Text

theses

Ground-borne vibrations from construction activities, high-speed trains, and machine foundations can adversely affect the operation of sensitive equipment and damage structures. A wave barrier installed near the vibration source or in the area requiring protection can attenuate the vibrations by reflecting or scattering the wave energy. Wave barriers, including piles, sheet piles, and open or in-filled concrete, bentonite slurry or geofoam trench barriers, have been studied comprehensively, with various degrees of success reported. For this dissertation, the beneficial use of tire shreds as an isolation medium in trench barriers was investigated, and design guidelines were developed. The performance of in-filled tire-shred trench barriers was comprehensively studied through numerical and experimental investigations. Two- and three-dimensional finite element models were developed using the ABAQUS package. The numerical models were validated, either through reference models or field measurements. The models were initially used to study the influence of geometrical parameters on the effectiveness of in-filled trench barriers for screening active (near-field) vibrations and for the design of a full-scale experimental program. Based on the findings of the numerical investigation, a full-scale experimental study was designed and implemented to study the performance of in-filled tire-shred trench barriers. Because of the size of the tire shreds used in this study (50mm and 200mm), a full-scale study was warranted. Conventional construction equipment was used for the trench installation and placement of the tire shreds. A series of tests was conducted for open and in-filled trench barriers (with circular, semi-circular and linear configurations) to assess the performance of tire shreds relative to air, which is the most effective isolator, for full and partial isolation. The experimental study confirmed that the screening effectiveness of in-filled trench barriers is comparable to that of open trench barriers. A parametric study was conducted to investigate the influence of key dynamic soil properties on the performance of in-filled trench barriers. For partial isolation cases, the limits of the effectively screened area behind a semi-circular and linear trench barrier were accurately delineated. Guidelines for the design of in-filled trench barriers were then developed.

ETD_7514

Ph.D.

Includes bibliographical references

by Farhad Jafari

doi:10.7282/T3571F9V

ETD doctoral