Desilting system and method for immersed tube tunnel gravel foundation bed

The invention provides a desilting system for an immersed tube tunnel gravel foundation bed. The desilting system comprises a foundation trench. The foundation bed is laid in the foundation trench and comprises a block stone layer and a gravel layer which are arranged from bottom to top. The gravel layer is internally provided with desilting pipes. Holes are formed in the pipe walls of the desilting pipes. Silt pumps are connected to the desilting pipes. According to the desilting system for the immersed tube tunnel gravel foundation bed, when the foundation bed is laid, the desilting pipes are buried in the gravel layer; when silt exists on the foundation bed, the silt pumps are opened, and the silt enters the desilting pipes through gaps of the gravel layer and is removed; the system is simple in structure, easy to operate, not prone to being affected by water flow, climate and other environmental factors and good in desilting effect; the laid foundation bed structure is not affected, the installing precision of an immersed tube can be ensured in a later period, and the service life of a tunnel is prolonged.