Disassembly method for well type temporary supports of shallow and unsymmetrical big-span tunnels

The invention relates to a disassembly method for well type temporary supports of shallow and unsymmetrical big-span tunnels, and belongs to the technical field of tunnel construction. Tunnels are divided into three areas of inverted arches, side walls and top arches in the longitudinal direction in sequence from bottom to top; and the disassembly method comprises three steps of: firstly, cuttingof vertical support parts intersected with the inverted arches; then, disassembly of transverse supports in the range of the side walls; and finally, disassembly of the transverse supports intersectedwith the top arches and cutting of the remained vertical supports intersected with the top arches. In each step of the support disassembly, a truss spacing disassembly mode is adopted to guarantee uniform stress of the tunnels; the precutting is performed within a range of 1 cm before the support disassembly, and the surrounding rock and tunnel deformation is observed; after the stabilization isconfirmed, the next operati