Abstract: Terzaghi consolidation theory assumes that the consolidation coefficient is constant. Laboratory observations of the consolidation behavior exhibit discrepancies between the theory and the results. Based on Terzaghi consolidation solusion the back analysis of consolidation coefficient is conducted. The results show that the consolidation coefficient keeps changing in the process of the consolidation, ranging up to 3 orders of magnitude. The consolidation coefficient is not a fixed parameter but a process factor which repeats in each load and constantly changes in the process of consolidation.