Lateral forces on vertical faces from sand backfill subjected to falling weights

Abstract

This project was undertaken to investigate the lateral pressures on the vertical face of a wall exerted by dynamic loadings. More specifically, it was the purpose of this thesis to investigate the pressure distribution and resulting lateral forces induced by sand backfill subjected to falling weights.

Briefly, a steel tank was filled with soil of known gradation and water content, filled to within nine (9) inches from the top. Two weights, one 32.5 lbs. and the other 65 lbs., were dropped from a height of 12'9'' above the surface of the soil. This was repeated twelve times. The load effects were picked up by BA-4 bridge amplifier and were recorded by a 447 oscillograph. The deflection on the recording paper was interpolated into pressure from calibration curves. Finally, the pressure at different levels, at different time intervals, were plotted for the final analysis.

The findings indicate that maximum stress was located at about three-fifths of the distance from the bottom, and decreased to nearly zero at about one-third of the distance from the bottom.