IS 14210:1995 is the Indian Standard (BIS) for rock bolting for underground excavations. This code of practice provides guidelines for the design, installation, and testing of rock bolting systems for supporting underground excavations like tunnels, mines, and caverns. It covers rock mass classification using the RMR system, selection of appropriate bolt types, and quality control procedures to ensure rock stability.
Lays down procedures for design, installation, testing, and maintenance of rock bolts used for supporting underground excavations.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Grout Compressive Strength (28-day) | Minimum 25 N/mm² (25 MPa) | Minimum 30 N/mm² (30 MPa) is common practice, specified in EN 447 | BS EN 1537:2013 |
| Grout Water/Cement Ratio (by mass) | Not to exceed 0.45 | Maximum 0.45, often closer to 0.40 is recommended to limit bleed and increase durability | BS EN 1537:2013 |
| Pull-out Test Load | Generally 1.5 times the design load | Proof load is typically 1.25 times the characteristic resistance (design load) | BS EN 1537:2013 |
| Grout Bleed Limit | Max 2% after 2 hours, 4% total | Max 2% after 3 hours at 20°C, 4% total (as per EN 445 test method) | BS EN 1537:2013 |
| Typical Bolt Steel Yield Strength | 250 MPa (for steel grade IS 2062 E250) | 379 MPa (for Grade 55) to 517 MPa (for Grade 75) | ASTM F432-19 |
| Pull-out Test Creep Acceptance | Residual load after 24 hours should not be less than 95% of design load. | Creep displacement (log time) should not exceed 1mm to 2mm between specific time intervals (e.g., 1 min to 10 min). | BS EN 1537:2013 |