Soil disturbance and excess pore water pressure generation, induced by dynamics and transient excitations such as pile driving, seismic loading, and impact effects, can significantly degrade the geotechnical strength and stiffness. Given the critical importance of axial capacity in sustaining superstructures, it is essential to recognize and mitigate potential damages. This research investigates the piles reduction of axial capacity through CPTu records, which offer rapid and reliable data. Aiming to quantify the consequences of soil sensitivity and excess pore water pressure, a comprehensive dataset has been compiled comprising CPTu and pile performance records from 11 diverse sites worldwide, focusing on soft and loose deposits. The research identifies problematic sublayers and, by incorporating an analytical approach, evaluates the intact and reduced shaft and toe resistance through three distinct methods. Results indicate a substantial reduction in bearing capacity due to dynamic loading on piles. Four levels of capacity loss concern are recognized quantitively. Through case studies, the response of the problematic deposit under dynamic loading is more apprehended, conforming with the findings. The current research addresses and emphasizes the necessity of realizing pile dynamics and problematic deposit interaction. It can lead to safe, reliable, and optimal design practices based on a comprehensive understanding of soil-pile interaction.

Vibratory penetration was successfully used to install 120 integral thin-walled steel cylinders 22 m in diameter in the Hong Kong-Zhuhai-Macao Bridge. However, the eight-hammer group was found overpowered at the western island and underpowered at the eastern site due to insufficient understanding of the mechanisms of vibratory piling. In this study, energy analysis was conducted to reveal the energy characteristics of vibratory penetration, including the periodical energy superposition along the cylinder shaft, the continuous energy consumption in the soil, and the dynamic equilibrium of the total energy. The influences of vibratory soil resistance and loading frequency on the energy distributions have been thoroughly discussed. In contrast to the notion that larger input energy leads to a faster penetration, it is revealed that the vibratory penetration velocity positively correlates to the energy stored in the cylinder, the ratio of kinetic to strain energy, and the characteristic frequencies of the soil-pile system. The actual output power of the vibratory motors is influenced by the vibratory force, the ultimate soil resistance, and the soil mobilization degree. The vibration frequency is optimized as 31.1 Hz for Cylinder E9 and 15 Hz for Cylinder W36 to ensure efficiency and safety.