This research aims to study the deformation behavior of polyvinyl chloride (PVC) and high-density polyethylene (HDPE) pipe buried in the trench containing various types of materials such as sand, sand-EPS (Expanded Polystyrene) derived aggregate, and sand-fly ash-cement-EPS derived aggregate. The sizes of beads in the range of 4-5 mm were considered for modelling, and EPS content varied from 0.05 to 0.20% for the sand-EPS derived aggregates and 0.25 to 0.45% for the sand-fly ash-cement-EPS derived aggregates. Other variables such as pipe diameter (from 0.5 to 1.2 m) and placing depth (from 0.3 to 0.9 m) were also considered. Results show that PVC and HDPE pipes generally have reduced deformations when wrapped with sand-EPS derived aggregate, with the exception of larger pipes with increased deformations at the bottom and left side of the pipe. The deformation decreases at all points for the HDPE pipes (0.9 m diameter), while for the larger diameter pipes (1.2 m), the deformation trend changes at certain points. The results of this study may help to understand the use of compressible material as a backfill for underground pipes and the different behaviours of the pipes when exposed to these materials depending on pipe material, pipe diameter.