Study on soil-water characteristic curves in the profiles of collapsing walls of typical granite Benggang in southeast China

PeerJ

article

Liting Zhang¹  Shujun Sun¹  Mengqi Lin¹  Kaijun Feng¹  Yue Zhang¹  Jinshi Lin¹  Hongli Ge¹  Yanhe Huang¹  Fangshi Jiang¹ 

[1] College of Resources and Environment, Fujian Agriculture and Forestry University

关键词: Gravity erosion;    Soil physics;    Soil water potential;    Undisturbed soil;    Weathering crust;   

DOI  :  10.7717/peerj.13526

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Benggang with steep collapsing walls is one of the worst soil erosion problems in South China. The collapse of walls is the most critical process in Benggang development. This is mainly due to the soil water properties. The soil water characteristic curve (SWCC) is a key indicator for analyzing soil moisture, but the SWCC and its mechanism of influence in collapsing walls remain obscure. A pressure plate meter was used for drying experiments to research the SWCCs of undisturbed soils of five layers (from top to bottom: red soil layer, transition layer I, sand soil layer, transition layer II and detrital layer) of two typical collapsing walls. The van Genuchten (VG) model can be fitted to the SWCCs for different layers (NSE ≥ 0.90). With increasing soil depth, the parameters a and θs first decreased and then increased, the parameters n first increased and then decreased, θr declined as the soil depth increased. These findings illustrate that soil water holding capacity decreases with increasing soil depth. The bottom of the soil is weak in water retention and water can easily reach saturation, resulting in a decline in soil stability, thus promoting soil collapse and finally inducing upper soil collapse. Furthermore, gravel content and particle morphology are factors that should not be neglected for SWCCs. The results of this study provide a theoretical basis for understanding the process of wall collapse in Benggang landforms in South China.

【 授权许可】

CC BY