Civil construction foundation pit drainage structure and construction method thereof

The civil construction foundation pit drainage structure comprises a drainage cylinder installed in a foundation pit, the drainage cylinder comprises an installation plate, an outer cylinder body, an inner cylinder body and a separation bottom plate, a filtering cavity is formed between the outer cylinder body and the inner cylinder body, and first filtering holes and second filtering holes are formed in the lower end surfaces of the inner cylinder body and the outer cylinder body correspondingly; a pump column is slidably inserted into the inner barrel, a tunneling drill is rotatably mounted at the bottom end of the drainage barrel, a driving assembly is further arranged on the drainage barrel, and the tunneling drill is controlled to act through the driving assembly. According to the drainage structure, along with layered excavation of the foundation pit and downward pushing of the drainage cylinder layer by layer, the rainfall depth is controlled to be 0.5-1 m below the excavation layer, the gradient of a