A method for monitoring multi-physical field information of formations by drilling layers

Abstract

The present invention belongs to the field of mine geological monitoring technology, and in particular relates to a method for monitoring multi-physical field information of strata by drilling layers, comprising the following steps: S1, drilling a monitoring hole, wherein the monitoring hole successively passes through a loose sand layer and a plurality of mutually spaced aquicludes and aquifers; S2, inserting a plurality of data acquisition optical fibers into the bottom of the monitoring hole, wherein a plurality of flexible water-blocking plugs are sleeved on the plurality of data acquisition optical fibers; S3, grouting, wherein a plugging layer is provided in the loose sand layer, a second slurry layer is provided in the aquiclude, and a third slurry layer is provided in the aquifer, wherein the flexible water-blocking plugs are located between the adjacent second and third slurry layers; S4, connecting one end of the plurality of data acquisition optical fibers passing through the plugging layer to a ground monitoring system signal. Based on the rock formation stress and strain monitoring, the present invention realizes the monitoring of the seepage water pressure and water temperature in the hole, reduces the negative effects of time and economic costs, and realizes the comprehensive monitoring of various rock and soil layer index parameters by drilling.

Description

Technical Field

[0001] The present invention belongs to the technical field of mine geological monitoring, and in particular relates to a method for monitoring multi-physical field information of strata by drilling layers. Background Art

[0002] Currently, the most common method for obtaining geological information about underground rock and soil strata in mines is to deploy highly precise and sensitive monitoring equipment within boreholes. This technology dynamically monitors rock and soil subsidence and deformation, groundwater level fluctuations, and aquifer pressure under the influence of mining activities. The diverse geostrata that make up the underground spatial structure complicates the study of these strata. Due to the constraints of the stratigraphic structure, current methods for dynamic monitoring of underground rock and soil strata in mines fail to fully integrate and monitor various dynamic indicators within boreholes. A single borehole can only measure stress and strain or seepage pressure in the rock and soil strata caused by underground coal mining, making it difficult to maximize borehole utilization. To obtain more geological information about the rock and soil strata, additional boreholes would be necessary within the study area, which would directly increase project costs and construction time, impacting future mine production succession plans. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for monitoring multi-physical field information of strata by drilling layers to solve the above problems.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A method for monitoring multi-physical field information of a stratum by drilling layers, comprising the following steps:

[0006] S1. Drilling monitoring holes, wherein the monitoring holes successively pass through a loose sand layer and a plurality of mutually spaced aquicludes and aquifers;

[0007] S2. Inserting a plurality of data acquisition optical fibers into the bottom of the monitoring hole, wherein a plurality of flexible water-blocking plugs are provided on the plurality of data acquisition optical fibers;

[0008] S3, grouting, providing a plugging layer in the loose sand layer, providing a second slurry layer in the water-blocking layer, and providing a third slurry layer in the aquifer, with the flexible water-blocking plug being located between the adjacent second and third slurry layers;

[0009] S4. Connect one end of the plurality of data acquisition optical fibers passing through the sealing layer to a ground monitoring system signal.

[0010] Preferably, in step S2, one end of a plurality of the data acquisition optical fibers located at the bottom of the monitoring hole is fixedly connected to a counterweight guide head.

[0011] Preferably, in step S3, the sealing layer includes a clay filling layer, the second slurry layer includes an activated fly ash cement mortar layer, and the third slurry layer includes a permeable cement mortar layer.

[0012] Preferably, in step S3, the grouting process of the activated fly ash cement mortar layer includes the following steps:

[0013] S31, vertically extending the first grouting pipe into the waterproof layer at the bottom of the monitoring hole;

[0014] S32, connecting the first grouting pipe to the grouting device, passing activated fly ash cement mortar into the waterproof layer through the first grouting pipe, and lifting the first grouting pipe upward while grouting;

[0015] S33. Grouting is completed, and the activated fly ash cement mortar forms the activated fly ash cement mortar layer in the waterproof layer. The flexible water-blocking plug is installed above the activated fly ash cement mortar layer, and the first grouting pipe is lifted to another adjacent waterproof layer. After the activated fly ash cement mortar layer is initially set, prepare to inject the permeable cement mortar layer into the aquifer.

[0016] Preferably, in step S3, the grouting process of the permeable cement mortar layer includes the following steps:

[0017] S34, vertically extending the second grouting pipe into the aquifer near the bottom of the monitoring hole;

[0018] S35, connecting the second grouting pipe to the grouting device, injecting permeable cement mortar into the aquifer through the second grouting pipe, and lifting the second grouting pipe upward while grouting;

[0019] S36: Grouting is completed, and the permeable cement mortar forms the permeable cement mortar layer in the aquifer. The flexible water-blocking plug is installed above the permeable cement mortar layer, and the second grouting pipe is lifted into another adjacent aquifer. After the permeable cement mortar layer initially sets, steps S31-S36 are repeated until grouting of the plurality of aquicludes and the plurality of aquifers is completed.

[0020] S37, filling the clay filling layer in the loose sand layer.

[0021] Preferably, the plurality of data acquisition optical fibers include a stress-strain optical fiber, a grating optical fiber with an osmometer, and a grating optical fiber with a thermometer, and one end of each of the stress-strain optical fiber, the grating optical fiber with an osmometer, and the grating optical fiber with a thermometer is fixedly connected to the counterweight guide head;

[0022] The ground monitoring system includes a signal modem connected to the stress-strain optical fiber, the grating optical fiber with a piezometer, and the grating optical fiber with a thermometer. The signal modem is connected to a terminal data storage computer.

[0023] Preferably, the grouting device includes: a cement mortar mixing barrel, the cement mortar mixing barrel is connected to the inlet of a grouting pump, the outlet of the grouting pump is connected to a ground grouting pipe, the outlet of the grouting pump is provided with a grouting pressure gauge, and the ground grouting pipe is connected to the second grouting pipe or the first grouting pipe.

[0024] Compared with the prior art, the present invention has the following advantages and technical effects:

[0025] The present invention overcomes the shortcoming that a single borehole can only monitor one formation parameter index by comprehensively and integratedly monitoring different physical parameters such as deformation of multiple layers of overburden and seepage water pressure and water temperature of aquifers during coal seam mining. At the same time, grouting into the monitoring hole can improve the coupling between the grating optical fiber and the rock formation, reducing the error of the monitoring value. The flexible water-blocking plug can not only play a water-isolating effect, but also protect the top of the lower injected section from direct impact during the pouring of cement mortar, which may cause damage to the injected slurry layer. Different slurry layers are injected into the aquifer and the aquifer, and the aquifer is injected into the third slurry layer. The third slurry layer ensures that the aquifer will not be blocked and discontinuous after grouting. On the basis of rock formation stress and strain monitoring, the synchronous monitoring of seepage water pressure and water temperature in the hole is realized, which reduces the negative effects of time and economic costs, realizes the comprehensive monitoring of various rock and soil index parameters of the borehole, and achieves "one hole for multiple uses". BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0027] Figure 1 This is a schematic diagram of the monitoring hole structure and the first waterproof layer grouting of the present invention;

[0028] Figure 2 This is a schematic diagram of grouting the first aquifer according to the present invention;

[0029] Figure 3 Schematic diagram of the whole-hole grouting and ground monitoring system of the monitoring hole of the present invention;

[0030] Figure 4 1 is a top view of the flexible water-blocking plug of the present invention;

[0031] Among them, 1. Seamless hole-protecting steel casing; 2. Stress-strain optical fiber; 3. Bragg grating optical fiber with piezometer; 4. Bragg grating optical fiber with thermometer; 5. Clay filling layer; 6. Monitoring hole; 7. Loose sand layer; 8. Water-proof layer; 9. Aquifer; 10. Seepage pressure sensor; 11. Flexible water-blocking plug; 12. Temperature sensor; 13. Activated fly ash cement mortar layer; 14. Permeable cement mortar layer; 15. Coal seam; 16. Counterweight guide head; 17. First grouting pipe; 18. Second grouting pipe; 19. Grouting pressure gauge; 20. Grouting pump; 21. Ground grouting pipe; 22. Cement mortar mixing barrel; 23. Clean water barrel; 25. Waterproof cabinet; 26. Signal modem; 27. Terminal data storage computer. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] Reference Figures 1 to 4 The present invention discloses a method for monitoring multi-physical field information of a stratum by drilling layers, comprising the following steps:

[0035] S1, drilling a monitoring hole 6, the monitoring hole 6 successively passes through a loose sand layer 7 and a plurality of mutually spaced aquicludes 8 and aquifers 9;

[0036] S2. Insert a plurality of data acquisition optical fibers into the bottom of the monitoring hole 6. A plurality of flexible water-blocking plugs 11 are provided on the plurality of data acquisition optical fibers;

[0037] S3, grouting, setting a plugging layer in the loose sand layer 7, setting a second slurry layer in the water-blocking layer 8, setting a third slurry layer in the aquifer 9, and the flexible water-blocking plug 11 is located between the adjacent second and third slurry layers;

[0038] S4. Connect one end of several data acquisition optical fibers passing through the blocking layer to the ground monitoring system signal.

[0039] As a further optimized solution, in step S2 , one end of a plurality of data acquisition optical fibers located at the bottom of the monitoring hole 6 is fixedly connected to the counterweight guide head 16 .

[0040] According to a further optimized solution, in step S3 , the sealing layer includes a clay filling layer 5 , the second slurry layer includes an activated fly ash cement mortar layer 13 , and the third slurry layer includes a permeable cement mortar layer 14 .

[0041] According to a further optimized solution, in step S3, the grouting process of the activated fly ash cement mortar layer 13 includes the following steps:

[0042] S31, vertically extending the first grouting pipe 17 into the water-proof layer 8 at the bottom of the monitoring hole 6;

[0043] S32, connecting the first grouting pipe 17 to the grouting device, passing the activated fly ash cement mortar into the waterproof layer 8 through the first grouting pipe 17, and lifting the first grouting pipe 17 upwards while grouting;

[0044] S33. Grouting is completed, and the activated fly ash cement mortar forms an activated fly ash cement mortar layer 13 in the water-proof layer 8. A flexible water-blocking plug 11 is installed above the activated fly ash cement mortar layer 13, and the first grouting pipe 17 is lifted to another adjacent water-proof layer 8. After the activated fly ash cement mortar layer 13 is initially set, prepare to inject a permeable cement mortar layer 14 into the aquifer 9.

[0045] Further optimizing the solution, in step S3, the grouting process of the permeable cement mortar layer 14 includes the following steps:

[0046] S34, vertically extending the second grouting pipe 18 into the aquifer 9 near the bottom of the monitoring hole 6;

[0047] S35, connecting the second grouting pipe 18 to the grouting device, passing the permeable cement mortar into the aquifer 9 through the second grouting pipe 18, and lifting the second grouting pipe 18 upward while grouting;

[0048] S36: Grouting is completed. The permeable cement mortar forms a permeable cement mortar layer 14 in the aquifer 9. A flexible water-blocking plug 11 is installed above the permeable cement mortar layer 14. The second grouting pipe 18 is lifted into another adjacent aquifer 9. After the permeable cement mortar layer 14 initially sets, steps S31-S36 are repeated until grouting of the plurality of aquicludes 8 and the plurality of aquifers 9 is completed.

[0049] S37 , filling the loose sand layer 7 with a clay filling layer 5 .

[0050] Further optimizing the scheme, several data acquisition optical fibers include a stress-strain optical fiber 2, a grating optical fiber 3 with an osmometer, and a grating optical fiber 4 with a thermometer. One end of the stress-strain optical fiber 2, the grating optical fiber 3 with an osmometer, and the grating optical fiber 4 with a thermometer are all fixedly connected to the counterweight guide head 16;

[0051] The ground monitoring system includes a signal modem 26 connected to the stress-strain optical fiber 2 , the grating optical fiber 3 with a piezometer, and the grating optical fiber 4 with a thermometer. The signal modem 26 is connected to a terminal data storage computer 27 .

[0052] To further optimize the solution, the grouting device includes: a cement mortar mixing barrel 22, the cement mortar mixing barrel 22 is connected to the inlet of the grouting pump 20, the outlet of the grouting pump 20 is connected to the ground grouting pipe 21, the outlet of the grouting pump 20 is provided with a grouting pressure gauge 19, and the ground grouting pipe 21 is connected to the second grouting pipe 18 or the first grouting pipe 17.

[0053] Working process: Based on the engineering geology and hydrogeology conditions of the study area, a monitoring hole 6 was vertically drilled on the ground to the top of the coal seam 15 roof collapse zone. The monitoring hole 6 successively penetrated the loose sand layer 7 located on the surface, the intermittent aquiclude 8, and the aquifer 9 (i.e., interbedded mudstone, siltstone, and sandstone). When drilling the monitoring hole 6, a φ200mm drill bit was first used to drill through the loose sand layer 7. At the interface between the drill bit and the bedrock, to prevent the monitoring hole 6 in the loose sand layer 7 from collapsing, a φ157mm seamless steel casing 1 was coaxially installed at the inner edge of the monitoring hole 6 in the loose sand layer 7. The outer wall of the seamless steel casing 1 was fixed with mortar. The monitoring hole 6 was then drilled using a φ133mm drill bit. The buried depth of each aquifer 9 and aquiclude 8 was recorded during the drilling process. A stress-strain optical fiber 2 (BOTDR distributed grating optical fiber), a grating optical fiber with an osmometer 3, and a grating optical fiber with a thermometer 4 are installed into the monitoring hole 6. To ensure the optical fibers reach the bottom of the hole smoothly and without bending or deformation, the front ends of the optical fibers are fixed to a counterweight guide 16. Under the action of the counterweight guide 16's own weight, the stress-strain optical fiber 2, the grating optical fiber with an osmometer 3, and the grating optical fiber with a thermometer 4 are continuously released into the hole. An osmotic pressure sensor 10 is mounted on the grating optical fiber with an osmotic pressure sensor 3, and a temperature sensor 12 is mounted on the grating optical fiber with a thermometer 4. Both the temperature sensor 12 and the osmotic pressure sensor 10 are located in the aquifer 9. A flexible water-blocking plug 11 is installed between the aquiclude 8 and the aquifer 9 to ensure that the aquiclude 8 and the aquifer 9 do not affect each other.

[0054] In the initial grouting state, the bottom end of the first grouting pipe 17 is located 0.2-0.4m above the bottom end of the aquiclude 8. The grouting pump 20 injects the activated fly ash cement mortar mixed in the cement mortar mixing barrel 22 into the aquiclude 8 in the monitoring hole 6 through the first grouting pipe 17 to form an activated fly ash cement mortar layer 13. The activated fly ash cement mortar can quickly solidify and ensure that the physical and mechanical properties of the slurry solidification layer are similar to those of the surrounding rock formations. The initial grouting pressure is 1. 8-2.2MPa. When the pumping slurry volume drops significantly, grouting is suspended for 5 minutes and then the second phase of grouting is carried out. The grouting pressure is increased to 4.0MPa and the steady pressure grouting is maintained until the end. During the grouting process, the first grouting pipe 17 is gradually lifted. After the grouting is completed, a flexible water-blocking plug 11 is installed above the activated fly ash cement mortar layer 13, and the first grouting pipe 17 is lifted into another adjacent waterproof layer 8. The bottom end of the first grouting pipe 17 is located 0.2-0.4m above the bottom end of the waterproof layer 8;

[0055] After the pulping of the waterproof layer 8 is completed, the ground grouting pipe 21 and the grouting pump 20 are cleaned with industrial water in the clean water bucket 23 until clear water appears in the outlet pipe. At the same time, the cement mortar mixing barrel 22 is cleaned to facilitate the injection of the permeable cement mortar layer 14 into the aquifer 9.

[0056] When grouting into the aquifer 9 in the monitoring hole 6, the water pressure of the aquifer 9 in the grouting section needs to be considered. The minimum grouting pressure should be 1.5 times the maximum water pressure of the aquifer 9 in the grouting section. The Veber viscosity of the slurry gradually increases from 5s to 20s to ensure that the slurry diffuses as far as possible in advance, thereby increasing the coupling integrity between the permeable cement mortar layer 14 and the aquifer 9 after solidification.

[0057] In the initial grouting state, the bottom end of the second grouting pipe 18 is located 0.2-0.4 m above the bottom end of the aquifer 9. The grouting pump 20 injects the permeable cement mortar stirred in the cement mortar mixing barrel 22 into the aquifer 9 in the monitoring hole 6 through the second grouting pipe 18 to form a permeable cement mortar layer 14. After the grouting is completed, the second grouting pipe 18 is raised to 0.2-0.4 m above the bottom end of the adjacent aquifer 9.

[0058] After the permeable cement mortar layer 14 has initially solidified, a flexible water-blocking plug 11 is installed on top of the aquifer 9, and then the upper aquiclude 8 is grouted and sealed. The process is repeated until the aquifer 9 and the aquiclude 8 are completely sealed.

[0059] The aquifer 9 is filled with a permeable cement mortar layer 14, which ensures that the aquifer 9 will not be blocked and discontinuous after grouting. The permeable cement mortar layer 14 poured into the aquifer 9 will form artificial pores. The aquifer around the monitoring hole 6 is interconnected with the artificial filling section in the monitoring hole 6 at the same layer. On the basis of rock formation stress and strain monitoring, the synchronous monitoring of the seepage water pressure and water temperature in the monitoring hole 6 is realized, which reduces the negative effects of time and economic costs, realizes the comprehensive monitoring of various rock and soil layer index parameters by drilling, and achieves "one hole for multiple uses".

[0060] 48 hours after the cement sealing the aquifer 9 and the aquiclude 8 has completely set, the monitoring hole 6 in the loose sand layer 7 is filled and compacted with a clay filling layer 5, and the ends of the stress-strain optical fiber 2, the grating optical fiber 3 with a piezometer, and the grating optical fiber 4 with a thermometer are led out, bundled, and connected to a relatively closed waterproof cabinet 25. The stress-strain optical fiber 2, the grating optical fiber 3 with a piezometer, and the grating optical fiber 4 with a thermometer are connected to the signal modem 26 located in the waterproof cabinet 25, and the signal modem 26 is connected to the terminal data storage computer 27, thereby realizing dynamic monitoring of the geological information in the monitoring hole 6.

[0061] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0062] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for monitoring multi-physical field information of formations by drilling layers, characterized in that: The following steps are involved: S1, drilling a monitoring hole (6), wherein the monitoring hole (6) successively passes through a loose sand layer (7) and a plurality of mutually spaced aquicludes (8) and aquifers (9); S2, inserting a plurality of data acquisition optical fibers into the bottom of the monitoring hole (6), wherein a plurality of flexible water-blocking plugs (11) are provided on the plurality of data acquisition optical fibers; S3, grouting, providing a plugging layer in the loose sand layer (7), providing a second slurry layer in the water-blocking layer (8), and providing a third slurry layer in the water-bearing layer (9), wherein the flexible water-blocking plug (11) is located between the adjacent second slurry layer and the third slurry layer; S4, connecting one end of the plurality of data acquisition optical fibers passing through the blocking layer to a ground monitoring system signal; In step S3, the blocking layer includes a clay filling layer (5), the second slurry layer includes an activated fly ash cement mortar layer (13), and the third slurry layer includes a permeable cement mortar layer (14); The data acquisition optical fibers include a stress-strain optical fiber (2), a grating optical fiber with a piezometer (3), and a grating optical fiber with a thermometer (4).

2. The method for monitoring multi-physical field information of a stratum by drilling layers according to claim 1, characterized in that: In step S2, one end of a plurality of data acquisition optical fibers located at the bottom of the monitoring hole (6) is fixedly connected to a counterweight guide head (16).

3. The method for monitoring multi-physical field information of a stratum by drilling layers according to claim 1, characterized in that: In step S3, the grouting process of the activated fly ash cement mortar layer (13) comprises the following steps: S31, vertically extending the first grouting pipe (17) into the water-proof layer (8) located at the bottom of the monitoring hole (6); S32, connecting the first grouting pipe (17) to the grouting device, passing the activated fly ash cement mortar into the waterproof layer (8) through the first grouting pipe (17), and lifting the first grouting pipe (17) upwards while grouting; S33, grouting is completed, the activated fly ash cement mortar forms the activated fly ash cement mortar layer (13) in the waterproof layer (8), the flexible water-blocking plug (11) is installed above the activated fly ash cement mortar layer (13), the first grouting pipe (17) is lifted to the other adjacent waterproof layer (8), and after the activated fly ash cement mortar layer (13) is initially set, the permeable cement mortar layer (14) is prepared to be injected into the aquifer (9).

4. The method for monitoring multi-physical field information of a stratum by drilling layers according to claim 3, characterized in that: In step S3, the grouting process of the permeable cement mortar layer (14) includes the following steps: S34, vertically extending the second grouting pipe (18) into the aquifer (9) near the bottom of the monitoring hole (6); S35, connecting the second grouting pipe (18) to the grouting device, passing the permeable cement mortar into the aquifer (9) through the second grouting pipe (18), and lifting the second grouting pipe (18) upwards during grouting; S36, grouting is completed, the permeable cement mortar forms the permeable cement mortar layer (14) in the aquifer (9), the flexible water-blocking plug (11) is installed above the permeable cement mortar layer (14), the second grouting pipe (18) is lifted into another adjacent aquifer (9), and after the permeable cement mortar layer (14) is initially set, steps S31-S36 are repeated until the grouting of the plurality of aquicludes (8) and the plurality of aquifers (9) is completed; S37, filling the clay filling layer (5) into the loose sand layer (7).

5. The method for monitoring multi-physical field information of a stratum by drilling layers according to claim 2, characterized in that: One end of the stress-strain optical fiber (2), the grating optical fiber with a piezometer (3), and the grating optical fiber with a thermometer (4) are all fixedly connected to the counterweight guide (16); The ground monitoring system comprises a signal modem (26) connected to the stress-strain optical fiber (2), the grating optical fiber with a piezometer (3), and the grating optical fiber with a thermometer (4), and the signal modem (26) is connected to a terminal data storage computer (27).

6. The method for monitoring multi-physical field information of a stratum by drilling layers according to claim 4, characterized in that: The grouting device comprises: a cement mortar mixing barrel (22), the cement mortar mixing barrel (22) is connected to the inlet of a grouting pump (20), the outlet of the grouting pump (20) is connected to a ground grouting pipe (21), the outlet of the grouting pump (20) is provided with a grouting pressure gauge (19), and the ground grouting pipe (21) is connected to the second grouting pipe (18) or the first grouting pipe (17).

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