The reason why the foundation of bailey bridge is buried deep

Bailey bridge is in the pier foundation in the water, the riverbed is scoured by the water flow, the bridge foundation must be deep enough, in order to prevent the bottom surface of the foundation (referred to as the basement) from scoured and causing the bridge subsidence or accidents. It is generally stipulated that the base of open excavation, caisson and caisson of the bridge should be buried at least 2 ~ 5 meters below the lowest scouring line of the riverbed according to its importance and the difficulty of maintenance and reinforcement. For frozen heaved soil, the base shall be at least 0.25 m below the freezing line. For the land pier foundation, in addition to considering the requirements of foundation frost heave, but also to consider the biological and human activities and other natural factors of topsoil damage, the basement should be no less than 1.0 meters below the ground. For urban Bridges, the top of the foundation is often placed below the lowest water level or the ground so as not to affect the appearance of the city. The plane size of the base top should be larger than the cross section size of the bottom of the pier, so as to facilitate construction.