Shield type tail water wetland filler modification method

The invention discloses a shield type tail water wetland filler modification method. The method comprises the following steps: S1, evaluating a tail water wetland needing to be modified according to the concentrations of nitrate nitrogen, total nitrogen and total phosphorus; s2, selecting a filler material and a filling amount; s3, a shield point suitable for shield tunneling is selected from the side face of the bed body structure; s4, the shield tunneling machine digs out the original filler in the filler layer, and the original filler is discharged through a mud discharging system of the mud chamber; s5, after the original filler in the filler layer is completely dug out, a mud discharging system is driven to completely discharge the residual original filler in the mud chamber, and then the mud chamber is filled with new filler through a material conveying system communicating with the mud chamber; and S6, the new filler is discharged into the digging hole from the front end of the cutter head of the shiel