Coupled TDA–Geocell Stress-Bridging System for Buried Corrugated Metal Pipes

Abstract

The interaction between surface structures and buried pipes is unavoidable. For instance, placing the pipe at a shallow depth, near to the surface, attracts substantial additional earth pressures due to the external surface loading, causing overstressing or unacceptable deformations of the buried pipe. Several alternatives may be used to mitigate this situation, including using induced trench construction, using lightweight fill material to reduce imposed loads, and finally relocation of the pipe, which is the most expensive and least desirable alternative. The characteristics of the used backfill material control the pipe–soil interaction mechanism and thus the amount of exerted pressures. Using lightweight compressible materials, such as tire-derived aggregates (TDA), above buried pipes has long been investigated to reduce pipe stress. However, such materials may result in undesirable surface settlement that may compromise the pipe performance. In this paper, a coupled TDA–geocell stress-bridging system was developed utilizing six full-scale tests and a comprehensive three-dimensional (3D) finite-element modeling component. The developed system uses a geocell-reinforced top granular backfill layer over the TDA layer to induce a stress-arching mechanism capable of reducing the imposed stresses on the pipe below and control the surface settlement.