A system and method for predicting the development height of water-conducting fracture zones

Abstract

The present invention discloses a system for predicting the height of a water-conducting fracture zone, comprising a support system, a rock formation simulation system fixed on the support system, a water supply system and a water storage system; the rock formation simulation system comprises an aquifer and an aquiclude; the water supply system is connected to the aquifer, and the water supply system is pre-loaded with water containing different characteristic isotopes; the water storage system is arranged at the bottom of the rock formation simulation system. By building a rock formation simulation system in proportion, effectively marking water from different aquifers, testing the thousand-difference deviation value of the marking isotope in the water storage system, and predicting the height of a water-conducting fracture zone, the shortcomings of the traditional on-site measurement method are overcome, and the system can be applied to different rock formation conditions, and can provide a more accurate basis for predicting the height of a water-conducting fracture zone.

Description

Technical Field

[0001] The invention relates to the field of mine water inrush prevention and control and overburden fissure prediction, and in particular to a system and method for predicting the development height of a water-conducting fracture zone. Background Art

[0002] After the coal seam is mined, the overburden in the upper part of the coal mine will be redistributed due to the impact of mining, causing the upper rock layer to deform and be destroyed. From the goaf upward, it is divided into three different characteristic zones: collapse zone, fracture zone and curved sinking zone. The collapse zone and fracture zone are good channels for water. When there is a water-rich layer above the coal seam, whether the overburden fractures penetrate the aquifer directly determines the safety of the working face. Accurately grasping the conductivity of overburden fractures is an important theoretical basis for judging the conditions for mine water inrush, predicting mine water inrush and formulating mine water hazard prevention and control measures. At present, the prediction of the height of the water-conducting fracture zone is mostly based on field measurements. The observation results only reflect the development of the entire overburden fracture through the observation results of a few points, and are only applicable to the current mine. Summary of the invention

[0003] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a system and method for predicting the development height of water-conducting fracture zones.

[0004] To achieve the above-mentioned purpose, the system for predicting the development height of water-conducting fracture zones provided by the present invention includes four parts: a support system, a rock formation simulation system, a water supply system and a water storage system.

[0005] Firstly, according to the actual rock conditions on site, the number and relative positions of all aquifers covering the working face were determined through drilling exploration, and a rock simulation system was built in proportion. Each aquifer, aquiclude, etc. were numbered and marked in sequence. A 12 mm thick plexiglass plate was installed on the front side of the support system. Rubber sealing rings were used to seal between the plexiglass plate and the support system, and between the rock simulation system and the support system. High water pressure sealing was achieved and fixed with an automatic locking device. The upper and lower adjacent plexiglass plates were sealed with sealant.

[0006] The water supply system includes a water supply tank; the water supply tank is provided with a water inlet and a water outlet; a water pressure pump is provided at the water outlet; the water supply system is placed on the side of the support system through a sliding wheel track and can be adjusted according to the location of the aquifer. The water supply tank is pre-loaded with water containing different characteristic isotopes through the water inlet. The specific selectable marker isotopes include 23 Na2 13 C 16 O3, 23 Na2 34 S 16 O4, 23 Na 37 Cl and 87 Sr35 Cl2.

[0007] The water storage system includes a discharge pipe, a water storage tank, a water guide plate and a control valve. The water guide plate is provided with two rows of water guide holes with an interval of 5 cm. The water storage system is placed at the bottom of the support system through a sliding wheel rail and is separated from the rock simulation system by the water guide plate.

[0008] The method for predicting the development height of a water-conducting fracture zone provided by the present invention comprises the following steps:

[0009] S1: According to the actual rock conditions on site, the number and relative positions of all aquifers covering the working face are determined through drilling exploration. Sand, gypsum, CaCO3 and other raw materials are used to build a rock simulation system in proportion, and each aquifer, aquiclude, etc. is numbered and marked in sequence.

[0010] S2: Place the water supply system on the side of the support system according to the corresponding position of the rock layer, add water containing different characteristic isotopes into the water supply tank, and use the water pressure pump in the water supply system to flow the water containing different isotopes into each aquifer respectively; the characteristic isotope only exists in the aquifer it corresponds to, and does not exist in other aquifers of the overlying rock.

[0011] S3: Every time the actual working face advances 30-50 m, the model is reflected in proportion. After the coal seam is excavated, the water from the working face is discharged into the water storage tank, and a water sample from the water storage system is collected for stable isotope testing. As the working face advances, the water samples are continuously tested, and the isotope content of the water samples during the advancement of the working face is recorded. The source of water at each gushing point is determined based on the stable isotope characteristics of the aquifer and the gushing point.

[0012] S4: Based on the source of water gushing obtained in S3, combined with the measured data of the mine's water-conducting fracture zone, and according to the changes in the isotopes of water samples at different advancement distances of the working face, by analyzing the relative deviation of the isotope ratio between the sample and the standard, it is inferred whether the water-conducting fracture zone has spread to the aquifer, and then the development height of the overburden water-conducting fracture zone can be known. Comprehensive analysis can be used to obtain the height change process of the overburden water-conducting fracture zone.

[0013] Beneficial effects: Based on the characteristics of strong isotope distinguishability and high sensitivity, the present invention realizes effective identification of water from different aquifers through the water supply system, and determines whether the water in each aquifer is introduced into the working face by comparing the thousand-difference deviation of the identification isotopes in the water supply system and the water storage system (the difference between the ratio of two stable isotopes of a certain element in the water of the aquifer to be tested and the ratio of two isotopes of the same element in the standard material, that is, the relative deviation between the isotope ratios between the sample to be tested and the standard), thereby determining the development height of the water-conducting fracture zone in the overburden. The present invention can predict the development height of the water-conducting fracture zone according to different mine conditions, and has great practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention;

[0015] Figure 2 is a schematic diagram of the structure of the present invention after coal seam excavation;

[0016] Figure 3 It is a schematic diagram of the structure of the water guide plate of the present invention;

[0017] In the figure: 1-support system; 2-rock simulation system; 3-water supply system; 4-water storage system; 5-automatic locking device; 6-water inlet; 7-water outlet; 8-water supply tank; 9-hydraulic pump; 10-water storage tank; 11-drain pipe; 12-water guide plate; 13-control valve; 14-water guide hole. DETAILED DESCRIPTION

[0018] The following is a further description of an implementation example of the present invention in conjunction with the accompanying drawings:

[0019] A system for predicting the height of water-conducting fracture zones includes a support system 1, a rock formation simulation system 2, a water supply system 3 and a water storage system 4. First, according to the actual rock formation conditions on site, the number and relative positions of all aquifers in the overburden of the working face are determined through drilling exploration, and the rock formation simulation system 2 is built in proportion.

[0020] Each aquifer, aquiclude, etc. is numbered and marked in sequence; a 12 mm thick plexiglass plate is installed on the front side of the support system 1, and a high water pressure seal is achieved by using rubber sealing rings between the plexiglass plate and the support system 1, and between the rock simulation system 2 and the support system 1, and is fixed by an automatic locking device 5; the upper and lower adjacent plexiglass plates are sealed with sealant.

[0021] The water supply system 3 includes a water supply tank 8; the water supply tank 8 is provided with a water inlet 6 and a water outlet 7; the water outlet 7 is provided with a hydraulic pump 9; the water supply system 3 is placed on the side of the support system 1 through a sliding wheel rail and can be adjusted according to the position of the aquifer; the water supply tank 8 is pre-loaded with different characteristic isotopes through the water inlet 6 23 Na2 13 C 16 O3, 23 Na2 34 S 16 O4, 23 Na 37 Cl and 87 Sr 35 Cl2 in water.

[0022] The water storage system 4 is placed at the bottom of the support system 1 through the sliding wheel rail. The working surface water storage system 4 includes a water storage tank 10; the water storage tank 10 is provided with a water discharge pipe 11 and a water guide plate 12; the water discharge pipe 11 is provided with a control valve 13, and the water guide plate 12 is provided with two rows of water guide holes 14 with an interval of 5 cm.

[0023] A method for predicting the height of a water-conducting fracture zone, comprising the following specific steps:

[0024] S1: According to the actual rock conditions on site, the number and relative positions of all aquifers covering the working face are determined through drilling exploration. Using sand, gypsum, CaCO3 and other raw materials, a rock simulation system 2 is built in proportion, and each aquifer, aquiclude, etc. is numbered and marked in sequence.

[0025] S2: Place the water supply system 3 on the side of the support system 1 according to the corresponding position of the rock layer, add water containing different characteristic isotopes into the water supply tank 8, and flow the water containing different isotopes into each aquifer through the hydraulic pump 9 in the water supply system 3; the characteristic isotope only exists in the aquifer to which it corresponds, and does not exist in other aquifers in the overlying rock.

[0026] S3: Every time the actual working face advances 30m, it is reflected in the system according to the ratio. After the coal seam is excavated, the water of the working face is discharged to the water storage tank 10, and a water sample of the water storage system 4 is collected for stable isotope testing. As the working face advances, the water samples are continuously tested, and the isotope content of the water samples during the advancement of the working face is recorded. The source of water at each gushing point is determined by combining the stable isotope characteristics of the aquifer and the gushing point.

[0027] S4: Based on the source of water gushing obtained in S3 and the measured data of the water-conducting fracture zone in the mine, the development height of the water-conducting fracture zone is analyzed; based on the changes in isotopes of water samples at different advancement distances of the working face, the height change process of the water-conducting fracture zone in the overburden rock is obtained through comprehensive analysis.

[0028] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A system for predicting the height of water-conducting fracture zones, characterized in that: The invention comprises a support system (1), a rock formation simulation system (2) fixed on the support system (1), a water supply system (3) and a water storage system (4); the rock formation simulation system (2) comprises an aquifer and an aquiclude; the water supply system (3) is connected to the aquifer, and the water supply system (3) is pre-filled with water containing different characteristic isotopes; the water storage system (4) is arranged at the bottom of the rock formation simulation system (2); The support system (1) is provided with an organic glass plate on the front side, and the organic glass plate and the support system (1), and the rock formation simulation system (2) and the support system (1) are sealed with rubber sealing rings and fixed with an automatic locking device (5); The water supply system (3) is placed on the side of the support system (1) via sliding wheels and rails and is adjusted according to the location of the aquifer; The water supply system (3) comprises a water supply box (8), and the water supply box (8) is provided with a water inlet (6) and a water outlet (7); the water outlet (7) is connected to the aquifer, and a water pressure pump (9) is provided on the water outlet (7); The water storage system (4) comprises a water storage tank (10), on which a water discharge pipe (11) and a water guide plate (12) are provided; the water discharge pipe (11) is provided with a control valve (13); The water guide plate (12) is provided with two rows of water guide holes (14); The water storage system (4) is placed at the bottom of the support system (1) via sliding wheel rails; The water containing different characteristic isotopes includes 23 Na2 13 C 16 O3, 23 Na2 34 S 16 O4, 23 Na 37 Cl and 87 Sr 35 Cl2.

2. A method for predicting the height of water-conducting fracture zones based on the system of claim 1, characterized in that The following steps are involved: S1: According to the actual rock formation conditions on site, the number and relative positions of all aquifers covering the working face are determined through exploration, and a rock formation simulation system (2) is built. Each aquifer and aquiclude is marked with numbers in sequence; S2: placing the water supply system (3) on the side of the support system (1) according to the corresponding position of the rock layer, adding water containing different characteristic isotopes into the water supply system (3), and letting the water containing different isotopes flow into each aquifer respectively; S3: Every time the actual working face advances 30-50m, the system is reflected according to the proportion; after the coal seam is excavated, the water of the working face is discharged to the water storage system (4), and a water sample of the water storage system (4) is collected for stable isotope testing; as the working face advances, the water samples are continuously tested, and the isotope content of the water samples during the advancement of the working face is recorded, and the source of the water at each water gushing point is determined by combining the stable isotope characteristics of the aquifer and the water gushing point; S4: Based on the source of water gushing obtained in S3 and the measured data of the water-conducting fracture zone in the mine, the development height of the water-conducting fracture zone is analyzed; based on the changes in isotopes of water samples at different advancement distances of the working face, the height change process of the water-conducting fracture zone in the overburden rock is analyzed.

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