Development and Application of Concrete-Filled Steel Tubular (CFST) Column Supporting High-stress Roof Strata in Large-span Mine Roadway

Abstract

The stability of large-span roadway junctions is challenging to control solely through simple passive support and conventional combined support. Therefore, this paper incorporates a novel high strength concrete-filled steel tubular (CFST) column considering the steel tube structure and concrete materials designed to offer adequate support for controlling the rock strata in large-span mining roadway. Subsequently, the CFST column model was designed based on a large-span roadway in a certain mine. The results show that circular-section CFST columns are significantly superior to square-section CFST columns. As the steel tube's wall thickness increases, the structure's bearing capacity significantly increases. Considering both performance and cost, a new concrete material was studied that enhances bearing capacity by increasing its strength and the tightness of contact with steel tubes. Circular steel tubes with an outer diameter of 800 mm and a wall thickness of 24 mm were used as columns, filled with a new type of concrete material, for supporting the roof strata of the large-span mining roadway. After calculating the support forces, it was concluded that CFST columns could effectively bear the stress released by the strata, thereby reducing the displacement of the top rocks, with a notable support effect.