Ice Bomb Bedrock Cracking Apparatus

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Solution Overview

Problem

Current tunnel excavation methods using tunnel boring machines (TBMs) face inefficiencies in bedrock excavation, as they require multiple holes and can lead to wear of equipment, reducing service life and excavation efficiency.

Innovation Solution

A bedrock crack apparatus using a powder keg type ice explosive, where a sealed tube filled with water and liquid nitrogen is inserted into a via hole formed in the bedrock, leveraging the principle of volume expansion upon freezing to efficiently crack the bedrock, with a packer and nitrogen injection nozzle for reliable sealing and cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tunnel boring machines are used for bedrock excavation, then excavation can be performed without explosives and with minimal vibration, but excavation efficiency is reduced due to the need to form multiple holes and equipment wear

Engineering Contradiction:
ImprovesafetyVSAvoidexcavation efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention utilizes the phase transition of water from liquid to solid (freezing) when liquid nitrogen is injected into the sealed tube. This phase change causes volume expansion of approximately 9%, generating sufficient force to crack the bedrock without using explosives, thereby maintaining safety while improving excavation efficiency

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The invention changes the temperature parameter by injecting liquid nitrogen (at approximately -196°C) into the sealed tube containing water. This extreme temperature change causes the water to freeze and expand, creating the necessary force to fracture the bedrock with a single hole instead of multiple holes

Inventive Principle:
Principle #35Parameter changes

2Strength

If multiple holes are formed and cracking work is performed with conventional methods, then bedrock can be broken, but excavation efficiency is low and equipment service life is reduced due to wear

Engineering Contradiction:
Improvebedrock breaking capabilityVSAvoidexcavation efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The invention extracts the essential cracking function into a dedicated sealed tube system that can be inserted into a single pre-formed via hole. This extracted system contains all necessary components (sealed tube, water, and nitrogen injection mechanism) to perform the cracking operation independently, eliminating the need for multiple holes and repeated equipment operations

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention performs preliminary action by pre-filling the sealed tube with water before insertion into the via hole. This preliminary preparation ensures that when liquid nitrogen is injected, the water is already in position to freeze and expand, immediately generating cracking force without requiring additional preparation steps or multiple operations

Inventive Principle:
Principle #10Preliminary action

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

This method allows for efficient cracking of bedrock with reduced equipment wear and faster excavation, as the expansion force from freezing water effectively breaks the bedrock, minimizing water leakage and extending equipment lifespan.

Implementation Method 1

a sealed tube filled with water and a liquid nitrogen is inserted in the interior of the via hole, thus causing cracks in the bedrock based on the principle where volume expands when water is frozen

Methodology Applied
Scientific EffectFreezing: Freezing

Implementation Method 2

based on the principle where volume expands when water is frozen and easily cracking the bedrock

Methodology Applied
Scientific EffectVolume expansion upon freezing: Phase Change

Implementation Method 3

a packer and nitrogen injection nozzle for reliable sealing and cracking

Methodology Applied
Scientific EffectSealing: Physical Containment

Data Source

PatentEP2907967B1Bedrock cracking apparatus using ice bomb in shape of powder keg
Publication Date: 2017.11.15 KOREA RAILROAD RESEARCH INSTITUTE
  • EP2907967B1 patent drawingFigure 1
  • EP2907967B1 patent drawingFigure 2
  • EP2907967B1 patent drawingFigure 3(a)~3(b)

AI summary

Disclosed is a bedrock crack apparatus using a powder keg type ice explosive wherein a via hole is formed at a bedrock using a via hole apparatus, and a sealed tube filled with water and a liquid nitrogen is inserted in the interior of the via hole, thus causing cracks in the bedrock based on the principle where volume expands when water is frozen and easily cracking the bedrock. The above bedrock crack apparatus may include a packer which is fixedly inserted in the mouth of a via hole formed at a bedrock; an inner tube which is disposed at the packer and is filled with water; an injection device which is connected to the packer; a nitrogen injection nozzle which is installed at the injection device and passes through the packer; and a supply unit which is connected to the injection device to supply liquid nitrogen.