Passive wedge formation and limiting lateral pressures on large foundations during lateral spreading

Four centrifuge tests supplemented by calibrated numerical simulations were performed to evaluate passive wedge formation and limiting lateral pressures imposed on a large, stiff foundation during liquefaction-induced lateral spreading. In the centrifuge tests lateral pressures on the upslope and downslope faces of the foundation were measured using tactile pressure sensors. Lateral pressure distributions also were extracted from the simulations. Available methods to estimate the limiting lateral pressure distributions, including the Rankine, Broms, Japanese Road Association, and strain wedge methods were compared to the measured and simulated pressures. However, existing models did not capture the observed pressure distributions even when the size and shape of upslope passive wedge was defined directly from surface and subsurface displacement patterns in the centrifuge tests. A new semiempirical method is proposed to estimate limiting lateral pressures that accounts for the three-dimensional shape of the upslope passive wedge. This method produces an upslope limiting pressure distribution consistent with centrifuge-measured pressure distributions.