Experimental investigation of the earth pressure distribution on buried pipes backfilled with tire-derived aggregate

This paper presents the results of an experimental investigation that has been conducted to measure the earth pressure distribution on a rigid pipe buried in granular material and backfilled with tire-derived aggregate (TDA). An experimental setup has been designed and built to allow for the installation of an instrumented pipe in granular material and measuring the contact pressure acting on the pipe wall. Tactile sensing technology is used in this study to measure the soil pressure acting on the pipe. This method allows for a continuous pressure profile to be recorded using flexible sheets that follow the cylindrical shape of the pipe. Two sets of experiments are performed in this study-one set with only granular backfill material (benchmark tests) and the second involved the introduction of a soft zone of tire-derived aggregate above the pipe. Results show that the induced trench installation, described in this study, was successful in reducing the vertical loads on the buried pipe. The average measured earth pressure above the crown of the pipe was found to be as low as 30% of the overburden pressure for installations with granular backfill material. Significant reduction in radial pressure was also recorded at the invert with pressure reduction of about 77% with the introduction of the soft TDA zone.