# Analysis of the Fracture Resistance of Buildings on Composite Foundations with Horizontal Reinforcement Crossing Normal Faults

## TL;DR

This study examines how horizontally reinforced composite foundations can help buildings resist damage from normal fault ruptures.

## Contribution

The study introduces a new method using geogrid reinforcement to guide fault rupture paths and improve structural safety.

## Key findings

- Increasing geogrid layers narrows the rupture zone and shifts it away from structures in sand sites.
- Clay sites with reinforcement show better fracture resistance due to soil cohesion and geogrid interaction.
- Geogrid reinforcement promotes safer deformation patterns and reduces structural strain and microseismic activity.

## Abstract

To investigate the performance of horizontally reinforced composite foundations in resisting surface rupture of normal faults, this study designed and conducted a series of physical model tests. A systematic comparative analysis was performed on the fracture resistance of sites with three-layer sand, five-layer sand, and three-layer clay geogrid horizontally reinforced composite foundations under 70° normal fault dislocation. The results indicate that significant changes in earth pressure serve as a precursor indicator of fault rupture, and their evolution process reveals the internal energy accumulation and release mechanism. Increasing the number of geogrid layers significantly enhances the lateral confinement of the foundation, resulting in a narrower macro-rupture zone located farther from the structure in sand sites, and promotes the formation of a step-fault scarp deformation mode at the surface, which is more conducive to structural safety. Under identical reinforcement conditions, the clay site exhibited comprehensively superior fracture resistance compared to the sand site due to the soil cohesion and stronger interfacial interaction with the geogrids, manifested as more significant deviation of the rupture path, and lower microseismic accelerations and structural strains transmitted to the building. Comprehensive analysis confirms that employing geogrid-reinforced composite foundations can effectively guide the surface rupture path and improve the deformation pattern, representing an effective engineering measure for mitigating disaster risk for buildings spanning active faults.