Research Progress of Initial Mechanism on Debris Flow and Related Discrimination Methods: A Review

Abstract

The initial of debris flow can be classified into two types based on their triggering positions, that is, debris flow from slope and debris flow from gully or channel. For the former, great progress has been achieved on the mechanisms of soil failure and liquefaction. The framework established by a series of theories or laws, such as the Mohr–Coulomb criteria, the unsaturated soil mechanics, and the critical state of soil mass, has been used widely in industry and research. However, the details and discrimination basis for the transformation process from landslide into debris flow still need to be further clarified. Relatively, debris flow from gully or channel is more complex due to its various mass sources and the diversity of processes. Nevertheless, through a great number of case studies and experimental statistics, people have gradually recognized the influential rule and critical condition of factors from landform, hydrology, and other aspects on debris flow initiation. Furthermore, based on the theories of granular flow, continuum mechanics, and rheological law, some typical event-based scenarios can also be reproduced by different single-/two-phase depth integral/average numerical models. However, some key knowledge on mechanism and application level is still insufficient, such as the erosion and entrainment mechanism of materials from different sources, the boundary tractions and materials exchange, as well as the selection of prediction indicators. Three current discriminated methodologies for debris flow initiation, that is, the safety factor method, the rainfall indicator method, and the comprehensive assessment method, were summarized in this article. Considering the technical limitation of each methodology, it is believed that the establishment or improvement of a unified, stable, and open-access database system for event registration and query, as well as the development of large-scale and high-precision rainfall monitoring, is still regarded as the important aspect of debris flow prevention in the future. In addition, as an economic and efficiency means for obtaining information on potential threats and real-time hazard messages, the multielement method for debris flow is recommended as a long-term reference.

Soil Related Factors Controlling Erosion And Landslides In Malaysia

“…The steeper the slope, the more the surface runoff and surface soil erosion as manifested by rill and gulley formation. Recent studies indicate that the characteristics of the slope material and corresponding stress state play a relatively more important role than rainfall and slope steepness in triggering slope debris flows (Du et al, 2021). This calls for further investigation on the link between soil related factors, erosion and slope stability.…”

“…Land management practices influence the rate of weathering and soil erosion and accelerate landslide occurrences in the tropics (Sidle et al, 2006;Sajinkumar et al, 2011). In Malaysia, the Environmental Quality Act (1974) and the Environmental Quality (Prescribed Activities) (Environmental Impact Assessment Order 1987) require owners of agriculture land to ensure that proper soil conservation measures are taken to minimise soil erosion (Government of Malaysia, 2000;2001).…”

Optimizing the Numerical Simulation of Debris Flows: A New Exploration of the Hexagonal Cellular Automaton Method

“…In the field of debris flow disaster mitigation, numerical technologies play a crucial role in disaster prevention [13,14]. Many studies focus on numerically solving the Navier-Stokes (N-S) equation.…”

Modelling the possible Debris Flow events in Swat Mountains Using Flow-R -A Case Study in Pakistan

“…Bank Collapse-Induced Debris Flow: Debris ow in this category results from the entrainment of deposits caused by bank collapse. (Du et al, 2021) Debris ows typically occur in mountainous regions with steep slopes and loose, unconsolidated materials such as rocks, gravel, sand, and clay. Several factors contribute to their formation: Intense rainfall or rapid snowmelt can saturate the soil and can cause debris ows.…”