Tunnel primary support double-layer lagging jack positioning device

The utility model relates to the field of buildings, in particular to a tunnel primary support double-layer arch center positioning device. The positioning device comprises a double-mantle-thread door-shaped connecting rib (2), the double-mantle-thread door-shaped connecting rib (2) is welded to the outer-layer steel arch frame (1), concrete is sprayed on the double-mantle-thread door-shaped connecting rib (2), a limiting plate (4) and a positioning plate (5) are arranged below the double-mantle-thread door-shaped connecting rib (2), and the position between the limiting plate (4) and the positioning plate (5) can contain the upper portion of the inner-layer arch frame I-shaped steel. The method has the beneficial effects that the mounting and positioning precision of the inner-layer lagging jack can be improved, coaxial stress of the inner-layer lagging jack and the outer-layer lagging jack is ensured, the splicing and adjusting time in the construction of the inner-layer lagging jack is shortened, and the c