Abstract: The process of velocity and sediment yielding on engineering accumulations slope are different from traditional due to differences in soil textures and mass fraction of gravel in production and construction projects. In this paper we examined the characteristic of flow velocity and sediment yielding on engineering accumulations with three soil textures (sandy soil, loam, and clay) via artificial simulation experiments. Results showed that: (1) Flow velocity increased at first within 3 minutes after the beginning of the runoff and then stabilized. (2) For sandy soil accumulations,erosion mainly occurred in the middle and late stages of runoff at small rainfall intensity; for loam, in the early and middle stages; and for clay accumulations, throughout the whole runoff process. The accumulative sediment yielding 21 minutes after runoff beginning accounted for 52.3%-95.6%,29.6%-44.9%, and 42.1%-50.0% of the total erosion amount of sand, loam and clay accumulations. (3) Significant correlations were found with runoff rate, infiltration rate, velocity, and sediment yielding rate against runoff time and rainfall intensity. Erosion amount increased by 1.2-39.8 times as rainfall intensity increased 1.5-2.0 times. Erosion amount for sandy accumulations was 6.0-6.3 times that of loam accumulations, 3.2-3.5 times that of clay accumulations under the same rainfall intensity, and 5.0-9.8 times and 2.7-3.8 times those of loam and clay accumulations with the same mass fraction of gravel. The research findings are of great significance for clarifying the mechanism of erosion process of engineering accumulations, and lay a foundation for establishing the erosion prediction model for engineering accumulations.

Key words: engineering accumulations, sediment yielding, flow velocity, mass fraction of gravel, soil textures