Torsional guided-wave attenuation in coal-tar-enamel-coated, buried piping

摘要

Attenuation of the fundamental torsional guided waves in a coal-tar-enamel-coated pipe was investigated experimentally over a 5 - 30-kHz frequency range and up to a 1.7-m soil cover. The attenuation coefficients in the coated pipe above the ground were an order of magnitude greater than in bare pipe and, over the frequency range studied, it increased approximately linearly with frequency. Soil cover on the pipe caused the attenuation to increase significantly further-by a factor of three to ten at a 1.7-m cover depth-and altered its frequency dependence to become somewhat parabolic with a minimum point.