Verification of the deflection measurements method in the Lebanese soft rocky geo-material in excavation

摘要

In order to validate the design of retaining systems in deep excavation, measurements of site deformations become necessary. Usually, horizontal displacements are measured using inclinometers and vertical 6×6 cm steel gains. These gains are often installed in the rigid or flexible vertical concrete element. In this case we consider that the displacement of soil is the displacement measured in this element. However, this assumption is to be reconsidered. The aim of this paper is to analyze the efficiency of this in situ method of measurement. We present qualitative comments on the measurements realized in three sides of a deep excavation in cohesive sandy soil in Lebanon. These measurements are performed using gains installed in vertical piles used for shoring and other gains installed freely in soil. The back analysis of the structure will show the influence of each method on the measurements. The influence of the friction between steel gain and the soil is calculated using the interface parameters in the calculation using finite element code.