A theoretical model for the initiation of debris flow in unconsolidated soil under hydrodynamic conditions
C.-X. Guo1,2, J.-W. Zhou3,4, P. Cui1, M.-H. Hao4, and F.-G. Xu41Key Laboratory of Mountain Hazards and Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, Sichuan 610044, China 2University of Chinese Academy of Science, Beijing, 100049, China 3State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China 4College of Water Resources & Hydropower, Sichuan University, Chengdu, Sichuan 610065, China
Received: 28 May 2014 – Accepted for review: 15 Jun 2014 – Discussion started: 26 Jun 2014
Abstract. Debris flow is one of the catastrophic disasters in an earthquake-stricken area, and remains to be studied in depth. It is imperative to obtain an initiation mechanism and model of the debris flow, especially from unconsolidated soil. With flume experiments and field investigation on the Wenjiagou Gully debris flow induced from unconsolidated soil, it can be found that surface runoff can support the shear force along the slope and lead to soil strength decreasing, with fine particles migrating and forming a local relatively impermeable face. The surface runoff effect is the primary factor for accelerating the unconsolidated slope failure and initiating debris flow. Thus, a new theoretical model for the initiation of debris flow in unconsolidated soil was established by incorporating hydrodynamic theory and soil mechanics. This model was validated by a laboratory test and proved to be better suited for unconsolidated soil failure analysis. In addition, the mechanism analysis and the established model can provide a new direction and deeper understanding of debris flow initiation with unconsolidated soil.
Guo, C.-X., Zhou, J.-W., Cui, P., Hao, M.-H., and Xu, F.-G.: A theoretical model for the initiation of debris flow in unconsolidated soil under hydrodynamic conditions, Nat. Hazards Earth Syst. Sci. Discuss., 2, 4487-4524, doi:10.5194/nhessd-2-4487-2014, 2014.