Usage of Tyre Derived Aggregates as Backfill Around Buried Pipelines Crossing Strike-Slip Faults; Model Tests

Abstract

Buried pipelines crossing active faults are exposed to excessive soil forces under fault movements due to large relative movement between pipes and the soil surrounding them. As a result, extreme longitudinal strains develop within pipelines under large fault movements and this leads to pipeline failures. Several seismic mitigation techniques were proposed to improve the performance of buried pipelines crossing active faults. In this study, the potential of using Tyre Derived Aggregates (TDA) as a backfill material for mitigating the effects of strike-slip faulting are investigated through physical model tests. First, the details of the physical model test setup and model configuration are presented. Then a comparative study is carried out to study the effect of TDA content in the backfill and trench configurations on TDA mitigation. Model tests revealed that using a sloped trench with 100% TDA content in the backfill can decrease peak axial pipe strains up to 62% and peak bending strains up to 19%. It is observed that enlarging the trench and using an inclined trench improve the performance of the TDA mitigation technique.