ANALYSIS MODEL TO SIMULATE THE CRACKED PIPE BURIED IN SOIL

This paper describes the use of the finite element method to simulate crack propagation in a pipeline in the presence of soil backfill. Sinc e typical values for soil modulus are known, a spring element can be u sed to simulate the effects of backfilled soil on crack propagation. T his consists of the relationship between the soil property and the sti ffness of the spring element, and the effect of backfill depth on the crack propagation in the pipes. By equating crack driving force, G, in the presence of soil, to the dynamic fracture toughness of the pipeli ne material, a theoretical predictive capability is obtained for the f irst time for the gas transmission and distribution pipelines. Numeric al calculations have also been carried out for the cracked pipe with b ackfill and without backfill.