In tunnel construction, there is a machine called shield machine, which is used for Original Heading. It has the functions of excavating and cutting soil, transporting soil ballast, and assembling tunnel lining; However, when the shield machine is lining the tunnel, it is assembled by several segments. A screw is used to connect and fasten, forming a cylindrical pipe. The segment is a cylindrical wall; During excavation, it can effectively control the ground subsidence, reduce the impact on the ground buildings, and do not affect the surface traffic during underwater excavation. The segments are combined to form a pipe, which is designed as a linear or arc fastener, namely segment bolt. Segment bolts are divided into circumferential and longitudinal. Some designs have the same circumferential and longitudinal specifications. In some designs, two specifications or even two strength grades are used for circumferential and longitudinal directions. In general, the length of circumferential segment bolts is longer than that of longitudinal segment bolts.

It is specially used for segment connection of various shield driven tunnels, such as: highway river crossing shield tunnel, railway shield tunnel, power cable shield tunnel, water absorption shield tunnel of power plant, gas pipeline shield tunnel, highway mountain road shield tunnel, ocean subsea shield tunnel, municipal projects, civil defense projects, military special projects and other engineering projects.

Common grades include 5.8, 6.8 and 8.8. Production materials include Q235, 45 # steel, 40Cr, etc.