Open caisson for mechanical excavation of barrier lake sluice channel and excavation method

The invention relates to an open caisson for mechanical excavation of a barrier lake sluice channel and an excavation method. The open caisson is characterized by being placed vertically, the open caisson is provided with an open bottom and openings on the two longitudinal sides, the open caisson is composed of a skeleton, an upper supporting beam, a lower supporting beam, enclosure plates, a transfer device and a safety patio, the enclosure plates are installed on the two transverse sides and at the top of the skeleton, the enclosure plates longitudinally enclose the skeleton into open caisson passages, the safety patio is installed at the top of the skeleton and communicates with the open caisson passages, a conveyor belt of the transfer device is longitudinally arranged in the open caisson passages, and the multiple open caisson passages are longitudinally spliced to form a sluice channel passage. The excavation method includes the following steps of open shallow slot excavation, open caisson structure ins