TBM Tunnel Detector Using Shielding Electrode System
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Solution Overview
Problem
Current geologic forecast technologies for TBM construction tunnels face challenges such as limited detection space, electromagnetic interference, and short available time, leading to inaccurate predictions and high costs, with existing methods like BEAM being inefficient and unsuitable for three-dimensional information gathering.
Innovation Solution
A forward three-dimensional induced polarization method is implemented, utilizing a shielding electrode system and tomography detection power supply and measurement system to minimize interference and provide three-dimensional geologic information, allowing for quantitative water forecasting by analyzing induced polarization half-decay time differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If common induced polarization method is used for advanced geologic forecast in TBM construction tunnel, then the detection principle is simple, but the electromagnetic interference from TBM metal members and power supply cables makes the detection effect extremely unsatisfactory
Solution Approach 1:
The patent introduces a shielding electrode system as an intermediary element between the TBM and the detection system. This shielding electrode system acts as a mediator that blocks or reduces the electromagnetic interference from TBM metal members and power supply cables, thereby improving the detection effect of the induced polarization method without requiring changes to the fundamental detection principle
Solution Approach 2:
The patent converts the harmful electromagnetic interference into a beneficial effect by using the shielding electrode system to redirect and control the electromagnetic field distribution. The interference that would normally degrade detection quality is transformed into a structured field pattern that enhances the detection of geologic features ahead of the TBM working face
2Measurement precision
If BEAM system is used for advanced geologic forecast, then induced polarization method is applied, but the test equipment installation is complex and test time is long, seriously influencing construction progress
Solution Approach 1:
The patent divides the detection system into modular components: a control device, a shielding electrode system with multiple independently controllable electrode groups, and a detection device. This segmentation allows for simplified installation and faster configuration compared to the complex BEAM system, reducing the time lost during setup while maintaining geologic forecast capability
Solution Approach 2:
The patent implements periodic detection cycles during TBM construction operations. The shielding electrode system can be quickly configured and deactivated in periodic intervals aligned with construction progress, enabling repeated fast measurements without requiring prolonged continuous setup time like the BEAM system
3Loss of information
If BEAM method is used for water-bearing condition detection, then induced polarization measurement is performed, but the detection distance is short and three-dimensional information of geologic bodies cannot be obtained
Solution Approach 1:
The patent transitions from the one-dimensional focusing-type measurement of the BEAM method to a three-dimensional detection approach. By arranging multiple electrode groups in spatial configurations and performing measurements from different positions and angles, the system reconstructs three-dimensional images of geologic bodies ahead of the TBM working face, significantly expanding the detection volume and distance
Solution Approach 2:
The patent employs dynamic electrode configuration where the shielding electrode system can be adjusted and repositioned during detection operations. This dynamic capability allows the system to adapt electrode positions and measurement parameters to extend detection distance and optimize three-dimensional coverage of geologic structures, overcoming the fixed limitation of the BEAM method
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 approach enhances detection efficiency and accuracy, increases forecast distance, and reduces costs by enabling three-dimensional location of water-bearing bodies and water quantity estimation, overcoming previous method limitations.
Implementation Method 1
forward three-dimensional induced polarization method
Implementation Method 2
general advanced geologic forecast technologies based on an electromagnetic principle
Data Source
AI summary
Disclosed is an advanced detector system and method using a forward three-dimensional induced polarization method for a TBM (Tunnel Boring Machine) construction tunnel. A narrow detection space of a full-face excavated tunnel is fully used, a controller controls doors of a source and measuring electrode compartment and a shielding electrode compartment to open and controls a corresponding hydraulic delivery device to automatically and quickly arrange a source electrode system, a measuring electrode system and a shielding electrode system. Under the action of a shielding current system, tomography detection supply current is directed ahead of the working face. Three-dimensional geologic information can be obtained, and the relationship between an induced polarization half-decay time difference and a water quantity can be used to quantitatively forecast the water quantity of a water-bearing body, and meanwhile, the half-decay time difference parameter has a high capacity of distinguishing free water from bound water.