CN106246162A - Floor undulation is across borescopic imaging device and slip casting effect monitoring method - Google Patents

Abstract

The invention discloses a real-time monitoring device for bottom plate grouting of a working face, which comprises a plurality of monitoring holes arranged in two roadways of a coal mine working face, and each monitoring hole is provided with a certain number of annular electrodes fixed in plastic sleeves and A cable, the ring electrode is evenly connected in series on the cable, the cables in the multiple monitoring holes are led out from the monitoring holes and connected in series, and then introduced under the floor of the roadway, and the cables are led out of the working face through the preset cable grooves. The cable is connected to the direct current method instrument outside the working face; the depth of the monitoring hole is greater than the depth from the aquifer to the bottom plate of the working face; a weight is added to the bottom end of the ring electrode and the cable to make the ring electrode and the cable and the hole of the monitoring hole The walls are kept parallel so that the ring electrodes are equally spaced. The invention also discloses a monitoring method using the monitoring device. The device and the method can not only monitor the grouting effect of the bottom plate of the working face, but also monitor the change of the water condition of the bottom plate of the working face, and the method is simple in principle and strong in practicability.

Description

Cross-hole imaging device and monitoring method of grouting effect in working face floor

technical field

The invention relates to the field of grouting for bottom plates of coal mine working faces, in particular to a cross-hole imaging device for bottom plates of working faces and a method for monitoring grouting effects.

Background technique

In recent years, with the continuous increase of coal mining depth, the shallow coal seams of North China type coalfields have almost been mined, and the deep coal seams are threatened by high confined water and thin water-resisting layers, and mine water inrush occurs from time to time. Sedimentary coal seams in North China type coalfields generally belong to coking coal, which is a must for steelmaking and cannot be replaced by other coal types. Therefore, how to liberate the coal seams in the deep mines of North China type coalfields that are subject to high confined water and thin aquifers has become an important research topic for mine water prevention and control.

The floor grouting technology of the working face is an important method to solve coal mining above high pressure water. The traditional method of grouting technology is the method of uniformly drilling holes for grouting. The disadvantages of this method are: large amount of grouting, low grouting efficiency, inability to be targeted during the grouting process, and poor grouting effect. With the development of technology, before grouting, many technicians use geophysical technology to explore the changes of rock strata, and carry out grouting reinforcement on the thin water layer of the bottom plate of the working face. Compared with the traditional method, this method can not only monitor the changes in the real grouting process, but also display the grouting situation of the entire working face through a three-dimensional visualization system, especially showing the weak areas of grouting to the mine water in real time. Preventers, preventers can make grouting improvement plans according to site changes, which can not only improve grouting efficiency, but also save grouting materials, which cannot be solved by other methods.

Chinese patent application 201210038167 uses transient electromagnetic instruments as part of the measuring point network on the working face. The advantages of transient electromagnetic instruments are that they are sensitive to low-resistance bodies and have high detection accuracy; but their disadvantages are that they are greatly affected by the surrounding environment and have a lot of interference, especially in Affected by the "low-resistance interference body" in the mining process, there are problems with data reliability. Not only is the monitoring inaccurate, but it is easy to cause false anomalies and affect the normal mining of the working face; in addition, the patent focuses on monitoring the key areas of the working face. It is just a general talk, and does not involve the key areas formed by the damage of rock formations caused by mine pressure during the mining process, let alone the problem of grouting in the working face.

Chinese patent application 201310728093 is mainly aimed at preventing the inrush of water and sand in coal mining under the water body and increasing the upper limit of coal seam mining. It is a special case of roof water inrush and does not have real-time dynamic monitoring of grouting and water regime in the working face general meaning.

Chinese patent applications 201410529007, 201410529019, and 201510134024. The above three patents are mainly aimed at studying the depth of floor damage in the mining process. Grouting and water regime in the working face are two completely different concepts. Therefore, the monitoring of the damage depth of the floor cannot be regarded as the real-time monitoring of the water regime in the working face. The public water regime monitoring of the working face, the technical scheme of this method is relatively complicated, and the on-site operation costs a lot. Transient electromagnetic is used to monitor the water regime change of the working face, the reliability of the collected data is low, and the monitoring effect is poor. This patent only realizes the monitoring of the hydrogeological conditions of the water gushing in the working face, and is powerless to the change law of the grout in the grouting process of the working face.

Chinese patent 200920143376.2 discloses a high-density resistivity monitoring system for dangerous rock loose circles. It first drills holes in multiple sections in the surrounding rock roadway, and embeds multi-core cables and exhaust pipes with electrodes in the holes. The grouting device will fill the borehole with couplant, measure multiple sets of resistivity data through the resistivity meter connected to the outer end of the multi-wire cable, and finally use the high-density resistivity method to realize the loose circle of surrounding rock according to the collected data. monitor. This patent is only a matter of changing the electrode layout method and observation device on the basis of the traditional high-density electrical method. It can only simply measure the change in roadway resistivity. Unlike the bottom plate imaging device of the working face, it is a real-time monitoring method for the grouting effect of the working face There is a fundamental difference. The floor grouting of the working face is not only a dynamic process, but also involves three-dimensional imaging technology and methods, from drilling construction to the design of the entire observation device, which is not involved in the 200920143376.2 patent.

Chinese patent 201420786793.X discloses a monitoring and forecasting device for water inrush disasters on the roof and floor of coal mining face. For electrodes, several directional boreholes are provided, and each directional borehole extends from the top or bottom plate of the working face, or the top or bottom plate of the local dangerous section to at least two layers underground; the several electrodes and The two infinity electrodes are connected to the processor installed on the ground through communication cables. The 201420786793.X patent simply changes the connection method of the electrode and the cable to monitor the water damage device. It is no different from the traditional mine DC two-dimensional electric method. It can only present a section and cannot observe the grouting of the working face in all directions. Therefore, the working The grouting effect of the face and bottom plate cannot be guaranteed.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, and provide a cross-hole imaging device and a method for monitoring the grouting effect of the bottom plate of the working face. The device and method can not only monitor the grouting effect of the bottom plate of the working face, but also monitor the The method is simple in principle and strong in practicability.

To achieve the above object, the present invention adopts the following technical solutions:

A cross-hole imaging device for the bottom plate of a working face, including a plurality of monitoring holes set in two roadways of a coal mine working face, each monitoring hole is provided with a certain number of ring electrodes and a cable fixed in a plastic casing, the The above-mentioned ring electrodes are evenly connected in series on the cables. After the cables in the monitoring holes are led out from the monitoring holes, they are introduced under the floor of the roadway. The cables are led out of the working face through the preset cable grooves, and the cables are connected to the DC method instrument;

The depth of the monitoring hole is greater than the depth from the aquifer to the bottom plate of the working face;

A weight is added to the bottom end of the ring electrode and the cable to keep the ring electrode and the cable parallel to the wall of the monitoring hole, so that the spacing between the ring electrodes is equal.

The distance between every two monitoring holes is between 50-120m.

The pressure resistance of the cable is greater than 6Mpa.

The monitoring hole is a vertical borehole or an inclined borehole.

The electrode is a copper ring-shaped electrode, which can increase the contact surface between the electrode and the grouting material, so that the electrode can fully contact with the external medium.

There are 15 electrodes evenly arranged in each monitoring hole, and the distance between every two electrodes is 5m, a total of 75m.

The plastic casing is 0.8m below the bottom plate of the roadway, and a screw hole is provided, and the cable joint is drawn out from the screw hole, and the screw hole is screwed with a nut.

On the floor of the roadway, a 0.8m deep cable trench is dug, and the cable is introduced to the DC instrument outside the working face through the preset cable trench to facilitate data collection.

The grouting effect monitoring method using the cross-hole imaging device on the bottom plate of the working face includes the following steps:

1) According to the conditions of the working face, reasonably design the drilling holes in the two upper and lower roadways of the working face;

2) Carry out cross-hole 3D imaging forward and inversion research according to the designed borehole, observe the imaging effect, and determine the rationality of the borehole according to the inversion imaging situation;

3) After determining the drilling position, carry out drilling construction:

a. In the construction process of drilling, casing technology must be used for drilling, and non-metallic casings are used. The diameter of the casing is smaller than the diameter of the drilling hole;

b When the drill hole exposes the aquifer, the aquifer must be grouted first to seal the cracks in the aquifer and seal the hole section of the aquifer; Construction to the drilling design depth position;

4) After the drilling construction is completed, connect the electrode and the cable; add a weight at the bottom of the electrode and the cable, the purpose is to keep the electrode and the cable hole wall in a parallel state, so that the electrode spacing is equal;

5) Grouting to plug the electrode and cable drilling holes and bury the cables connected in the drilling holes; in order to ensure the normal data collection, bury the electrodes and cables to ensure that the data will be transmitted to the host computer through the cables.

6) Detect the connection status of the whole set of equipment. Only when the connection is intact can the normal three-dimensional imaging of the cross-hole be performed, the grouting situation be monitored, and the grouting poor areas be focused on.

The forward and reverse of the trans-hole 3D imaging in the step 2) is specifically:

According to the geoelectric theory point power three-dimensional electric field differential equation is:

σ represents the electrical conductivity, Represents the potential difference, I represents the current, δ is the Dirac function, (x ₀ , y ₀ , z ₀ ) is the position of the power supply, (x, y, z) is the position of the measuring point, change the above formula into a three-dimensional rectangular coordinate Conditional format:

$\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; (</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; z</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; x</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; z</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>$

The above formula is changed into a finite difference equation as A is a large symmetric positive definite matrix, is the potential vector on the grid node, b is the position vector of the power supply point; and the two-way conjugate gradient method is used to solve the three-dimensional potential distribution Value, the process of solving the potential distribution of the three-dimensional electric field is the forward modeling process; after the three-dimensional forward modeling is completed, the smooth least square method is used for inversion to invert the rock formation resistivity distribution map of the working face.

After the grouting is completed, this method can continue to be used as a method for monitoring the mining face. During the recovery process of the working face, the mining damage process of the bottom plate of the working face can be monitored in real time until the safe recovery of the working face is completed.

On the basis of the traditional direct current method, the present invention designs a certain number of ring-shaped electrodes and cables in the two tunnels of the working face, and uses plastic sleeves to fix the electrodes and cables. Seal the electrodes and cables into the borehole in the tube, lead the cables under the floor of the roadway at the drill hole, lead the cables out of the working face through the preset cable trench, and connect the cables to the DC instrument for data acquisition, processing, imaging, etc. In the process, based on the cross-hole three-dimensional resistivity imaging technology between different drilling holes, the real-time monitoring of the resistivity change of the working face due to grouting is carried out, and reasonable grouting arrangements are made according to the monitoring situation to improve the grouting effect. After the grouting is completed, during the recovery process of the working face, the change of the water regime of the bottom plate of the working face can be monitored, and the water inrush of the bottom plate of the working face can be predicted and forecasted, so as to ensure the safe mining of the working face. The invention can not only monitor the grouting effect of the bottom plate of the working face, but also monitor the change of the water condition of the bottom plate of the working face. The principle of the method is simple and the practicability is strong.

The device of the present invention includes a plurality of monitoring holes on the working face (designed according to requirements), cables, ring electrodes, direct current method instruments and other devices. The number of monitoring holes is designed according to the length of the working face and the monitoring accuracy. Generally, the position of the monitoring holes is between 50-120m. The depth of the monitoring holes is designed according to the depth of the aquifer in the mining face. The depth of the layer to the floor of the work surface. The cable requires pressure resistance, which is generally greater than 6-8Mpa; the length of the cable and the cable of each monitoring hole must be connected to the position of the DC method instrument. The number of ring electrodes is designed according to the requirements, and the connection between the electrode and the cable is required to be well connected and the connection is sealed. It is enough that the direct current method instrument can collect data across the air.

Description of drawings

Fig. 1 is a schematic diagram of grouting drilling design in working face of the present invention;

Fig. 2 is a schematic diagram of the monitoring hole structure of the present invention;

Fig. 3 is the cross-air imaging model of the 200m * 100m working face of the present invention;

Fig. 4 is the 200m * 100m cross-air imaging inversion diagram of the present invention;

Fig. 5 is a cross-hole imaging model of a working face of the present invention;

Fig. 6 is an inversion diagram of a cross-hole imaging model of a certain working face of the present invention;

Fig. 7 is an inversion diagram of cross-hole imaging after grouting in a working face of the present invention;

Fig. 8 is a cross-hole imaging Z-direction horizontal slice after grouting in a working face of the present invention;

Fig. 9 is a cross-hole imaging vertical slice in the X direction after grouting in a working face of the present invention;

Among them, 1. Monitoring hole, 101. Screw hole, 102. Ring electrode, 103. Plastic sleeve, 2. Cable, 3. Direct current method instrument.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The structures, proportions, sizes, etc. shown in the drawings attached to this specification are only used to match the content disclosed in the specification for the understanding and reading of those who are familiar with this technology, and are not used to limit the conditions for the implementation of the present invention , so it has no technical substantive meaning, and any modification of structure, change of proportional relationship or adjustment of size shall still fall within the scope of the disclosure of the present invention without affecting the functions and objectives of the present invention. The technical content must be within the scope covered. At the same time, terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit this specification. The practicable scope of the invention and the change or adjustment of its relative relationship shall also be regarded as the practicable scope of the present invention without any substantial change in the technical content.

As shown in Figures 1-2, the cross-hole imaging device for the bottom plate of the working face includes a plurality of monitoring holes 1 set in the two roadways of the coal mine working face, and each monitoring hole 1 is equipped with a plastic sleeve 103 A certain number of ring electrodes 102 and a cable 2, the ring electrodes 102 are evenly connected in series on the cable 2, the cables 2 in a plurality of monitoring holes 1 are drawn out from the monitoring holes and then connected in series and then introduced under the roadway floor, the cables 2 The cable 2 is connected to the direct current method instrument 3 outside the working face through the preset cable groove; the depth of the monitoring hole 1 is greater than the depth from the aquifer to the bottom plate of the working face; A weight is added to the lowermost end of 2 to keep the ring electrode 102 and the cable 2 parallel to the wall of the monitoring hole 1, so that the distance between the ring electrodes 102 is equal.

The distance between every two monitoring holes 1 is between 50-120m. The compression resistance of the cable 2 is greater than 6Mpa. The monitoring hole 1 is a vertical borehole or an inclined borehole.

The ring electrode 102 is a circular electrode made of copper, which can increase the contact surface between the electrode and the grouting material, so that the electrode can fully contact with the external medium.

16 ring electrodes are evenly arranged in each monitoring hole 1, and the distance between every two ring electrodes is 5m, totaling 75m.

The plastic casing 103 is 0.8m away from the bottom plate of the roadway, and a screw hole 101 is provided, and the cable joint is drawn out from the screw hole 101, and the screw hole is screwed to death with a nut.

On the floor of the roadway, a 0.8m deep cable trench is dug, and the cable 2 is introduced to the DC method instrument 3 outside the working face through the preset cable trench to facilitate data collection.

The grouting effect monitoring method using the cross-hole imaging device on the bottom plate of the working face includes the following steps:

1) According to the actual situation of the working face, reasonably design drilling holes in the two upper and lower roadways of the working face; design a working face with a length of 328m and a width of 110m, and design a total of 8 drilling holes, 4 drill holes in the upper and lower roadways 15 electrodes are used for each drilling hole, and a total of 120 electrodes are used.

2) After the borehole and electrode coordinates are designed, the three-dimensional electric field differential equation of the point power supply according to the geoelectric theory is:

σ represents the electrical conductivity, Represents the potential difference, I represents the current, δ is the Dirac function, (x ₀ , y ₀ , z ₀ ) is the position of the power supply. (x, y, z) is the position of the measuring point, change the above formula into the format under the condition of three-dimensional rectangular coordinates:

$\mathrm{<span\; class="notranslate">\; \&sigma;</span>}<span\; class="notranslate">\; (</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; x</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; +</span>\frac{{<span\; class="notranslate">\; \&part;</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>{\mathrm{<span\; class="notranslate">\; z</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; x</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; x</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}}<span\; class="notranslate">\; +</span>\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; z</span>}}\frac{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; u</span>}}{<span\; class="notranslate">\; \&part;</span>\mathrm{<span\; class="notranslate">\; z</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; I</span>}\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; x</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; y</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>\mathrm{<span\; class="notranslate">\; \&delta;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; z</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>$

The above formula is changed into a finite difference equation as A is a large symmetric positive definite matrix, is the potential vector on the grid node, b is the position vector of the power supply point; and the two-way conjugate gradient method is used to solve the three-dimensional potential distribution value, the process of solving the potential distribution of the three-dimensional electric field is the forward modeling process. After the 3D forward modeling is completed, the smoothed least squares method is used for inversion, and the resistivity distribution map of the working face rock formation is inverted. As can be seen in Figure 6, the low resistance and resistance in the model are well displayed, indicating that the device plays an important role in monitoring imaging.

3) Drilling construction, during drilling construction:

a. Drilling During the construction process, the drilling must adopt casing technology, use non-metallic casing, and the diameter of the casing is smaller than the diameter of the drilling hole; the purpose of using the casing: First, to prevent drilling during the drilling construction process Hole collapse occurs. During the drilling construction process, the casing is drilled while the drilling is being constructed. This purpose is also to prevent the drilling from collapsing. Second, after the drilling construction is completed, electrodes need to be laid in the drilling hole. If a metal casing is used, all electrodes become one electrode, and the monitoring device loses its monitoring function;

b When the drill hole exposes the aquifer, the aquifer must be grouted first to seal the cracks in the aquifer and seal the hole section of the aquifer; Construction to the drilling design depth position;

4) After the drilling construction is completed, connect the electrode and the cable, and place it in the drill hole, and add a weight at the bottom of the electrode and the cable, so that the electrode and the cable hole wall are kept parallel, so that the distance between the electrodes is equal ;When the electrode and cable reach the bottom of the hole and keep parallel to the hole wall, fix the bottom end, grout the drilled hole, and fix the electrode and cable at the designed position in the hole;

5) Grouting sealing and cable embedding:

After the preparatory work is completed, the grouting sealing can be carried out. For the grouting sealing, it should be carried out according to the conventional method; if the high-pressure grouting is used for the drilling, the following problems must be solved: the cable must withstand high pressure; prevent the joint from being injected into the grout ;In order to facilitate the extraction of the cable joint, design a screw hole at a distance of 0.8m from the bottom plate of the roadway, lead the cable joint out of the hole, and screw the hole with a nut; on the bottom plate of the roadway, dig 0.8m deep to get the cable Groove, the cable is transported to the host to facilitate data collection;

6) After connecting the above equipment, carry out data collection and inspection on the equipment. After the inspection is qualified, carry out data collection. Carry out imaging between holes, monitor the effect of grouting according to requirements, adjust the grouting pressure and amount in real time, and improve the efficiency and accuracy of grouting; Figures 7 to 9 show the 3D inversion of cross-holes after grouting in a certain working face It can be seen from the figure that the grouting effect of the working face is good, but there are still two abnormal areas of grouting at this time. It is mainly concentrated in the vicinity of 109m and the left side of the roadway with 0 in the y direction of the working face and 219m, which is the key area for the next step of grouting.

After the grouting is completed, this method can continue to be used as a method for monitoring the mining face. During the recovery process of the working face, the mining damage process of the bottom plate of the working face can be monitored in real time until the safe recovery of the working face is completed.

On the basis of the traditional direct current method, the present invention designs a certain number of ring-shaped electrodes and cables in the two tunnels of the working face, and uses plastic sleeves to fix the electrodes and cables. Seal the electrodes and cables into the borehole in the tube, lead the cables under the floor of the roadway at the drill hole, lead the cables out of the working face through the preset cable trench, and connect the cables to the DC instrument for data acquisition, processing, imaging, etc. In the process, based on the cross-hole three-dimensional resistivity imaging technology between different drilling holes, the real-time monitoring of the resistivity change of the working face due to grouting is carried out, and reasonable grouting arrangements are made according to the monitoring situation to improve the grouting effect. After the grouting is completed, during the recovery process of the working face, the change of the water regime of the bottom plate of the working face can be monitored, and the water inrush of the bottom plate of the working face can be predicted and forecasted, so as to ensure the safe mining of the working face. The invention can not only monitor the grouting effect of the bottom plate of the working face, but also monitor the change of the water condition of the bottom plate of the working face. The principle of the method is simple and the practicability is strong.

The device of the present invention includes a plurality of monitoring holes on the working face (designed according to requirements), cables, ring electrodes, direct current method instruments and other devices. The number of monitoring holes is designed according to the length of the working face and the monitoring accuracy. Generally, the position of the monitoring holes is between 50-120m. The depth of the monitoring holes is designed according to the depth of the aquifer in the mining face. The depth of the layer to the floor of the work surface. The cable requires pressure resistance, which is generally greater than 6-8Mpa; the length of the cable and the cable of each monitoring hole must be connected to the position of the DC method instrument. The number of ring electrodes is designed according to the requirements, and the connection between the electrode and the cable is required to be well connected and the connection is sealed. It is enough that the direct current method instrument can collect data across the air.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it does not limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. floor undulation is across a borescopic imaging device, it is characterized in that, arrange in being included in coal mine work area two tunnel is multiple Monitoring holes, is equipped with a number of annular electrode and a cable in being fixed on plastic bushing in each monitoring holes, described Annular electrode is uniformly connected on cable, and the cable in multiple monitoring holes is introduced into tunnel after connecting after drawing at monitoring aperture Under base plate, cable is incorporated into outside work surface by the cable trench preset, the DC electrical method instrument that cable is connected to outside work surface； The degree of depth of described monitoring holes is more than the degree of depth in water-bearing layer to floor undulation；Described annular electrode adds a weight with the bottom of cable Thing, makes the hole wall keeping parallelism state of annular electrode and cable and monitoring holes, makes annular electrode spacing impartial.

2. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, the spacing between each two monitoring holes Between 50-120m；Described monitoring holes is vertical boring or the boring tilted.

3. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, the compressive resistance of described cable is more than 6Mpa。

4. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, described electrode is copper annular electricity Pole, by increasing capacitance it is possible to increase electrode and the contact surface of injecting paste material, makes electrode be fully contacted with extraneous medium.

5. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, is evenly arranged with in each monitoring holes 16 electrodes, the spacing between each two electrode is 5m, altogether 75m.

6. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, at the bottom of described plastic bushing distance tunnel Below plate at 0.8m, being provided with screw hole, cable connector is drawn from this screw hole, and uses nut to be screwed on by this screw hole.

7. floor undulation as claimed in claim 1 is across borescopic imaging device, it is characterized in that, on described roadway floor, has dug The cable trench that 0.8m is deep, cable is by the DC electrical method instrument that is incorporated into outside work surface of cable trench preset, it is simple to number According to collection.

8. utilize floor undulation across the slip casting effect monitoring method of borescopic imaging device, it is characterized in that, comprise the following steps:

1) according to the situation of work surface, appropriate design boring in work surface about two two tunnel；

2) carry out, across hole three-dimensional imaging Forward Modeling and Inversion research, observing imaging effect, according to inversion imaging situation according to the boring of design Determine the reasonability of boring；

3), after determining bore position, drilling construction is carried out:

A holes in work progress, and boring must use sleeve technology, uses non-metallic casing, and sleeve pipe aperture is less than drilling hole Both may be used in footpath；

B is when boring discloses water-bearing layer, it is necessary to water-bearing layer first carries out slip casting, plugging water-bearing stratum crack, confining bed of aquifer hole Section；Close intact after, again boring is constructed, continues to the construction of boring deep, until construction is to drilling design degree of depth position Put；

4), after drilling construction, electrode and cable are connected；A weight is added, it is therefore an objective to electricity in the bottom of electrode Yu cable Pole and cable hole wall keeping parallelism state, make electrode spacing impartial；

5) slip casting closure electrode and cable are holed and bury the cable picked out in boring underground；In order to ensure that data acquisition is normally adopted Collection, by good to electrode and cable burial, it is ensured that data will be transmitted to main frame through cable.

6) detect the connection of package unit, connect intact after can carry out being normally carried out, across hole three-dimensional imaging, monitoring slip casting Situation, carries out emphasis slip casting to slip casting defective region.

Utilize floor undulation across the slip casting effect monitoring method of borescopic imaging device the most as claimed in claim 8, it is characterized in that, Described step 2) in across hole three-dimensional imaging Forward Modeling and Inversion particularly as follows:

The base area electric theory point source three-dimensional electric field differential equation is:

σ represents electrical conductivity,Representing potential difference, I represents that electric current, δ are Dirac functions, (x₀,y₀,z₀) it is position of source, (x, y, Z) for measuring the position of point into, upper formula is made form under the conditions of three-dimensional rectangular coordinate:

$\mathrm{\&sigma;}\left(\frac{{\&part;}^{2}U}{\&part;x^2}+\frac{{\&part;}^{2}U}{\&part;y^2}+\frac{{\&part;}^{2}U}{\&part;z^2}\right)+\frac{\&part;\mathrm{\&sigma;}}{\&part;x}\frac{\&part;U}{\&part;x}+\frac{\&part;\mathrm{\&sigma;}}{\&part;y}\frac{\&part;U}{\&part;y}+\frac{\&part;\mathrm{\&sigma;}}{\&part;z}\frac{\&part;U}{\&part;z}=-I\mathrm{\&delta;}\left(x-x_0\right)\mathrm{\&delta;}\left(y-y_0\right)\mathrm{\&delta;}\left(z-z_0\right)$

Above formula makes finite difference equations intoA is large-scale symmetric positive definite matrix,For the potential vectors on grid node, b For supply terminals position vector；And utilize two-way conjugate gradient method to solve three-dimensional Potential distributionValue, solves the electricity of three-dimensional electric field Position distributed process is process of just drilling；After D integral pin-fin tube completes, utilize round and smooth method of least square to carry out inverting, be finally inversed by work surface Formation resistivity scattergram.

Utilize the monitoring method of floor undulation slip casting real-time monitoring device the most as claimed in claim 8, it is characterized in that, note After having starched, continue monitoring and adopt work surface, during working face extraction, real-time monitoring face base plate Mining failure mistake Journey, until work surface safety coal extraction completes.