Experiment Research On The Limit Scour About Qianjiang Tunnel Across Qiantang Esturay

In the Qiantang Estuary, the sedimentation and bed scouring range usually reached to10m under the action of the flood and tidal flows.There are so many human beings and hydraulic structures such as bridges and submarine tunnels. The city economy and society will be greatly influenced by their destruction. Scour problem in the Qiantang Estuary is one of the most important factors which led to the destruction of hydraulic structures. So the study on the maximum erosion depth is of great significance to near-shore programs.This thesis carried out the research with the Qianjiang channel. The physical model was built for the research on the maximum erosion depth under natural condition and calibrated using hydrographic field data as well as data on morphological changes. On the other hand, the flume experiment was adopted to study the addition bed changes caused by the hydraulic structures with the strong water flow condition. Finally the paper presented the design bed scour elevation for the Qianjiang tunnel across.According to the simulation of the maximum erosion depth in Qianjiang channel, the erosion mechanism and process was recognized. With the analysis of effect factors such as water depth and velocity, the expression for maximum erosion depth is derived, which is also based on dimensional analysis and multiple regression method.