Rock mass stress monitoring system and method

Abstract

The invention discloses a coal-rock mass stress monitoring system and method, and belongs to the technical field of coal mining, the coal-rock mass stress monitoring system comprises a stress sensor, the stress sensor is hollow, the stress sensor is communicated with an oil valve connector through an oil pipe, the upper part of the top end of the stress sensor is provided with an exhaust hole, and two ends of the stress sensor are respectively provided with a centralizer; one end of the oil valve connector is provided with an oil inlet, the other end of the oil valve connector is provided with an oil outlet, the oil outlet is fixedly connected with a pressure transmitter, and the pressure transmitter is electrically connected with a data acquisition instrument. The stress sensor is installed in the coal rock mass and used for receiving the stress change condition of the coal rock mass, the oil pipe is used for pumping hydraulic oil and transmitting hydraulic oil pressure outwards, and the oil valve connector is used for connecting the oil pump and the stress transmitter. By means of reliable coal rock stress monitoring, roadway arrangement and anti-scour measures can be planned more reasonably, and the resource utilization rate is increased; and extra engineering and safety risks caused by unreliable coal rock stress monitoring are reduced, so that the economic cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mining, and in particular relates to a rock mass stress monitoring system and method. Background Art

[0002] As my country's coal mining progresses from shallow to deep, the resulting high ground stresses, large deformations, and rock bursts are becoming increasingly prominent. These stresses are directly related to the stress distribution within the coal and rock masses. Monitoring stress changes within the coal and rock masses during mining and uncovering their patterns is crucial for managing ground stress and preventing rock bursts.

[0003] At present, there are two main methods for monitoring coal rock stress in my country: the hollow inclusion method and the oil pressure pillow method. The first method uses strain gauges to indirectly measure coal rock stress by pre-installing a measuring probe in a borehole. It relies on a complete and continuous elastic medium as the measurement basis, and is less effective in weak rock formations such as coal and has low reliability. The second method measures stress changes based on the principle of hydraulic conduction. It can only measure the change in vertical stress and cannot reflect the actual state of coal rock stress changes. At the same time, the oil pressure pillow method is limited by the material and its installation method, resulting in poor coupling between the sensor and the surrounding rock interface, small measurable stress values, and low sensitivity. Therefore, the existing coal rock stress monitoring equipment and methods can no longer fully meet the production needs of mines, and there is an urgent need to improve the sensitivity and reliability of coal rock stress monitoring through technical breakthroughs. Summary of the Invention

[0004] The purpose of the present invention is to provide a rock stress monitoring system and method to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a coal rock stress monitoring system, including a stress sensor, which is hollow inside and connected to an oil valve connector through an oil pipe. An exhaust hole is provided at the upper top of the stress sensor, and stabilizers are provided at both ends of the stress sensor. One end of the oil valve connector is provided with an oil inlet, and the other end of the oil valve connector is provided with an oil outlet. A pressure transmitter is fixedly connected to the oil outlet, and the pressure transmitter is electrically connected to a data acquisition instrument.

[0006] Preferably, an oil inlet hole is provided at the top of the bottom end of the stress sensor, and the oil inlet hole is connected to the oil pipe.

[0007] Preferably, a tubular one-way valve is provided at one end of the oil valve connector close to the oil inlet.

[0008] Preferably, the tubular one-way valve includes a valve body, a valve core is provided in the valve body, and a spring is provided in the valve core.

[0009] Preferably, a grout outlet is provided at the center of the top of the stress sensor, a grouting pipe head is provided at the center of the bottom of the stress sensor, and the centralizers are respectively provided outside the grout outlet and the grouting pipe head.

[0010] A method for monitoring the stress of coal and rock masses includes the following steps:

[0011] S1. Inject oil and exhaust air from the stress sensor;

[0012] S2. Drill a borehole with a designed size at a specific location;

[0013] S3. Transport the stress sensor filled with oil to the predetermined depth of the borehole, and seal the borehole and grout it;

[0014] S4. After the grout solidifies, pressurize the stress sensor to the initial required stress, and start monitoring the stress of the coal and rock masses.

[0015] Preferably, in step S1, close the oil outlet, open the exhaust hole, pump hydraulic oil into the oil inlet using an oil pump, and after all the air in the stress sensor is completely exhausted, close the exhaust hole.

[0016] Preferably, in step S2, use a drill rig to drill a borehole with a designed diameter and depth in the coal and rock mass at the monitoring location to meet the installation requirements of the stress sensor.

[0017] Preferably, in step S3, connect the grouting pipe to the grouting pipe head at the bottom of the stress sensor, use the grouting pipe to transport the stress sensor to the predetermined depth of the borehole, seal the hole opening with a hole-sealing material, at the same time connect the grouting pipe to the grouting machine, then pump grouting liquid into the hole until the pressure of the grouting pump increases, stop grouting after the hole is full of grout, and seal the grouting pipe.

[0018] The present invention discloses the following technical effects: The stress sensor is installed in the coal and rock mass to receive the stress change of the coal and rock mass. The oil pipe is used to pump hydraulic oil and transmit the hydraulic oil pressure outward. The oil valve connector is used to connect the oil pump and the stress transmitter. The pressure transmitter is connected to the oil outlet of the oil valve connector by a thread connection to convert the hydraulic oil pressure signal into an electrical signal; the data acquisition instrument is electrically connected to the pressure transmitter to collect, store and analyze the electrical signal in real time. Through reliable monitoring of coal and rock stress, the present invention can more reasonably plan roadway layout and anti-bumping measures, improve resource utilization rate; reduce additional engineering and safety risks caused by unreliable monitoring of coal and rock stress, thereby reducing economic costs; reliable real-time monitoring of coal and rock mass stress helps prevent coal mine accidents. The present invention realizes automatic monitoring and data transmission through the pressure transmitter and the data acquisition instrument, significantly improves the accuracy and reliability, is applicable to complex mine environments, and solves the problems of low sensitivity and poor data reliability of traditional coal body stress monitoring technologies. Description of the Drawings

[0019] The accompanying drawings, which form a part of this application, are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0020] Figure 1 is a schematic structural diagram of the coal and rock mass stress monitoring system of the present invention;

[0021] Figure 2 is a side view of the stress sensor of the present invention;

[0022] Figure 3 is a schematic diagram of the oil valve connector of the present invention.

[0023] In the figure: 1, stress sensor; 2, oil pipe; 3, oil valve connector; 4, grout outlet hole; 5, exhaust hole; 6, oil inlet hole; 7, grouting pipe head; 8, oil inlet; 9, oil outlet; 10, spring; 11, valve core; 12, valve body; 13, centralizer; 14, pressure transmitter; 15, data acquisition instrument. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0026] Referring to Figures 1-3 as shown, this embodiment provides a coal and rock mass stress monitoring system, including a stress sensor 1. The stress sensor 1 is hollow inside. The stress sensor 1 is connected to an oil valve connector 3 through an oil pipe 2. An exhaust hole 5 is provided above the top end of the stress sensor 1. Centralizers 13 are respectively provided at both ends of the stress sensor 1. An oil inlet 8 is provided at one end of the oil valve connector 3. An oil outlet 9 is provided at the other end of the oil valve connector 3. A pressure transmitter 14 is fixedly connected to the oil outlet 9. The pressure transmitter 14 is electrically connected to a data acquisition instrument 15. The inner side of the exhaust hole 5 is provided with threads and is blocked with a screw. The inner sides of the oil inlet 8 and the oil outlet 9 are respectively provided with threads.

[0027] The stress sensor 1 is installed in the coal rock body and is used to receive the stress changes of the coal rock body. The oil pipe 2 is used to pump hydraulic oil and transmit the hydraulic oil pressure to the outside. The oil valve connector 3 is used to connect the oil pump and the stress transmitter. The pressure transmitter is connected to the oil outlet of the oil valve connector by a threaded connection and is used to convert the hydraulic oil pressure signal into an electrical signal. The data acquisition instrument is electrically connected to the pressure transmitter to collect, store and analyze the electrical signal in real time. Through reliable coal rock stress monitoring, the present invention can more reasonably plan the layout of the tunnel and the anti-bumping measures, improve resource utilization, reduce the additional engineering and safety risks caused by unreliable coal rock stress monitoring, and thus reduce economic costs. Reliable real-time monitoring of coal rock stress helps prevent coal mine accidents. The present invention realizes automated monitoring and data transmission through a pressure transmitter and a data acquisition instrument, significantly improving accuracy and reliability. It is suitable for complex mine environments and solves the problems of low sensitivity and poor data reliability of traditional coal stress monitoring technology.

[0028] As a further optimization solution, an oil inlet hole 6 is provided at the top of the bottom end of the stress sensor 1 , the oil inlet hole 6 is connected to the oil pipe 2 , and the oil inlet hole 6 and the oil pipe 2 are welded together.

[0029] As a further optimization solution, a tubular one-way valve is provided at one end of the oil valve connector 3 near the oil inlet 8 , and the tubular one-way valve includes a valve body 12 , a valve core 11 is provided in the valve body 12 , and a spring 10 is provided in the valve core 11 .

[0030] According to a further optimization scheme, a slurry outlet hole 4 is provided at the top center of the stress sensor 1, a grouting pipe head 7 is provided at the bottom center of the stress sensor 1, and centralizers 13 are provided on the outer sides of the slurry outlet hole 4 and the grouting pipe head 7 respectively.

[0031] A method for monitoring coal rock mass stress comprises the following steps:

[0032] S1, filling and exhausting the stress sensor 1;

[0033] S2. Drill holes of designed size at specific locations;

[0034] S3, transporting the stress sensor 1 filled with oil to a predetermined depth of the borehole, and sealing the hole with grouting;

[0035] S4. After the slurry solidifies, the stress sensor 1 is pressurized to the required initial stress, and the stress of the coal rock mass is monitored.

[0036] To further optimize the solution, in step S1, the oil outlet 9 is closed, the exhaust hole 5 is opened, and hydraulic oil is pumped into the oil inlet 8 using an oil pump. When the air in the stress sensor 1 is completely exhausted, that is, when no bubbles appear in the hydraulic oil discharged from the exhaust hole 5 for one minute, the exhaust hole 5 is closed.

[0037] For a further optimized solution, in step S2, a drill is used to construct a borehole with a designed diameter and depth in the coal and rock mass at the monitoring position to meet the installation requirements of the stress sensor 1.

[0038] For a further optimized solution, in step S3, the grouting pipe is connected to the grouting pipe head 7 at the bottom of the stress sensor 1. The stress sensor 1 is transported to the predetermined depth of the borehole by using the grouting pipe. The orifice is sealed with a hole-sealing material. At the same time, the grouting pipe is connected to a grouting machine. The grouting liquid sequentially passes through the grouting pipe head 7 and the slurry outlet 4 and enters the borehole until the pressure of the grouting pump increases. When the slurry in the hole is full, stop grouting and seal the grouting pipe. The centralizer 13 is used to center the stress sensor 1.

[0039] After the grouting liquid solidifies, open the screw plug at the oil outlet 9 of the oil valve connector 3, install the pressure transmitter 14 at the oil outlet 9 of the oil valve connector 3, and connect its output end to the data acquisition instrument 15 through a cable; start the data acquisition instrument 15, then pump hydraulic oil into the oil inlet 11 of the oil valve connector 3 by using an oil pump, and observe the data acquisition instrument 15. When the designed pressure value of 5 MPa is reached, stop oil injection and fix the data acquisition instrument 15, and start to monitor the stress change value of the coal and rock mass.

[0040] A coal and rock mass stress monitoring system and method provided by the present invention are at least applied to the following scenarios: 1) During coal mine mining, it is used to guide mine pressure control to reduce safety risks. 2) In mine rock mechanics analysis, it is used to evaluate the stress state of coal and rock to provide data support for underground engineering. 3) In the mine design stage, it is used to optimize the roadway layout to improve the mining efficiency and safety of the mine.

[0041] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is 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 should not be construed as a limitation to the present invention.

[0042] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A coal and rock mass stress monitoring system, characterized in that: It includes a stress sensor (1). The stress sensor (1) is hollow inside. The stress sensor (1) is connected to an oil valve connector (3) through an oil pipe (2). An exhaust hole (5) is provided above the top end of the stress sensor (1). Centralizers (13) are respectively provided at both ends of the stress sensor (1). An oil inlet (8) is provided at one end of the oil valve connector (3). An oil outlet (9) is provided at the other end of the oil valve connector (3). A pressure transmitter (14) is fixedly connected to the oil outlet (9). The pressure transmitter (14) is electrically connected to a data acquisition instrument (15).

2. The coal and rock mass stress monitoring system according to claim 1, wherein: An oil inlet hole (6) is provided at the top of the bottom end of the stress sensor (1). The oil inlet hole (6) is communicated with the oil pipe (2).

3. The coal and rock mass stress monitoring system according to claim 1, characterized in that: A tubular one-way valve is provided at one end of the oil valve connector (3) close to the oil inlet (8).

4. The coal-rock mass stress monitoring system according to claim 3, wherein: The tubular one-way valve includes a valve body (12). A valve core (11) is provided inside the valve body (12). A spring (10) is provided inside the valve core (11).

5. The coal and rock mass stress monitoring system according to claim 1, characterized in that: A grout outlet hole (4) is provided at the center of the top of the stress sensor (1). A grouting pipe nozzle (7) is provided at the center of the bottom of the stress sensor (1). Centralizers (13) are respectively provided outside the grout outlet hole (4) and the grouting pipe nozzle (7).

6. A method for monitoring the stress of coal and rock masses, based on the rock mass stress monitoring system according to any one of claims 1-5, characterized in that, It includes the following steps: S1. Inject oil and exhaust air for the stress sensor (1). S2. Drill a hole with a designed size at a specific position. S3. Transport the stress sensor (1) filled with oil to the predetermined depth of the hole, and seal the hole and grout. S4. After the grout solidifies, pressurize the stress sensor (1) to the initial required stress, and start monitoring the stress of the coal and rock mass.

7. The coal and rock mass stress monitoring method according to claim 6, characterized in that: In step S1, close the oil outlet (9), open the exhaust hole (5), use an oil pump to pump hydraulic oil into the oil inlet (8). Wait until the air in the stress sensor (1) is completely exhausted, and then close the exhaust hole (5).

8. The coal and rock mass stress monitoring method according to claim 6, characterized in that: In step S2, use a drill to drill a hole with a designed diameter and depth in the coal and rock mass at the monitoring position, meeting the installation requirements of the device (1).

9. The method for monitoring the stress of coal and rock mass according to claim 6, characterized in that: In step S3, connect the grouting pipe to the grouting pipe nozzle (7) at the bottom of the stress sensor (1). Use the grouting pipe to transport the stress sensor (1) to the predetermined depth of the hole. Seal the hole opening with a hole-sealing material. At the same time, connect the grouting pipe to the grouting machine. Then pump grouting liquid into the hole until the pressure of the grouting pump increases. Stop grouting after the hole is full of grout, and seal the grouting pipe.

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