USE OF CHARTS FOR RELIABILITY-BASED DESIGN OF EMBANKMENTS ON SATURATED CLAY LAYER

ABSTRACT Many research works on the method of the reliability-based design for the geotechnical engineering field have been published for this decade and the applications to the practical design are tried now. In this phase, two problems which bother the engineers occur. One is difficulty and trouble to calculate the probability of failure and the other is the engineers’ feeling to resist to accept the new design method. The present study mainly aims to overcome the former difficulty. The optimum design problems of an embankment constructed on a saturated clay layer are taken up and the charts to easily obtain the probability of failure are given after the general formulations are carried out. In order to soften the second difficulty mentioned above, the procedure to decide the probability of failure through the safety factor is introduced. It is possible for the engineers through this procedure to compare the results of the reliability-based design with those by their traditional methods. In addition, the loss functions to estimate the design alternatives are also formulated and for the purpose to make it easy to understand how to use the charts, several numerical examples optimizing the design of an embankment are shown and the results are discussed in comparison with those by the traditional safety factor method.