Tunnel Electromagnetic Joint Scanning for 3D Inversion
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Solution Overview
Problem
Current tunnel advanced prediction using transient electromagnetic (TEM) methods faces challenges such as low construction efficiency, limited data coverage, low signal-to-noise ratio, and one-dimensional inversion models that fail to accurately describe three-dimensional underground spaces, leading to false anomalies and unstable inversions.
Innovation Solution
The introduction of a new tunnel electromagnetic detection system called TEJS, which enables three-dimensional joint inversion of multi-component, time domain, and frequency domain signals, using a deep learning-based parameter inversion method. This system employs surface transmission, underground reception, multi-source transmission, and multi-component reception modes, along with a UNet neural network for rapid prediction of low resistance anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If combined batteries are used to supply power in tunnel areas, then deflagration risk is reduced, but transmit power is limited leading to low signal-to-noise ratio
Solution Approach 1:
The patent replaces the traditional mechanical/electrical power transmission system with an electromagnetic field-based detection system. By using electromagnetic signals transmitted through the ground rather than direct electrical power transmission, the system eliminates deflagration risks while maintaining sufficient signal strength through optimized electromagnetic coupling between transmitter and receiver coils.
Solution Approach 2:
The patent transitions from one-dimensional signal transmission (single direction) to three-dimensional electromagnetic field interaction. By utilizing multi-component reception (Fx, Fy, Fz) and spatially distributed transmitter-receiver pairs, the system captures electromagnetic signals from multiple directions and depths, significantly improving signal-to-noise ratio while maintaining safety.
2Device complexity
If one-dimensional inversion based on layered media is used, then computational simplicity is maintained, but inversion results are prone to false anomalies and poor lateral continuity
Solution Approach 1:
The patent explicitly transitions from one-dimensional layered media inversion to three-dimensional inversion. The system uses spatially distributed multi-component electromagnetic data from multiple transmitter-receiver positions to construct 3D resistivity models, capturing lateral variations and improving accuracy while maintaining computational feasibility through efficient algorithms.
Solution Approach 2:
The patent combines multiple types of electromagnetic data (time-domain transient electromagnetic and frequency-domain electromagnetic) with multi-component reception to create a composite dataset. This composite approach integrates information from different physical domains and measurement configurations, enabling more robust three-dimensional inversion with reduced false anomalies.
3Ease of operation
If only vertical electromagnetic field components are collected, then measurement simplicity is maintained, but important effective information is lost
Solution Approach 1:
The patent implements multi-component electromagnetic receivers that simultaneously measure all three spatial components (Fx, Fy, Fz) of the electromagnetic field. This multi-functional approach allows the same receiver to capture horizontal and vertical field variations, providing comprehensive information about subsurface structures without increasing operational complexity.
Solution Approach 2:
The system extends measurement from one dimension (vertical component only) to three dimensions (all spatial components). By measuring electromagnetic field vectors in all three directions and utilizing spatially distributed receivers, the system captures the full three-dimensional structure of subsurface anomalies while maintaining manageable data processing through systematic inversion algorithms.
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 TEJS system significantly improves the accuracy and efficiency of tunnel electromagnetic detection by enhancing signal coverage, increasing the signal-to-noise ratio, and providing a reliable three-dimensional imaging mechanism, which reduces false anomalies and improves the stability of inversion results.
Implementation Method 1
Transient electromagnetic (TEM) method is widely used to identify low resistivity areas before tunnel construction based on the obvious conductivity difference between the underground detection target body and the surrounding rock
Implementation Method 2
the current tunnel transient electromagnetic technology usually collects the magnetic field component or induced electromotive force perpendicular to the coil plane
Data Source
AI summary
Provided herein is a tunnel electromagnetic joint scanning detection method and a system thereof. It introduces a new tunnel electromagnetic detection system called TEJS, realizes three-dimensional joint inversion of multi-component, time domain and frequency domain signals, and forms tunnel joint scanning imaging. This method adopts the mode of surface transmission, underground reception, multi-source transmission and multi-component reception. Based on an observation system, a large number of stochastic models are constructed and numerically simulated, and a large number of training data sets are constructed by using the simulated data to complete the training of UNet model. This model can realize real-time and fast imaging of the position of the low-resistance anomalous body in three-dimensional space. An algorithm forms a dual checking mechanism through surface imaging and underground imaging, which constrains the three-dimensional spatial position of anomalous body together to prevent misjudgment.