened in a hydropower station located in Sichuan province (China). A combination of on-site investigations, field experiments, and numerical simulations are employed to recognize the abnormal vibrations, replicate soil vibration patterns, and comprehend the underlying causes of settlement. Guided by the identified causes, a judicious selection of the optimal vibration reduction solution transpired, subsequently validated through numerical simulations. The outcomes underscore that during operational phases uneven settlement ensues owing to the presence of a feeble foundation. This differential settlement in turn exacerbates foundation settlement by amplifying vibrations in the generator units. The geological conditions of the hydropower station remain in a perpetual state of evolution influenced by surface geological processes. Consequently, a protracted and scientific assessment of hydropower station geological conditions holds enduring significance for both the realms of engineering construction and operational maintenance.

Most Pb/Zn smelter contaminated sites in China are often encountered natural phenomenon known as freeze-thaw (F-T) cycles and acid rain. However, the coupled effects of F-T cycles and acidification on the release behavior of potentially toxic elements (PTEs) from soils remains unclear. A mechanistic study on PTEs release from soils was conducted by revealing the physicochemical weathering characteristics of minerals under F-T cycles combined with acidification. The results from F-T test indicated that among F-T parameters, F-T frequency were the more important factors influencing PTEs release, with the corresponding contribution ranges of 21.20-94.40 %. As pH decreased, the leaching concentrations of As, Cd, Cu, Mn, Pb and Zn did not increase under the same F-T frequency. As F-T frequency increased, the leaching concentrations of these studied PTEs also did not increase under the same pH condition. Microstructure characteristics revealed that the soils were a complex system with multi-mineral aggregates, which had experienced complex physicochemical weathering after F-T combined with acidification treatment. Combined with geochemical modeling results, PTEs release was found to be mainly influenced by the microstructure damage and proton corrosion of minerals, while little affected by their precipitation and dissolution. The mutual coupling relationships of mineral weathering and PTEs release were conducive to the better understanding of the migration behavior of PTEs in contaminated sites under complex environment scenarios. The present study results would provide theoretical instruction and technical support for the longevity evaluation of multi-metal stabilization remediation.

Post-earthquake scientific investigation is considered as one of the pillars supporting earthquake engineering. On the 6th of February, 2023, two deadly strong earthquakes, which magnitudes were M(w)7.8 and M(w)7.5, respectively, shook Southern-Central Turkiye, caused significantly large casualties and tremendous economy loss. Through on-site field survey, liquefaction phenomena and liquefaction-induced damage to buildings were observed. The observations are: (1) the consequences of soil liquefaction included sandboils, lateral spreading, ground subsidence and ground failure caused by loss of bearing capacity; (2) in two liquefied areas, lateral spreading was investigated and the spreading displacement ranged from several centimeters to meters, resulting in damage or demolishing of buildings; (3) in Golbasi town, many 6 to 10-story buildings significantly subsided and tilted due to liquefaction-induced loss of ground bearing capacity. Buildings subsided by tens of centimeters to 2 similar to 3 m, and tilted by several degrees to tens of degrees; (4) ground subsidence of tens of centimeters with respect to adjacent buildings was detected. The liquefaction phenomena were compared with those triggered by the 2008 Wenchuan, China, earthquake which maintained similar in magnitude and focal depth. The findings and lessons learnt will enhance the understanding of liquefaction hazard, challenge the current liquefaction countermeasures, and eventually facilitate to improve liquefaction mitigation techniques.