Shield tunneling in urban areas can generate ground vibrations that may threaten adjacent buildings, especially in hard rock strata. However, the effect of foundation type on the vibration response of multi-story buildings is not yet fully understood. This study investigates this issue through a combined approach of field monitoring and three-dimensional numerical simulation based on the Jinan Metro Line 4 project. Five-story frame buildings with pile, raft, and isolated footing foundations were analyzed, and the numerical model was validated against measured data to ensure reliability. The results show that vibration waves attenuate in an approximately symmetric elliptical pattern and are amplified by the presence of buildings. A significant vertical amplification effect is observed, with peak particle velocity at the top floor reaching up to 2.11 times that at the ground surface. Foundation type exerts a significant influence on vibration transmission. Raft foundations exhibit a more uniform vibration distribution, whereas isolated footings demonstrate a weaker attenuation capacity, with only 23.6% attenuation and a first-floor response approximately 3.3 times greater than that of pile foundations. Although the structural safety requirements are satisfied, the vibration levels at upper floors may still exceed the human comfort limit of 75 dB, with the pile-founded building reaching 85.38 dB. These findings improve the understanding of vibration transmission mechanisms under symmetric disturbance conditions and provide a scientific basis for foundation selection and vibration mitigation in urban tunneling projects.
Wang et al. (Wed,) studied this question.