Centrifuge modeling of ground-improvement layer to reduce tunneling-induced building deformation

This technical note investigates the effectiveness of a horizontal stiff ground-improvement layer in reducing tunneling-induced deformation of a framed building with individual footings. Two centrifuge tests were conducted in dry dense sand, and the horizontal layer was idealized as an embedded aluminum plate. Results show that the layer reduces maximum and differential settlements and produces a more uniform footing settlement profile. The layer also decreases horizontal displacements and horizontal strains at the foundation level. Subsurface measurements indicate that the layer interrupts the upward propagation of tunneling-induced settlements and mobilizes a bridging and lateral load-transfer mechanism as the gap develops between the layer and the underlying soil. The layer effectively mitigates panel shear distortion, and the settlement and differential-settlement efficiencies increase with tunnel volume loss. The results demonstrate the potential of horizontal stiff ground improvement as a protective measure for reducing tunneling-induced displacements.