Effectiveness of the Observational Procedure for Excavation Works

Abstract

The observational procedure is often used for difficult excavation works such as large-scale excavation, excavation with extensive depth, excavation in soft ground and excavation neighboring other structures to improve construction management. Features of the observational procedure are in respect of the optimum design change (the posteriori design) from measurement data under construction, when the uncertainty in the design before construction (the prior design) was positively recognized. However, it is difficult to judge whether it was “optimum design”, sincethe construction work is generally a single item production in the field. Therefore, there are not small cases in which the evaluation that it becomes the disturbance of the construction is received on the observational procedure. In this paper, the effectiveness in safety and economical efficiency of the observational procedure is objectively evaluated by the comparison between non-observation construction and observational procedure. The approach of expectation total cost used in the reliability design is used for the method of the evaluation of the effectiveness.