Expandable Anchor Wings for Grout Leakage Prevention

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Solution Overview

Problem

Conventional permanent anchors face issues with grout leakage due to cracks in the anchor hole, leading to reduced grout filling rates, increased construction time, and structural instability, making it difficult to achieve substantial ground reinforcement and potentially causing accidents.

Innovation Solution

A leading end anchor with expandable and unfoldable anchor wings, fixed by a steel wire and anchored with a pressurizing tube, which expands and unfolds with grout injection pressure to improve anchoring force and prevent grout leakage, allowing for high-quality reinforcement without pore generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If grout is injected into the anchor hole through a grout hose, then the anchor hole is filled with grout to anchor the leading end anchor, but grout leaks from the anchor hole through cracks formed within the anchor hole, decreasing the grout filling rate

Engineering Contradiction:
Improvegrout filling rateVSAvoidgrout leakage through cracks
Core Design Contradiction:
Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The anchor hole is divided into multiple segments by inserting plugs at different positions (first plug, second plug, third plug) along the anchor hole. Grout injection is performed in stages, with each segment being filled separately. This segmentation prevents grout from leaking through cracks in one segment from affecting other segments, thereby maintaining high grout filling rates despite the presence of cracks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Plugs are inserted into the anchor hole before grout injection to seal off segments in advance. This preliminary action creates isolated compartments that prevent grout leakage through cracks from compromising the overall grout filling. The plugs are positioned at specific depths (first plug at 1/3 depth, second plug at 2/3 depth, third plug near the bottom) to create effective segmentation before the harmful grout leakage can propagate.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the anchor hole is perforated deeper to achieve better anchoring in weak ground, then anchoring strength is improved, but construction time and costs increase

Engineering Contradiction:
Improveanchoring strengthVSAvoidconstruction time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The plug insertion method concentrates grout and anchoring force at specific local positions within the anchor hole rather than requiring uniform deep anchoring. By creating segmented zones with plugs, the system achieves effective anchoring at moderate depths by ensuring complete grout saturation in each segment, thereby improving anchoring strength without proportionally increasing anchor hole depth and construction time.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the grout injection parameters by injecting grout in multiple stages with plug insertion, rather than continuous injection. This parameter change allows for better grout distribution and saturation at each stage, achieving sufficient anchoring strength at shallower depths compared to conventional single-stage injection, thus reducing construction time while maintaining anchoring quality.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If grout is injected under high pressure to ensure complete filling, then grout filling efficiency is improved, but grout leaks more readily through cracks in the anchor hole

Engineering Contradiction:
Improvegrout filling efficiencyVSAvoidgrout leakage through cracks
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The anchor hole is segmented into multiple isolated zones using plugs, allowing high-pressure grout injection to be applied to each segment separately. This segmentation contains the high pressure within individual segments, preventing grout from escaping through cracks to adjacent segments, thereby maintaining both high filling efficiency and preventing leakage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Plugs are inserted into the anchor hole before grout injection to create sealed segments in advance. This preliminary action establishes pressure containment barriers that allow high-pressure injection to proceed efficiently without grout leakage through cracks, as the plugs prevent pressure-driven grout from escaping into un.injected zones.

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

The improved anchoring system enhances the fixing force and grout filling efficiency, reducing construction time and costs, ensuring stable anchoring even in weak ground conditions and preventing structural failures.

Implementation Method 1

the fluid is slid by a filling pressure of grout injected into the pressurizing tube body so as to expand and unfold the anchor wings to the outside

Methodology Applied
Scientific EffectGrout injection pressure: Pressure Increase

Implementation Method 2

the anchor wings are expanded and unfolded and then strongly stuck into an inner wall of the anchor hole

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

the anchor wings are expanded and unfolded by a pressure applied by the fluid

Methodology Applied
Scientific EffectNormal force: Force

Implementation Method 4

grout is injected through the grout hose inserted into the anchor hole

Methodology Applied
Scientific EffectGrout injection pressure: Pressure Increase

Data Source

PatentEP3135821B1Structure of permanent anchor
Publication Date: 2018.03.07 WHA RANG FOUND CO LTD
  • EP3135821B1 patent drawingFigure 1
  • EP3135821B1 patent drawingFigure 2
  • EP3135821B1 patent drawingFigure 3

AI summary

The present disclosure relates to a permanent anchor used for suppression of a collapse of cut slopes in a rock or ground cutting area or suppression of a collapse of excavation walls during engineering works and more particularly, to a permanent anchor including a steel wire fixing part (10) for fixing and coupling tension members (110) and an anchoring head part (20) to be expanded and unfolded by a grout injection pressure. The anchoring head part (20) is configured to be coupled to a lower end of the steel wire fixing part (10), and includes a fluid (50) operating by the grout injection pressure and a plurality of anchor wings (60,60') configured to be expanded and unfolded by a pressure applied by the fluid.