Excavation-induced ground movements can impose significant horizontal strain on adjacent structures, potentially causing damage. This study quantitatively examines the effect of foundation axial stiffness on horizontal strain induced by such ground movements. A numerical parametric study consisting of 350 cases was performed over a wide range of relative soil-to-foundation axial stiffness (E s L²/E F A) and foundation contact pressures. The results show a clear nonlinear relationship between the normalized building-to-ground horizontal strain ratio (ε L /ε hg ) and relative axial stiffness. Specifically, ε L /ε hg increases from less than 0.1 at low relative stiffness (E s L²/E F A 10³), with a distinct transition over E s L²/E F A ≈ 1–100. Within this range, a representative reference point appears around E s L²/E F A ≈ 10, beyond which foundation axial stiffness significantly reduces horizontal strain transfer, limiting induced structural strain to about 40% or less of green-field ground strain. Foundation contact pressure also affects the response envelope, especially at low to moderate stiffness levels. The proposed upper-bound design curve agrees well with previous numerical and field studies. These findings highlight the importance of explicitly considering foundation axial stiffness in design and assessment to mitigate excavation-induced structural damage.
Moorak Son (Fri,) studied this question.