Improved prediction of pile bending moment and deflection due to adjacent braced excavation

Deep excavations in dense urban areas have caused damage to nearby existing structures in numerous
past construction cases. Proper assessment is crucial in the initial design stages. This study develops equations to predict
the existing pile bending moment and deflection produced by adjacent braced excavations. Influential parameters (i.e.,
the excavation geometry, diaphragm wall thickness, pile geometry, strength and small-strain stiffness of the soil, and soft
clay thickness) were considered and employed in the developed equations. It is practically unfeasible to obtain
measurement data; hence, artificial data for the bending moment and deflection of existing piles were produced from
well-calibrated numerical analyses of hypothetical cases, using the three-dimensional finite element method. The
developed equations were established through a multiple linear regression analysis of the artificial data, using the
transformation technique. In addition, the three-dimensional nature of the excavation work was characterized by
considering the excavation corner effect, using the plane strain ratio parameter. The estimation results of the developed
equations can provide satisfactory pile bending moment and deflection data and are more accurate than those found in
previous studies.