Immersed tube foundation trench treatment process and immersed tube installation process of offshore inland river intersection area

The invention discloses an immersed tube foundation trench treatment process and an immersed tube installation process of an offshore inland river intersection area. The immersed tube foundation trench treatment process comprises the following steps that S1, dredging construction is carried out, a foundation trench is excavated, a bad section is marked, dredged soil is thrown and unloaded through a mud barge, foundation trench excavation is divided into a rough excavation stage and a fine excavation stage, foundation trench surface soil excavation is carried out firstly, and then deep water excavation grooving, desilting and leveling operation are carried out; S2, a foundation trench is detected; and S3, broken stone replacement and filling are carried out on the bad section, the foundation trench area is subjected to broken stone replacement and filling for the bad section, a broken stone leveling ship is used for construction, a barge is used for transporting broken stone to a leveling ship, and the broken