Papers by Author: Jong Woo Rhee

Abstract: This paper examined the fundamental problem of an interaction between a soil medium that experiences frost heave in a closed system and an underground pipeline. The coupled thermal transfer and structural analysis, considering the material nonlinearity of freezing soil, for an underground pipeline subjected to the low cyclic load was focused on the development of computational scheme by introducing the effective heat capacity concept and the effective thermal expansion coefficient into the study. The effective heat capacity model in the thermal transfer analysis took into consideration the phase-change effect in the frozen fringe of a soil medium. The comparative analyses between the theory and the actual performances were valuable in establishing a level of confidence in the application of introduced theory to the field. The numerical results in the paper illustrated the influence for the frost heave of a soil medium on the temperature-dependent development of stress fields on metallic underground pipe walls in South Korea.

Abstract: This study performs dynamic analysis of underground structures on multi-layered half planes in frequency domain by using the coupled finite and boundary element method. The near field including underground structures is modeled with onventional finite elements, while the far field is modeled with boundary elements which satisfies radiation conditions. In evaluating the dynamic fundamental solutions, semi-analytical solutions due to line loads are employed. Therefore, the range of wavenumber integration can be reduced significantly. These solutions satisfy the reflection and transmission conditions of waves at each layer interface, so that the multi-region problem can be analyzed. Numerical examples are given to demonstrate the accuracy and efficiency of the proposed method.