Transient Electromagnetic Correction for Tunnel Water Detection

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Solution Overview

Problem

Current methods for predicting water-bearing structures in tunnel construction, such as seismic and electromagnetic methods, are inefficient and costly, with low success rates in detecting water presence, especially in inclined or crushed zones, and existing technologies struggle to accurately determine water-filled zones.

Innovation Solution

A correction method for transient electromagnetic method-based prediction that involves eliminating the effects of the transition process in the reception probe using earth conductivity, by calculating a correction coefficient based on known earth conductivity and subtracting interference signals to obtain accurate information about water-bearing structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If transient electromagnetic method is used for water-bearing structure detection, then detection speed is improved, but measurement precision deteriorates due to transition process interference in reception probe

Engineering Contradiction:

Improvedetection speedVSAvoidwater-bearing structure detection accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary measurements of the reception probe's transition process characteristics in a known uniform geological environment before actual detection. These pre-measured transition process data are then used to correct and eliminate interference in subsequent measurements, enabling both rapid detection and high precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces a correction coefficient as an intermediary element. This coefficient is calculated by comparing measured transition process data with theoretical values, and then applied to correct the actual detection signals, effectively separating the useful geological information from the probe's transition process interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If traditional seismic methods are used for geological prediction, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improvegeological prediction accuracyVSAvoidprediction system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical seismic measurement systems with a simplified transient electromagnetic detection system. By using electromagnetic fields instead of mechanical wave propagation, the system achieves comparable or superior measurement precision while dramatically reducing device complexity and operational costs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If advanced exploratory drilling is used for water detection, then measurement precision is improved, but loss of time increases significantly

Engineering Contradiction:

Improvewater detection accuracyVSAvoidconstruction progress time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces time-consuming mechanical drilling operations with rapid transient electromagnetic detection. The electromagnetic method can identify water-bearing structures in real-time during tunneling, eliminating the need for frequent stopping and drilling, thus maintaining high measurement precision while minimizing time loss and maximizing construction progress.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enhances the accuracy of water-bearing structure detection, providing more precise information on location, size, and shape, significantly improving geological prediction during tunnel construction.

Implementation Method 1

transient electromagnetic sounding method

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a primary field transmitted... a secondary field received by the reception device

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnetic Induction

Implementation Method 3

a secondary field received by the reception device is the sum of the two secondary fields

Methodology Applied

Scientific EffectElectromagnetic field detection: Electromagnetic Induction

Implementation Method 4

with known earth conductivity (named data1) of an engineering site... using earth conductivity to eliminate effects of transition process

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10823872B2Correction method for transient electromagnetic method-based prediction of water-bearing structure ahead of tunnel wall

Publication Date: 2020.11.03 INSTITUTE OF GEOLOGY AND GEOPHYSICS CHINESE ACADEMY OF SCIENCES

AI summary

The present invention relates to a correction method for transient electromagnetic method-based prediction of water-bearing structure ahead of tunnel wall, which pertains to the technical field of transient electromagnetic sounding method. The correction method includes a method for eliminating effects of transition process in a reception probe and a method of using earth conductivity to eliminate effects of transition process. By using the correction technique, more accurate information about the location, size and shape of the object in front of the tunnel wall can be obtained, which is of great significance to the study of the fine water-bearing geological structure.