Theoretical and numerical analyses of a half space with overlying liquid subjected to an internal line load. Issue 126 (November 2019)

• Record Type: Journal Article
• Authors: Yang, Y.B.; Li, P.L.
• Is Part Of: Soil dynamics and earthquake engineering. Issue 126(2019)
• Publication Date: 2019-11
• Subjects: Finite/infinite approach -- Half space -- Line load -- Liquid -- Wave propagation; Soil dynamics -- Periodicals; Earthquake engineering -- Periodicals; Sols -- Dynamique -- Périodiques; Génie parasismique -- Périodiques; 624.176205
• DOI: 10.1016/j.soildyn.2019.105823
• Languages: English
• ISSNs: 0267-7261

Abstract

Abstract: The dynamic response of a 2D half space with overlying liquid under an internal line load is analytically and numerically studied, as a first attempt toward simulating undersea tunnels with moving loads. Firstly, the wave equations in partial differential form are derived from the equations of motion of the solid and liquid in rectangular coordinates. By the Fourier transformation, the wave equations are converted to the ordinary differential form. Then, a formulation is presented for the Scholte waves existing at the interface between the liquid and solid, with related properties unveiled. Numerically, the 2D half space is modeled by finite and infinite elements for the near and far fields, respectively, and the liquid of infinite depth as equivalent nodal loads. The present analytical solutions compare well with Ewing's, with minor deviations owing to different load definitions. Also, the computed results are consistent with, but more reliable than the analytical ones, since the singularity effect near the loading point has been circumvented. Shallow liquid has little effect on the response of the solid. The displacement of the solid decreases as the liquid depth increases. It fluctuates with decay along the horizontal axis and reaches a limit for liquid depth approaching infinite. Highlights: Dynamic response of 2D half space in seabed under internal load. Liquid classified as finite or infinite based on its attenuation. Analytical solution differs slightly from Ewing's due to loading. FEM solutions are more reliable than analytical ones for no singularity. Deep liquid decreases the half-space displacement.