紧邻既有电力管廊多桩旋挖施工振动影响研究OA

Rotary drilling for bored cast-in-place piles in hard strata generates significant vibration loads.Especially,si-multaneous operation of multiple rotary drilling rigs can severely affect the safety of nearby underground structures.To in-vestigate the combined vibration effects of multi-pile construction,the excavation of a station on Jinan Metro Line 4 was tak-en as the research project.A combined approach of field testing,numerical simulation,and on-site monitoring was used to analyze the vibration effects of multi-pile rotary drilling near the existing power pipe gallery.It is concluded that during rota-ry drilling in hard strata,the maximum vibration acceleration occurs at the depth of the drill bit,and primarily affects the ar-ea about two times of pile diameter above and below the drill tip point.Compared to single-pile construction,as the number of simultaneous piles increases,there is a significant amplification effect for the vertical vibrations of the power pipe gallery's sidewalls and both horizontal and vertical vibrations of the top slab,pronounced multi-peak phenomena occur in the side-wall's horizontal vibrations,but the peak vibration velocity remains nearly constant.The coupling effect of vibration decreas-es as the pile spacing increases during multi-pile simultaneous construction.When two piles are drilled at the same depth,the amplification effect is notable,and the coupling effects are obvious within the range of twice the pile diameter relative to drilling depths.The coupling effects diminish as depth differences increase,and approximate to single-pile effects at a differ-ence of five times of the pile diameter.Based on these results and discussions,vibration control measures for multi-pile rota-ry drilling were proposed and validated through on-site monitoring.This study has provided a reference for related engineer-ing projects.