Real-time detection system and real-time detection method for grouting slurry diffusion range

Abstract

The application discloses a real-time detection system for grouting slurry diffusion range, which comprises a first power supply electrode, a second power supply electrode and a measurement electrode arranged between the first power supply electrode and the second power supply electrode, wherein the first power supply electrode adopts a conductive cable with the same potential in the length direction. The detection system can perform high-precision and high-resolution real-time detection on the diffusion range of the slurry in the grouting process without affecting the construction progress.

Description

Technical Field

[0001] This invention relates to the field of grouting engineering, and in particular to a real-time detection system and method for detecting the diffusion range of grout. Background Technology

[0002] In grouting projects such as goaf treatment, coal mine water control, and grouting and filling of mining delamination zones, the complexity and concealment of geological conditions mean that the filling effect of the grout is mainly controlled by grouting pressure and volume. However, it is difficult to predict and detect the grout flow range of a single grouting hole. When the grouting range of a single hole is larger than the design specification, it leads to a waste of grouting workload and grouting material; when it is smaller than the design specification, there will be areas of missed grouting, affecting the filling effect. Moreover, most grouting projects require the installation of curtain holes to prevent grout from spreading outside the grouting area. When real-time detection of the grout diffusion range is not possible, the diffusion range of a single hole must be increased and the spacing between curtain holes reduced to ensure that the grout from each curtain hole can form a complete curtain wall, greatly increasing economic and time costs. When large cracks or channels appear around the curtain holes, grout overflow will occur, leading to insufficient grouting pressure and a large increase in grout volume, resulting in significant grout waste and loss of sealing effect.

[0003] Methods for detecting the diffusion range of grouting fluid mainly include drilling, geophysical exploration, and excavation. Drilling typically requires core sampling for verification three months after grouting is completed, making immediate core sampling impossible due to both time and economic costs. Geophysical exploration suffers from uncertainties in geological data inversion, resulting in unintuitive grouting detection. Furthermore, surface geophysical exploration has low resolution for deep grouting areas, failing to meet the requirements for single-hole grouting detection. In-hole geophysical exploration cannot provide real-time and continuous monitoring, and additional drilling can cause grout leakage, making it impractical in engineering.

[0004] The patent application CN111997687A, entitled "A Method for Real-Time Detection of Grouting Effect in Goaf Areas," provides a method for real-time detection of grouting effect. This method primarily utilizes a combined observation approach with grouting holes, employing a specially designed liquid level detection device to monitor real-time changes in the borehole liquid level around the grouting holes. It then uses three quantitative coefficient indicators to evaluate the grouting effect, thereby enabling real-time detection of the grouting effect in the goaf area. However, this method requires multiple detection holes and only performs single-point detection, making it unable to accurately determine the grout diffusion range and limiting its engineering applications.

[0005] The patent application with publication number CN114137036A, entitled "A rapid detection method for grouting range based on adjacent source potential resistivity", provides a rapid detection method for grouting range. However, this method is actually just a high-density electrical resistivity AMN device and MNB device, which has low resolution and cannot achieve real-time detection, making it difficult to meet the requirements of actual engineering.

[0006] In the patent application with publication number CN115220109A entitled "A Data Acquisition Method for Trans-hole Resistivity CT", a new resistivity CT electrode running method is provided. This method mainly improves the traditional single-point to multi-point trans-hole CT measurement into a multi-point to multi-point device, which is closer to the in-hole application of high-density electrical resistivity spectroscopy. However, it cannot well meet the requirements of real-time detection of grouting slurry range.

[0007] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0008] The purpose of this invention is to provide a real-time detection system and method for the diffusion range of grout, which can perform high-precision and high-resolution real-time detection of the diffusion range of grout during the grouting process without affecting the construction progress.

[0009] To achieve the above objectives, embodiments of the present invention provide a real-time detection system for the diffusion range of grouting slurry, characterized in that it includes a first power supply electrode, a second power supply electrode, and a measuring electrode disposed between the first power supply electrode and the second power supply electrode, wherein the first power supply electrode is a conductive cable, and the conductive cable has the same potential along its length.

[0010] In one or more embodiments of the present invention

[0011] The conductive cable includes an inner core and a metal mesh outer layer covering the inner core. The inner core is a single conductive metal body or is made of multiple strands of metal wire twisted together.

[0012] In one or more embodiments of the present invention, a plurality of power supply electrodes are provided at intervals and can be powered independently, wherein the distance between two adjacent power supply electrodes is 0.5m-2m.

[0013] In one or more embodiments of the present invention, each of the power supply electrodes includes an electrode core, an electrode support, and a multi-layer metal mesh layered around the outside of the electrode core. The electrode support is connected between the electrode core and the multi-layer metal mesh. The mesh spacing of the metal mesh is 0.5mm-2mm, and the layer spacing between adjacent metal meshes is 1mm-3mm.

[0014] In one or more embodiments of the present invention, the second power supply electrode is an infinity power supply electrode, or the second power supply electrode is a conductive cable with the same potential along its length.

[0015] In one or more embodiments of the present invention, the measuring electrode is a series electrode, comprising a plurality of measuring electrodes spaced apart and capable of independent measurement, wherein the spacing between two adjacent measuring electrodes is 0.2m-1m.

[0016] In one or more embodiments of the present invention, each of the measuring electrodes includes an electrode core, an electrode support, and a multilayer metal mesh layered around the outside of the electrode core. The electrode support is connected between the electrode core and the multilayer metal mesh. The mesh spacing of the metal mesh is 0.5mm-2mm, and the layer spacing between adjacent metal meshes is 1mm-3mm.

[0017] The present invention also provides a method for real-time detection of the diffusion range of grout using the above system, specifically including the following steps:

[0018] The first power supply electrode is installed in the target grouting hole, and the end of the first power supply electrode extends to the area to be filled.

[0019] Obtain the electrical signal between the measuring electrode and the first power supply electrode, or obtain the electrical signal between the measuring electrode and the second power supply electrode.

[0020] In one or more embodiments of the present invention, the measuring electrode and the second power supply electrode are respectively arranged in the detection hole and the power supply hole, the target grouting hole, the detection hole and the power supply hole are located on the same straight line, and the depth of the power supply hole is greater than or equal to 15% of the depth of the target grouting hole.

[0021] In one or more embodiments of the present invention, a method for acquiring an electrical signal includes:

[0022] S1. Measure the current and voltage between the string electrodes on all detection electrodes and the first power supply electrode when the first and second power supply electrodes are not energized;

[0023] S2. Sequentially perform energizing and de-energizing operations on one or more string electrodes on the first power supply electrode and the second power supply electrode, and measure the current and voltage between all string electrodes on the detection electrode and the first power supply electrode until all string electrodes on the second power supply electrode have been energized.

[0024] S3. Grouting, and repeat step S2.

[0025] Compared with existing technologies, the real-time detection system and method for grout diffusion range in this invention has the following advantages: it does not affect the construction of the grouting project, there will be no grout leakage, the detection process will not affect the construction of existing engineering equipment, and it does not require the use of special grout or additional drilling, saving a lot of manpower and resources; for a single grouting hole, only one detection device needs to be laid from before grouting to after grouting, which is convenient to set up, and the data testing is all automated, and it can calculate and display the real-time detection data of grout diffusion range; it provides high-precision detection of grout diffusion range, and the detection accuracy is minimally affected by the burial depth of the area to be grouted; there are many ways to arrange the detection system, which can be applied to different construction scenarios and has a wide range of applications; the device that needs to be placed in the borehole is low-cost, and the loss is small when phenomena such as borehole collapse occur and cannot be recovered. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a real-time detection system for the diffusion range of grouting fluid according to an embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram of a string electrode according to an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of a cable according to an embodiment of the present invention;

[0029] Figure 4 These are two power supply waveform diagrams according to an embodiment of the present invention.

[0030] Explanation of key figure labels:

[0031] 100-Real-time detection system for grout diffusion range, 10-Processing system, 20-Measurement system, 21-First detection cable, 22-Second detection cable, 221-Detection electrode, 30-Power supply system, 31-First power supply cable, 32-Second power supply cable, 321-Power supply electrode, 33-Exposed cable, 33-40-Grouting hole, 50-Power supply hole, 60-Detection hole, 71-Electrode core, 72-Metal mesh, 73-Electrode support, 74-Electrode lead. Detailed Implementation

[0032] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0033] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0034] like Figures 1 to 3 As shown, the real-time detection system 100 for the diffusion range of grouting slurry according to a preferred embodiment of the present invention includes a processing system 10, a power supply system 20, and a measurement system 30.

[0035] The power supply system 30 is connected to two power supply cables. The first power supply cable 31 serves as electrode A (first power supply electrode) and connects to the grouting hole 40. The second power supply cable 32 connects to the power supply hole 50 and serves as electrode B (second power supply electrode). A power supply electrode 321 is installed on the second power supply cable 32. It should be noted that the electrode distance between adjacent power supply electrodes B should be adjusted according to the required measurement accuracy. In this embodiment, it is between 0.5m and 2m.

[0036] In other embodiments, if the detection conditions are complex and it is not possible to lay out the power supply electrode 321, the electrode can be laid out directly inside the power supply hole 50. Figure 3 The exposed cable shown has no insulation between any of its inner cores, and is wrapped with multiple layers of metal mesh 72 arranged on the string electrodes to improve contact performance.

[0037] It should be noted that when construction conditions do not allow the electrode B to be laid out in the above manner, the second power supply cable 32 can be selected to be in direct contact with the ground as an infinity power supply electrode. In this case, the distance between its contact point with the ground and the electrode A is 5-10 times the depth of the grouting hole 40. At this time, the electrode B, the grouting hole 40 and the detection hole 60 are located on the same straight line to improve the measurement accuracy.

[0038] When power supply hole 50 is selected, multiple power supply electrodes 321 are connected in series on the second power supply cable 32, which are named electrodes B1, B2, B3, etc. It should be noted that the depth of the selected power supply hole 50 should not be less than 15% of the depth of the target grouting hole 40, so as to avoid the measurement accuracy being affected by the shallow depth. At the same time, it should be basically in the same straight line as the target grouting hole 40 and the detection hole 60, and the error should be controlled within 15%.

[0039] Preferably, saline solution or other highly conductive liquid can be added into the power supply hole 50 to ensure contact and conductivity between the cable and the hole wall. It should be noted that all power supply electrodes 321 should be submerged when adding the liquid.

[0040] The measurement system 20 extends two detection cables. The first detection cable 21 connects to the first power supply cable 31 as electrode M, and the second detection cable 22 is laid inside the detection hole 60 and on the surrounding ground as electrode N (measuring electrode). When ground laying is difficult, it can be laid only inside the detection hole 60. Multiple detection electrodes 221 are arranged on electrode N, which are named N1, N2, N3, etc. It should be noted that the electrode distance between adjacent detection electrodes N should be adjusted according to the measurement accuracy requirements, and in this embodiment it is between 0.2m and 1m.

[0041] In this embodiment, the first detection cable 21 (electrode M) and the first power supply cable 31 (electrode A) preferably share a single cable. Therefore, the first power supply cable 31 serves as both the power supply end and the detection end, which simplifies the system and the operation process. Of course, in other embodiments, the two may not share a cable, but it is necessary to ensure that they do not come into contact to prevent detection distortion.

[0042] It is conceivable that the detection hole 60 can be selected from other grouting holes adjacent to the target grouting hole 40 (or excavated separately), with a depth not shallower than the area to be detected, and the distance between it and the target grouting hole 40 is 1-3 times the estimated maximum diffusion distance of the grout.

[0043] In this embodiment, the detection electrode 221 and the power supply electrode 321 have the same structure, as shown below. Figure 2 The string electrode shown includes an electrode core 71, a multi-layer metal mesh 72 layered around the electrode core 71, and an electrode support 73 that provides support. The string electrode is connected to a cable via an electrode lead 74.

[0044] In this embodiment, the mesh gap of the metal mesh 72 is controlled between 0.5mm and 2mm, and the gap between each layer of metal mesh 72 is controlled between 1mm and 3mm.

[0045] In other embodiments, to control costs, columnar or block electrodes made of conductors such as pure copper or stainless steel can be used instead of the string electrodes described above.

[0046] Since multiple aforementioned string electrodes are connected to the second power supply cable 32 and the second measuring cable 22, and power may be supplied to one of the electrodes on the second power supply cable 32 at the same time, the cables used are as follows: Figure 3 As shown, it consists of multiple metal wires twisted into a spiral shape to enhance the strength and flexibility of the cable, and each metal wire is insulated from the others.

[0047] It should be noted that the number of metal wires in a single cable should be at least equal to the number of series electrodes connected in the cable. Each series electrode is connected to one of the metal wires and is insulated from each other. The power supply electrode 321 can be switched on or off at any time through the internal program of the power supply system 20.

[0048] It is conceivable that, considering transportation and construction conditions, the number of metal wires in a single cable and the number of series electrodes that can be connected in series are limited. Therefore, when the number of series electrodes installed exceeds the upper limit of the number of series electrodes in a single cable, it is necessary to add cables in the hole and connect the series electrodes exceeding the upper limit to different cables to meet construction and testing requirements.

[0049] As for the first power supply cable 31, since it is not connected to the series electrodes, and in order to improve the measurement effect, it is necessary to further reduce its contact resistance with the surrounding medium and maintain equipotential at all points on the cable. Therefore, the first power supply cable 31 is directly exposed, the inner cores of the cable are not insulated from each other, and a single or several layers of metal mesh 72 are wrapped around the outside to improve the contact effect.

[0050] Meanwhile, to avoid polarization effects, all connecting cables (including power supply cables and detection cables) are made of non-polarizing conductors such as pure copper and stainless steel. To reduce costs, the first power supply cable 31 can be made directly of steel wire rope.

[0051] It is easy to imagine that the aforementioned string electrodes are also made of non-polarizing conductors such as copper and stainless steel.

[0052] The power supply system 30 adopts a DC constant current source or a constant voltage source, and is equipped with an automatic power supply electrode switching device (not shown in the figure), which can switch the polarity between electrode A (first power supply cable 31) and electrode B (second power supply cable 32) according to measurement requirements.

[0053] The measurement system 20 can simultaneously measure the voltage and current between the measuring electrode M (electrode A) and electrode N. It internally includes a multi-channel measurement system that can switch between different measuring electrodes N for parallel measurement of multiple electrodes. If necessary, it can include only a single channel for polling measurement. Simultaneously, the measurement system 20 has the function of coordinating with the power supply system 30 to perform timed or uninterrupted measurements.

[0054] The processing system 10 calculates the diffusion range of the slurry in real time based on the voltage and current of the power supply system 30 at different times, the voltage and current between different electrodes measured by the measurement system, the electrode distance, and the detection information of the detection hole, and stores and displays the information.

[0055] The real-time detection method for the grouting slurry range corresponding to the detection system 100 described above is described in detail here. The main steps include: setting up the first power supply electrode in the target grouting hole, with the end of the first power supply electrode extending to the area to be filled; obtaining the electrical signal between the measuring electrode and the first power supply electrode, or obtaining the electrical signal between the measuring electrode and the second power supply electrode.

[0056] Before measurement, the system 100 is set up, the target grouting hole 40 is selected, the exposed first power supply cable 31 (electrode A and electrode M) is placed into the target grouting hole 40 and connected to the bottom. According to the site conditions, the power supply hole 50 and the detection hole 60 are selected. The corresponding second power supply cable 32 and power supply electrode 321 (electrode B) are laid in the power supply hole 50, and the second detection cable 22 and detection electrode 221 (electrode N) are laid in the detection hole 60.

[0057] The following testing steps are then performed, specifically including:

[0058] S1. Measure the current and voltage between electrode M and each electrode N without power.

[0059] S2. Perform energizing and de-energizing operations sequentially on one or more string electrodes on the first power supply electrode (electrode A) and the second power supply electrode (electrode B), and measure the current and voltage between all string electrodes on the detection electrode (electrode N) and the first power supply electrode (electrode M) until all string electrodes on the second power supply electrode have been energized.

[0060] S3. Grouting, and repeat step S2.

[0061] Because the Earth's surface has a weak electrical signal, calibration is performed by measuring the surface signal in step S1.

[0062] All data is transmitted to the processing system 10, where the natural potential, resistivity, and polarizability of the survey profile are calculated and recorded.

[0063] Preferably, to avoid polarization, the single power-on and power-off time in steps S2 and S3 is not less than 300ms.

[0064] Grouting is performed after all electrodes B have undergone energization (surface signal calibration) through repeated energizing and de-energizing. During the grouting process, energizing and de-energizing operations are repeated at certain intervals according to construction requirements, and the signal between electrodes M and N is detected. For applications requiring high precision, continuous or full-process detection can be performed.

[0065] It should be understood that the polarization effect requires a liquid as an electrolyte. When there is little underground moisture and the environment is relatively dry, the polarization effect is weak. In this case, during the detection process, the power supply system 20 can keep electrode A and electrode B from switching between one polarity, i.e. Figure 4 The power supply and de-energization methods shown in the upper diagram involve electrodes A and B having only positive (negative) potentials or zero potential. When the underground environment has high moisture content or has just rained, the polarization effect is severe. To counteract the polarization effects of the natural field and the electrodes themselves, the polarity of electrodes A and B needs to be switched during each power-on and power-off process. Figure 4 The power supply and power outage methods shown in the lower figure are such that electrodes A and B cycle between positive potential, zero potential, and negative potential.

[0066] To cope with complex construction sites, when choosing to use the infinity electrode B or to lay an exposed cable in the power supply hole 60 as electrode B, since there is no need to switch between multiple power supply electrodes 321, only the power supply disconnection operation needs to be performed between the first power supply cable 32 and the second power supply cable 32, thus simplifying the operation steps and shortening the total cycle time.

[0067] The processing system 10 compares the differences between the natural potential, resistivity, and polarizability measured each time and the measurement results before grouting. The portion with a rate of change much greater than the overall rate of change is the grout diffusion range. This threshold is related to the water filling conditions of the area to be grouted; the lower the water filling volume, the smaller the threshold, but it is generally more than twice. When the grouting volume continues to increase while the grouting pressure and measurement results remain basically unchanged, it can be determined that a large crack or channel has appeared, and its location is slightly smaller than the farthest diffusion distance in the measurement results.

[0068] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A real-time detection system for the diffusion range of grouting slurry, characterized in that, include: The power supply system includes a first power supply electrode, a second power supply electrode, and a measuring electrode disposed between the first power supply electrode and the second power supply electrode. The first power supply electrode is a conductive cable with the same potential along its length. The first power supply electrode extends to the bottom of the target grouting hole. A measurement system extending from a first detection cable for connecting the first power supply electrode and a second detection cable for being routed into a detection hole, the measurement system being used to measure the voltage and current of the first and second detection cables; The processing system calculates the diffusion range of the slurry based on the voltage and current of the power supply system and the voltage and current measured by the measurement system.

2. The real-time detection system for the diffusion range of grouting slurry as described in claim 1, characterized in that, The conductive cable includes an inner core and a metal mesh outer layer covering the inner core. The inner core is a single conductive metal body or is made of multiple strands of metal wire twisted together.

3. The real-time detection system for the diffusion range of grouting slurry as described in claim 1, characterized in that, The second power supply electrode is a series electrode, which includes multiple power supply electrodes that are spaced apart and can be powered independently, with a spacing of 0.5m-2m between two adjacent power supply electrodes.

4. The real-time detection system for the diffusion range of grouting slurry as described in claim 3, characterized in that, Each of the power supply electrodes includes an electrode core, an electrode support, and a multi-layer metal mesh layered around the outside of the electrode core. The electrode support is connected between the electrode core and the multi-layer metal mesh. The mesh spacing of the metal mesh is 0.5mm-2mm, and the layer spacing between adjacent metal meshes is 1mm-3mm.

5. The real-time detection system for the diffusion range of grouting slurry as described in claim 1, characterized in that, The second power supply electrode is an infinity power supply electrode, or the second power supply electrode is a conductive cable with the same potential along its length.

6. The real-time detection system for the diffusion range of grouting slurry as described in claim 1, characterized in that, The measuring electrodes are in series, comprising multiple measuring electrodes spaced apart and capable of independent measurement, with a spacing of 0.2m-1m between adjacent measuring electrodes.

7. The real-time detection system for the diffusion range of grouting slurry as described in claim 6, characterized in that, Each of the measuring electrodes includes an electrode core, an electrode support, and a multi-layer metal mesh layered around the outside of the electrode core. The electrode support is connected between the electrode core and the multi-layer metal mesh. The mesh spacing of the metal mesh is 0.5mm-2mm, and the layer spacing between adjacent metal meshes is 1mm-3mm.

8. A real-time detection method using the system described in any one of claims 1 to 7, characterized in that, Includes the following steps: The first power supply electrode is installed in the target grouting hole, and the end of the first power supply electrode extends to the area to be filled. A second power supply electrode is installed in the power supply hole, and a detection electrode is installed in the detection hole; In the absence of power, obtain the electrical signal between the measuring electrode and the first power supply electrode, or obtain the electrical signal between the measuring electrode and the second power supply electrode; The first and second power supply electrodes are sequentially energized and de-energized, and the current and voltage between the detection electrode and the first power supply electrode are measured. Grouting, repeating the sequential energizing and de-energizing operations of the first and second power supply electrodes, as well as the current and voltage measurement operations of the detection electrode and the first power supply electrode.

9. The real-time detection method as described in claim 8, characterized in that, The measuring electrode and the second power supply electrode are respectively arranged in the detection hole and the power supply hole. The target grouting hole, the detection hole and the power supply hole are located on the same straight line. The depth of the power supply hole is greater than or equal to 15% of the depth of the target grouting hole.

10. The real-time detection method as described in claim 8, characterized in that, The method for acquiring electrical signals includes the following steps: S1. Measure the current and voltage between the string electrodes on all detection electrodes and the first power supply electrode when the first and second power supply electrodes are not energized; S2. Sequentially perform energizing and de-energizing operations on one or more string electrodes on the first power supply electrode and the second power supply electrode, and measure the current and voltage between all string electrodes on the detection electrode and the first power supply electrode until all string electrodes on the second power supply electrode have been energized. S3. Grouting, and repeat step S2.

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