Fixing device for controlling angle of advanced small guide pipe in tunnel and construction method

The invention provides a fixing device for controlling the angle of an advanced small guide pipe in a tunnel and a construction method, and belongs to the technical field of construction tools. The fixing device comprises an outer-layer fixing frame, wherein a mounting groove hole is formed in the center of the outer-layer fixing frame; the inner-layer plate is arranged in the mounting slotted hole and is detachably and rotatably connected with the outer-layer fixing frame through a connecting piece, a guide through hole is formed in the center of the inner-layer plate, and the guide pipe is embedded into the guide through hole and is fixedly connected with the inner-layer plate; and the two sets of clamping pieces are arranged on the upper portion and the lower portion of the outer layer fixing frame correspondingly, and the clamping pieces are detachably connected with the steel arch frame. The construction method comprises the following steps that firstly, the steel arch frame is installed, and punching is