Bearing properties and influence laws of concrete-filled steel tubular arches for underground mining roadway support

Abstract

The concrete-filled steel tubular (CFST) arch is a new high-strength support form for a mine roadway in deep/soft rock stratum; however, the bearing characteristics have not been clearly elucidated for scientifically guiding field applications. Numerical simulation tests with 15 schemes shaped as a ‘half circle with two straight legs’ and 10 schemes shaped as a circle were conducted, and the main responses of the numerical model were verified by performing the laboratory tests to evaluate the basic CFST structures and global CFST arches. The bearing and failure behaviors of the CFST arches were studied, and the influence laws, in terms of the arch shape, size and lateral pressure coefficient λ, were further investigated. The results show that the bearing capacity of a circular arch is significantly higher than that of a straight-leg arch under a uniform load. Furthermore, the bearing capacity of the circular arch decreases considerably with the increase in the arch size or λ. In addition, the bearing capacity of a straight-leg arch decreases with the increase in the leg height and arch size; however, it first increases and later decreases with the increase in λ. The failure modes of all the arches correspond to the instability at the extreme point caused by the strength deterioration, except in the case of a circular arch under a uniform pressure, the failure mode of which corresponds to the instability at the branch points. Finally, the recommendations for the field practice are proposed and verified.

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

“…In the field of building construction, the axial bearing capacity of CFST columns was mainly studied from the perspective of structural parameters such as the ratio of steel tube to concrete, the shape of the steel tube, and the slenderness ratio of CFST [18][19][20]. In the field of mining, high-stress soft rock large deformation tunnel surrounding rocks can be controlled using CFST columns, or employed as a protective structure for goaf development in coal mines [21][22][23].…”