CN109765627B

CN109765627B - Plane wave electromagnetic depth sounding method suitable for mountainous region

Info

Publication number: CN109765627B
Application number: CN201910175763.2A
Authority: CN
Inventors: 席振铢; 龙霞; 周胜; 陈兴朋; 王亮; 韦洪兰; 肖炜; 薛军平; 王鹤
Original assignee: Hunan Wuwei Geological Science And Technology Co ltd; Central South University
Current assignee: Hunan Wuwei Geological Science And Technology Co ltd; Central South University
Priority date: 2019-03-08
Filing date: 2019-03-08
Publication date: 2020-04-03
Anticipated expiration: 2039-03-08
Also published as: CN109765627A

Abstract

The invention discloses a plane wave electromagnetic depth measurement method suitable for mountainous regions, which comprises the steps of designing a measuring line and a measuring point; determining the placing state of the observation device; measuring, collecting and processing electric field and magnetic field data; and drawing images of the resistivity and depth cross section of the measuring place. The plane wave electromagnetic depth measurement method suitable for mountainous regions provided by the invention has the advantages that the resistivity depth measurement data are more accurate, the observation horizontal electric field moves along the direction of a hillside, the observation magnetic field is tangential along the hillside, the observation result is slightly influenced by the terrain, and the field operation is simple.

Description

Plane wave electromagnetic depth sounding method suitable for mountainous region

Technical Field

The invention particularly relates to a plane wave electromagnetic depth sounding method suitable for mountainous regions.

Background

With the development of economic technology and the improvement of living standard of people, people pay more and more attention to basic subjects.

The plane wave electromagnetic sounding method is mainly used for researching the underground resistivity space distribution situation based on the Carnia resistivity. The traditional plane wave electromagnetic sounding method comprises a magnetotelluric sounding Method (MT), an audio magnetotelluric sounding method (AMT), a controllable source magnetotelluric sounding method (CSAMT) and the like, which are all used for detecting mutually orthogonal horizontal electric field and magnetic field components, wherein manual operation (pit digging) is required to observe a horizontal electric field and a horizontal magnetic field during inclined ground observation, the electrode distance needs to be converted into the length of a horizontal electrode distance, and the sounding direction is vertical and horizontal ground downwards.

In practice, the mountainous terrain is inclined, and the operation of obtaining the horizontal electromagnetic field through manual operation and conversion such as pit digging is not only complicated, but also easy to generate large errors.

Disclosure of Invention

The invention aims to provide a plane wave electromagnetic depth sounding method which is convenient to operate and can accurately evaluate the change condition of the underground resistivity of the mountainous region.

The invention provides a plane wave electromagnetic depth sounding method suitable for mountainous regions, which comprises the following steps:

s1, designing a measuring line and a measuring point according to a measuring task and the topographic characteristics of a measuring place;

s2, determining the placing state of the observation device according to the topographic features of the measuring place;

s3, starting measurement, collecting and processing electric field and magnetic field data;

and S4, drawing an image of the resistivity and the depth section of the measuring place according to the data processed in the step S3.

Step S2, determining the placement state of the observation device, specifically, determining the placement state by using the following rules:

r1, the direction of the mountain body is the horizontal y direction;

r2, the horizontal direction of the vertical mountain is the horizontal x direction;

r3, taking the tangential direction along the hillside interface as the direction t;

r4, observing an electrode-electrode connecting line of the electric field, wherein the electrode-electrode connecting line is parallel to the direction of the mountain body and is along the y direction;

r5. the magnetic rod is perpendicular to the direction of mountain and is placed on the ground along the slope section along the direction t.

And step S4, drawing the resistivity and depth section image of the survey area, wherein the depth measuring direction in the drawing is the normal downward direction of the ground surface.

The plane wave electromagnetic depth measurement method suitable for mountainous regions provided by the invention has the advantages that the resistivity depth measurement data are more accurate, the observation horizontal electric field moves along the direction of a hillside, the observation magnetic field is tangential along the hillside, the observation result is slightly influenced by the terrain, and the field operation is simple.

Drawings

FIG. 1 is a process flow diagram of the process of the present invention.

Fig. 2 is a schematic image of a conventional resistivity and depth profile.

FIG. 3 is a graphical representation of resistivity and depth profiles of the method of the present invention.

Detailed Description

FIG. 1 shows a flow chart of the method of the present invention: the invention provides a plane wave electromagnetic depth sounding method suitable for mountainous regions, which comprises the following steps:

s2, determining the placing state of the observation device according to the topographic features of the measuring place; specifically, the following rules are adopted to determine the placing state:

r1, the direction of the mountain body is the horizontal y direction;

r3, taking the tangential direction along the hillside interface as the direction t; (if the ground is horizontal, then the x-direction is the same as the t-direction)

R4, observing that an electrode-electrode connecting line of the electric field is parallel to the mountain trend, namely along the y direction;

r5. the magnetic rod is perpendicular to the mountain body and is placed on the ground along the slope section, i.e. along the direction t;

s3, starting measurement, collecting and processing electric field and magnetic field data; data acquisition and processing are carried out according to the traditional plane wave electromagnetic sounding method theory;

s4, drawing an image of the resistivity and the depth section of the measuring place according to the data processed in the step S3; in the drawing, the depth measurement direction is the normal downward direction of the ground surface.

FIG. 2 is a schematic diagram of an image of a conventional resistivity and depth profile; as shown in FIG. 3, which is a schematic diagram of the resistivity and depth profile of the method of the present invention, data points are distributed along the transmission direction of the electromagnetic wave at the position of the measurement point.

Claims

1. A plane wave electromagnetic sounding method suitable for mountainous regions comprises the following steps:

s1, designing a measuring line and a measuring point according to the measuring task and the topographic characteristics of the measuring place;

s2, determining the placement state of the observation device according to the topographic features of the measurement area; specifically, the following rules are adopted to determine the placing state:

r1, the direction is the horizontal y direction along the mountain body;

r3, the tangential direction along the hillside interface is the direction t;

r4, electrode-electrode connecting lines of the observation electric field are parallel to the direction of the mountain body and along the y direction;

r5, the magnetic rod is perpendicular to the trend of the mountain body, and is placed on the ground along the slope section along the direction t;

and S4, drawing an image of the resistivity and the depth section of the measured place according to the data processed in the step S3.

2. The method according to claim 1, wherein the step S4 is performed by mapping the resistivity and depth profile of the survey area, specifically, the mapping is performed in a depth direction of a ground surface facing downward.