Experimental Study on Local Scour Protection and Contact Pressure of Facing Water at the Bridge Pier Based on the Guide Pillar

Abstract

This research presents the design of a high-stability anti-scour device-guide pillar. Distributed thin-film pressure sensors were placed on the bridge pier to measure the pressure distribution; scouring tests were conducted under various hydraulic conditions in order to investigate the characteristics of the water flow force distribution on the bridge pier, as well as the guide pillar's ability to prevent scour and the mechanical ability to mitigate disasters. The results show that: the optimal installation position of the guide pillar is 2d, and the height is 8 cm as the optimal shape; the guide pillar reduces the maximum scour hole depth by 59.3%, the volume by 76.1%, and the area by 79.0%; the velocity and the turbulence intensity of the down flow are significantly reduced. The center of gravity is in h/3, and the pressure on the bridge pier's water surface is primarily at the bottom of the pier. After subtracting the hydrostatic pressure, the greatest value of pressure is at 9h/10, while the center of gravity is at 2h/3. The maximum flow force is decreased by 61.3% by the guide pillar, which is crucial for the bridge pier to prevent and lessen floods and tragedy.

Keywords: Guide pillar, Scour hole volume, Scour hole area, Down flow, Water flow force, Distributed thin film pressure sensor