T/CSPSTC 56-2020 in English

本文件规定了隧道瞬变电磁法超前地质预报的术语和符号、基本规定、瞬变电磁法预报系统、地质预报方案设计、地质预报实施、地质预报成果等方法与要求。
本文件适用于隧道掌子面前方80 m以内的断层、岩溶、裂隙发育程度及地质情况变化的地质预报工作，在工作中除应符合本技术规程外，尚应符合国家、行业现行有关标准的规定。

Scope

As the scale of underground engineering construction in our country continues to expand, hydrogeological disasters such as sudden water and mud outbreaks during the excavation of deep tunnels pose significant safety hazards. To effectively control the detection problems of sudden water and mud disasters during tunnel and mine shaft construction, it is of great practical significance to deeply study the advanced forecasting method of transient electromagnetic (TEM) for water-bearing structures in tunnels.

Electromagnetic methods are primary techniques used for groundwater exploration. Since the late 1950s, large-scale electro-prospecting applications for agricultural water have been carried out in northern China. Initially, mainly direct current resistivity profiling and sounding methods were utilized, followed by induced polarization water-finding methods in the 1970s. In recent years, electromagnetic methods have become widely used and over a thousand major and medium-sized groundwater sources have already been discovered in China.

In terms of advanced detection for underground engineering, TEM can detect water issues in zones with structural fractures, highly fractured areas, karst formations, collapse columns, and other water-rich regions. Recently, TEM has gradually been applied to predict adverse geological conditions in coal mines and tunnels, such as detecting sudden water outbreaks in deep mine workings, predicting old mine shaft water ahead of time, investigating karst fissure waters and faults in tunnels, and forecasting poor geology in advance.

Based on electrical property differences, TEM delineates different rock formations and structural fracture zones. The rapidness or slowness of the transient curve’s decay is related to the conductivity properties of geological bodies or layers, allowing for differentiation based on anomalies to determine the geological structure and hydrogeological conditions ahead of tunnel faces. This project utilizes shallow TEM theory, on-site array equipment at tunnel faces, data image processing and display technology to conduct advanced geological forecasting in tunnels with TEM methods. It has been successfully applied across multiple tunnel sectors nationwide, leading to the compilation of this standard for improved application effects.

Scope: This document applies to the advanced detection of faults, karst formations, changes in geological conditions, and development levels of fractures within a certain range ahead of tunnel construction faces.

Main regulations include on-site layout, parameter setting, data acquisition, processing and interpretation, spectral characteristics of fault and karst geological hazards, among others.

Technical content includes: 1 General Provisions; 2 Terminology; 3 Basic Regulations; 4 Work Preparation; 5 Instruments and Equipment; 6 On-Site Data Collection; 7 Data Analysis and Processing; 8 Results Interpretation; 9 Engineering Applications; 10 Result Reports.

References are based on the theoretical, methodological, and technical aspects of TEM detection, as well as requirements for tunnel geological prediction.