Effective temperature control measures are crucial for achieving temperature regulation and preventing cracking in the dam body during the construction of large-volume concrete gravity dams. Due to the low ambient temperatures in winter, it is especially important to focus on temperature control measures for concrete dam construction in cold regions. This paper employs a numerical simulation method that takes into account dam temperature control measures to simulate and predict the overall temperature and stress fields of the Guanmenzuizi Reservoir Dam, and validates these simulations with field monitoring results. This study finds that the ambient temperature significantly impacts the temperature and stress of the dam body’s concrete. The internal temperature of the dam reaches its highest value approximately 7 days after pouring, followed by periodic fluctuations, with the dam body’s temperature changes exhibiting a certain lag compared to the ambient temperature. The interior of the dam is under compression, while the upstream and downstream surfaces experience significant tensile stress. This project adopts targeted temperature control measures for the cold environmental conditions of the region, which are reasonably implemented and effectively reduce the temperature rise of the concrete during construction, achieving the temperature control objectives. This study also explores the impact of the cooling water pipe density on the dam body. The research results offer valuable references for the implementation of temperature control measures and the establishment of temperature control standards for concrete gravity dams in cold regions.

The mechanism by which litter–soil interface properties interact to shape the composition and diversity of litter decomposition-driving microorganisms remains unclear. Here, litter and surface soil samples were collected from three typical forest types on the Loess Plateau: Pinus tabulaeformis forest (PF), Quercus acutissima forest (QF), and their mixed forest (MF). Litter and soil chemical properties, along with litter microbial community structure, were analyzed to clarify microbial diversity differences across stands. Across the three forests, litter microbes showed no significant differences in multiple diversity indices, but dominant genera differed significantly. At all taxonomic levels, litter bacterial and fungal diversity followed the order MF < PF < QF. QF had the highest litter total nitrogen (LTN) and phosphorus (LTP) and significantly higher soil ammonia nitrogen (NH₄⁺-N) than PF and MF. Correlation analysis indicated that LTN, LTP, soil organic carbon (SOC), and soil NH₄⁺-N primarily influenced bacterial and fungal community composition and diversity. Redundancy analysis revealed litter organic carbon (LOC) as the dominant environmental driver shaping both communities, with soil NH₄⁺-N exerting a stronger effect on bacteria and nitrate nitrogen (NO₃⁻-N) on fungi. These findings deepen understanding of soil–litter–microbe interactions in forest ecosystems, laying a scientific foundation for forest management and protection.