High-strength confined concrete support system for underground tunnel

A high-strength confined concrete support system for an underground tunnel, comprising:

• multiple confined concrete arches, bolts and cables, and a prestressed steel strand backfilling system, wherein:
• the confined concrete arches form an internal bearing layer of the support system;
• the bolts and the cables form an external bearing layer of the support system;
• the bolts and the cables are embedded into surrounding rock, and a filling material is between the arches and the surrounding rock to form an intermediate bearing structure layer;
• 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, the plurality of steel bar meshes including a first layer on the surrounding rock side and a second layer on the tunnel side, and shotcrete layers are on the support system and the steel bar meshes;
• the prestressed steel strand backfilling system comprises a prestressed steel strand system and the filling material;
• the prestressed steel strand system comprises steel strands that connect the arches with the bolts, and the cables sequentially run through arch cable-passing holes and tray cable-passing holes to form a continuous grid between outer edges of the arches and the surface of the surrounding rock, thereby connecting the arches with the bolts and the cables;
• the filling material fills space between each confined concrete arch and the surrounding rock to equalize a load on the confined concrete arch and generate a prestress;
• the longitudinal connection structure is a longitudinal connecting rod;
• one end of a connecting steel bar is provided with a thread for connection with a connector on a confined concrete arch before the confined concrete arch is installed;
• the other end of the connecting steel bar is provided with a protrusion for insertion into a connector at a corresponding position of a previously assembled confined concrete arch when confined concrete arches are assembled;
• and
• inverted wedge-shaped snap rings are utilized for automatic fixation to connect the two confined concrete arches.

A high-strength confined concrete support system for an underground tunnel, comprising:

• multiple confined concrete arches, bolts and cables, and a prestressed steel strand backfilling system, wherein:
• the confined concrete arches form an internal bearing layer of the support system;
• the bolts and the cables form an external bearing layer of the support system;
• the bolts and the cables are embedded into surrounding rock, and a filling material is between the arches and the surrounding rock to form an intermediate bearing structure layer;
• 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, the plurality of steel bar meshes including a first layer on the surrounding rock side and a second layer on the tunnel side, and shotcrete layers are on the support system and the steel bar meshes;
• the prestressed steel strand backfilling system comprises a prestressed steel strand system and the filling material;
• the prestressed steel strand system comprises steel strands that connect the arches with the bolts, and the cables sequentially run through arch cable-passing holes and tray cable-passing holes to form a continuous grid between outer edges of the arches and the surface of the surrounding rock, thereby connecting the arches with the bolts and the cables;
• the filling material fills space between each confined concrete arch and the surrounding rock to equalize a load on the confined concrete arch and generate a prestress;
• each confined concrete arch is constituted by a plurality of spliced steel tubes;
• the steel tubes are connected by quantitative yielding joints, and each joint is constituted by a quantitative yielding device, a sleeve and a retaining collar;
• the quantitative yielding device is mounted between the ends of two sections of the arch;
• the ends of two sections of the arch are connected by using the sleeve;
• and
• the retaining collar is located at the lower side of the sleeve.