Rock Reinforcement Member Cavity Detection System

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Solution Overview

Problem

Current rock reinforcement systems face challenges in ensuring complete grout filling and anchoring of bolts due to the inability to directly detect cavities in drill-holes, leading to potential loss of tensile strength and increased corrosion risk.

Innovation Solution

A method and system for direct cavity detection in drill-holes using a reinforcement member with a channel for introducing a pressurized medium, where changes in pressure or flow indicate cavity presence, utilizing a pressure gauge and flow meter to measure and verify the absence of cavities post-grout hardening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If indirect methods (tensile testing or sound wave transmission) are used to investigate bolt attachment, then investigation can be performed, but it is not possible to verify with certainty whether grout is missing from the drill-hole

Engineering Contradiction:
Improveverification certaintyVSAvoidcavity detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A channel is introduced as an intermediary element within the reinforcement member to directly access and detect cavities in the drill-hole. This channel allows pressurized medium to be injected directly into the grout-filled space, enabling certain verification of grout presence rather than relying on indirect bolt performance testing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces indirect mechanical testing methods (tensile resistance testing) and acoustic methods (sound wave transmission) with a direct pressure-based detection system. By injecting pressurized medium through the channel and monitoring pressure changes, the system directly detects cavities without relying on bolt mechanical response or sound wave reflection

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If grout injection is performed without cavity detection, then reinforcement process is simple, but cavities may remain undetected leading to lost tensile strength and increased corrosion risk

Engineering Contradiction:
Improvereinforcement safetyVSAvoiddetection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection channel is merged with the reinforcement member itself, combining the structural function (reinforcement) with the detection function (cavity detection) into a single integrated component. This eliminates the need for separate detection equipment while ensuring reinforcement safety

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reinforcement member serves dual purposes: providing structural reinforcement and enabling self-detection of grout filling quality. The channel within the reinforcement member allows the system to self-verify its own installation quality through pressure medium injection

Inventive Principle:
Principle #25Self-service

3Measurement precision

If a channel with radially directed holes is used to introduce pressurized medium, then cavity detection is enabled, but the channel may become clogged by unhardened grout

Engineering Contradiction:
Improvecavity detection capabilityVSAvoidchannel functionality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A cover is placed over the radially directed holes in the channel before grout injection to prevent grout from entering and clogging the holes. This preliminary protective action ensures the channel remains functional for subsequent pressure medium injection and cavity detection

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cover acts as a protective barrier that cushions against the harmful effect of grout clogging the channel holes. By providing this protection in advance, the system ensures reliable channel functionality when needed for cavity detection

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Ensures complete grout filling and secure anchoring of bolts, enhancing the strength and safety of rock reinforcement systems by accurately detecting cavities and preventing corrosion.

Implementation Method 1

with a pressure gauge, changes in pressure in the medium are measured

Methodology Applied
Scientific EffectPressure measurement: Pressure Gradient

Implementation Method 2

with a flow meter, flow of the medium is detected

Methodology Applied
Scientific EffectFluid flow detection: Flow Separation

Data Source

PatentEP2427633B1Method, system, use of the system and reinforcement member for rock reinforcement
Publication Date: 2019.12.04 ROCK SAFETY SWEDEN AB
  • EP2427633B1 patent drawingFigure 1a~1d
  • EP2427633B1 patent drawingFigure 2
  • EP2427633B1 patent drawingFigure 3a~3b

AI summary

The present invention concerns a method, a system, the use of the system and a reinforcement member for the direct detection of the presence of a cavity in a drill-hole intended for the reception of a reinforcement member. The method comprises the injection of a drill-hole with hardening grout 6, the introduction of a reinforcement member 7, 40 to introduce a pressurised medium 37 and the measurement of the change in pressure or the detection of a flow of medium, whereby the fall in pressure or the presence of a flow of medium indicates the presence of a cavity. The system comprises a container 26 comprising a pressurised medium 37, a reinforcement member 7, 40 comprising a channel 15, 41 through which the pressurised medium in the container is added to the drill-hole at the presence of a cavity, and a pressure gauge 27 or a flow meter 50, where the pressure gauge measures a change in pressure or the flow meter detects a flow of medium, whereby a fall in pressure or a flow of medium indicates the presence of a cavity. The invention is used during the construction of tunnels and mines in order to ensure the quality of rock reinforcement that has been carried out.