Thin-covering anti-soil-backing drag reduction measure for rectangular tunnel

A thin-covering anti-soil-backing drag reduction measure for a rectangular tunnel comprises the following steps: 1, conducting water injection loading on an oil drum in the tunneling direction of therectangular tunnel; 2, drilling holes in the tunneling direction of the rectangular tunnel and injecting water; 3, downwards prefabricating concrete retaining blocks in the tunneling direction of therectangular tunnel; and 4, grouting at intervals. By the adoption of the technical scheme, the measure has the beneficial effects that the soil backing phenomenon occurring in the tunneling process ofa rectangular shield tunneling machine is reduced to the minimum through measures such as drilling hole and water injection and ceaseless anti-friction mud injection. The rectangular shield tunnelingmachine capable of discharging soil at the top is used, a hard soil layer cannot be formed at the tops of the rectangular shield tunneling machine, a pipe jacking machine and an annular pipe joint, and the soil backing problem