Foundation enhancement for reducing tunnel-building seismic interaction on soft clay

Seismic tunnel-soil-building interaction in high plasticity soft clays can led to important ground motion variability that affect medium to low rise buildings located adjacent to the underground structure. This paper presents a numerical study aiming at establishing the performance of an enhanced foundation system to be used as a mean to reduce detrimental interaction and enhanced the seismic performance of mid to low buildings located nearby tunnels. Initially, interaction effects are revised considering the effect that frequency content, intensity, and strong ground motion duration have on the interplay between incoming seismic waves reflected in the tunnel, and the energy feeding back from the building swinging back and forth during a large earthquake. Series of three-dimensional finite difference models were developed. Seismic analyses considered both normal and subduction events with a return period of 250 years were carried out. Finally, the seismic performance of the enhanced foundation system was established. From the results gathered in here, it was clearly established the effectiveness of the proposed system to reduce both foundation ground motions and building seismic demand.

Automated summary

This study aimed to reduce the impact of seismic tunnel-soil-building interaction in high plasticity soft clays through an enhanced foundation system, using three-dimensional finite difference models for seismic analysis and verifying the seismic performance of the enhanced system under a return period of 250 years.