Effect of Backfilling Material Under Structures on Ground Motion Characteristics Due to Earthquake

Abstract

Due to limited areas and excessive cost of land for projects, backfilling process is become necessary. Also, backfilling will be done to overcome the un-leveling depths or raising levels of site construction, especially near the sea region. Therefore, backfilling soil materials used under the foundation of structures should be investigated regarding its effect on ground motion characteristics, especially at regions subjected to earthquakes. In this research, three thicknesses of sandy fill material of 20 m, 40 m and 60 m thicknesses are used to predict the modified ground motion characteristics effect at the foundation level. Comparison between the effect of using different thicknesses of sandy fill material above the natural soil strata on the recorded earthquake is studied, i.e., peak ground acceleration, time history, and spectra acceleration values. Shake computer program was used to perform this study. Strong earthquake records, with PGA (Peak Ground Acceleration) of (0.35 g) were used in the analysis. It was found that, higher fill material thickness has a significant effect on eliminating the earthquake ground motion properties at surface layer of fill material, near foundation level. It is recommended to consider the fill material thickness in the design of foundations subjected to seismic motions and more future studies should be analyzed for different fill and natural soil deposits.