Prediction of Pore Pressure Dissipation Behavior from CPTU Dissipation Test Data

For normally consolidated clay, several researchers have developed a number of theoretical time factors to determine a coefficient of consolidation from piezocone test results. These researches are basically related to the distribution of initial excess pore pressures. However, the coefficient of consolidation determined by those methods not only make predicted dissipation curve matched to measured dissipation curve only at 50% degree of dissipation but also make it difficult to predict the excess pore pressure at high-degree of dissipation which is used to evaluate the degree of consolidation of in-situ site. Therefore, such methods have some troubles in predicting long-term behavior of soft soil by using a linear consolidation theory with their prediction of the coefficient of consolidation. Based on the previous results that the coefficient of consolidation could be reasonably estimated by the optimization technique, in this paper, we have tried to predict more realistic excess pore pressure at high degree of dissipation. Even though more researches are needed to apply the proposed method to the domestic construction sites, the results show that excess pore pressure at high degree of dissipation can be well predicted if the proposed method uses the dissipation curve data up to around 50% degree of dissipation.