Caisson cofferdam based on prepacked foundation bed

The present invention discloses one kind of caisson coffer based on foundation bed grouting and its construction process. The caisson coffer is constructed through the following steps: digging foundation ditch and desilting, filling rubble and leveling, prefabricating and sinking caisson, grouting foundation bed, grouting curtain, etc. The present invention has the advantages of high stability, easy construction, saving in material, short construction period, less environmental influences, small coffer demolishing workload and low engineering cost.