Fabricated supporting assembly for trench excavation and construction method

The invention provides a fabricated supporting assembly for trench excavation and a construction method. The fabricated supporting assembly comprises a first U-shaped plate pile set and a second U-shaped plate pile set. Each U-shaped plate pile set is provided with a plurality of U-shaped plate piles which are sequentially connected. A supporting frame is connected between every two U-shaped plate piles. Each supporting frame comprises an enclosure steel plate and a connecting rod. The supporting frames are connected with the U-shaped plate piles through fixing supporting hooks, and therefore a stable supporting structure is formed. The invention further provides the construction method for trench excavation based on the fabricated supporting assembly. The construction method comprises the steps of firstly, manufacturing the supporting frames and the fixing supporting hooks according to the design of a pipeline; then carrying out excavation by a certain depth, and placing the supporting frames and the fixing