Study on the Compression and Collapsibility Characteristics of Yangling Loess Under Different Wet and Dense States

To investigate the deformation characteristics of loess in the Yangling region of Shaanxi Province, China, under different wet-dense states, a fully automatic air pressure consolidation apparatus was used to conduct compression and collapsibility tests. The compression and collapsible deformation mechanisms were revealed from the evolution patterns of compression yield pressure, compression coefficient, and collapsible coefficient. The tests results indicate the following: (1) the greater the compaction degree and the smaller the initial water content, the smaller the amplitude of the compression curve change, the greater the compressive yield stress, and the smaller the compression coefficient; a compression curve model considering initial water content and compaction degree was constructed. (2) The collapsibility coefficient shows a trend of first increasing and then decreasing under low pressure compaction and high initial water content, while under high pressure compaction and low initial water content, it exhibits a continuous increase. The increase in compaction degree and initial water content will both lead to a decrease in the coefficient of collapse. The collapsibility coefficient exhibits a more pronounced response under high pressure compared to low pressure. Soil samples with low compaction and low initial water content demonstrate significantly greater collapsibility sensitivity. (3) A collapsible prediction model applicable to Yangling loess was established based on SPSS software, and the research findings can offer theoretical support for the rapid assessment of loess collapsibility in this region.