ABSTRACT
A model ground was constructed in a soil chamber 98 cm wide, 40 cm long and 45 cm high as schematically shown in Figure 1. The backfill material used was Toyoura sand, a uniform fine sand with a mean particle size of 0.16 mm and a specific gravity GS of 2.65. The maximum void ratio emax was 0.709 and the minimum void ratio emin was 0.480. A model pipe
1 INTRODUCTION
An underground conduit laid under different environments exhibits various behaviours according to the ground and external load as well as the loading time and conditions. The design of buried pipes usually demands ensuring good compaction of backfill soil, as it is well known that their behaviour is largely governed by the properties of surrounding backfill. However, in practice, it does not seem to be always easy to ensure good compaction, due to the congested and limited surrounding space.
