Coal seam creep monitoring equipment

Abstract

The utility model provides coal seam creep monitoring equipment which comprises a creep monitoring sensor, a liquid injection module and a metering module which are arranged in a coal seam, the creep monitoring sensor comprises a flexible expansion rubber pipe, a circular end protection plate and an axial displacement limiting connecting rod, and a liquid inlet and a liquid outlet are formed in the circular end protection plate; the internal creep state of the coal seam is indirectly reflected by monitoring the deformation of the flexible expansion rubber pipe, the difficulty of direct measurement is ingeniously avoided, the rigidity of the flexible expansion rubber pipe is obviously lower than that of the coal seam, the real creep process of the coal seam reaction is ensured by utilizing a low-rigidity structure, and the flexible expansion rubber pipe is tightly attached to the hole wall through a liquid injection expansion mechanism of the flexible expansion rubber pipe; the coal seam creep monitoring device is simple in structure, high-precision liquid discharge amount monitoring is matched, the coal seam creep situation can be obtained in real time, the defect that a traditional method cannot monitor internal creep of a coal seam is overcome, the special requirement of creep monitoring for the rigidity of the sensor is met, and a brand new technical means is provided for early warning of rock burst induced by creep.

Description

TECHNICAL FIELD

[0001] The utility model relates to coal mine monitoring related technical field, especially a coal seam creep monitoring equipment. BACKGROUND

[0002] With the increasing depth of coal seam mining, high ground stress environment aggravates the creep behavior of coal and rock mass, and the time-lag type rock burst phenomenon caused thereby becomes more and more frequent. This kind of disaster has obvious time limit characteristics, and often breaks out suddenly after a long time of creep accumulation, which brings great challenge to traditional monitoring and early warning.

[0003] At present, stress monitoring technology is mainly used in coal mine site to early warn rock burst, including borehole stress meter, microseismic monitoring and other means. These methods have good early warning effect on stress concentration type rock burst, and can timely capture the stress mutation signal of coal and rock mass.

[0004] However, for creep-induced rock burst, the existing stress monitoring technology has obvious deficiencies. Stress monitoring can only reflect the instantaneous stress state, and cannot effectively identify the progressive damage process of coal and rock mass under long-term load, and it is more difficult to capture the strain accumulation, which is the key precursor information.

[0005] To realize effective early warning of creep-induced rock burst, long-term monitoring of the creep situation inside the coal seam must be carried out. However, it is extremely difficult to directly monitor the strain inside the coal seam by traditional strain monitoring method, and the embedded sensor measurement data has low reliability due to the heterogeneity of coal body; the existing sensor is designed with high rigidity, which cannot meet the low rigidity requirement of strain monitoring. According to the principle of elasticity, stress monitoring requires the rigidity of sensor to be much greater than that of coal body, while strain monitoring requires the rigidity of sensor to be much smaller than that of coal body in order to accurately follow the deformation of coal body. UTILITY MODEL CONTENTS

[0006] The utility model aims at providing a coal seam creep monitoring equipment, which realizes close adhesion with the hole wall through liquid injection expansion mechanism, cooperates with high-precision liquid discharge amount monitoring, can realize real-time acquisition of coal seam creep situation, and thus accurately monitors the coal seam creep amount and improves early warning effect.

[0007] Therefore, the utility model adopts the technical scheme that a coal seam creep monitoring equipment, which comprises a creep monitoring sensor arranged in a coal seam, a liquid injection module connected with the creep monitoring sensor and used for injecting liquid, and a metering module connected with the creep monitoring sensor and used for measuring the pressure generated by the discharged liquid at the bottom of a measuring cylinder, the creep monitoring sensor comprises a flexible expansion rubber tube, circular end plates arranged at both ends of the flexible expansion rubber tube, and a plurality of axial displacement limiting connecting rods arranged inside the flexible expansion rubber tube and used for connecting the circular end plates, a cylindrical cavity is formed between the flexible expansion rubber tube and the circular end plates, and a liquid inlet and outlet are formed in one of the circular end plates.

[0008] As a preferred embodiment of the above scheme, a liquid conduit is installed on the liquid inlet / outlet, and a three-way stopcock valve is provided on the liquid conduit, which is connected to the liquid injection module and the metering module respectively.

[0009] More preferably, the injection module includes a hydraulic oil tank connected to a three-way stopcock valve via an injection pipe, a peristaltic pump mounted on the injection pipe, and a pressure sensor.

[0010] More preferably, the metering module includes a liquid outlet pipe disposed on a three-way stopcock valve, a measuring cylinder connected to the free end of the liquid outlet pipe, and a high-precision pressure sensor disposed at the bottom of the measuring cylinder, wherein the high-precision pressure sensor is connected to a data acquisition device.

[0011] More preferably, the connection between the flexible expansion tube and the circular end guard is sealed.

[0012] More preferably, the number of axial displacement limiting links is three, arranged in a triangle.

[0013] The beneficial effects of this invention are as follows: By monitoring the deformation of the flexible expansion hose, the creep state inside the coal seam can be indirectly reflected, cleverly avoiding the difficulties of direct measurement. The stiffness of the flexible expansion hose is significantly lower than that of the coal seam. By utilizing the low-stiffness structure, the true creep process of the coal seam reaction is ensured. The liquid injection expansion mechanism of the flexible expansion hose achieves tight contact with the borehole wall. Combined with high-precision liquid discharge monitoring, the creep situation of the coal seam can be obtained in real time. This not only solves the defect of traditional methods that cannot monitor the creep inside the coal seam, but also meets the special requirements of creep monitoring for sensor stiffness, providing a brand-new technical means for early warning of creep-induced rockbursts. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 This is a schematic diagram of the creep monitoring sensor in this utility model.

[0016] Figure 3 yes Figure 2 Side view. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] like Figures 1-3 As shown, a coal seam creep monitoring device includes a creep monitoring sensor 6 installed in the coal seam, a liquid injection module connected to the creep monitoring sensor 6 for injecting liquid, and a metering module connected to the creep monitoring sensor 6 for measuring the pressure generated by the discharged liquid at the bottom of the measuring cylinder.

[0019] The creep monitoring sensor 6 includes a flexible expansion tube 1, circular end plates 4 disposed at both ends of the flexible expansion tube 1, and several axial displacement limiting links 2 disposed inside the flexible expansion tube 1 for connecting the circular end plates 4. A cylindrical cavity is formed between the flexible expansion tube 1 and the circular end plates 4, and one of the circular end plates 4 has a liquid inlet / outlet 3. The connection between the flexible expansion tube 1 and the circular end plates 4 is sealed.

[0020] A liquid conduit 7 is installed on the liquid inlet / outlet 3. The liquid conduit 7 is equipped with a three-way stopcock valve 8, which is connected to the injection module and the metering module respectively. By controlling the three-way stopcock valve 8, the liquid conduit 7 is connected to the injection module or the metering module, thereby realizing the injection of liquid into the creep monitoring sensor 6 and the monitoring of coal seam creep.

[0021] A closed cavity is formed by the flexible expansion hose 1 and the circular end guard plate 4, and connected to the liquid inlet / outlet 3 by the liquid conduit 7. The volume change of the flexible expansion hose 1 at this time is the volume of coal seam creep. Then, the liquid discharged from the flexible expansion hose 1 is measured by the metering module to obtain accurate information on coal seam creep.

[0022] The injection module includes a hydraulic oil tank 14 connected to a three-way stopcock valve 8 via an injection pipe, a peristaltic pump 13 mounted on the injection pipe, and a pressure sensor 12.

[0023] The metering module includes a liquid outlet pipe installed on a three-way stopcock valve 8, a measuring cylinder 9 connected to the free end of the liquid outlet pipe, and a high-precision pressure sensor 10 installed at the bottom of the measuring cylinder 9. The high-precision pressure sensor 10 is connected to a data acquisition device 11.

[0024] The pressure generated at the bottom of the graduated cylinder 9 by the high-precision pressure sensor 10 placed below the graduated cylinder 9 is measured, and the pressure change pattern of the discharged liquid at the bottom of the graduated cylinder 9 is recorded and stored by the data acquisition unit 11 connected to the high-precision pressure sensor 10.

[0025] There are three axial displacement limiting links 2 arranged in a triangle. This ensures the connection strength of the axial displacement limiting links 2 and prevents the circular end guard plate 4 from moving, which could lead to hydraulic oil leakage from the flexible expansion hose 1.

[0026] The specific steps for coal seam creep monitoring are as follows: First, drill a hole in the coal seam with a diameter of 130mm and a depth exceeding the coal seam to be measured. Install the coal seam creep monitoring sensor 6 at the test position in the drilled hole. Adjust the three-way stopcock valve 8 to connect the sensor and the peristaltic pump 13. Inject hydraulic oil into the sensor through the peristaltic pump 13, causing the flexible expansion tube 1 of the sensor to expand and fit tightly against the inner wall of the drill hole. During the injection of hydraulic oil into the sensor, monitor the hydraulic oil pressure through the pressure sensor 12. When the pressure exceeds 1kPa, adjust the three-way stopcock valve 8 to disconnect the sensor from the peristaltic pump 13. At the same time, connect the sensor and the pressure measurement module generated at the bottom of the measuring cylinder by the discharge liquid. After the sensor and the measurement module are connected, record the initial value of the high-precision pressure sensor 10 after it stabilizes. Collect data from the high-precision pressure sensor 10 at a frequency of 10min / time using the data acquisition device 11, and record the pressure change generated at the bottom of the measuring cylinder by the discharge liquid.

[0027] Calculate coal seam creep using the following formula:

[0028] The height of the discharged liquid in the graduated cylinder can be calculated using Equation 1:

[0029] h=(P t -P0) / (ρ*g)(Equation 1)

[0030] Where: h is the height of the discharged liquid in the graduated cylinder, P t P0 is the pressure generated at the bottom of the graduated cylinder by the discharged liquid, ρ is the liquid density, and g is the acceleration due to gravity.

[0031] The volume of liquid discharged can be calculated using Equation 2:

[0032] V = S * h (Equation 2)

[0033] In the formula: V is the volume of liquid discharged, and S is the bottom area of ​​the measuring cylinder.

[0034] Calculate the coal seam creep using Equation 3:

[0035]

[0036] In the formula: u r Let r0 be the coal seam creep variable, r0 be the borehole radius, and L be the sensor length.

[0037] By monitoring the deformation of the flexible expansion hose 1, the creep state inside the coal seam is indirectly reflected, cleverly avoiding the difficulties of direct measurement. The stiffness of the flexible expansion hose 1 is significantly lower than that of the coal seam. The low-stiffness structure ensures the real creep process of the coal seam reaction. The liquid injection expansion mechanism of the flexible expansion hose 1 achieves tight fit with the borehole wall. Combined with high-precision liquid discharge monitoring, the creep status of the coal seam can be obtained in real time. This not only solves the defect of traditional methods that cannot monitor the creep inside the coal seam, but also meets the special requirements of creep monitoring for sensor stiffness, providing a brand-new technical means for early warning of creep-induced rockburst.

[0038] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A coal seam creep monitoring device, characterized in that: The device includes a creep monitoring sensor (6) installed in the coal seam, a liquid injection module connected to the creep monitoring sensor (6) for injecting liquid, and a metering module connected to the creep monitoring sensor (6) for measuring the pressure generated by the discharged liquid at the bottom of the measuring cylinder. The creep monitoring sensor (6) includes a flexible expansion tube (1), circular end guards (4) installed at both ends of the flexible expansion tube (1), and several axial displacement limiting links (2) installed inside the flexible expansion tube (1) for connecting the circular end guards (4). A cylindrical cavity is formed between the flexible expansion tube (1) and the circular end guards (4), and a liquid inlet / outlet (3) is opened on one of the circular end guards (4).

2. The coal seam creep monitoring device according to claim 1, characterized in that: A liquid conduit (7) is installed on the liquid inlet / outlet (3), and a three-way stopcock valve (8) is provided on the liquid conduit (7) and is respectively connected to the liquid injection module and the metering module.

3. The coal seam creep monitoring device according to claim 2, characterized in that: The injection module includes a hydraulic oil tank (14) connected to a three-way stopcock valve (8) via an injection pipe, a peristaltic pump (13) mounted on the injection pipe, and a pressure sensor (12).

4. The coal seam creep monitoring device according to claim 2, characterized in that: The metering module includes an outlet pipe installed on a three-way stopcock valve (8), a measuring cylinder (9) connected to the free end of the outlet pipe, and a high-precision pressure sensor (10) installed at the bottom of the measuring cylinder (9). The high-precision pressure sensor (10) is connected to a data acquisition device (11).

5. The coal seam creep monitoring device according to claim 1, characterized in that: The connection between the flexible expansion tube (1) and the circular end guard plate (4) is sealed.

6. The coal seam creep monitoring device according to claim 1, characterized in that: The number of axial displacement limiting links (2) is three, arranged in a triangle.

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