Runoff erosion processes on artificially constructed conically-shaped overburdened stockpiles with different gravel contents: Laboratory experiments with simulated rainfall

• Published in: Catena (Giessen) 2019-04, Vol.175, p.93-100
• Main Authors: Luo, Han, Rong, Yubo, Lv, Jiaorong, Xie, Yongsheng
• Format: Article
• Language: English
• Subjects: Conical overburdened stockpiles; Erosion process; Gravel; Runoff
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2018.12.010

Overburdened stockpiles during construction projects are typically loose mixtures with different proportions of fines and gravel. They are common sources of anthropogenic accelerated erosion that threatens environmental quality and the quality of life for people in many parts of the world. Overburdened stockpiles have unique three-dimensional shapes. However, studies with these materials are usually performed in traditional planar soil bins. Therefore, in this study, a specially designed mobile experimental device was used to accurately evaluate the runoff erosion process on overburdened stockpiles in a three-dimensional conical shape. A series of indoor rainfall simulation experiments at 60 mm/h rainfall intensity was conducted using material with different gravel contents (0%, 10%, 20%, 30%, and 40%). The results showed that the runoff rate and flow velocity exhibited the same trend, i.e., a rapid increase, followed by a slow increase and then stabilization. The runoff regime in all experiments manifested as laminar and subcritical flow during the runoff process. Re and Fr values were much smaller than those on two-dimensional plane simulation of overburdened stockpiles. The presence of gravel caused the runoff to be slow and stable. Runoff rate, flow velocity, Re and Fr values all decreased with increasing gravel content. The sediment yield decreased logarithmically in response to the increasing gravel content. The study findings are not only helpful for understanding the hydraulic characteristics and erosion features that characterize overburdened stockpiles, but also have implications for prediction models of soil and water loss from this material during production and use in construction projects. •A mobile device of three-dimensional conical overburdened stockpiles was designed.•Rainfall simulation experiment on the conical overburdened stockpiles.•Re and Fr were much smaller than those on two-dimensional overburdened stockpiles.•The presence of gravel reduced the runoff rate and sediment yield.