Investigating heat flow evolution characteristics and stability of collapsible loess based on microwave sintering

High-temperature sintering technology offers rapid processing speeds and effective reinforcement, making it a superior method for treating loess foundations. However, research on microwave high-temperature sintering for loess is currently limited. This article designed microwave sintering experiments on saturated remolded loess with varying compaction levels. The temperature field distribution characteristics of the sintered soils were assessed and one-dimensional compression experiments were carried out to assess changes in soil compressibility post-sintering. The findings indicate that the compressibility of the sintered loess is directly proportional to the initial compaction degree of the soil sample and inversely proportional to the distance from the waveguide. Specifically, for samples compacted to 80% and 90%, the core temperature predominantly concentrates in the upper layer of the model, whereas for those compacted to 70% and 60%, it is primarily in the middle and lower layers. When the sintering temperature reaches 200 °C, soils with high compressibility can be converted into medium compressibility soils, and at 400 °C, into low compressibility soils. After the sintering was completed, the compression coefficient of the centrally sampled loess decreased by 38.31%–95.65%, while that of the peripherally sampled loess decreased by 0.80%–27.95%. These results provide valuable insights for the further advancement of microwave thermal reinforcement technology in collapsible loess.