Abstract: Following the construction of immersed tube base groove in inland river, the flow of water through the groove leads to the deposition of silt within it. To obtain the distribution of silting thickness in tube base groove, this paper focuses on the Xiangyang immersed tube tunnel project. By combining observation with numerical simulation, we obtain the silting thickness of the base groove at different positions, and examine the influence of sediment concentration in the river on the silting thickness in tube base groove. Results demonstrate that sediment concentration in the direction vertical to the groove increases as the water depth increases. As water flows through the groove, the reduced flow velocity results in a decreased sediment carrying capacity. Consequently, the silting is mainly concentrated in the front slope and the base groove, whereas the thickness of silting is minimal in the back slope of the groove. After the installation of immersed tube, the flow area of the groove decreases, leading to a larger silting thickness at the bottom of the immersed tube compared to the top.

Key words: silting thickness, sediment concentration, immersed tube base groove, scour and siltation terrain, flow field distribution