Ground Movements and Nonlinear-Inelastic Response of Buildings Induced by Excavations in Glacial Clay Deposits

The analysis of ground movements and nonlinear response of buildings induced by excavations in glacial clay deposits is conducted using finite element models built in PLAXIS2D and OpenSees. PLAXIS2D was used to simulate the performance of an urban cofferdam excavation braced with a concrete bracing system. Measured ground movements were compared with the computed response, and the influence of the temperature, installation, and curing effects on the concrete bracing is evaluated. Concrete time-dependent effects contributed to 32% of the maximum lateral wall movements. The numerical studies are expanded in a second finite element analysis to characterize the coupled fluid-solid response of fully saturated soils. Parametric analyses are conducted, and a design method aimed at determining the governing drainage characteristics, changes in excess pore water pressures, and ground movements induced by the excavation is presented. The method is validated with published case histories. The proposed method adequately described the pore water pressure buildup and excavation-induced ground deformations. A quasi-static framework for the modeling of fully saturated soils under partially drained or fully undrained conditions is presented. The implementation of a traction interface for the interaction between soil and foundation is also presented. Results confirmed the assumption that initial gravity forces acting on buildings can lead to more flexible responses, developing settlement profiles similar to those computed under free-field conditions. The nonlinear-inelastic building response to excavation-induced ground movements in glacial clay deposits is evaluated for the first time in the technical literature using OpenSees. Soil-structure interaction effects are parametrically studied, varying the proximity of the buildings to the excavation, the building aspect ratio, and stiffness and strength of beams and columns. Deep-seated movements caused beams to mobilize their flexural capacity and form plastic hinges. Curvature ductilities up to a maximum of five were computed for buildings designed for low LLD