Spiral Sensing Cable for Rock-Soil Deformation Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing TDR sensing cables are prone to breaking under tension, making them unsuitable for large-scale distributed measurement of rock and soil deformation, which is critical for predicting and mitigating geological disasters like landslides and ground subsidence.
Innovation Solution
A sensing cable with a parallel spiral transmission line structure, featuring a silicone strip with tightly wound, mutually-insulated spiral wires and a silicone shroud, allowing for increased elongation without breaking, and utilizing a TDR measurement instrument to record impedance changes for deformation detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If existing TDR sensing cables (coaxial or parallel lines) are used, then the cable structure is simple and easy to manufacture, but the cable breaks easily under tension and cannot be stretched longer
Solution Approach 1:
The sensing cable is divided into multiple segments: a flexible silicone strip base, spiral transmission lines wound on the strip, insulating layers, and outer protective sheath. This segmentation allows each component to perform its specific function while collectively providing both flexibility and tension strength.
Solution Approach 2:
The cable uses composite material construction combining silicone rubber (flexible base), copper or aluminum wires (conductive elements), insulating materials (polyester or polyethylene), and protective sheath materials. This composite structure achieves properties that no single material could provide alone, specifically both elongation capability and tension strength.
2Length of moving object
If existing TDR sensing cables are used, then the manufacturing process is simple, but the cable cannot achieve large elongation for distributed measurement of rock and soil deformation
Solution Approach 1:
The spiral transmission lines are designed to be dynamic in nature, allowing their helix pitch to change as the cable elongates. The spiral structure naturally accommodates stretching by increasing its pitch, enabling the cable to achieve large elongation while maintaining electrical characteristics and reliability.
Solution Approach 2:
The cable design allows the helix pitch parameter of the spiral transmission lines to change dynamically during elongation. This parameter change enables the cable to stretch longer while maintaining functional integrity, solving the contradiction between elongation capability and durability.
3Measurement precision
If the sensing cable is stretched to measure deformation, then the helix pitch increases and characteristic impedance changes enabling deformation detection, but the cable may break under tension
Solution Approach 1:
The cable structure incorporates inherent cushioning through the spiral transmission line design and flexible silicone base, which absorb tension stresses during elongation before they can cause damage. This beforehand cushioning allows the cable to be stretched for precise deformation measurement without breaking under tension.
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
Enables effective distributed positioning and measurement of rock and soil deformation by recording changes in the TDR waveform due to increased helix pitch, overcoming the limitations of existing cables and providing a robust tool for geotechnical deformation monitoring.
Implementation Method 1
Because of the elastic silicone strip and the spiral structure, during the process of being stretched, a helix pitch of the spiral wires is allowed to increase over a relatively large range without resulting in the sensing cable being broken
Implementation Method 2
The local change in the characteristic impedance leads to a change of a TDR waveform which may be recorded by the TDR measurement instrument. With the changed TDR waveform, the position of the deformation may be located and the size of the deformation may be measured
Data Source
AI summary
This present disclosure provides a sensing cable of parallel spiral transmission line structure for distributed sensing and measuring of rock-soil mass deformation. A circular cross-section of a silicone strip is tightly wounded by two mutually-insulated wires. The two mutually-insulated wires form the spiral cable. The two mutually-insulated wires are wrapped around and covered by a silicone shroud. They constitute a sensing cable. A termination matching impedance is connected to one end of each of the two mutually-insulated wires. A time domain reflectometry measurement instrument is connected to the other end of the two mutually-insulated wires. The present disclosure implements a distributed positioning and measurement of rock-soil mass deformation.