Aiming at the influence characteristics of high-pressure jet on the performance of point suction dredging,a physical model test system for the high-pressure jet-point suction dredging coupling is designed and fabricated,and a slurry concentration measurement method adapted to small-diameter pipelines is proposed.Through a series of working-condition tests,the effects of different high-pressure jet velocities on the dynamic variation of suction slurry concentration,water turbidity,and post-dredging terrain features are systematically investigated.The results indicate that under high-pressure jet action,the concentration-time curve of point suction dredging displays a distinct zigzag-shaped pattern,with the concentration peak achieved in the initial dredging stage.As the high-pressure jet velocity increases,both the suction slurry concentration and water turbidity exhibit a significant upward trend.Further analysis of terrain evolution reveals that an increase in high-pressure jet velocity drives the gradual development of the dredging pit morphology into a “gentle slope-platform-steep slope” three-stage structure.Both the axial length and depth of the dredging pit grow significantly with rising jet velocity.However,when the velocity exceeds a critical threshold,the axial length growth rate decelerates.The differential allocation of jet kinetic energy between vertical and horizontal directions ultimately leads to a decreasing trend in the length-to-depth ratio.