Experimental study on influences of shield machine reception on existing shield tunnels during construction of connecting channels

The influence mechanism of shield machine reception on the deformation of the existing shield tunnels under loads during the mechanical construction of connecting channels is not clear. By designing the scale model tests of 1∶10, the influences of shield machine reception on the built shield tunnels during the mechanical construction of connecting channels are investigated. The analysis of the test results shows that during the mechanical construction of connecting channels, the additional horizontal earth pressures on the excavation face of the shield machine cause the earth pressures on the opposite side of the built shield tunnels at the receiving end to increase significantly in the middle, while decreasing at both sides. That is to say, the horizontal passive soil arching occurs at the opposite side of the jacking. Under the action of the additional horizontal earth pressures in the middle, the tunnel has a significant vertical elliptical deformation in the middle. At both sides, a certain transverse elliptical deformation occurs. The vertical elliptical deformation in the middle of the tunnel compresses the upper and lower strata, and also forms the passive soil arching phenomenon vertically. A certain reverse bending phenomenon occurs during the longitudinal deflection of the tunnel. As a tubular structure in the strata, the shield tunnel needs to consider the influences of the cross-section deformation when analyzing the longitudinal deformation in the strata.