A high-strength confined concrete support system for an underground tunnel. The support system includes multiple confined concrete arches, bolts and cables, and a prestressed steel strand backfilling system. The confined concrete arches all support the surrounding rock of the tunnel and are sequentially arranged along the tunnel. Every two adjacent confined concrete arches are connected by a longitudinal connection structure. The support system is provided with a plurality of layers of steel bar meshes on the surrounding rock side and the tunnel side, and shotcrete layers are sprayed on the support system and the steel bar meshes. The prestressed steel strand backfilling system comprises a prestressed steel strand system and a filling material. The filling material fills the space between each confined concrete arch and the surrounding rock to equalize a load on the confined concrete arch and generate prestress.

An arrangement for a rock bolt that is intended to be embedded in grout in a borehole, a method for using said arrangement, and a reinforcement system including such an arrangement. The rock bolt is equipped with a longitudinal tube with a passage, wherein an extended electrically conducting sensor is introduced into the passage of the tube and the sensor is connected with the anchoring end of the rock bolt, a monitoring arrangement designed to be connected to the rock bolt, an electrically conducting circuit is formed through the connection of the rock bolt, the sensor and the monitoring arrangement, wherein the monitoring arrangement includes evaluation means intended to evaluate the presence of changes in the condition of the bolt, and signaling means designed for the signaling of the condition of the bolt.

An arrangement for a rock bolt that is intended to be embedded in grout in a borehole, a method for using said arrangement, and a reinforcement system including such an arrangement. The rock bolt is equipped with a longitudinal tube with a passage, wherein an extended electrically conducting sensor is introduced into the passage of the tube and the sensor is connected with the anchoring end of the rock bolt, a monitoring arrangement designed to be connected to the rock bolt, an electrically conducting circuit is formed through the connection of the rock bolt, the sensor and the monitoring arrangement, wherein the monitoring arrangement includes evaluation means intended to evaluate the presence of changes in the condition of the bolt, and signaling means designed for the signaling of the condition of the bolt.

A carbon fiber rock bolt including: an outer carbon fiber rope including a series of tow fibers; and an inner core material. As the tension on the rock bolt increases beyond a predetermined limit, the inner core material undergoes a spatial compression, whilst the angle of twist in the carbon fiber rope strands decreases, resulting in extension of the carbon fiber rock bolt, replicating the ductility seen in steel rock bolts.

A carbon fiber rock bolt including: an outer carbon fiber rope including a series of tow fibers; and an inner core material. As the tension on the rock bolt increases beyond a predetermined limit, the inner core material undergoes a spatial compression, whilst the angle of twist in the carbon fiber rope strands decreases, resulting in extension of the carbon fiber rock bolt, replicating the ductility seen in steel rock bolts.

A methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

A methods and systems for determining a change in condition of a rock bolt. Some methods may comprise, at a first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a first time of flight for each of the shear and longitudinal waves, at a second point in time after the first point in time, propagating shear and longitudinal ultrasonic waves along the rock bolt to measure a second time of flight for each of the shear and longitudinal waves, and using the relative changes of the first and second time of flights, determining the change in condition of the rock bolt section.

A sensor carrier (16; 16; 16a, 16b, 16c) for a device (10; 10) for fastening an object (11) to a support element (12) and/or for stabilizing the support element (12) is provided. The device (10; 10) has a condition monitoring system for determining a deformation and a mounting body (13) with a mounting portion (14; 14) for insertion into the support element (12). The mounting body (13; 13a, 13b; 13a, 13b, 13c) is designed to accommodate the sensor carrier. The sensor carrier (16; 16; 16a, 16b, 16c) includes at least one conductive pathway (17; 17a, 17b), which is electrically conductive and applied along a strip-shaped path for measuring mechanical stress on the mounting portion (14; 14).

A sensor carrier (16; 16; 16a, 16b, 16c) for a device (10; 10) for fastening an object (11) to a support element (12) and/or for stabilizing the support element (12) is provided. The device (10; 10) has a condition monitoring system for determining a deformation and a mounting body (13) with a mounting portion (14; 14) for insertion into the support element (12). The mounting body (13; 13a, 13b; 13a, 13b, 13c) is designed to accommodate the sensor carrier. The sensor carrier (16; 16; 16a, 16b, 16c) includes at least one conductive pathway (17; 17a, 17b), which is electrically conductive and applied along a strip-shaped path for measuring mechanical stress on the mounting portion (14; 14).

The present disclosure relates to a self-diagnosis type ground anchor and a construction method. The self-diagnosis type ground anchor includes: a bond length part located at a predetermined depth of a boring hole excavated from a target surface of the ground; a head part located near the target surface; and a tensile material provided by connecting the bond length part and the head part in a state of receiving a tensile force, so as to deliver an anchorage force of the bond length part to a structure. The self-diagnosis type ground anchor further includes a displacement measurement material of which one end is fixed at a predetermined position of the bond length part and the other end is placed in a free end form on the target surface, provided such that a relative displacement of the target surface for the bond length part can be detected.