Design and Numerical Modeling of Light Compactor for Very Low Energy Dynamic Compaction by Finite Element Method

The purpose of this study is to find a method for obtaining all soil dynamic parameters numerically. Moreover, it is intended to predict the dynamic parameters after each impact, and to obtain the predicted compaction as well as the desired dynamic parameters after a certain number of impacts. In the study, four hammers with different dimensions are modeled on sandy soil using ABAQUS. Additionally, the activated wave stiffness test is used to extract the dynamic parameters of each hammer for loose sand, and it is shown that which hammer under what conditions yields the highest efficiency. The peak particle velocity is obtained using the finite element technique for each hammer, and the results are used to determine the safe distance after each blow. The results indicate that the unsafe distance of compactor from the location of impact increases with the weight of the compactor. In the study, a hammer with a mass of 875 kg, falling through a distance of 1 m. horizontal safe distance of 3.80 m, and a vertical safe distance of 2.30 m is designed to deliver five blows to achieve the maximum stiffness with an improved depth under the foundation from 0.9 to 1.2 m in a loose soil and a relative error of 5% is obtained. The improvement depth obtained numerically is in good agreement with the experimental results of centrifuge tests at accelerations of 1, 10, 20, and 30 g as well as the field results of Parvizi and Merrifield, Allen, Maxwell and Briaud.