Abstract
Crater depth is a vital issue in dynamic compaction (DC) because it is a controlling parameter in DC and a characterization index of soil properties. A continuous mathematical model capturing the time-domain process of tamper displacement is presented in this paper. The model is simple and the parameters involved are easy to obtain. It was found that the accumulated crater depth increases but its increment in the crater depth decreases with multiple impacts. Three groups of large-scale DC tests with 10,000 kN∙m were conducted to evaluate the performance of the proposed model. The results showed that the proposed model captures the typical trends in the tamper displacement of single and multiple impacts. In addition, a concept of the crater depth ratio is proposed based on the proposed model, and the concept is used to evaluate the efficiency of DC and to predict the optimum tamping number of DCs.
Highlights
The foundation treatment method of dynamic compaction (DC) mainly involves a free-falling heavy tamper to impact the soil foundation
The single tamping of a DC process contains two parts: (i) the impact loading stage that is from the tamper colliding with the soil foundation to the lowest point; and (ii) the unloading rebound stage that is the subsequent rebound of the tamper
The crater depth with further tamping was less than 10 cm and the tamping ratio of the seventh tamping time was only 4.263%. This meant that the contribution of the seventh tamping to the total crater depth of the first seven times was less than 5%, and the contribution of the later tamping to the whole DC was lower
Summary
The foundation treatment method of dynamic compaction (DC) mainly involves a free-falling heavy tamper to impact the soil foundation. The three key elements in studying the DC process are: (i) the time-domain characteristics of the input affecting the soil changes; (ii) the regular pattern of the soil response with the impact load; and (iii) the method for evaluating the foundation reinforcement level. Qian et al [24] proposed an improved method to determine the time-domain characteristics of the impact stress, the time needed, and the residual deformation in a DC tamping. He failed to consider the influence of soil damping in the loading stage, and the law of crater depth evolution with multiple DCs was not analyzed. The revised mathematical model was verified through a series of large-scale DC tests
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
