Effect of Surrounding Soil Properties on the Attenuation of the First Guided Longitudinal Wave Mode Propagating in Water-filled, Buried Pipes

J. Ocean Eng. Technol. 2010;24(4):32-37.

Lee Ju-Won,Na Won-Bae,Shin Sung-Woo,Kim Jae-Min

Department of Ocean Engineering Pukyong National University,Department of Ocean Engineering Pukyong National University,Division of Safety Engineering Pukyong National University,Department of Civil and Environmental Engineering Chonnam National Unive

주변 흙의 특성이 물이 찬 매립된 배관에서 전파되는 기본 유도 종파 모드 감쇠에 미치는 영향

이주원,나원배,신성우,김재민

부경대학교 해양공학과,부경대학교 해양공학과,부경대학교 안전공학부,전남대학교 건설환경공학부

Keywords: Degree of saturation, Compaction, Guided ultrasonic waves, Buried pipe, First longitudinal wave mode, Attenuation, Frequency range

핵심용어: 포화도, 다짐, 유도초음파, 매립된 배관, 기본종파모드, 감쇠, 주파수 대역

Abstract

This study presents the attenuation characteristics of the first guided longitudinal wave mode propagating in water-filled, buried steel pipes in order to investigate the effects of soil saturation and compaction on the attenuation patterns. For numerical calculation of attenuation, 10 different combinations of S-wave velocity, P-wave velocity, and soil densities were considered. From the attenuation dispersion curves, which were obtained using Disperse software, we determined that the attenuation decreases as saturation increases, whereas it increases as compaction increases. Over the frequency range from 0.2 to 0.4 MHz, the first longitudinal wave mode has attenuations that are relatively lower than for other ranges, is faster than the first flexural wave mode, and is sensitive to defects aligned in the axial direction. Hence, the first longitudinal wave mode over the mentioned frequency range would be the proper choice for long-range buried pipelines that transport water.