1. First, Evaluate Your Rock Mass & Ground Condition
Rock bolt selection starts with site geology. You need to check these points first:
- Rock strength: hard rock, medium rock, soft rock or extremely weak broken rock
- Fracture degree: intact, slightly fractured, heavily broken, loose and crushed strata
- Ground pressure: low stress, normal stress, high stress or rockburst-prone ground
- Water condition: dry, wet, or corrosive groundwater
- Service life requirement: temporary support or permanent support
Simple rule: Hard and intact rock needs simple reinforcement; heavily fractured or high-stress ground requires high-performance or energy-absorbing bolts.
2. Main Types of Rock Bolts & Their Suitable Scenarios
Split Set Friction Bolts
Working principle: Friction anchoring by elastic compression. No grout or resin needed.
✅ Advantages: Instant support after installation, fast installation, low cost
✅ Best for: Temporary support, development roadways, medium fractured rock, mesh fixing
❌ Not ideal: Permanent support, corrosive water, strong rockburst areas
Resin Anchored Bolts
Working principle: Fixed by cured resin cartridge. Full contact between bolt and borehole.
✅ Advantages: High anchoring force, reliable, good for medium and hard rock
✅ Best for: Permanent support, main haulageways, stable fractured rock
❌ Notes: Needs resin capsules, waiting for curing; installation takes longer
Grouted Bolts (Cement Grout Bolts)
Working principle: Cement mortar fills the gap between bolt and hole wall.
✅ Advantages: Good corrosion resistance, long service life
✅ Best for: Long-term permanent support, humid and corrosive mine water
❌ Notes: Slow curing, higher requirement for grouting equipment
Energy-Absorbing / Yielding Bolts
Working principle: Designed to deform and absorb energy under large rock displacement.
✅ Advantages: Can release burst energy, avoid sudden breakage
✅ Best for: High stress, rockburst risk, squeezing soft rock roadways
❌ Notes: Higher unit cost
3. Key Parameters to Confirm
Bolt Length
The bolt must go through the loosened failure zone and anchor into stable intact rock below.
- Shallow loose zone: short bolts
- Deep broken zone: longer bolts Common lengths: 1.2m, 1.5m, 1.8m, 2.0m, 2.4m, customized lengths available.
Bolt Diameter & Material
- Larger diameter usually means higher load capacity
- Common material: Q235, Q355, alloy steel for high-strength demand
- Surface treatment: plain, galvanized for anti-rust in wet mines
Borehole Matching
Different bolts have strict matching borehole ranges. Too large hole → anchoring force drops; too small hole → hard to install, easy to damage bolts.
Required Load Capacity
Calculate based on rock weight and ground pressure. Confirm design load with mine technical department.
4. Auxiliary Accessories Cannot Be Ignored
Matching accessories directly affect support effect:
- Bearing plate: distributes load evenly on rock surface
- Nut, washer, retaining ring
- Steel mesh, straps, shotcrete (for combined support) Broken rock usually needs bolts + mesh + straps together.
5. Quick Selection Checklist
- Temporary support, fast installation → Split Set bolt
- Permanent support, medium-hard rock → Resin bolt
- Permanent support + corrosive water → Cement grouted bolt
- High stress / rockburst risk → Energy-absorbing yielding bolt
- Extremely soft, squeezing ground → Combined support system
6. Final Reminder
There is no universal rock bolt suitable for all mine conditions. Before ordering, collect geological report, support design drawing, temporary/permanent usage, water corrosion situation and target anchoring load. If the geology changes in different sections of the same mine, you may need to use mixed bolt solutions. Correct selection plus standardized drilling and installation is the guarantee of safe roadway support.
Post time: 2026-10-26 10:49:20
