A CONSTITUTIVE EQUATION OF ONE-DIMENSIONAL CONSOLIDATION DERIVED FROM INTER-CONNECTED TESTS

Abstract

In order to investigate the general relationship between void ratio e, effective stress σ' and time t at any element in a consolidating clay specimen, an inter-connected consolidometer was developed and a series of experiments on a remolded marine clay was conducted. In the experiments, several thin subspecimens were prepared in individual consolidation cells in the same way, while their drainage channels were connected successively. During consolidation, the settlement of each subspecimen and the pore water pressure between adjacent subspecimens were measured continually, and vertical distributions of e and σ' in the specimen and their changes with time were obtained by calculation. The results obtained showed that on an e-σ' plane there exists a family of e-σ' lines each of which uniquely corresponds to certain value of void ratio rate e. This constitutive model f(e, σ', e) = 0 for the clay skeleton was further experimentally verified for different consolidation conditions. Then the model was used as a tool to explain the effects of layer thickness on compressive strain by consolidation, resulting in good agreement with simulated experiments. The permeability characteristics were also examined for the clay by use of the experimental data. It was found that permeability coefficient varies exponentially with void ratio.