Construction of pipe joint anchor rod in mine shaft support engineering(2)

Construction of Pipe Joint Anchor rod in mine shaft support engineering

3. Technical performance of pipe joint anchor rod

3.1 Installation of pipe joint anchor rod and its supporting properties and characteristics

The pipe seam installation process is simpler than other forms of anchor rods. In the installation process, first use a pneumatic rock drill to design anchor positions and drill holes according to the corresponding angle requirements. The depth of the hole is generally greater than the length of the anchor rod of 50 mm. It is recommended not to bounce, and then use the short shank drill pipe to set it on the pneumatic rock drill (usually the short drill pipe is about 0.5 meters long), and insert the short drill pipe into the hole of the anchor rod, start the drill to insert the anchor rod into the hole , Stick the tray on the rock, so that the anchor rod is inserted into the rock, and it is firmly fixed with the rock. In contrast, this kind of bolt support can better support the roadway. The principle of bolt support is actually to use bolts and trays fixed in the rock to support when the surrounding rock of the roadway is deformed, and the bolts have extremely strong toughness and can withstand the deformation of the rock. pressure. Pipe joint anchor support has better support effect under this condition, and is convenient for construction. According to the engineering conditions and anchoring characteristics, it can be used for anchor shotcrete and steel wire mesh support, and can also be used for beam support, Grouting and other methods.

3.2 The anchoring force is high, and its anchoring force increases with time

After the slotted-tube bolt is arranged, the resistance of the bolt hole wall is restricted, and the initial anchoring force is 40 to 50 KN/m, which provides favorable conditions for effectively controlling the deformation of the surrounding rock of the roadway after blasting. Slotted pipe bolts rely on their own radial deformation and strain and the uniform effect of the roadway wall to generate strong static friction and anchoring force. When the rock is deformed, the anchoring force of the bolt will increase the pressure as the time is longer: (1) Affected by the pressure of rock deformation and external vibration, the anchoring force is twisted and deformed, thus strengthening the anchoring force. (2) The rock deformation causes the hole to shrink, the anchor rod is compressed, and the radial deformation increases. (3) The anchor rod is corroded by factors in the rock medium, so that the surface roughness of the anchor rod increases, and the friction force is relatively increased.

4. Matching of three diameters of bolt support

The matching of three diameters of bolt support is an important part of bolt support. The mismatch of the three diameters will lead to plugging of the card or insufficient filling defects in the mixing area, reducing the anchoring force. Through the long-term comparative analysis of the construction site test (see the table for the matching of three diameters), the effect is better.