摘 要 Terzaghi於1925年所提出的單向度壓密理論其優點是解析解易求得；缺點則是低估了超額孔隙水壓，Gibson等人便根據Terzaghi理論的缺失來進行修正，於1967年提出飽和黏土的壓密方程式，為一非線性的偏微分方程式。其優點為假設條件較符合土壤壓密的實際情況；缺點則是解析解不容易求得。不過由最近發表的文獻中，可知已能將Gibson理論的薄黏土層的單向度壓密方程式予以線性化，進而求出其近似解。 本研究主要是利用差分法來求出Gibson薄、厚土層壓密方程式的近似解，並且跟Terzaghi壓密理論與速算公式的結果作一比較，以提供作為工程設計時的一個參考。 Abstract Gibson and his co-workers proposed a nonlinear theory of consolidation in 1967, which was derived by conditions more realistic than those applied in the Terzaghi’s theory. Even if the analytic solutions to the nonlinear theory are difficult to obtained, some progress has been made recently using a special type of linearization. A handy formula has thus derived which can calculate the settlement quickly. This research try to compare this handy formula with the Gibson’s theory as well as the Terzaghi’s theory. And some positive results has been obtained.