According to the different contours of the roadway, the cross-sectional shape of the roadway can be divided into two categories: a broken line shape and a curved shape. Characteristics broken line (trapezoidal, rectangular) cross section of the roadway is a high efficiency, excavation is the most economical, easily erected scaffold; disadvantage is wood or metal for the stent, can not resist a large rock pressure. Curved shapes, especially arches, are now commonly used in metallurgical mines. The arches are mostly used in circular arcs, semi-circular arches and three-center arches. The elliptical arches are not used much now, but due to their superiority, they are a promising arch. Wrinkle Thermosetting Powder Coating Wrinkle Thermosetting Powder Coating,Wrinkle Texture Powder Coating,Wrinkle Powder Coat,Wrinkle Finish Powder Coat Longkou Guomei Decoration Material Co.,Ltd. , https://www.lkgmcoating.com