Earth Pressure due to Vibratory Compaction

Abstract

This paper presents experimental data on the variation of lateral earth pressure against a nonyielding retaining wall due to soil filling and vibratory compaction. Air-dry Ottawa sand was placed in five lifts and each lift was compacted to achieve a relative density of 75%. Each compacted lift was 0.3 m thick. The instrumented nonyielding wall facility at National Chiao Tung University in Taiwan was used to investigate the effects of vibratory compaction on the change of stresses at the soil-wall interface. Based on the experimental data it has been found that, for a compacted backfill, the vertical overburden pressure can also be properly estimated with the traditional equation v = ␥z. The effects of vibratory compaction on the vertical pressure in the backfill were insignificant. On the vertical nonyielding wall, extra horizontal earth pressure was induced by vibratory compaction. After compaction, the lateral earth pressure measured near the top of the wall was almost identical to the passive Rankine pressure. It is concluded that as the cyclic compacting stress applied on the surface of the backfill exceeded the ultimate bearing capacity of the foundation soil, a shear failure zone would develop in the uppermost layer of the backfill. For a soil element under lateral compression, the vertical overburden pressure remained unchanged, and the horizontal stress increased to the Rankine passive pressure. It was also found that the compaction-influenced zone rose with the rising compaction surface. The horizontal earth pressure measured below the compaction-influenced zone converged to the Jaky state of stress.

Experimental and Numerical Study of At-Rest Lateral Earth Pressure of Overconsolidated Sand

“…As the backfill height increases beyond 0.5 m, the earth pressure significantly increases at the top of the backfill compared to the bottom, due to compaction effort. These results are in good agreement with the experimental results of Chen and Fang [33], which showed higher earth pressure at the top of vibratory compacted model wall compared to the bottom. It can be concluded that the distribution of earth pressure resulted from overconsolidated sand on nonyielding walls is not hydrostatic nor following the traditional jacky's formula.…”

Interval-based parameters for stress diffusion in granular medium

“…When experimental results are given in terms of intervals the average values are generally used. Figure 3 shows variation of lateral earth pressure based on different tests (Chen & Fang, 2008). Chen & Fang (2008) studied variation of lateral earth pressure in a block of sand.…”

The Residual Lateral Earth Pressure on Retaining Wall Due to Vibratory Rollers

“…At a certain depth, the residual lateral pressure may be high enough to cause passive failure in the soil behind the retaining wall; also, the lateral earth pressure measured near the top of the wall was almost identical to the passive earth pressure estimated by Rankine theory. If the cyclic compacting stress applied on the surface of the backfill exceeded the ultimate bearing capacity of the foundation soil, a shear failure zone would develop in the uppermost layer of soil [3]. The effect of compaction on the lateral earth pressure behind retaining walls can be calculated by various methods.…”