Analyzing Three-dimensional Consolidation Problems of Multi-aquifers due to Point Force and Point Sink by Displacement Function

Abstract

This thesis used the displacement function method to solve three-dimensional consolidation problems caused by point force or point sink The displacement functions are the fundamental solutions of Biot’s poroelastic equations in the Laplace-Fourier transformed domain and are represented by exponential functions However at extremely short time or when soil layer is very thick or when the permeability between soil layers differs significantly the components in the exponential functions exceed the limit of calculation in MATLAB Hence numerical difficulty occurs in these extreme cases To improve this method and to reduce computational time we developed several numerical techniques We solved the consolidation of multi-aquifers cause by point force or point sink applied at different depths We also discussed the effect of aquitard on the consolidation Finite element axisymmetric models were carried out to compare with the numerical results calculated by the displacement function method The comparison show very good agreement between two methods According to the results (1) when the location of point force or the point sink is closer to the surface the maximum settlement is larger but the range of influence is smaller Also the range of influence due to point sink is wider than that due to point force (2) In general the pore pressure observed at a single point cannot be used to determine whether the displacement at the same point has reached a steady state

Date of Award	2019
Original language	English
Supervisor	Yu-Yun Lin (Supervisor)