Passive earth pressure with various backfill densities

Abstract

This paper presents experimental data of earth pressure acting against a vertical rigid wall, which moved toward a mass of dry sand. The backfill had been placed with air-pluviation method to achieve relative densities of 32.5%, 60.4%, and 82.4%. The instrumented retaining-wall facility at National Chiao Tung University in Taiwan was used to investigate the effects of soil density on the development of earth pressure. It has been found that the Coulomb and Terzaghi solutions calculated with the peak internal friction angle significantly overestimated the ultimate passive thrust for the retaining wall filled with dense sand. As the passive wall movement S exceeds 14% of the wall height H, the passive soil thrust would reach a constant value, regardless of the initial density of the backfill. The ultimate passive earth pressure was successfully estimated by adopting the critical state concept to either Terzaghi or Coulomb theory.