Spatial nonuniformity of landslide dam deposition and its quantitative characterization

Abstract

Landslide dams are formed by rapidly depositing landslide bodies with a loose structure and poor stability. The strong spatial nonuniformity of dam soil is a key factor for study on the seepage stability of landslide dams. In this paper, a 500×500×500 mm cubic model box was made and the dam soil was deposited in it by different sliding modes to investigate the nonuniformity of the deposition. Based on the basic principle of grading entropy, the distribution characteristics of the soil in different depositing zones using the entropy parameters A-B coordinates were analyzed. Finally, an index describing the degree of nonuniformity N d was proposed to assess the deposition quantitatively. It was found that with the increasing sliding angle, the deposition showed prominent sorting characteristics in the sliding direction. The coarser and ner particles were mainly concentrated in the front and back parts of the deposition, respectively. Grading entropy has the advantage of being meticulous compared with traditional characteristic parameters. In the entropy parameters A-B coordinates, the points for the expected uniform deposition are more concentrated. And the points of different zones for the sliding deposition are archshaped in this coordinates. The N d of the expected uniform deposition is only 0.057. And that of the deposition made by the sliding angle of 60° is the largest of 0.173. The research results can provide references for studying the spatial nonuniformity of landslide dam deposition.