Auxiliary trolley for modifying tunnel second lining

The utility model discloses an auxiliary trolley for modifying a tunnel second lining. The auxiliary trolley comprises a trapezoid main frame, wherein two sides of the main frame are respectively provided with a fixed belt and a step ladder; the periphery of the lower part of the main frame is respectively provided with a cross arm, and four bottom feet of the main frame are respectively provided with idler wheels; first and second layers of working platforms which are supported by a triangle tie are respectively arranged on positions, which are positioned outside the step ladder, of the two sides of the main frame, one end of the triangle tie is connected with a position close to the outer end of the first and second layers of working platforms, and the other end of the triangle tie is connected with the main frame; the top of the main frame is provided with a third layer of working platform the height of which can be adjusted by four oil cylinders fixed on four main supports of the main frame. The auxiliary