Constant-Resistance Anchor Cable Frustum Sleeve Plastic Deformation

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Solution Overview

Problem

Conventional pre-stress anchor cables used for monitoring and early warning of soft rock slope stability and seismogenic fault activity are prone to fracture when the sliding force exceeds the material strength, leading to a breakdown of the mechanical signal transmission system and loss of monitoring capability.

Innovation Solution

A constant-resistance and large deformation anchor cable system featuring a sleeve and constant-resistance body with a frustum structure, where the constant-resistance body has a higher strength than the sleeve, allowing the sleeve to deform plastically and generate friction resistance, preventing the anchor cable from fracturing under excessive sliding force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional pre-stress anchor cable is used, then the anchor cable can provide sufficient strength to resist sliding force, but the anchor cable may fracture when the sliding force exceeds its material strength, causing the monitoring system to fail

Engineering Contradiction:
Improveanchor cable strengthVSAvoidmonitoring system reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The anchor cable system is segmented into multiple functional components: a high-strength constant-resistance body, a sleeve with cuneiform portion, and cable elements. The constant-resistance body is divided into sections with different diameters that interact with the sleeve's cuneiform portion to create staged resistance zones, allowing the system to handle varying sliding forces without catastrophic failure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sleeve with cuneiform portion acts as an intermediary between the constant-resistance body and the external loading. It transforms the axial sliding force into radial friction resistance through the cuneiform geometry, providing a controlled resistance mechanism that prevents sudden cable fracture while maintaining monitoring capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If the anchor cable is designed with high strength to resist large sliding forces, then the anchor cable can withstand greater loads, but the deformation capacity is limited and the cable may fracture abruptly

Engineering Contradiction:
Improveload-bearing capacityVSAvoidstructural integrity under deformation
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The constant-resistance body employs parameter changes in its geometric configuration, with sections of varying diameters (first section with diameter D1, second section with diameter D2 where D1 > D2). This creates different friction resistance zones as the body slides through the sleeve, allowing progressive deformation and energy absorption without abrupt structural failure.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system combines materials and structures with different mechanical properties: the high-strength constant-resistance body, the friction-providing sleeve material, and the cable elements. This composite approach allows the system to exhibit both high strength capacity and controlled deformation characteristics, preventing catastrophic failure.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If the anchor cable relies solely on its material strength to resist sliding force, then the structure is simple, but the cable will fracture when the sliding force exceeds its strength

Engineering Contradiction:
Improvestructure simplicityVSAvoidcontinuous monitoring capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The constant-resistance body serves multiple functions: it provides high strength resistance, generates friction through sliding in the sleeve, and maintains structural integrity throughout the deformation process. This multi-functionality is achieved within a relatively compact structure, balancing complexity and reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system utilizes the sliding motion itself to generate the required resistance through friction between the constant-resistance body and the sleeve's cuneiform portion. The structure serves itself by converting kinetic energy of sliding into frictional resistance, eliminating the need for additional active components while maintaining reliability.

Inventive Principle:
Principle #25Self-service

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 system effectively resists fracture by sliding the constant-resistance body within the sleeve, maintaining continuous monitoring and early warning capabilities during rock slide processes, even when the sliding force exceeds the anchor cable's ultimate strength.

Implementation Method 1

the sleeve to have plastic deformation to generate constant resistance

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

the constant resistance being a friction resistance between the sleeve and the constant-resistance body

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2719858B1Constant-resistance and large deformation anchor cable and constant-resistance device
Publication Date: 2018.02.21 CHINA UNIV OF MINING & TECH (BEIJING)
  • EP2719858B1 patent drawingFigure 1
  • EP2719858B1 patent drawingFigure 2~4
  • EP2719858B1 patent drawingFigure 5~7

AI summary

A constant-resistance and large deformation anchor cable and a constant-resistance device are provided. The constant-resistance and large deformation anchor cable comprises cables (7), an anchoring device (13), a loading plate (12) and clipping sheets (4). The upper end of cables (7) is fixed on the anchoring device (13) and the loading plate (12) by clipping sheets (4). The constant-resistance and large deformation anchor cable also comprises a constant-resistance device, and the constant-resistance device comprises a sleeve (8) and a constant-resistance body (5). The sleeve (8) is a straight tube. The constant-resistance body is conical, and the diameter of the lower end of the constant-resistance body is bigger than the diameter of the upper end of the constant-resistance body. The inner diameter of the sleeve (8) is smaller than the diameter of the lower end of the constant-resistance body. A cuneiform part is arranged on inner wall of the lower end of the sleeve (8), and the constant-resistance body (5) is arranged on the cuneiform part. The strength of constant-resistance body (5) is higher than the strength of the sleeve (8), thus the sleeve (8) generates plastic deforming and the shape of the constant-resistance body (5) is not changed, when the constant-resistance body (5) moves in the sleeve (8). The lower end of the cables (7) is fixed on the constant-resistance body (5). The constant-resistance and large deformation anchor cable and the constant-resistance device have the properties of constant-resistance and preventing fracture, and can detect and early warn the all process of the activity of the landslides and the causative fault.