Theoretical analysis for thermal consolidation of marine sediments with depth variability subjected to time-dependent loading and heating

Abstract

Because the spatial distribution of energy is restricted, many energies geotechnics would build on marine sediments and the resulting thermal consolidation would pose an inevitable threat to the safety and stability of the project. In this study, a new governing equation for thermal consolidation of saturated marine sediments is proposed, by considering the depth variability of the marine sediment layer and the time-dependent external loading and temperature. The corresponding one-dimensional (1D) analytical solution for thermal consolidation of saturated marine sediments is derived. The average degree of consolidation (Ua) and the normalized excess pore water pressure (u/u0) in the saturated marine sediment layer at different depths and time durations are calculated and compared with the typical loading case. The results show that the loading rate of the external force only affects the amplitude of the excess pore water pressure u and does not affect the proportion of u with depth; the depth variability of bulk modulus has a greater effect on the distribution of Ua relative to the depth variability of permeability; the depth variability of permeability has a greater effect on the distribution of u/u0 with depth relative to the depth variability of bulk modulus when Ua = 50%; the assumption of instant thermal loading will lead to an over-assessment of Ua and u/u0. This study provides useful insights for energy geotechnical engineering design and practice.