1, The steel arch support should be installed according to the design position, the steel support must be longitudinal connection with reinforcement, and to ensure the welding quality. In the process of arch installation, when there is a large gap between the steel arch and the surrounding rock, precast concrete blocks shall be wedged every 2m along the outer edge of the steel arch.
2. The arch foot of the steel arch support is supported by longitudinal joists and anchor pipes.
3. The steel arch support should be welded with the rock bolt outcrop and steel mesh as much as possible to enhance the effect of joint support.
4. When spraying concrete, the gap between the steel arch support and the rock surface should be saturated with jet to achieve compaction.
5. Shotcrete shall be sprayed in different levels and sections. The initial shotcrete shall be sprayed with "early anchor" as soon as possible, and the compound shotcrete shall be sprayed under the guidance of measurement, namely the basic principle of "frequent measurement", so as to ensure the timely and effective re-spraying of shotcrete.
6, steel arch support should be cold formed, steel arch frame processing welding shall not have false welding, welding seam surface shall not have cracks, welding tumor and other defects.
7. After processing, each steel arch should be placed on the cement floor for testing. The allowable error of surrounding assembly is ±3cm, and the plane warpage should be less than 2cm.
8. The steel arch support shall be erected in time after the initial shotcrete. The steel arch frames shall be connected by bolts and the connecting plates shall be closely affixed.
9, before the installation of the steel arch support should be removed at the bottom of the bottom of the empty ballast and debris, the bottom foot of the steel arch frame should be placed on a solid foundation.
