阅读说明：本技术 一种基于探地雷达获取动态裂缝多期地下三维形态的方法 (Method for acquiring multi-period underground three-dimensional form of dynamic crack based on ground penetrating radar ) 是由 胡振琪 张帆 浮耀坤 石国牟 梁宇生 冯泽伟 白铭波 周竹峰 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种基于探地雷达获取动态裂缝多期地下三维形态的方法,包括如下步骤：在裂缝所在区域表面铺设一薄膜,并保证裂缝表面被该薄膜完全覆盖；向薄膜上浇筑液体；在裂缝近地表处将探地雷达对准裂缝,沿列缝走向的垂直方向作为路径进行间隔扫描,得到当期裂缝地下形态多个剖面的电磁波数据；将液体抽出存储并撤去薄膜；对获取的当期所有电磁波数据进行数据处理,并通过目视解译的方法描绘得到当期各剖面处裂缝的轮廓；利用该裂缝的轮廓构建出裂缝当期地下形态的三维模型得到裂缝当期地下三维形态及其相关数据；不断重复上述步骤,得到裂缝发育动态变化过程中的多期地下三维形态及其相关数据。本发明可无损的获取动态裂缝的多期地下形态。(The invention discloses a method for acquiring a multi-period underground three-dimensional form of a dynamic fracture based on a ground penetrating radar, which comprises the following steps: laying a film on the surface of the area where the crack is located, and ensuring that the surface of the crack is completely covered by the film; pouring liquid on the film; aligning a ground penetrating radar to the crack at the position close to the ground surface of the crack, and scanning at intervals along the vertical direction of the trend of the line of the crack as a path to obtain electromagnetic wave data of a plurality of sections of the underground form of the crack at the present stage; pumping out the liquid for storage and removing the film; carrying out data processing on all the acquired electromagnetic wave data in the current period, and drawing and obtaining the contour of the crack at each section in the current period by a visual interpretation method; constructing a three-dimensional model of the current underground form of the crack by utilizing the contour of the crack to obtain the current underground three-dimensional form of the crack and related data thereof; and continuously repeating the steps to obtain the multi-stage underground three-dimensional form and the related data thereof in the dynamic change process of the crack development. The method can nondestructively acquire the multi-stage underground form of the dynamic fracture.)

1. A method for acquiring a dynamic fracture multi-period underground three-dimensional form based on a ground penetrating radar is characterized by comprising the following steps:

step 1) laying a film on the surface of an area where a crack is located, and ensuring that the surface of the crack is completely covered by the film; pouring liquid on the film in the crack to enable the liquid to fill an area A formed by the film in the whole crack in an enclosing mode, and isolating the liquid from the crack through the film; aligning a ground penetrating radar to the crack at the near-surface position of the area A, and scanning at intervals from one end to the other end along the direction of the line of the crack to obtain electromagnetic wave data of a plurality of sections of the underground form of the crack at the present stage; pumping out the liquid in the area A for storage and removing the film;

step 2) carrying out data processing on all the electromagnetic wave data acquired in the step 1) at the current period, and describing by a visual interpretation method to obtain the contour of the crack at each section at the current period;

step 3) drawing the contour of the fracture at each section in the current period obtained in the step 2) in three-dimensional image processing software, and constructing a three-dimensional model of the underground form of the fracture in the current period in an interpolation mode so as to obtain the underground three-dimensional form of the fracture in the current period and related data thereof;

and 4) continuously repeating the steps 1) to 3) according to the set frequency to obtain the multi-period underground three-dimensional form and related data thereof in the dynamic change process of the crack development.

2. The method according to claim 1, wherein the liquid in step 1) is selected to avoid interference with radar wave energy.

3. The method according to claim 1, wherein in step 1), the ground penetrating radar is not in contact with the liquid.

4. A method according to claim 3, wherein the ground penetrating radar is kept out of contact with the liquid by laying a thin plate on the film.

5. The method of claim 4, wherein the sheet is selected to avoid interference with radar wave energy.

6. The method as claimed in claim 1, wherein in step 1), when scanning along the line of cracks from one end to the other end at intervals, a mark line is made at every 10cm interval in the direction perpendicular to the direction of the crack, and the ground penetrating radar is used for scanning from a position 30cm on one side of the crack to a position 30cm on the other side of the crack along the mark line.

7. The method according to claim 1, wherein in step 2), the data processing comprises background dessication, one-dimensional filtering processing, wavelet transformation and gain operation.

8. The method according to any one of claims 1 to 7, wherein in step 3) the correlation data comprises the average width, average depth, surface area and volume of the fracture.

Technical Field

The invention relates to the field of land reclamation of coal mining subsidence lands, in particular to a method for acquiring multi-period underground three-dimensional forms of dynamic cracks based on a ground penetrating radar.

Background

In western regions of China, particularly western windage sand areas and loess areas, ground cracks are one of geological environment problems caused by coal mining, which cause the problems of building deformation, underground pipeline damage, farmland damage, accelerated soil moisture evaporation, vegetation damage, water and soil loss and the like, bring great difficulty to mining area management workers, and are also an important link for land reclamation in mining areas. In order to study the influence of the ground fissure on the ecological environment, the underground morphology of the ground fissure is necessary for evaluating the risk and studying the development rule of the ground fissure. At present, a student injects gypsum slurry into a crack, and obtains the underground form of the crack through a ground penetrating radar technology after the gypsum is solidified, but the method can damage the structure of the crack and influence the subsequent development process of the crack, and the gypsum slurry is not uniformly poured, so that the filling inside the crack is insufficient, and the method cannot be used for carrying out the underground form research of dynamic cracks. Meanwhile, a student excavates a working section on one side of a ground crack, and then acquires the underground form of the crack through a ground penetrating radar technology transverse scanner.

Disclosure of Invention

In order to solve the problems, the invention provides a method for acquiring the multi-stage underground three-dimensional form of the dynamic fracture based on the ground penetrating radar, which has the characteristics of simple process, easy realization, no influence on the surface environment, extremely small required engineering amount, time saving and labor saving, does not influence the form of the fracture and the subsequent development process thereof, can acquire the multi-stage underground three-dimensional form in the dynamic fracture development process in a nondestructive manner, and has important significance for researching the development process and rule of the dynamic fracture underground form along with the change of time.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides a method for acquiring a multi-period underground three-dimensional form of a dynamic fracture based on a ground penetrating radar, which is characterized by comprising the following steps of:

step 1) laying a film on the surface of an area where a crack is located, and ensuring that the surface of the crack is completely covered by the film; pouring liquid on the film in the crack to enable the liquid to fill an area A formed by the film in the whole crack in an enclosing mode, and isolating the liquid from the crack through the film; aligning a ground penetrating radar to the crack at the near-surface position of the area A, and scanning at intervals from one end to the other end along the vertical direction of the trend of the row of cracks to obtain electromagnetic wave data of a plurality of sections of the underground form of the crack at the present stage; pumping out the liquid in the area A for storage and removing the film;

step 2) carrying out data processing on all the electromagnetic wave data acquired in the step 1) at the current period, and describing by a visual interpretation method to obtain the contour of the crack at each section at the current period;

step 3) drawing the contour of the fracture at each section in the current period obtained in the step 2) in three-dimensional image processing software, and constructing a three-dimensional model of the underground form of the fracture in the current period in an interpolation mode so as to obtain the underground three-dimensional form of the fracture in the current period and related data thereof;

and 4) continuously repeating the steps 1) to 3) according to the set frequency to obtain the multi-period underground three-dimensional form and related data thereof in the dynamic change process of the crack development.

Further, the liquid in step 1) is selected to avoid interference on radar wave energy.

Further, in the step 1), the ground penetrating radar is not in contact with liquid. Optionally, the ground penetrating radar is kept out of contact with the liquid by laying a thin plate on the film.

Further, the thin plate is selected to avoid interference with radar wave energy.

Further, in the step 1), when scanning is carried out at intervals from one end to the other end along the direction of the column seam, a marking line is made at intervals of 10cm in the direction perpendicular to the direction of the seam, and the ground penetrating radar is used for scanning from a position of 30cm on one side of the seam to a position of 30cm on the other side of the seam along the marking line.

Further, in step 2), the data processing includes background drying, one-dimensional filtering, wavelet transformation and gain operation.

Further, in step 3), the correlation data includes an average width, an average depth, a surface area, and a volume of the fracture.

The invention has the characteristics and beneficial effects that:

the invention provides a method for acquiring a multi-period underground three-dimensional form of a dynamic crack based on a ground penetrating radar, which solves the defect that the underground form of the crack can be damaged by injecting gypsum slurry into the crack, simultaneously avoids the defects of extremely large engineering amount and time and labor consumption when a ground penetrating radar technology is adopted for excavating a working section at one side of the crack, ensures that the crack can not permeate into soil by injecting liquid which can be extracted into the crack and can not damage the underground form of the crack and using a film, ensures that the ground penetrating radar can not contact with the liquid so that the ground penetrating radar can scan, has the characteristics of simple process, easy realization, no influence on the ground surface environment, extremely small required engineering amount, time and labor saving, simultaneously does not influence the form of the crack and the subsequent development process thereof, can nondestructively model the underground form of the dynamic crack, the method has the advantages that morphological parameters such as the average width, the average depth, the surface area and the volume of the crack are obtained, and the method has important significance for researching the development process and rule of the underground three-dimensional shape of the dynamic crack along with the change of time.

Drawings

FIGS. 1 (a) - (d) are respectively a three-dimensional view, a front view, a side view and a top view of a method of applying a film and filling a liquid in a ground fracture in step 1) of an embodiment of the method of the present invention;

fig. 2 (a) - (d) are respectively a three-dimensional view, a front view, a side view and a top view of the scanning mode of the ground penetrating radar in step 2) of the embodiment of the method of the present invention;

FIG. 3 is an electromagnetic wave image scanned by the ground penetrating radar in the embodiment of the present invention;

FIG. 4 is a cross-sectional view of a fracture subterranean formation depicted using visual interpretation in an embodiment of the present invention;

FIG. 5 is a cross-sectional view of a fracture subterranean formation of different scan profiles acquired in an embodiment of the present invention;

FIG. 6 is a schematic diagram of a multi-stage three-dimensional model during dynamic fracture development constructed according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

For better understanding of the present invention, an application example of the method for acquiring the multi-phase underground three-dimensional morphology of the dynamic fracture based on the ground penetrating radar is described in detail below.

The method for acquiring the multi-period underground three-dimensional form of the dynamic fracture based on the ground penetrating radar comprises the following steps:

step 1) scanning and acquiring electromagnetic wave data of crack area by using ground penetrating radar

Referring to fig. 1, a film which is large enough is laid on the surface of the area where the crack is located, and the surface of the crack is ensured to be completely covered by the film; pouring liquid on the film in the crack to make the liquid fill the area A formed by the film in the crack, and isolating the liquid from the crack through the film; the liquid should be selected from liquid with small interference degree on radar wave energy, such as water, oil, carbohydrate and the like, the thin film is solvent-resistant, friction-resistant, tear-resistant and liquid-sealed, the ground penetrating radar is aligned to the crack at the position close to the earth surface of the area A, scanning is carried out at intervals from one end to the other end along the trend of the line of the crack, and the vertical direction of the trend of the crack is used as a scanning path to obtain electromagnetic wave data of a plurality of sections of the underground form of the crack at the present time; then, the liquid in the area A is pumped out for storage and the film is removed.

In this embodiment, the specific scanning process is as follows:

referring to fig. 2, in order to ensure that the liquid in the crack does not contact the ground penetrating radar so as to avoid damaging the ground penetrating radar, a thin plate (except for isolating the liquid from the ground penetrating radar by the thin plate, other modes for isolating the liquid from the ground penetrating radar can be used) is laid on the plastic film in the scanning range, the thin plate can be a plastic plate or other polymeric thin plates which do not interfere with the scanning result of the ground penetrating radar, a marking line is made at every 10cm in the vertical direction of the crack trend, and the high-frequency ground penetrating radar is used for scanning from the 30cm position on one side of the crack to the 30cm position on the other side of the crack along the marking line, so that electromagnetic wave data of the underground form of the crack in the current period inclined to.

In the embodiment, the ground penetrating radar adopts a 1.6GHz high-frequency ground penetrating radar of China university of mining (Beijing) coal resources and a key laboratory of the safe mining country.

Step 2) processing all the electromagnetic wave data acquired in the step 1) at the current period, and drawing by a visual interpretation method to obtain the contour of the crack at each section at the current period

And (3) carrying out data processing on the image data of the region where the crack is located, which is obtained in the step 1), by using data processing software. In this embodiment, the data processing software adopts a GR radar processing and analyzing system developed by the university of mining china (beijing). And (2) respectively carrying out conventional background drying removal, one-dimensional filtering processing, wavelet transformation, gain and other operations on each image data acquired in the step 1) to obtain an electromagnetic wave image with an interference region as shown in fig. 3.

Referring to fig. 4, the contour of the fracture of the cross section is judged according to the interference area in the electromagnetic wave image, and the contour of the fracture at each cross section at present is depicted by a visual interpretation method.

Step 3) modeling based on SolidWorks three-dimensional morphology

Referring to fig. 5, the contour of the crack at each section in the current period obtained in the step 2) is drawn in a three-dimensional image processing software SolidWorks software according to the proportion of 1:1, and a three-dimensional model of the underground form in the current period of the crack is constructed in an interpolation mode, so that the underground three-dimensional form in the current period of the crack and related data thereof are obtained.

And 4) continuously repeating the steps 1) to 3) according to the set frequency to obtain the multi-period underground three-dimensional form and related data thereof in the dynamic change process of the crack development.

Referring to fig. 6, the present example obtained a three-phase subsurface three-dimensional morphology with the morphological parameters shown in table 1, with the volume accuracy being the fracture volume and the volume of fluid injected into the fracture.

TABLE 1 fracture morphology parameters

From table 1, it can be seen that the method of the present invention can obtain the volume of the fracture three-dimensional morphological modeling without damage, the error is about 20%, the main causes of the error are the error of the ground penetrating radar scanning image and the error in the three-dimensional modeling process, if more accurate depth information is required, the number of scanning layers can be encrypted or more accurate ground penetrating radar equipment and image processing software can be used.

The present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention and is not actually limited thereto. Therefore, if the person skilled in the art receives the teaching, it is within the scope of the present invention to design the similar manner and embodiments without departing from the spirit of the invention.