Research on the development and application of the device for measuring soil erosion characteristics

The soil erosion characteristics mainly include two indexes, such as the critical shear stress for the incipient motion of soil and the soil erosion rate, which are the controlling factors of breach flow and breach morphology evolution during the embankment dam breaching. Traditional erosion experiments deduce the flow shear stress by converting measured the sectional flow velocity into the friction velocity. This study has developed an innovative technique for directly measuring the shear stress at the water-soil interface by using a bridge-type micro strain shear stress sensor. Based on this, a device for measuring soil erosion characteristics has been developed. The soil erosion testing device includes a hydrodynamic system, a soil erosion system, and a data acquisition system. The hydrodynamic system can provide water flow conditions ranging from 0 to 6 m/s; the soil erosion system can automatically adjust the height of the sample during the erosion process to capture changes in shear stress; and the data acquisition system records the relationship between the flow shear stress and the erosion rate. Validation tests indicate that the erosion rate of cohesive soils has a good linear correlation with water flow shear stress. The critical shear stress of cohesive soils significantly increases with higher compaction and clay content, while the influence of water content on critical shear stress is minimal. The paper also proposed a predictive model for the critical shear stress and erosion coefficient of cohesive soil based on experimental data. Validation results show that the model can accurately reflect the relationship between the critical shear stress, erosion coefficient, and soil properties by optimizing model parameters and incorporating more soil-related features, which provide a scientific basis for selecting erosion parameters for dam materials in simulations of dam breaches.