Benefits & Features
Product Introduction:
The self-drilling friction bolt features a hollow rod design, with a central hole serving as a channel for high-pressure drilling and grouting. Compared to solid rods, the hollow rod design offers higher stiffness and shear strength. The standard high-pitch thread structure on the outer surface of the rod facilitates cutting and extension. Compared to smooth rods, the hollow rod increases the bonding area between the friction bolt and the grouting material, thereby improving anchorage strength.
Product Features:
1. Easy installation, ensuring timely prestressing.
2. Active tensioning, with prestress up to 50 kN, and the ability to achieve appropriate over-tensioning.
3. Tensioning can be performed by a single person using conventional tools.
4. The hollow rod allows for high-pressure grouting, improving the surrounding rock mass.
5. Comprehensive control from production to installation ensures product quality. Structure:
Composed of a steel expansion shell anchor head, hollow grouting friction bolt body, grout plug, gasket, and nut.
Quality Control and Inspection:
1. The allowable deviation for friction bolt installation shall comply with the following provisions:
(1) The diameter of the bolt hole shall meet the design requirements.
(2) The depth of the bolt hole shall be greater than 250px of the friction bolt length.
(3) The allowable deviation for the bolt hole spacing is ±375px.
(4) The insertion length of the friction bolt shall not be less than 95% of the design length.
2. The direction of the bolt hole shall meet the design requirements.
The friction bolt support plate shall be in close contact with the base surface. The friction bolt shaft shall be straight, undamaged, and free of cracks, oil stains, granular or flaky rust.
3. Quality Control
Pre-job training is mandatory.
Operators must understand the construction procedures and standards.
A comprehensive explanation must be given before commencement of work.
A friction bolt layout diagram must be drawn, and its position strictly controlled.
The water-cement ratio of the mortar must be controlled.
The grouting pressure and grouting volume must be controlled. Safety Requirements and Measures:
1. During construction, the support structure should be inspected regularly and irregularly. In areas with poor geological conditions, dedicated personnel should conduct inspections every shift.
2. When construction is suspended, the support should rest directly against the excavation face.
3. Simple friction bolt devices should be securely placed.
4. During construction, if air, water, or material pipelines become blocked or burst, the supply of air, water, and materials must be stopped immediately.
5. When monitoring and measuring the friction bolt support system, if deformation, cracking, or other dangerous conditions are found, remedial measures should be taken. In emergency situations, personnel should be evacuated immediately.
6. If significant deformation or damage occurs in the anchoring area, additional reinforcing friction bolts should be installed in that area immediately, with a length at least 1.5 times that of the original friction bolts.
Precautions:
1. Grouting personnel must wear protective equipment.
2. Carefully inspect machinery, equipment, and wiring to avoid injury due to electrical leakage.
3. Machinery operators must strictly adhere to operating procedures.
4. Grouting personnel and grouting pump operators must cooperate closely.
5. After grouting is completed, the valves must be closed first, followed by the grouting pump.
6. The grouting port must not be exposed to personnel contact.
