Experimental study on a geosynthetics isolator for the base vibration isolation of buildings neighboring metro transportation

Abstract

By replacing the polyethylene terephthalate (PET) package of stacked sandbags by polyethylene naphthalate (PEN) textile capsule from air springs, a new geosynthetics isolator is developed to improve the mechanical properties of stacked sandbags. Sand and rubber particles were mixed and used to fill the isolator as a soil skeleton. The mechanical testing results showed that the vertical stiffness and damping performance could be easily adjusted by changing the particle mixture ratio. The horizontal stiffness is approximately a quarter of the vertical value, and the horizontal damping ratio is as high as 25%. The ultimate shear strain and compressive stress are 15% and 40 MPa, respectively. Both of these values are much greater than that of stacked sandbags and are appropriate for most buildings near metro transportation. The feasibility of the isolator is verified via field experiments with a full-scale building. After installing the new isolators, the vibration comfort of occupants in the vertical and horizontal directions is significantly improved, as is the secondary air-borne noise comfort. Moreover, the resonant influences caused by vertical and horizontal low-frequency road vibrations are suppressed by the isolator's high-damping performance. Therefore, this geosynthetics isolator is feasible for the base isolation of buildings neighboring metro transportation.