Disclosed is a method of adapting a metal bar, for use as a rock bolt, to ensure that the bar will break in a predictable manner, the method including the step of removing material from the bar in a circumferential band to reduce a diameter of the bar within the band to a minor diameter thereby to provide a failure zone within which the bar will break if subjected to enough tensile load.

A self-drilling rock anchor assembly includes: a friction fit tubular sleeve extending longitudinally between leading and trailing ends; a rod extending through the sleeve between first and second ends, and projecting from each sleeve end; a drill bit member engaged with the rod's first end having an exterior surface part of which tapers towards a back end of the member; a backstop element engaged with the rod's second end having a first drive surface; a load bearing element on the rod between the sleeve's trailing end and the backstop that has a second drive surface. The rod moves relative to the sleeve between a drill position, wherein the drill bit is spaced from the sleeve's leading end, and an insertion position, wherein the sleeve's leading end abuts the bit. The drill and insertion positions are achieved by applying a force to the first and second drive surfaces, respectively.

A self-drilling rock anchor assembly includes: a friction fit tubular sleeve extending longitudinally between leading and trailing ends; a rod extending through the sleeve between first and second ends, and projecting from each sleeve end; a drill bit member engaged with the rod's first end having an exterior surface part of which tapers towards a back end of the member; a backstop element engaged with the rod's second end having a first drive surface; a load bearing element on the rod between the sleeve's trailing end and the backstop that has a second drive surface. The rod moves relative to the sleeve between a drill position, wherein the drill bit is spaced from the sleeve's leading end, and an insertion position, wherein the sleeve's leading end abuts the bit. The drill and insertion positions are achieved by applying a force to the first and second drive surfaces, respectively.

An anchor rod includes a sleeve open at one end and having a blocking plate at the other end; a pressure relief pipe fixedly arranged on an inner wall of the sleeve; and a rod body. A guide hole is formed in a center of the blocking plate. A part of the rod body penetrates through the guide hole and extends into the sleeve. A gap is formed between the pressure relief pipe and the blocking plate. An overflow valve is connected to the pressure relief pipe. A piston in sliding seal fit with the sleeve and the pressure relief pipe is arranged at the rod body. A sealing ring in sliding seal fit with the rod body is arranged at the inner wall of the guide hole; and a sealing cavity between the blocking plate and the piston in the sleeve is filled with emulsion.

Provided are a grouting anchor bolt and a grouting anchor cable for supporting of large deformation and constant resistance and a quantitative roadway supporting method, wherein an anchor bolt comprises a casing, a hollow rod body, an anchor cylinder, a tray, a fastening nut and a clamping pin, a front end of the casing is sealed and a rear end of the casing is opened, a middle position of the casing is provided with a plurality of grouting holes, an inner diameter of the casing from the middle position of the casing to the rear end becomes small gradually, a side surface of a front end of the hollow rod body is sleeved with an anchor cylinder, the anchor cylinder is inserted into the casing and movably connected with the casing, the anchor cylinder is connected with the casing through the clamping pin, a rear end of the hollow rod body is sequentially assembled and connected with the tray and the fastening nut. The beneficial effects herein are as follows: the anchor bolt and the anchor cable simple in structure, easy to process, simplifies operations of supporting and grouting, and therefore particularly suitable for supporting of large deformation for surrounding rocks. The self-bearing capability of surrounding rocks is improved, and the supporting of large deformation of surrounding rocks is provided through constant resistance, thereby realizing organic combination of “yielding-supporting” and “active-passive supporting”; the quantitative roadway supporting method may realize quantitative supporting for a roadway.

Provided are a grouting anchor bolt and a grouting anchor cable for supporting of large deformation and constant resistance and a quantitative roadway supporting method, wherein an anchor bolt comprises a casing, a hollow rod body, an anchor cylinder, a tray, a fastening nut and a clamping pin, a front end of the casing is sealed and a rear end of the casing is opened, a middle position of the casing is provided with a plurality of grouting holes, an inner diameter of the casing from the middle position of the casing to the rear end becomes small gradually, a side surface of a front end of the hollow rod body is sleeved with an anchor cylinder, the anchor cylinder is inserted into the casing and movably connected with the casing, the anchor cylinder is connected with the casing through the clamping pin, a rear end of the hollow rod body is sequentially assembled and connected with the tray and the fastening nut. The beneficial effects herein are as follows: the anchor bolt and the anchor cable simple in structure, easy to process, simplifies operations of supporting and grouting, and therefore particularly suitable for supporting of large deformation for surrounding rocks. The self-bearing capability of surrounding rocks is improved, and the supporting of large deformation of surrounding rocks is provided through constant resistance, thereby realizing organic combination of yielding-supporting and active-passive supporting; the quantitative roadway supporting method may realize quantitative supporting for a roadway.

A rock anchor assembly includes: a tubular sleeve between first and second ends, having an anchor retaining portion opening on the second end; a rock anchor with an elongate body extending between distal and proximal ends, received in the tubular sleeve with the proximal and distal ends of the body projecting from the first and second ends respectively of the sleeve; a tensioning and locking assemblage on the anchor body between the proximal end and the first end of the sleeve, a forward part being engageable with the first end of the sleeve; and a mechanical anchor engaged to the anchor body at the distal end which, from an unexpanded configuration, expands radially to an expanded configuration. The anchor retaining portion at least partially retains the mechanical anchor in the unexpanded configuration. The anchor retaining portion expands circumferentially to accommodate retracted ingress of the anchor in the expanded configuration.

A rock anchor assembly includes: a resiliently radially deformable tubular member longitudinally extending between leading and trailing ends and which has an arrestor formation integral with, or engaged to, a trailing end part of the member; an elongate element longitudinally extending through the member between first and second ends and which attaches to the tubular member at spaced distal and proximal load points and which has a failure arrestor fixed at a point within the member; and a faceplate on the tubular member or the elongate member. When the assembly is inserted in a rock hole, with the faceplate bearing against the rock face, and load is applied along the elongate element that will cause the element to sever above the point at which the arrestor is fixed, the failure arrestor engages the arrestor formation, arresting the ejectment of a proximal portion of the elongate element from the hole.

An elongated connecting element for anchoring members, which is provided with a first anchoring end portion designed to be inserted into an anchoring region and a second end portion which defines a head, which lies opposite the first anchoring end portion and is designed to interact with an element to be anchored. The elongated connecting element includes an external tubular element which accommodates an internal elongated body, the external tubular element defining, at the head, at least one feeding port for a synthetic anchoring mix and, at the first anchoring end portion, at least one exit opening for the synthetic anchoring mix. The synthetic anchoring mix is configured to set, penetrating at least partially into the anchoring region and creating a stable connection between the anchoring region and the elongated connecting element and between the respective portions of the external tubular element and of the internal elongated body.

An anchor rod includes a sleeve open at one end and having a blocking plate at the other end; a pressure relief pipe fixedly arranged on an inner wall of the sleeve; and a rod body. A guide hole is formed in a center of the blocking plate. A part of the rod body penetrates through the guide hole and extends into the sleeve. A gap is formed between the pressure relief pipe and the blocking plate. An overflow valve is connected to the pressure relief pipe. A piston in sliding seal fit with the sleeve and the pressure relief pipe is arranged at the rod body. A sealing ring in sliding seal fit with the rod body is arranged at the inner wall of the guide hole; and a sealing cavity between the blocking plate and the piston in the sleeve is filled with emulsion.