Arch leg strength failure mode.

<p>(a) SQCC arch leg failure. (b) Maximum deformation in CCC arch leg on the position of 1.55m-1.75m high.</p

Curve of the arch specimen’s overall load vs. time.

<p>(a) Curve of the SQCC arch’s overall load vs. time. (b) Curve of the CCC arch’s overall load vs. time.</p

The cross-section layout of SQCC high-strength support system.

<p>The cross-section layout of SQCC high-strength support system.</p

The influence curve of steel tube thickness on the ultimate bearing capacity of the confined concrete arch.

<p>The influence curve of steel tube thickness on the ultimate bearing capacity of the confined concrete arch.</p

Geographical location of Zhao Lou Coal Mine.

<p>Geographical location of Zhao Lou Coal Mine.</p

The table of monitoring statistics.

<p>The table of monitoring statistics.</p

Curve of individual cylinder load vs. displacement.

<p>(a) Curve of SQCC arch’s individual cylinder load vs. displacement. (b) Curve of CCC arch’s individual cylinder load vs. displacement.</p

Numerical calculation schemes of different steel tube thicknesses of SQCC and CCC with the same steel content.

<p>Numerical calculation schemes of different steel tube thicknesses of SQCC and CCC with the same steel content.</p

Arch centering test.

<p>(a) SQCC arch test. (b) CCC arch test.</p

The numerical model establishment and meshing.

<p>The numerical model establishment and meshing.</p