CENTRIFUGE MODEL TEST FOCUSING ON DEFORMATION BEHAVIOR AFTER PRELOAD REMOVAL ON SOFT GROUND AND ITS EVALUATION

Abstract

 A preloading method is one of the typical soft ground improvement technologies. This method is often used in combination with vertical drains. The amount of residual settlement after the start of service is determined by conventional calculation methods or consolidation analysis using the finite element method. However, the calculation of settlement after preload removal is not necessarily accurate. Therefore, predicting the final settlement based on observations during construction is generally performed. To predict the residual settlement with high accuracy, it is necessary to evaluate the long-term settlement including secondary consolidation. For model experiments on preload removal, it is important to consider the self-weight of soft ground with thick layers. In this study, centrifuge model tests were conducted focusing on the deformation behavior after the preload is removed to improve the accuracy of residual settlement calculations. To predict the behavior after preload removal, a simple calculation method using a finite difference method based on the isotache concept was proposed. This method enables the evaluation of behavior after unloading including secondary consolidation.