Performance of buried rigid pipes under the application of incrementally increasing cyclic loading

Abstract

In this research, the performance of buried rigid pipes under the application of incrementally increased cyclic loadings was experimentally investigated as a function of the pipe burial depth variation using a fully instrumented laboratory rig. Results illustrated that the maximum footing settlement occurred during the first 300 cycles of the 1st loading phase, where its rate significantly decreased while applying further loading cycles. At a shallow burial depth and under the application of the 1st loading phase, the pipe strains and deformations followed non-uniform patterns, which were controlled by the crown pressure behaviour. An invert rebound occurred, where it was quick and sharp at shallow burial depth, and smooth at deeper burial depths. Significant decrease in the pipe strains and deformations, and the footing settlement was observed with the increase in the pipe burial depth; despite the passive arching mechanism domination. Similar strain patterns were recorded along the pipe crown, invert and spring-line, where maximum and minimum values were observed along the invert and the spring-line, respectively. The paper provides deeper understanding of the overall behaviour of shallowly and deeply buried rigid pipes under cyclic loadings. The results may enhance the current design guidelines for pipes installation to maintain the long-term durability of these pipes.