Npr anchor rod

Abstract

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.

What is claimed is: 
     
         1 . An NPR rock bolt, comprising a bolt body ( 1 ), a tray ( 2 ) and a lock ( 3 ), wherein
 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; and   the tray ( 2 ) and the lock ( 3 ) are directly sleeved on a tail of the NPR spiral steel bar.   
     
     
         2 . The NPR bolt according to  claim 1 , wherein the tail of the NPR spiral steel bar is untreated. 
     
     
         3 . The NPR bolt according to  claim 1 , wherein the NPR spiral steel bar has a yield strength of 800-950 MPa and a tensile strength of 900-1050 MPa, and a deformation displacement of the NPR spiral steel bar is 200-350 mm/m. 
     
     
         4 . The NPR bolt according to  claim 1 , wherein a nominal diameter of the NPR bolt is 14-26 mm. 
     
     
         5 . The NPR rock bolt according to  claim 1 , wherein the tray ( 2 ) is a metal butterfly tray. 
     
     
         6 . The NPR rock bolt according to  claim 1 , wherein the lock ( 3 ) comprises a metal lock piece and a lock sleeve that cooperate with each other. 
     
     
         7 . The NPR rock bolt according to  claim 1 , wherein the spiral ribs extend along an axial direction of the NPR spiral steel bar. 
     
     
         8 . The NPR bolt according to  claim 1 , wherein the quantity of the spiral ribs is 3-6. 
     
     
         9 . The NPR rock bolt according to  claim 1 , wherein a number of the spiral ribs are evenly disposed along a circumferential direction of the NPR spiral steel bar.