A system or method for a structural mine roof support includes a roof support apparatus that includes a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder. Also, a roof support apparatus with a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder, and voids between adjacent bamboo sections, the voids being injected with a filler material, e.g., polyurethane foam, to maintain axial positioning of the bamboo sections when under load. The support apparatus configured to load and to yield in a predetermined fashion to control a mine roof from sudden failure.

An internally injected replacement support room-type coal pillar recovery method is provided. During the recovery the room-type coal pillars with an aspect ratio greater than 0.6 are divided into two parts: reserved coal pillars and pre-mined coal pillars. After the mining of the pre-mined coal pillars, a cemented filling material is injected into a goaf surrounded by the reserved coal pillars, and is stabilized to replace the coal pillars for support, and the reserved coal pillars are recovered. A mechanical model of the reserved coal pillars in a support overburden stage is established based on the Winkler beam theory, to obtain displacement and stress conditions of a roof of the reserved coal pillar in a support stage. A theoretical reserve-width of the reserved coal pillars is obtained according to a first strength theory of the roof and a criterion of ultimate strength of the reserved coal pillars.

An internally injected replacement support room-type coal pillar recovery method is provided. During the recovery the room-type coal pillars with an aspect ratio greater than 0.6 are divided into two parts: reserved coal pillars and pre-mined coal pillars. After the mining of the pre-mined coal pillars, a cemented filling material is injected into a goaf surrounded by the reserved coal pillars, and is stabilized to replace the coal pillars for support, and the reserved coal pillars are recovered. A mechanical model of the reserved coal pillars in a support overburden stage is established based on the Winkler beam theory, to obtain displacement and stress conditions of a roof of the reserved coal pillar in a support stage. A theoretical reserve-width of the reserved coal pillars is obtained according to a first strength theory of the roof and a criterion of ultimate strength of the reserved coal pillars.

A underground support includes a first row of panels, and a second row of panels configured to be secured to the first series of panels to define an interior space for receiving construction aggregate or concrete. Each panel of the first row of panels and the second row of panels includes a body having a top edge, a bottom edge positioned opposite from the top edge, a left edge, and a right edge positioned opposite from the left edge, with the top edges of the panels of the first row of panels configured to abut the bottom edges of the panels of the second row of panels.

A underground support includes a first row of panels, and a second row of panels configured to be secured to the first series of panels to define an interior space for receiving construction aggregate or concrete. Each panel of the first row of panels and the second row of panels includes a body having a top edge, a bottom edge positioned opposite from the top edge, a left edge, and a right edge positioned opposite from the left edge, with the top edges of the panels of the first row of panels configured to abut the bottom edges of the panels of the second row of panels.

A system or method for a structural mine roof support includes a roof support apparatus that includes a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder. Also, a roof support apparatus with a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder, and voids between adjacent bamboo sections, the voids being injected with a filler material, e.g., polyurethane foam, to maintain axial positioning of the bamboo sections when under load. The support apparatus configured to load and to yield in a predetermined fashion to control a mine roof from sudden failure.

A system or method for a structural mine roof support includes a roof support apparatus that includes a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder. Also, a roof support apparatus with a cylindrical cladding defining a hollow interior, a plurality of bamboo sections disposed in the hollow interior and coaxial with an axis of the cylinder, and voids between adjacent bamboo sections, the voids being injected with a filler material, e.g., polyurethane foam, to maintain axial positioning of the bamboo sections when under load. The support apparatus configured to load and to yield in a predetermined fashion to control a mine roof from sudden failure.

An apparatus for pre-loading a mechanical constant-resistance single prop includes a rhombic stretchable bracket, a screw rod, a first cylindrical sleeve ring, and a second cylindrical sleeve ring. The screw rod is connected to two opposite apex corners of the rhombic stretchable bracket. A tail end of the screw rod is fixedly connected to one apex corner of the rhombic stretchable bracket. An end head of the screw rod passes through another apex corner of the rhombic stretchable bracket. The remaining two opposite apex corners of the rhombic stretchable bracket are respectively fixedly connected to edges of the first cylindrical sleeve ring and the second cylindrical sleeve ring through connecting rods. The screw rod is threadedly connected to the apex corner of the rhombic stretchable bracket through which the screw rod passes. A method for pre-loading a mechanical constant-resistance single prop is also provided.

An apparatus for pre-loading a mechanical constant-resistance single prop includes a rhombic stretchable bracket, a screw rod, a first cylindrical sleeve ring, and a second cylindrical sleeve ring. The screw rod is connected to two opposite apex corners of the rhombic stretchable bracket. A tail end of the screw rod is fixedly connected to one apex corner of the rhombic stretchable bracket. An end head of the screw rod passes through another apex corner of the rhombic stretchable bracket. The remaining two opposite apex corners of the rhombic stretchable bracket are respectively fixedly connected to edges of the first cylindrical sleeve ring and the second cylindrical sleeve ring through connecting rods. The screw rod is threadedly connected to the apex corner of the rhombic stretchable bracket through which the screw rod passes. A method for pre-loading a mechanical constant-resistance single prop is also provided.