5. Conclusion
In this study, a new simple theoretical model was developed based on Bernoulli’s principle to understand the erosion process in the hole erosion test (HET). The constitutive equation of erosion characteristics was further developed into a differential equation to find out the dynamic prediction model of erosion process. It was found that eroded hole radius as a function of time (\(R\left(t\right)\)) followed the power function with an exponent of 0.25. Based on the known\(R\left(t\right)\), other physical quantities namely erosion rate, pressure drop, and erosion characteristics can be deduced. Besides, a new equation was proposed to determine the erosion coefficient by observing the realistic change of hole radius (soil loss). The model was validated with HETs for various flow conditions. Model performance was also evaluated based on tests conducted in the literature. These was reasonably good agreement between measured and predicted erosion characteristics (from newly developed model) under different hydraulic conditions. Furthermore, the reported phenomenon of HETs in the literature was considerably interpreted by proposed equations. The interpreted experimental results suggested that erosion coefficient marginally increased during the entire process of internal erosion in HET. Three distinct phases (i.e. initial, normal, and final phases) were used to explain the internal erosion process in HET. The advantage of the proposed model is that the erosion characteristics are determined by considering the realistic measured change in radius of the soil hole. The proposed formulation in this study was tested only for HETs. However, further studies are needed to understand its applicability for determining the internal erosion in various geotechnical infrastructures in the field.