Roadbed pit supporting mechanism

The utility model relates to a roadbed pit supporting mechanism which comprises a bottom plate. The top of the bottom plate is fixedly connected with a pair of first fixing blocks; a first rotating shaft is rotationally connected between the opposite side walls of the pair of first fixing blocks, and the two ends of the first rotating shaft penetrate through the first fixing blocks. First gears are fixedly connected to the two ends of the first rotating shaft; a supporting plate is fixedly connected to the first rotating shaft; a pair of first sliding grooves are formed in the top of the bottom plate. A power assembly is arranged in the first sliding groove. The power assembly is used for driving the first gear to rotate so as to solve the problems that in order to prevent excavation collapse, a supporting device is used for supporting and protecting a pit wall, although an existing supporting mechanism can conduct stable supporting, the integrity of the supporting mechanism is low, a worker needs a large amo