Machine-Induced Vertical Responses of Single and Pile Groups

Abstract

The main objective of this study is to understand the dynamic characteristic of pile foundations subjected to machine based vertical vibrations. To accomplish this objective, forced vibration field tests are performed on hollow steel single and pile group to obtain the vertical responses of the pile foundations. It is found from dynamic frequency-amplitude response curves that the resonant frequencies are decreases and resonant amplitudes are not proportional when excitation forces are increases which indicate the nonlinear characteristics of soil-pile systems. The values of resonant frequencies are found higher and resonant amplitudes are found lower when the number of pile is increase due to increase in soil-pile stiffness. For theoretical study, the continuum approach method is used to determine the analytical response curves of piles and further it is compared with the field test results. To understand the behavior of pile group, the variations of group efficiency ratio with varying frequencies are also predicted form the analysis.

Machine Induced Dynamic Field Responses of Group Pile with Different Pile Arrangements

“…Further, these dynamic results are studied under harmonic vibration and analytically with the use of the continuum approach method by Elkasabgy and El Naggar (2013) and Sinha et al (2015) to know the effect on soil nonlinearity subjected to dynamic excitation and the combined soil-pile responses in terms of frequency and amplitude and their influence on impedance parameters. Some other researchers (Elkasabgy and Naggar 2018;Biswas and Manna 2018;Ralli et al 2022;Kumar et al 2022) also worked in this area and did experimental field and laboratory tests on different setups and compared their datasets with the theoretical curves measured from the continuum approach. This theoretical approach is also used for the study of stiffness and damping with a combination of soil and pile under varying frequencies.…”