What are the key points of mine tunnel construction? How is the measurement organized?

Mining method is a generalized method in the traditional sense. At present, it has developed into very detailed classification: step method, CD method (large span), CRD method, double-side heading method and double-arch tunnel middle hole method. In fact, the emphasis of these methods in construction is very clear, that is, the control of measurement is above all else, then the control of excavation section, that is, the control of overbreak, and finally the forming quality of secondary lining. The organization of measurement is to set up double lines, which can check each other. When measuring the cross section, it mainly controls the spatial position of the tunnel excavation center, that is, the plane coordinates and elevation. The upper arc must be controlled at three points, the arch position should be in the same mileage, and the arch foot should be at the same height to ensure that the arch is not distorted in the process of sequential connection. When measuring the middle arc guide rail and the lower arc guide rail, two control points should be released to ensure that the arch will not be caused by individual errors of the upper arc guide rail. Laugh.