Abstract: To investigate the hydrological response and coordinated deformation mechanism of the three-tier bridge abutment slope reinforced with basalt fiber reinforced polymer (BFRP) anchor system under rainfall conditions, indoor physical model experiments were conducted based on actual engineering cases. The experiments collected data on slope moisture content, earth pressure, anchor axial force, and strain responses. The phased evolution patterns and response process of slope rainfall-infiltration-deformation were analyzed. A comprehensive control strategy for the strength, permeability, and deformation of the slope was proposed, following the principle of “graded reinforcement, balancing overall and local considerations”. By utilizing a multi-attribute response data system, the coordinated deformation mechanism of the bridge abutment slope-BFRP anchor system was elucidated. The results indicate that under rainfall conditions, the bridge abutment slope undergoes a deformation evolution trend from three-tier to two-tier and then to one-tier. The bottom of the first-bench slope is more susceptible to cumulative damage due to water softening, unloading rebound, and stress concentration effects. When tensile cracks initially formed or expanded in the slope, the axial force of the BFRP anchors exhibited a sudden increase trend, aligning the stage deformation characteristics of the slope with the axial force trend of BFRP anchors more effectively. This index is anticipated to offer a dependable foundation for monitoring slope deformation during rainfall. The flexible reinforcement capability of BFRP anchors can efficiently mitigate slope deformation caused by rainfall. Subsequently, actions like slope drainage and implementing green slope protection should be implemented to strengthen the slope.

Key words: bridge abutment slope, basalt fiber reinforced polymer (BFRP), coordinated deformation mechanism, rainfall conditions