A Review of Research on the Stability of Fine-Grained Sediments in Debris Flows

Fine-grained sediments in debris flows refer to Quaternary sediments with grain sizes smaller than 2 mm. Their stability is closely related to the initial water threshold that triggers the debris flows and thus controls the density, scale, and damage of the debris flows. Based on this, they play a key “probe” role in early warnings of debris flows. Studies on fine-grained sediment stability are related to the accuracy and efficiency of early warnings of debris flows and thus play an important role in ensuring the safety of people and property. There have been some studies on fine-grained sediment stability in debris flows, but no one has carried out a systematic analysis and summary of this field. Therefore, in response to the urgent need for high-precision early warnings of debris flows, firstly, we review the current research on the aspects of fine-grained sediment stability, initiation, triggering, physical properties, hyperspectral remote sensing, and early warning systems; secondly, we summarize the main problems related to high-precision early warnings of debris flow hazards; and finally, we outline the future directions of research on fine-grained sediment stability in debris flows.