Large underground space construction system and method based on underpinning and underground excavation

The invention provides a large underground space construction system and method based on underpinning and underground excavation, and relates to the technical field of building construction. The system comprises a pipe shed supporting system and a bench formwork system, the pipe shed supporting system is used for reinforcing the upper portion, the lower portion and the side portion of a soil body in the ruin area, a pipe shed supporting structure is arranged below the pipe shed supporting system, the top of the pipe shed supporting structure is supported below the pipe shed supporting system, and the bottom of the pipe shed supporting structure vertically extends downwards; the bench formwork system can be movably arranged below the pipe shed supporting system, and after the bench formwork system moves in place, a space for pouring concrete is formed between the top of the bench formwork system and the bottom of the pipe shed supporting system. Shallow-buried excavation construction is completed through the p