In-tunnel jacking method for cross underneath pass sewage pipeline of underground excavation power tunnel

The invention relates to a temporary back shore technology in the construction process of a cross underneath pass sewage pipeline of an underground excavation electric power tunnel by a shallow underground excavation method, and the back shore structure is characterized in that four steel stand columns are supported at the positions of side walls at two sides of the tunnel, # imgabs0 # steel bars are processed into U-shaped clamping rings to be welded with primary lining steel bars, two cross beams are respectively welded with the stand columns to form two portal steel frames, and the two portal steel frames are connected with the primary lining steel bars; the two portal frames are welded into a whole through three longitudinal steel beams, and the two portal frame stand columns are vertically welded and connected through reinforcing steel bars at the interval of 500 mm. According to the tunnel inner back shore method, materials are convenient to take, that is, local materials can be used on a construction s