Grouting, plugging and repairing method for overlying strata mining damage area

Abstract

The invention relates to a grouting plugging repair method for an overlying strata mining damage area. The grouting plugging repairing method comprises the steps that a first wave velocity set in a monitoring area before overlying strata mining is obtained; acquiring a second wave velocity set in the monitoring area after overlying strata mining; determining a damage area of the overlying strata according to the first wave velocity set and the second wave velocity set; according to the filling layer position where the damaged area is located, grouting slurry with the corresponding proportion is debugged; and grouting plugging operation is executed. By obtaining the first wave velocity set and the second wave velocity set before and after overlying strata mining, the position of the overlying strata mining damage area can be accurately judged, the self-repairing evolution process of the overlying strata mining damage area is further manually improved in a grouting plugging mode, and finally the purpose of green coal mining is achieved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of green coal mining, and in particular to a grouting and plugging repair method for an overburden mining damaged area. Background Art

[0002] At present, the methods for treating the overburden mining damage area can be divided into two types: active and passive. The active method is to minimize the formation of the overburden mining damage area from the perspective of the working face mining technical conditions, and to reduce the overburden damage by reasonably controlling the working face length and mining speed, and adopting strip mining, backfill mining and other methods. However, this method is costly, and the coal resource recovery rate is low, and it is slow to promote the self-repair process of the overburden damage area.

[0003] Passive methods often use grouting reinforcement to seal the damaged area. This method generally requires collecting ground borehole columnar data from each coal mining area in advance, using the key layer identification method to determine the location of the overburden key layer, and then determining the drilling construction parameters according to the working face conditions. This method has been widely used in the field of preventing and controlling groundwater loss, but it is less involved in promoting the self-repair of the overburden mining damaged area. In the process of promoting the self-repair of the overburden mining damaged area, relying solely on the key layer to judge the grouting plugging construction position is biased, and the overburden mining damaged area cannot be accurately obtained. In addition, the location of the grouting borehole is mostly determined before the working face is recovered, ignoring the changes in the overburden mining damaged area after mining.

[0004] Therefore, there is an urgent need for a new grouting and plugging system and grouting and plugging method for overburden mining damaged areas, which can accurately determine the location of the overburden mining damaged area, and artificially improve the self-repair evolution process of the overburden mining damaged area through grouting and plugging, ultimately achieving the goal of green coal mining. Summary of the invention

[0005] The purpose of the present disclosure is to provide a grouting and plugging repair method for overburden mining damaged areas, so as to accurately determine the location of the overburden mining damaged areas, and to artificially improve the field self-repair evolution process of the overburden mining damaged areas by grouting and plugging, so as to at least partially solve the related technical problems.

[0006] In order to achieve the above-mentioned purpose, the present disclosure provides a grouting and plugging repair method for an overburden mining damaged area. The grouting and plugging repair method comprises: Obtain the first wave velocity set in the monitoring area before overburden mining; Obtain the second wave velocity set in the monitoring area after overburden mining; determining a damaged area of ​​the overburden according to the first wave velocity set and the second wave velocity set; According to the filling layer where the damaged area is located, adjust the grouting slurry with corresponding proportion; Perform grouting and sealing operations.

[0007] Optionally, before obtaining the first wave velocity set in the monitoring area before overburden mining, the method further includes: A monitoring area is determined, wherein the monitoring area includes a horizontal monitoring area and a vertical monitoring area.

[0008] Optionally, determining the monitoring area includes: The horizontal projection area of ​​the goaf is used as the horizontal monitoring area; Conduct drilling sampling in the horizontal monitoring area to determine the key layers of the overburden; The vertical height between the key layer and the ground is taken as the vertical monitoring area; The horizontal monitoring area and the vertical monitoring area together form a monitoring area; Construct multiple detection boreholes within the monitoring area.

[0009] Optionally, the drilling sampling in the horizontal monitoring area to determine the key layers of the overburden rock includes: Drilling sampling is carried out in the horizontal monitoring area to obtain the thickness of each overburden rock layer, and uniaxial compression test is carried out on the collected rock samples to obtain the compressive strength of each layer of rock. The rock layer with a thickness greater than 10m and a compressive strength greater than 30MPa is determined as the key layer.

[0010] Optionally, the damaged region includes a first damaged region located in a separation zone and a second damaged region located in a fracture zone; According to the filling layer where the damaged area is located, before debugging the grouting slurry with the corresponding proportion, it also includes: A first grouting borehole is constructed on the surface of the overburden rock for the first damaged area, and a second grouting borehole is constructed on the surface of the overburden rock for the second damaged area.

[0011] Optionally, according to the filling layer where the damaged area is located, the grouting slurry with a corresponding proportion is adjusted, including: The grouting slurry material for the first damaged area is 425# ordinary Portland cement with a water-cement ratio of 1; the grouting slurry material for the second damaged area is 425# ordinary Portland cement with a water-cement ratio of 0.8.

[0012] Optionally, the performing of the grouting and plugging operation includes: Grouting is located in the second damaged area of ​​the fracture zone; The grouting is located in the first damaged area of ​​the abscission zone.

[0013] Optionally, the performing of the grouting and plugging operation further includes: The completion degree of the grouting and sealing operation is determined by the pressure gauge of the grouting pump.

[0014] Optionally, the performing of the grouting and plugging operation further includes: Verify the repair results.

[0015] Optionally, the inspection and repair result includes: Monitor the amount of surface subsidence during the first period; During the second time period, observe the loss of soil and water resources and the development of ground fissures within the scope of the mining surface impact.

[0016] Through the above-mentioned technical scheme, that is, the grouting and plugging repair method for the overburden mining damaged area, the grouting and plugging repair method comprehensively considers the changes of the damaged area before and after the overburden mining, which is different from the technical scheme in the related technology that determines the position of the grouting borehole before the working face is mined and ignores the changes of the overburden mining damaged area after mining. By respectively obtaining the first wave velocity set and the second wave velocity set before and after the overburden mining, the position of the overburden mining damaged area can be accurately determined, and further grouting and plugging can be used to artificially improve the self-repair evolution process of the overburden mining damaged area, ultimately achieving the purpose of green coal mining.

[0017] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings: Figure 1 It is a schematic flow chart of a grouting plugging and repair method provided according to an embodiment of the present disclosure; Figure 2 It is a structural schematic diagram of a grouting plugging and repairing device provided according to an embodiment of the present disclosure; Figure 3 is a schematic diagram of the structure of a grouting pipe provided according to an embodiment of the present disclosure; Figure 4 It is a schematic diagram of the construction status of the grouting plugging and repairing device provided according to an embodiment of the present disclosure.

[0019] Description of Reference Numerals 100. Grouting plugging and repair device; 1. Pumping station; 2. Conveyor; 3. Mixer; 4. Grouting pump; 41. High-pressure pipe; 42. Pressure gauge; 5. Grouting pipe; 51. Grouting wall protection; 511. Grouting channel; 52. Grouting conduit; 521. Delivery pipe section; 522. Grouting pipe section; 523. Grouting hole; 53. Grouting gap; 54. Annular airbag; 55. Stopper; 6. Casing. DETAILED DESCRIPTION

[0020] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0021] In the present disclosure, unless otherwise specified, “inside and outside” refer to the inside and outside of the corresponding component outline; in addition, it should be noted that the terms used, such as “first, second”, etc., are used to distinguish one element from another.

[0022] According to one embodiment of the present disclosure, Figure 1 As shown, a grouting and plugging repair method for an overburden mining damaged area is provided. The grouting and plugging repair method may include the following steps S1 to S5.

[0023] In step S1, a first wave velocity set in a monitoring area before overburden mining is obtained.

[0024] In step S2, a second wave velocity set in the monitoring area after overburden mining is obtained.

[0025] In step S3, the damaged area of ​​the overburden is determined according to the first wave velocity set and the second wave velocity set.

[0026] In step S4, the grouting slurry with corresponding proportion is adjusted according to the filling layer where the damaged area is located.

[0027] In step S5, a grouting and plugging operation is performed.

[0028] In the embodiments provided by the present invention, the changes of the damaged area before and after the overburden mining are comprehensively considered, which is different from the technical solution in the related art that determines the position of the grouting borehole before the working face is mined and ignores the changes of the damaged area after mining. By respectively obtaining the first wave velocity set and the second wave velocity set before and after the overburden mining, the position of the damaged area caused by overburden mining can be accurately determined, and further artificial improvement of the self-repair evolution process of the damaged area caused by overburden mining can be achieved through grouting and sealing, thereby ultimately achieving the goal of green coal mining.

[0029] It should be noted that in step S1 of obtaining the first wave velocity set in the monitoring area before overburden mining and step S2 of obtaining the second wave velocity set in the monitoring area after overburden mining, the wave velocity detection and acquisition operation can be realized by an ultrasonic detector. Specifically, the ultrasonic detector may include a transmitting end and a receiving end. The ultrasonic detector may be extended into multiple detection boreholes in the monitoring area to obtain the above-mentioned first wave velocity set and the second wave velocity set. Before overburden mining, multiple first wave velocity values ​​may be obtained by using an ultrasonic detector in the monitoring area, and the multiple first wave velocity values ​​form the above-mentioned first wave velocity set. Correspondingly, after overburden mining, multiple second wave velocity values ​​may be obtained by using an ultrasonic detector in the monitoring area, and the multiple second wave velocity values ​​form the above-mentioned second wave velocity set. By comparing the changes in the first wave velocity value and the second wave velocity value at the same detection borehole, it is specifically determined whether the area belongs to the overburden mining damage area. Generally, when the degree of change in the first wave velocity value and the second wave velocity value at the same detection borehole is greater than 5%, it is determined that the area belongs to the overburden mining damage area.

[0030] In some embodiments, before obtaining the first wave velocity set in the monitoring area before overburden mining, the method may further include: determining the monitoring area, where the monitoring area includes a horizontal monitoring area and a vertical monitoring area.

[0031] It should be noted that the related technology that simply relies on the key layer to determine the plugging construction position of the grouting borehole is biased and cannot achieve good repair of the overburden mining damage area. In this embodiment, the monitoring area is divided into a horizontal monitoring area and a vertical monitoring area. The monitoring area formed by the horizontal monitoring area and the vertical monitoring area can more comprehensively realize the sampling of the overburden mining damage monitoring area, so as to further accurately obtain the overburden mining damage area, so as to realize the artificial improvement of the overburden mining damage area field self-repair evolution process by grouting plugging, and finally achieve the purpose of green coal mining.

[0032] Specifically, in order to enable those skilled in the art to better understand the technical solution of the present application, the specific operation of determining the monitoring area will be schematically illustrated below.

[0033] Determining the monitoring area may include the following steps.

[0034] The mined-out area (refer to Figure 2 The horizontal projection area (the area indicated by the arrow A in the figure) is used as the horizontal monitoring area.

[0035] Drilling sampling is carried out in the horizontal monitoring area to determine the key layers of the overburden.

[0036] The vertical height between the key layer and the ground is taken as the vertical monitoring area.

[0037] The horizontal monitoring area and the vertical monitoring area together form a monitoring area.

[0038] Construct multiple detection boreholes within the monitoring area.

[0039] Furthermore, in order to enable those skilled in the art to better understand the technical solution of the present application, the specific operation of determining the key layer of the overburden will be schematically illustrated below.

[0040] Conducting drilling sampling in the horizontal monitoring area to determine the key layers of the overburden may include: conducting drilling sampling in the horizontal monitoring area to obtain the thickness of each overburden layer, and conducting uniaxial compression tests on the collected rock samples to obtain the compressive strength of each layer of rock, and determining the rock layer with a thickness greater than 10m and a compressive strength greater than 30MPa as the key layer.

[0041] In some embodiments, the damaged region may include a first damaged region located in a delamination zone and a second damaged region located in a fracture zone.

[0042] According to the filling layer where the damaged area is located, before debugging the grouting slurry with a corresponding ratio, it can also include: constructing a first grouting borehole on the overburden surface for the first damaged area, and constructing a second grouting borehole on the overburden surface for the second damaged area.

[0043] Among them, it is worth mentioning that when constructing multiple corresponding grouting boreholes in the corresponding damaged area, the location of the underground working face mining tunnel, the depth of the coal seam and the ground drilling conditions can be comprehensively considered to determine the drilling construction location, drilling parameters, construction direction, final hole location, etc. After the specific drilling parameters are determined, multiple corresponding grouting boreholes are constructed. The preparatory work before the construction of grouting drilling is the existing technology in this field. For the sake of simplicity, this will not be repeated. In addition, it is also worth explaining that before debugging the grouting slurry of the corresponding ratio, the grouting drilling is constructed in advance to prevent the grouting slurry from solidifying prematurely.

[0044] It should be noted that the material ratio of grouting slurry should be different according to the filling layer. Usually, the grouting of the separation zone may cause grouting to seep down into the working surface (refer to Figure 2In the area indicated by the arrow B in the middle), there will be problems of well flooding, water damage and waste of resources. Furthermore, the implementation of grouting in the fracture zone may cause safety hazards of water inrush on the underground working face. Based on this, in some embodiments, the grouting slurry with corresponding proportions can be debugged according to the filling layer where the damaged area is located to avoid the above-mentioned problems of slurry leakage and water inrush. Specifically, the debugging of the grouting slurry with corresponding proportions may include: the grouting slurry material of the first damaged area is 425# ordinary Portland cement, and the water-cement ratio is 1; the grouting slurry material of the second damaged area is 425# ordinary Portland cement, and the water-cement ratio is 0.8. For the second damaged area located in the fracture zone, the water-cement ratio of silicate cement is 0.8, which can enable the grouting slurry to quickly fill the first damaged area of ​​the fracture zone and solidify, prevent the further expansion and development of the fracture, and at the same time limit the development space of the delamination in the delamination zone. Furthermore, for the first damaged area located in the delamination zone, a silicate cement water-cement ratio of 1 can make the grouting slurry have better fluidity, reliably fill the second damaged area of ​​the delamination zone, and improve the filling effect.

[0045] In some embodiments, performing a grouting plugging operation may include.

[0046] The grouting was located in the second damaged area of ​​the fracture zone.

[0047] The grouting is located in the first damaged area of ​​the delamination zone. During the grouting and plugging process, the fracture zone is grouted first, and then the delamination zone is grouted. On the one hand, this operation method can first fill the fracture zone with grouting slurry that can solidify quickly, prevent the fracture from further expanding and developing, and limit the development space of the delamination zone in the delamination zone; on the other hand, since the fracture zone is located below the delamination zone, grouting in the fracture zone first can form a protective layer to prevent the delamination zone from flowing into the goaf through the fracture when the grouting slurry material with good fluidity is filled, reducing the cost of repairing the overburden damaged area while ensuring the repair effect.

[0048] In some embodiments, performing the grouting and plugging operation may further include: judging the degree of completion of the grouting and plugging operation according to the pressure gauge 42 of the grouting pump 4 .

[0049] Specifically, during the continuous grouting operation, the indication of the pressure gauge 42 gradually increases. When the pressure gauge 42 shows that the predetermined pressure has been reached, the grouting operation is stopped and the sealer is installed. When the pressure gauge 42 shows that the pressure decreases, it indicates that the slurry has solidified.

[0050] In some embodiments, after performing step S5 of the grouting and plugging operation, the following may also be included: inspecting the repair result.

[0051] In some embodiments, verifying the repair result may include the following steps.

[0052] Monitor the surface subsidence during the first time period.

[0053] During the second time period, the loss of water and soil resources and the development of ground fissures within the scope of the mining surface are observed. It should be noted that it can be understood here that the first time period can be understood as a short period of time, during which an observation station can be set up on the surface or drone technology can be used to monitor the surface settlement and judge the grouting effect. For example, if the surface settlement is within 0.3m, it means that the self-repair is good. Furthermore, the second time period can be understood as a long period of time, during which the loss of water and soil resources and the development of ground fissures within the scope of the mining surface can be tracked and observed, and the self-repair of the overburden damaged area can be comprehensively analyzed.

[0054] According to another embodiment of the present disclosure, Figure 2 and Figure 4 As shown, a grouting and plugging repair device for an area damaged by mining in overburden is provided. The grouting and plugging repair device may include a grouting pump 4 and a grouting pipe 5. Among them, the grouting pump 4 has a high-pressure pipe 41 and a pressure gauge 42. The pressure gauge 42 is used to judge the completion of the grouting and plugging operation. The grouting pipe 5 is pre-buried in the grouting borehole and is connected to the high-pressure pipe 41 to grout the corresponding filling layer. In this embodiment, each filling layer corresponds to a set of grouting and plugging repair devices, so that each grouting and plugging repair device can be independently operated on the basis of improving the efficiency of the grouting and plugging operation, so as to achieve the aforementioned first treatment of the fracture zone (reference Figure 4 The area indicated by the arrow D in the middle) was grouting-sealed, and then the separation zone (reference Figure 4 The grouting and sealing operation is performed in the area indicated by the arrow C in the figure.

[0055] In some embodiments, Figure 3As shown, the grouting pipe 5 may include a grouting protective wall 51, a grouting conduit 52 and a plurality of annular air bags 54. The grouting protective wall 51 has a grouting channel 511. The grouting conduit 52 is arranged in the grouting channel 511. The grouting conduit 52 includes a delivery pipe section 521 and a grouting pipe section 522. One end of the grouting pipe section 522 is connected to the high-pressure pipe 41, and the other end is connected to the grouting pipe section 522. A plurality of grouting holes 523 are provided on the side wall of the grouting pipe section 522. A grouting gap 53 for grouting slurry to flow out is formed between the grouting pipe section 522 and the grouting protective wall 51. A plurality of annular air bags 54 are spaced apart and sleeved on the outside of the delivery pipe section 521 of the grouting conduit 52 along the length direction of the grouting conduit 52 to fix the grouting conduit 52 inside the grouting channel 511. When in use, the grouting and plugging operation of the corresponding filling layer can be realized through the multiple grouting holes 523 on the grouting pipe section 522 of the grouting conduit 52. The setting of the grouting gap 53 can reserve part of the buffer space for the grouting slurry, so that the grouting slurry can be grouted and filled into the corresponding filling layer. Of course, it can be understood that the bottom of the grouting pipe section 522 of the grouting conduit 52 is also an open structure, and the grouting slurry can also be injected into the corresponding filling layer from the bottom of the grouting pipe section 522. Further, the setting of the annular airbag 54 can reliably fix the grouting conduit 52 in the grouting protective wall 51, so that the grouting conduit 52 and the grouting protective wall 51 are designed as a split structure, which is convenient for the replacement, maintenance and installation of the grouting conduit 52.

[0056] In some embodiments, Figure 3 As shown, a stopper 55 is provided or formed at the bottom of the grouting channel 511. The stopper 55 is located outside the grouting conduit 52 and between the grouting pipe section 522 and the delivery pipe section 521, so as to prevent the grouting slurry from flowing back toward one side of the delivery pipe section 521. The stopper 55 can be constructed as a stopper boss formed by the grouting protective wall 51 extending toward the grouting conduit 52, or can be constructed as a separately provided stopper block or stopper sheet, which is not limited here, and those skilled in the art can make design adjustments according to actual conditions. The provision of the stopper 55 can effectively prevent the grouting slurry flowing out of the grouting hole 523 from flowing back toward the delivery pipe section 521 of the grouting conduit 52, thereby improving the reliability of the grouting plugging operation.

[0057] In some embodiments, Figure 2 As shown, the grouting plugging and repairing device can also include a pump station 1, a conveyor 2 and a mixer 3 connected in sequence, and a grouting pump 4 is connected to the mixer 3. Among them, the pump station 1 is mainly used as a grouting slurry supply source, which can be delivered to the conveyor 2 through the casing 6. The conveyor 2 can realize continuous delivery of the slurry. The slurry is further stirred by the mixer 3, and the corresponding filling layer is injected into the grouting pipe 5 through the grouting pump 4. It should be noted that the pump station 1, the conveyor 2, the mixer 3 and the grouting pump 4 can be implemented by any suitable equipment in the prior art, and no limitation is made here.

[0058] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0059] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0060] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A grouting and plugging repair method for overburden mining damage area, characterized in that: include: Obtain the first wave velocity set in the monitoring area before overburden mining; Obtain the second wave velocity set in the monitoring area after overburden mining; determining a damaged area of ​​the overburden according to the first wave velocity set and the second wave velocity set; According to the filling layer where the damaged area is located, adjust the grouting slurry with corresponding proportion; Perform grouting and sealing operations.

2. The grouting plugging and repairing method according to claim 1, characterized in that: Before obtaining the first wave velocity set in the monitoring area before overburden mining, the method further includes: A monitoring area is determined, wherein the monitoring area includes a horizontal monitoring area and a vertical monitoring area.

3. The grouting plugging and repairing method according to claim 2, characterized in that: Determining the monitoring area includes: The horizontal projection area of ​​the goaf is used as the horizontal monitoring area; Conduct drilling sampling in the horizontal monitoring area to determine the key layers of the overburden; The vertical height between the key layer and the ground is taken as the vertical monitoring area; The horizontal monitoring area and the vertical monitoring area together form a monitoring area; Construct multiple detection boreholes within the monitoring area.

4. The grouting plugging and repairing method according to claim 3 is characterized in that: The drilling sampling is carried out in the horizontal monitoring area to determine the key layers of the overburden, including: Drilling sampling is carried out in the horizontal monitoring area to obtain the thickness of each overburden rock layer, and uniaxial compression test is carried out on the collected rock samples to obtain the compressive strength of each layer of rock. The rock layer with a thickness greater than 10m and a compressive strength greater than 30MPa is determined as the key layer.

5. The grouting plugging and repairing method according to claim 1, characterized in that: The damaged area includes a first damaged area located in the delamination zone and a second damaged area located in the fracture zone; According to the filling layer where the damaged area is located, before debugging the grouting slurry with the corresponding proportion, it also includes: A first grouting borehole is constructed on the surface of the overburden rock for the first damaged area, and a second grouting borehole is constructed on the surface of the overburden rock for the second damaged area.

6. The grouting plugging and repairing method according to claim 5, characterized in that: According to the filling layer where the damaged area is located, the grouting slurry with corresponding proportion is debugged, including: The grouting slurry material for the first damaged area is 425# ordinary Portland cement with a water-cement ratio of 1; the grouting slurry material for the second damaged area is 425# ordinary Portland cement with a water-cement ratio of 0.

8.

7. The grouting plugging and repairing method according to claim 1, characterized in that: The grouting and plugging operation comprises: Grouting is located in the second damaged area of ​​the fracture zone; The grouting is located in the first damaged area of ​​the abscission zone.

8. The grouting plugging and repairing method according to claim 7, characterized in that: The performing of the grouting and plugging operation also includes: The completion degree of the grouting and sealing operation is determined by the pressure gauge of the grouting pump.

9. The grouting plugging and repairing method according to claim 1, characterized in that: The grouting and plugging operation is then performed, and further includes: Verify the repair results.

10. The grouting plugging and repairing method according to claim 9, characterized in that: The inspection and repair results include: Monitor the amount of surface subsidence during the first period; During the second time period, observe the loss of soil and water resources and the development of ground fissures within the scope of the mining surface.

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