Utility Trench Backfill Compaction Using Vibratory Plate Compactor versus Excavator-Mounted Hydraulic Plate Compactor

Abstract

Excavator-mounted hydraulic plate compactors have been widely used in utility trench backfill compaction due to their efficiency. However, there are industry concerns on the possibility of pipe damage due to the combination of static downward earth pressure exerted by the excavator arm and dynamic earth pressure induced by the excavator-mounted hydraulic plate compactor. This paper presents the results of a field study that aims to compare the performances of utility trench compaction using a conventional walk-behind vibratory plate compactor with a lift thickness of 200 mm (8 in.) and an excavator-mounted hydraulic plate compactor with a lift thickness of 200 mm (8 in.), 300 mm (12 in.), 450 mm (18 in.), and 600 mm (24 in.). A flexible PVC pipe was used. The field test results indicate that the excavator-mounted hydraulic plate compactor delivered comparable compacted dry mass densities with a lift thickness of 200 and 300 mm as the walk-behind vibratory plate compactor did with a lift thickness of 200 mm; however, the excavator-mounted hydraulic plate compactor was not able to consistently achieve adequate compacted dry mass densities with a lift thickness of 450 and 600 mm. The excavator-mounted hydraulic plate compactor induced larger dynamic vertical earth pressures than did the walk-behind vibratory plate compactor.