Coefficient of resilience for rock fall onto gravel soil cushion based on wavelet transform theory

The inversion of the coefficient of resillience is an important method based on the experimental data. The model experiments are designed as follows: 12 kinds of density and 5 kinds of height of rock fall based on 4 kinds of soil-rock ratio cushion of gravel soils. The impact waves are gained by use of the dynamic strain gauge. Using the wavelet theory, the maximum impact force is extracted. Based on the hertz collision theory and the conversion of engery, and by using the coefficient of resilience to consider the lose of engery in the course of lashing, an formula for the impact force of rock fall is established. The deformation modulus and the Poisson's ratio of gravel soils are gained through experiments. The coefficient of resillience is gained using the inversion analysis based on model data. The results show that: (1) the coefficient of resillience increases with the increase of dry desnity of cushion; (2) the coefficient of resilience of the cushion with compactnesses of 4:6 is the largest among 4 kinds of cushions, with the maximum value being 0.314 and that of the cushion with compactnesses of 3:7 is the smallest, with the minimum value being 0.266. Compared with the former relative studies, the results are basically consistent. This study provides a scientific basis for the motion trajectory of rock fall and the relevant measures.