Impact-Driven Penetration of Multi-Strength Fiber Concrete Pyramid-Prismatic Piles

The article focuses on studying the impact-driven penetration of multi-strength fibroconcrete pyramid-prismatic piles. The research object includes multi-strength pyramid-prismatic piles with varying types of reinforcement and different levels of concrete compressive strength. The aim of the study is to experimentally investigate the enhancement of pile impact resistance through the differentiated selection of concrete strength based on the dynamic stresses in the pile shaft caused by impact forces. As a result of the experimental studies on the piles, it was found that the difference in energy costs for driving them does not exceed 3.7–4.1%, proving the insignificant influence of the type of reinforcement and fiber concrete strength on the energy expenditure during driving. At the same time, it was established that the type of reinforcement and the type of fiber significantly affect the strength and impact-resistant properties of the pile shaft, ensuring defect-free driving. For example, the defectiveness (e.g., chips, cracks, potholes, spalling) of the head of the steel fiber concrete (SFC) pile reaches 57.5%, while for the polypropylene fiber concrete (PFC) pile it does not exceed 5.2%, demonstrating the advantages of using polypropylene fiber under impact conditions.