STUDY ON THE INFLUENCE OF SHALLOW GROUNDWATER AND HYDROLOGICAL PROCESSES ON LOESS LIQUEFACTION AND MUD FLOW SITES

Water content is a critical prerequisite for loess liquefaction,and groundwater usually plays a decisive role in the instability of loess liquefaction. This study explores the distribution of shallow groundwater and its flow direction at the Yongguang Village liquefaction site using the 1 m ground temperature method. Hydrological analysis,topographical trend analysis,and the Topographic Wetness Index(TWI)were used to explore the relationship between geological disasters in Yongguang Village and shallow groundwater distribution and rainfall runoff. Validation through drilling data and results from high-density electrical methods has confirmed the effectiveness of 1-meter ground temperature measurements for identifying shallow groundwater veins in areas prone to loess liquefaction. The study identifies three main flow paths of shallow groundwater in Yongguang Village,with the flow direction ranging from the northern part of the higher terrain to the southwestern gully. Pre-earthquake topographical trend analysis and TWI calculations reveal that the western landslide of Yongguang Village(loess liquefaction flow slide) has a larger slope runoff area,making it more susceptible to regional topography and thus groundwater enrichment. Post-earthquake comparisons between TWI values and the 1-meter ground temperature method reveal that areas with high and concentrated TWI values correspond to regions in the study area with abundant shallow groundwater. Therefore,the development of shallow groundwater veins and the accumulation of runoff from rainfall,resulting in rising groundwater levels,are crucial causes of loess liquefaction disasters.