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.

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.

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.

A device for connecting the structural elements, in particular elements of ribs used to support and to consolidate an excavation, reticular structures and similar, comprises at least a first housing (4; 44; 403; 411) having a cavity (14; 414; 144) and capable of being associated with a first structural element (2; 20; 200; 121), at least one connection body (5; 56; 511) having at least one insertion portion (119; 58; 591) for insertion in the said cavity (14; 414; 144) of the said first housing (4; 44; 403; 411) and capable of being associated with a second structural element (3; 30; 131), and locking means (11, 12, 13, 15, 17; 60, 61, 62, 63, 47; 621, 623, 653) for locking the said insertion portion (119; 58; 591) of the said connection body (5; 56; 511) inside the said cavity (14; 414; 144). The housing may be arranged in a cup-shaped element and may be linked in a revolving/hinging manner with the connection body.

A device for connecting the structural elements, in particular elements of ribs used to support and to consolidate an excavation, reticular structures and similar, comprises at least a first housing (4; 44; 403; 411) having a cavity (14; 414; 144) and capable of being associated with a first structural element (2; 20; 200; 121), at least one connection body (5; 56; 511) having at least one insertion portion (119; 58; 591) for insertion in the said cavity (14; 414; 144) of the said first housing (4; 44; 403; 411) and capable of being associated with a second structural element (3; 30; 131), and locking means (11, 12, 13, 15, 17; 60, 61, 62, 63, 47; 621, 623, 653) for locking the said insertion portion (119; 58; 591) of the said connection body (5; 56; 511) inside the said cavity (14; 414; 144). The housing may be arranged in a cup-shaped element and may be linked in a revolving/hinging manner with the connection body.