Key Technologies for Scour Protection of Inland River Bridge Foundations Using Solidified Soil

Abstract

Abstract This work investigates the key scour protection techniques for bridge foundations of an inland river bridge—Chongqing Jiangjin Highway Yangtze River Bridge in China. It incorporates a water retaining wall, gabion cofferdam, geotextile, and solidified soil. The gabion cofferdam, in conjunction with the geotextile, is engineered to minimize the loss rate of the solidified soil during the infill process. Unidirectional flow of water surrounding the inland river bridge group pile foundation, with high vortex energy, renders the gabion susceptible to being swept away. To mitigate this risk, a water retaining wall was constructed upstream of the bridge abutment. The utilization of solidification technology to enhance the quality of waste material fosters a circular economy. The integration of solidified soil and the bridge pier foundation can restore the coordination of the riverbed’s stiffness and the bridge pier structure, thereby ensuring optimal stability and functionality of pier. In this case study, through numerical simulation analysis, a low-velocity environment is formed around the bridge piers with a water retaining wall height exceeding the water depth. The techniques of gabion placement and solidified soil grouting were explored. Through on-site measurement, the combined protection method effectively reduces the average flow velocity from 2.44 to 0.06 m / s , with a solidified soil loss rate of 9.92% during construction. Compared to riprap protection, the proposed method offers lower costs and superior protective performance in this case. This indicates that the proposed combined method holds broad application prospects for large-scale inland river bridges subjected to high-velocity unidirectional flow.