New Method to Predict Crater Depth Obtained in Dynamic Compaction

This article presents a method to estimate dynamic compaction crater depth using empirical equations. As main reference, three physical model studies that used sand and clay soils were considered (Jafarzadeh in Proceedings of the international conference on performance-based design in earthquake geotechnical engineering, pp 1–8, 2006; Arslan et al. in ICE Ground Improv 11(2):61–66, 2007; Yuan et al. in Geotech Geol Eng 36:1873–1883, 2017). These studies considered variables such as the weight (W), height (H), soil density (γ_nat), number of strikes (N) and the angle at the bottom of the compaction hammer (θ). It was possible to plot the relation E versus ρ (Energy vs. Depth of crater produced) adequately as well as to estimate the craters depths. The linear correlation between α (Energy Factor) and β (Stiffness Factor) factors was observed (R² between 0.93 and 1), considering the following parameters: height (H) and soil density (γ_nat). Also, the linear correlation of the relation η (Wcosθ /AH γ) versus (αβ)^0.5 presented a R² between 0.91 and 0.8, and the use of hammers with different weights affect the linear relation between η versus (αβ)^0.5. After calibrating, it is possible to predict the development of the craters based on the number of blows on the proposed model. As the relation between the factors presented was linear, it’s practical to use them in the prediction of craters and in the definition of the depth of effective influence based on other formulas expressed in the literature.