Performance Improvement of Underground Pipe Line Foundation Using Recycled Materials

Abstract

According to the Seoul City survey, about 84% of the occurrence of ground subsidence was the main cause of damage to the sewer pipe, and it was related to the aging of the sewage pipe foundation and the sewage pipe itself. To reduce the damage, a combination of field-assembled recycled plastic foundation and a fluid backfill material was applied. The bearing capacity, settlement, and pipe safety factor were evaluated for comparison with the existing crushed stone foundation and concrete foundation. The change in settlement was relatively small, according to the type of backfill used in the analysis. As for the support method used when selecting the foundation for the sewage pipe for a rigid pipe, it was found that applying a fixed type rather than a free type improved the safety of the pipe. The field-fabricated recycled plastic foundation has less material rigidity than the concrete foundation, but to compensate for this, applying the fluid backfill using 2% to 4% cement had the effect of increasing adhesion and enhancing the strength of the backfilling material, thus increasing the safety of the installed pipe.