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NB/T 11445-2023Technical specification for full-length anchored prestressed cable support of mine roadway (English PDF)

矿用全长锚固预应力锚索支护技术规范

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Issued by

NEA

Level / Type

Industry · Recommended

Issue date

December 28, 2023

Implementation date

June 28, 2024

Scope

NB/T 11445-2023 is the English-translated version of 矿用全长锚固预应力锚索支护技术规范.

NB/T 11445-2023 is the Chinese energy industry specification for supporting mine roadways with full-length anchored prestressed cables, which combine end anchoring and pretension with delayed grouting along the whole cable.

Support design starts from site investigation and geomechanical assessment of the surrounding rock. Material clauses cover solid cables with sleeve-assisted grouting, hollow grouting cables made of hollow-pipe steel strand, resin anchoring agents, grouting materials, combined components and protective mesh.

Construction covers drilling, cable installation and protection, delayed grouting and safety, followed by quality inspection and support monitoring, including station layout, observation frequency, information feedback, staff training and record keeping. Issued on 28 December 2023, it has applied since 28 June 2024.

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Document preview — NB/T 11445-2023

National Standard of the People's Republic of China

ICS: 73.040
Classification: D 24

Issued by: National Energy Administration of the People's Republic of China

Preface
1 Scope
2 Normative references
3 Terms and Definitions
4 Support design
4.1 Site investigation and geomechanical assessment of tunnel surrounding rock
4.2 Anchor cable support design
5 Support materials
5.1 General requirements
5.2 Material composition
5.3 Solid anchor cable
5.4 Hollow grouting anchor cable
5.5 Resin anchoring agent
5.6 Grouting materials
5.7 Composite components
5.8 Protective net
6 Support construction
6.1 General Provisions
6.2 Drilling
6.3 Anchor cable installation
6.4 Anchor cable protection
6.5 Delayed Grouting
6.6 Construction safety requirements
7 Construction quality inspection
8 Support quality monitoring
8.1 Monitoring content
8.2 Draw a map of station locations and instrument distribution
8.3 Monitoring requirements
8.4 Observation frequency
8.5 Information Feedback
8.6 Monitoring staff training
8.7 Archiving System

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.

1 Scope

This document specifies the support design, support materials, support construction, and construction quality inspection of the full-length anchor prestressed anchor cable support technology for mines. And the usage requirements of support quality monitoring.

This document is applicable to mines with full-length anchored prestressed anchor cable support.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB 175 General purpose Portland cement

GB/T 5224 Steel strand for prestressed concrete

GB/T 14370 Anchors, clamps and connectors for prestressed tendons

GB/T 35056 Technical specification for bolt support in coal mine tunnels

MT/T 146.1 Resin anchors Part 1: Anchoring agents

MT/T 861 W-shaped steel strip for mining

MT/T 879 Technical Specification for Prestressed Anchor Construction in Coal Mines

MT/T 942 Mining Anchor Cable

3 Terms and definitions

The terms and definitions defined in GB/T 5224, GB/T 35056, MT/T 942 and the following apply to this document.

3.1 Full-length anchored prestressed cable

The mining anchor cable adopts the method of combining end prestressed anchoring with delayed grouting to realize prestressed anchoring support along the entire length of the cable body.

Note: There are two types. solid anchor cables with casing-assisted grouting and hollow grouting anchor cables.

3.2 Hollow grouting cable

Mining anchor cable consists of hollow tube steel strand, slurry stopper, lock and other related accessories.

3.3 Hollow-pipe steel strand

A stranded steel wire bundle is formed by winding several steel wires around the outside of the grouting pipe.

3.4 External grouting pipe

External metal or plastic pipe used for grouting of solid anchor cables.

3.5 Point of sudden deterioration of surrounding rock

The point where the depth, number and aperture of the cracks in the weak surrounding rock suddenly increase after excavation is located at the critical position where the cracks develop slowly and expand rapidly.

......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 19 pages — is available in the English PDF.

Referenced standards

Normative references

MT/T 146.1 · MT/T 879

Cited by

NB/T 11542-2024Technical specification for cage type cable to floor bolt-grouting support in coal mine roadway

Similar standards

NB/T 11542-2024|NB/T 11551-2024|NB/T 11446-2023|NB/T 51030-2015|GB 50419-2017|GB/T 23639-2017

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