A constant-resistance and large deformation anchor cable and a constant-resistance device are provided. The constant-resistance and large deformation anchor cable comprises cables (7), an anchoring device (13), a loading plate (12) and clipping sheets (4). The upper end of cables (7) is fixed on the anchoring device (13) and the loading plate (12) by clipping sheets (4). The constant-resistance and large deformation anchor cable also comprises a constant-resistance device, and the constant-resistance device comprises a sleeve (8) and a constant-resistance body (5). The sleeve (8) is a straight tube. The constant-resistance body is conical, and the diameter of the lower end of the constant-resistance body is bigger than the diameter of the upper end of the constant-resistance body. The inner diameter of the sleeve (8) is smaller than the diameter of the lower end of the constant-resistance body. A cuneiform part is arranged on inner wall of the lower end of the sleeve (8), and the constant-resistance body (5) is arranged on the cuneiform part. The strength of constant-resistance body (5) is higher than the strength of the sleeve (8), thus the sleeve (8) generates plastic deforming and the shape of the constant-resistance body (5) is not changed, when the constant-resistance body (5) moves in the sleeve (8). The lower end of the cables (7) is fixed on the constant-resistance body (5). The constant-resistance and large deformation anchor cable and the constant-resistance device have the properties of constant-resistance and preventing fracture, and can detect and early warn the all process of the activity of the landslides and the causative fault.

A rock bolt to be embedded in a borehole and a method of manufacturing a rock bolt, the rock bolt including an extended energy-absorbing part, the first end of the energy-absorbing part including an anchor and the second end of the energy-absorbing part including a screw joint for prestressing the rock bolt. The rock bolt includes an extended tubular part with a jacket and a first end section and a second end section, with an internal dimension that is larger than the external dimension of the energy-absorbing part and arranged in such a manner that it surrounds the energy-absorbing part.

A rock bolt arranged for installation within a bore formed in rock strata includes an elongate shaft with the leading end for installation into the bore and a trailing end projecting from an open end of the bore. A locking nut is threadably attached to the trailing end and is arranged to display product information and the like at a display face. The display face is recessed axially into the nut to provide protection against damage to the display face that may otherwise render the information unreadable.

A rock bolt arranged for installation within a bore formed in rock strata includes an elongate shaft with the leading end for installation into the bore and a trailing end projecting from an open end of the bore. A locking nut is threadably attached to the trailing end and is arranged to display product information and the like at a display face. The display face is recessed axially into the nut to provide protection against damage to the display face that may otherwise render the information unreadable.

An NPR steel material for rock bolt and a production method thereof are disclosed. The NPR steel material for rock bolt has a composition, in weight percent, consisting of: C: 0.4-0.7%, Mn: 15-20%, Si: ≤0.1%, Cu: ≤0.03%, Cr: ≤0.01%, Ni: ≤0.02%, S: ≤0.001%, P: ≤0.001%, and the rest being Fe and unavoidable impurity elements. The NPR steel material for rock bolt and the production method thereof effectively solve the problem that rock bolts in the prior art have low tensile strength and low effective elongation. The NPR steel material for rock bolt has a yield strength adjustable in the range of 500-1100 MPa, and an elongation adjustable in the range of 10-80%.

The present invention relates to a device, method and system for the installation of a fixative in a drill-hole, such as to secure rock bolts. The device comprises (a) a chamber adapted to hold the fixative, and (b) a thrust member, wherein the fixative is displaced from the chamber into the drill-hole following application of force to the thrust member.

An encapsulation system for use in securing a rock bolt in a bore hole drilled into a rock face to be stabilised, the encapsulation system comprising at least two separate encapsulation mediums and one or more elongate cartridges containing the encapsulation mediums, each the cartridge having a frangible casing, the encapsulation mediums including: a first encapsulation medium comprising a curable first resin formulation; and a second encapsulation medium; wherein, following use in securing a rock bolt, the second encapsulation medium has a lower bond strength and/or a lower compressive strength than the first resin formulation.

The invention relates to an improved bolt apparatus for installation, the improved bolt apparatus including, a bolt having a head, shaft and an end and the head of the bolt including an improvement means. The bolt also including an engagement means, associated with the shaft, between the head and the end of the bolt, for engaging with or into a surface where the bolt is to be installed. The improved bolt apparatus may be installed into a suitable hole in the surface, and the improvement means enables the type, kind, or characteristic of the bolt to be known and or the bolt installation to be adjusted within the hole. The invention also provides many variants thereon, and methods of use.

An NPR rock bolt according to the present disclosure comprises a bolt body (1), a tray (2) and a lock (3). The bolt body (1) is an NPR spiral steel bar, an outer surface of the NPR spiral steel bar is provided with a number of convex spiral ribs, and the spiral ribs have a spiral structure. The tray (2) and the lock (3) are directly sleeved on a tail of the NPR spiral steel bar. The NPR bolt according to the present disclosure can effectively solve the problem in the prior art that conventional rock bolts have a low elongation and cannot meet the requirement of large deformation of the surrounding rock.

The present invention discloses a self-anchored opposite-pulling anti-impact anchor cable for sectional coal pillars and a using method thereof. The anchor cable includes a steel strand (100), with an energy-absorbing and yielding terminal (200) and a stressed expansion-cracking terminal (300) respectively fixed to two ends of the steel strand, a bushing (400) sleeved outside the steel strand, a first lock (610) provided at one end of the steel strand and a second lock (620) provided at the other end of the steel strand; the stressed expansion-cracking terminal includes a self-anchored bushing (420) with a plurality of pre-splitting lines (440) arranged in the wall of the self-anchored bushing. Under stress, the wall of the self-anchored bushing cracks along the pre-splitting lines and bends and expands, so that it abuts against and is self-anchored to the edge of a sectional coal pillar at the outer side.