Study on the Consolidation Mechanism of Clays under Cyclic Loading by Using the Separate-Type-Consolidometer

The soft clay layers are often subjected to the change in vertical load due to the tide, the pumping of ground water and the repetition of the process of filling and discharging from oil storage tank, etc. From the results observed in the field or in laboratory tests, it can be seen that the settlement characteristics of clay layers under such a cyclic loading conditions are different from that under static loading conditions. The consolidation mechanism under cyclic loading conditions, however, has not been clarified. So, in this paper, consolidation tests using the separate-type-consolidometer for the Ariake Clay were performed under cyclic loading conditions. The excess pore water pressure and the deformation inside the clay specimen were then measured and evaluated using Wilson's consolidation theory. As a conclusion, the following properties are obtained. 1) The distribution of the settlement in strain inside the clay layer does not become uniform in the drainage direction even if the number of cycles increase remarkably. 2) The distribution of the excess pore water pressure is considerably affected by the number of loading cycles