FIELD MEASUREMENT AND ANALYSIS OF VIBRATION REDUCTION EFFECT OF STEEL SPRING FLOATING PLATE AND VIBRATION RESPONSE STUDY ON SURROUNDING BUILDING

Shan Ao, Feng Lili, Wang Dongfang, Luo Yanyun

ABSTRACT: In order to realize the vibration reduction effect of steel-spring floating slab to surrounding buildings, by taking the rail transit underground of a city as the research object, three sites, with the ordinary track bed on the line, with the steel-spring floating slab on the line and the curve, were picked out. At the former two sides, a series of field measurements of vibration characters of the rail, the bed and the tunnel wall induced by the train passing by were carried out to explore the vibration reduction effect of steel-spring floating slab on the line. Meanwhile, the vibration response of surrounding buildings around the line were also tested and analyzed. The experimental results showed that: (1) With the steel-spring floating slab on the line and the curve, the vertical vibration acceleration level of the tunnel wall was both lower than that on the line with the ordinary track bed in the frequency range of 20- 200 Hz. Therefore, the steel-spring floating slab on the line had a good vibration isolation performance. (2) At the sites with the steel-spring floating slab on the line and the curve, the acceleration level of the measurement points on the ground were mainly concentrated on the frequency range of 0-160 Hz, with the significant peaks around 40-80 Hz. With the increase of the distance away from the central line of the tunnel, the levels decreased first, then increased and decreased again. Specifically, the increase of the acceleration level appeared mainly at the distance 5.5-10 meters away from the line. (3) At the site on the curve, the acceleration levels of all the measurement points on the ground were higher considerably than that at the site on the line. As a consequence, the vibration reduction effect of the steel-spring floating slab on the curve had a relative bad performance on the response of the surrounding buildings, which might be caused by rail corrugation or track irregularity. This cause would be studied in the further study.

Keywords: Steel-spring floating slab, vibration transmission, field experimental analysis, curve