A rock bolt (10) is provided for frictionally engaging with the internal surface of a bore drilled into rockmass. The bolt comprises a tube having a circular cross-section (12) defining a longitudinal split (14) and a longitudinal axis (10a). The tube (12) in is radially expandable. The bolt (10) has a first leading end (12b) for insertion into a bore, a second end defining a head (12a) and expander means (30) for expanding the diameter of the tube at least one location along the tube. The expander means comprises first (42) and second (44) expander/wedge elements arranged so that relative movement of the two elements causes the diameter of the tube to expand at that location. The first expander element (42) is mounted on an elongate rod (30) which is aligned generally along the longitudinal axis of the tube. Rotation of the rod (30) causes the relative movement of the two elements to cause the diameter of the tube to expand at the location. The rock bolt includes an arrestor (100) in the form of a ring, which defines an aperture which locates on the proximal end of the rod (30). The aperture is larger than the proximal end of the rod so that the arrestor is able to move along the proximal end of the rod. The arrestor includes a laterally extending protrusion (102) which locates in the longitudinal split (14) and is narrower than the longitudinal split and which is configured to engage with the head of the friction bolt when moved towards the proximal end of the friction bolt.

A rock bolt (10) is provided for frictionally engaging with the internal surface of a bore drilled into rockmass. The bolt comprises a tube having a circular cross-section (12) defining a longitudinal split (14) and a longitudinal axis (10a). The tube (12) in is radially expandable. The bolt (10) has a first leading end (12b) for insertion into a bore, a second end defining a head (12a) and expander means (30) for expanding the diameter of the tube at least one location along the tube. The expander means comprises first (42) and second (44) expander/wedge elements arranged so that relative movement of the two elements causes the diameter of the tube to expand at that location. The first expander element (42) is mounted on an elongate rod (30) which is aligned generally along the longitudinal axis of the tube. Rotation of the rod (30) causes the relative movement of the two elements to cause the diameter of the tube to expand at the location. The rock bolt includes an arrestor (100) in the form of a ring, which defines an aperture which locates on the proximal end of the rod (30). The aperture is larger than the proximal end of the rod so that the arrestor is able to move along the proximal end of the rod. The arrestor includes a laterally extending protrusion (102) which locates in the longitudinal split (14) and is narrower than the longitudinal split and which is configured to engage with the head of the friction bolt when moved towards the proximal end of the friction bolt.

A sock anchor unit (10) comprises an inner longitudinal hollow spine (12), an outer fabric sleeve (14) arranged to envelop the outside surface of the inner hollow spine (12) such that a gap is defined between the outside surface of the inner hollow spine (12) and an inner surface of the outer fabric sleeve (14) and a plurality of elongated reinforcing members (22), wherein each elongated reinforcing member (22) extends longitudinally within the gap. The inner hollow spine (12) comprises at least one substantially laterally extending opening from inside to outside of the inner hollow spine (12). The opening allows cementitious fluid which is pumped into the anchor unit to fill the gap between the hollow spine (12) and outer fabric sleeve. A fastening member (28, 32) is provided on each end of the sock anchor unit (10). Both fastening members (28, 32) are compatible with each other and each fastening member (28, 32) is configured such that a trailing end of a first sock anchor unit (10) is attachable to a leading end of a second sock anchor unit (10) thereby facilitating creating a multiple piece sock anchor system of a desired length.

Provided is a mounting method for an extensible reaming self-anchoring anchor rod, which is especially applicable to roadway construction in coal mines. A big helical structure is arranged on two rod sections of a sectional type anchor rod, a simple drill bit drills and reams a bore and cuts the coal mass in one operation, the outer diameter of the simple drill bit is smaller than the outer diameter of the big helical rod body, and the big helical structure accomplishes secondary reaming, self-drilling and self-anchoring in the drilling process; the big helical structure inhibits propagation and development of sheet cracks of the coal wall in the radial direction, and is embedded in the coal mass through a self-stabilization process of the rock mass.

A system for re-tensioning mine roof channels includes a roof plate having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, where the first side is configured to engage a surface of a mine roof, and where the sidewall defines a radially extending slot configured to receive a mine roof bolt. The system also includes a spacer having a first side, a second side positioned opposite the first side, and a sidewall extending therebetween, with the first side of the spacer configured to engage with the second side of the roof plate, and the sidewall defining a slot configured to receive a mine roof bolt, and a nut having a first side, a second side positioned opposite the first side, a sidewall therebetween, and a threaded opening, with the sidewall defining a radially extending slot configured to receive a mine roof bolt.

The present invention pertains to a yieldable rock anchor (10), comprising an elongated tendon (12) extending longitudinally along a tendon axis (A) from a proximal end (16) to a distal end (18), wherein the tendon includes a substantially non-yielding rigid first anchor portion (20) at or near said distal end (18) and extending towards said proximal end (16), and at least one plastically deformable axially yielding portion (26) intermediate said non-yielding rigid first anchor portion (20) and said proximal end (16). The first anchor portion (20) may be a hollow bar member, and the first anchor portion (20) and the at least one yielding portion (26) are integrally joined or coupled to one another to form at least part of said elongated tendon (12).

The present invention relates to a method and an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, which are applicable in geotechnical engineering. The method provided by the invention is for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt; the method is convenient to operate, non-destructive to an anchor bolt, and capable of testing an anchorage length of the anchor bolt. The present invention further provides an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt. The apparatus has a simple structure, is convenient to install, and is capable of measuring an anchorage length of an anchor bolt without damaging the anchor bolt.

The present invention relates to a method and an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt, which are applicable in geotechnical engineering. The method provided by the invention is for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt; the method is convenient to operate, non-destructive to an anchor bolt, and capable of testing an anchorage length of the anchor bolt. The present invention further provides an apparatus for non-destructive testing of an effective anchorage depth of a fully grouted anchor bolt. The apparatus has a simple structure, is convenient to install, and is capable of measuring an anchorage length of an anchor bolt without damaging the anchor bolt.

A fractured roof 110 mining method entry-side anti-collapsed structure, one working face of the 110 mining method corresponds to one roadway but without retaining any coal pillar, the roadway retains an entry after the previous working face implements mining top-cutting pressure release, and a roof of the roadway is arch-shape, directional cutting is conducted on one side of the roadway, and the cutting angle is between 15-20 degrees. One working face corresponds to one roadway but without retaining any coal pillar when underground mining is conducted, which can save resources and improve recovery rate of mining. And, the roof of the roadway of the retained entry is arch-shaped, which can improve safety and ensure safety of the coal mining working face. In addition, a cutting angle is 15-20 degrees, which can effectively determine a roof caving direction after top-cutting and reduce affect to the retained entry.

A fractured roof 110 mining method entry-side anti-collapsed structure, one working face of the 110 mining method corresponds to one roadway but without retaining any coal pillar, the roadway retains an entry after the previous working face implements mining top-cutting pressure release, and a roof of the roadway is arch-shape, directional cutting is conducted on one side of the roadway, and the cutting angle is between 15-20 degrees. One working face corresponds to one roadway but without retaining any coal pillar when underground mining is conducted, which can save resources and improve recovery rate of mining. And, the roof of the roadway of the retained entry is arch-shaped, which can improve safety and ensure safety of the coal mining working face. In addition, a cutting angle is 15-20 degrees, which can effectively determine a roof caving direction after top-cutting and reduce affect to the retained entry.