Performance Evaluation of a Plastic Foundation for Sewage Pipeline

Abstract

Abstract Earth pressure (i.e., the overburden pressure caused by hydraulic pressure and vehicle traffic loads) affects sewage pipelines. In particular, backfill materials and the execution of works considerably affect the amount of damage to sewage pipelines. A plastic foundation has been developed to reduce this damage. The load-deformation test results obtained using a universal testing machine show that the load of a rigid concrete pipe (a typical rigid pipe) increased when the contact angle of the lightweight plastic foundation increased. When the contact angle was 135°, as in case A1 in this study, 4.1 tons and 3.4 tons were measured at the sockets and pipe body, respectively. For a contact angle of 90° (case A2), the destructive strength was measured as 3.7 tons at the sockets and 2.9 tons at the pipe body. Overall, the deformation of the pipe resulted in tensile strain in the diametrical direction, and slight shrinkage occurred in the longitudinal direction of the pipe as a result of loading on a prefabricated lightweight plastic foundation. For the foundation of the polyethylene triple-wall corrugated pipe, 100 % new plastic was used for case B1, whereas 50 % recycled plastic was used for case B2. The results show that 1.49 tons were observed at 5 % of pipe strain for case B1, whereas 1.35 tons were observed at 5 % of pipe strain for case B2. The recycled plastic foundation showed a tendency to somewhat reduce the load relative to the foundation that consisted of original materials. The results of destructive strength tests on a plastic foundation show that case B1 featured 13.78 tons of loading and 5.16 mm of deformation, whereas case B2 showed 9.66 tons of loading and 5.41 mm of deformation.