CN-115585923-B - Drilling type three-way multipoint coal rock mass wireless stress meter and coal rock mass stress monitoring method

CN115585923BCN 115585923 BCN115585923 BCN 115585923BCN-115585923-B

Abstract

The invention relates to the safety fields of coal rock mass, underground engineering and the like, and provides a wireless stress meter for a drilling three-dimensional multipoint coal rock mass and a coal rock mass stress monitoring method, wherein a unidirectional stress monitoring unit in the stress meter comprises a polyvinylidene fluoride piezoelectric film, a wire, an upper protective layer and a lower protective layer which are arranged on the upper surface and the lower surface of the polyvinylidene fluoride piezoelectric film; the frames comprise a main frame and a secondary frame, the frames are tubular, a unidirectional stress monitoring unit which is axially arranged along the frames is embedded in the side, close to the protective cap, of the main frame, at least two unidirectional stress monitoring units which are vertically arranged along the radial directions of the frames are embedded in the main frame and the secondary frame, polyvinylidene fluoride piezoelectric films of the unidirectional stress monitoring units which are radially arranged are coplanar with the outer walls of the frames, a signal processing module which is connected with a wire is arranged in a hollow pipeline of each frame or the adjacent frames, and the signal processing module is in wireless communication with external equipment. The stress meter according to the present disclosure improves the accuracy of stress monitoring data.

Inventors

ZHENG JIANWEI
QI QINGXIN
LI CHUNYUAN
He Tuan
ZHANG LIANG
YANG GUANYU

Assignees

煤炭科学研究总院有限公司

Dates

Publication Date: 20260508
Application Date: 20220919

Claims (9)

1. The wireless stress meter for the drilling type three-way multipoint coal rock mass is characterized by comprising a plurality of unidirectional stress monitoring units, a plurality of signal processing modules, a plurality of frameworks and a protective cap; The unidirectional stress monitoring unit comprises a polyvinylidene fluoride piezoelectric film, an upper protective layer and a lower protective layer which are respectively arranged on the upper surface and the lower surface of the polyvinylidene fluoride piezoelectric film, and a wire connected with the polyvinylidene fluoride piezoelectric film, wherein the upper protective layer or the lower protective layer is formed by pouring target concrete, and the target concrete is obtained based on materials and proportions determined by the basic physical and mechanical characteristics of a rock sample of a stress monitoring point of a field coal rock mass; The frames comprise a main frame and a secondary frame, one end of the main frame is connected with the protective cap, the other end of the main frame is connected with the secondary frame, the frames are tubular, a unidirectional stress monitoring unit which is axially arranged along the frames and is positioned in a hollow pipeline and a unidirectional stress monitoring unit which is radially arranged along the frames are embedded in the side, close to the protective cap, of the main frame, and at least two unidirectional stress monitoring units which are radially arranged along the frames and are perpendicular to each other are embedded in the side, close to the main frame, of the secondary frame, wherein a polyvinylidene fluoride piezoelectric film of the unidirectional stress monitoring unit which is radially arranged is coplanar with the outer wall of the frame; One signal processing module is arranged on one hollow pipeline in the adjacent framework or one signal processing module is respectively arranged on two hollow pipelines, the signal processing modules are connected with the wires of all the unidirectional stress monitoring units in the corresponding frameworks, and the signal processing modules are in wireless communication with external equipment.
2. The wireless stress meter for the three-dimensional multi-point coal and rock mass of the drilling type according to claim 1, wherein the polyvinylidene fluoride piezoelectric film is in a strip shape, the length and the width of the polyvinylidene fluoride piezoelectric film are at least 100 times of the thickness of the polyvinylidene fluoride piezoelectric film, and the length and the width of the upper protective layer and the length and the width of the lower protective layer are respectively larger than or equal to the length and the width of the polyvinylidene fluoride piezoelectric film.
3. The wireless stress meter of the drilling three-way multipoint coal rock mass according to claim 1, wherein a silica gel layer is smeared on the surface of the polyvinylidene fluoride piezoelectric film.
4. The wireless stress meter for the three-dimensional multi-point coal rock mass of the drilling type according to claim 1, wherein slurry outlets are formed in the outer wall of each framework, and the slurry outlets are communicated with the hollow pipeline in the framework and the outer wall.
5. The wireless stress meter of a three-way multi-point coal rock of claim 1, wherein the number of sub-skeletons is plural, the wireless stress meter of a three-way multi-point coal rock of the drill type further comprising a joint through which each skeleton is connected.
6. The wireless stress meter for the three-way multi-point coal rock mass according to claim 1, wherein the signal processing module comprises an analog-to-digital conversion circuit, a temperature compensation unit and a wireless transmission unit, the analog-to-digital conversion circuit is used for converting analog stress data acquired by the unidirectional stress monitoring unit into digital stress data, and the wireless transmission unit is used for sending the digital stress data to external equipment.
7. A coal rock mass stress monitoring method based on a borehole type three-way multipoint coal rock mass wireless stress meter, which is suitable for the borehole type three-way multipoint coal rock mass wireless stress meter according to any one of claims 1 to 6, comprising: Determining the number of skeletons based on a plurality of stress monitoring points in the field coal rock mass borehole; Acquiring a prefabricated unidirectional stress monitoring unit and a plurality of tubular frameworks, wherein the frameworks comprise a main framework and a secondary framework; Connecting one end of the main framework with the protective cap and then placing the main framework into a drill hole, axially arranging a unidirectional stress monitoring unit positioned in the hollow pipeline along the framework on the side, close to the protective cap, of the main framework, radially arranging at least two unidirectional stress monitoring units perpendicular to each other along the framework, and arranging a signal processing module in the hollow pipeline of the main framework; After the main framework and the secondary framework are connected through the connector, at least two unidirectional stress monitoring units which are vertical to each other in the direction close to the main framework are arranged on the side of the secondary framework along the radial direction of the framework, a signal processing module is arranged in a hollow pipeline of the secondary framework, wherein a polyvinylidene fluoride piezoelectric film of the unidirectional stress monitoring units which are arranged along the radial direction is coplanar with the outer wall of the framework, and after each signal processing module is arranged, the signal processing module is connected with leads of all unidirectional stress monitoring units of the framework; After the arrangement of all the frameworks is completed, hole sealing is carried out on the orifice positions of the frameworks, grouting is carried out on hollow pipelines in the frameworks, so that the wireless stress meter of the drilling type three-way multipoint coal rock mass is poured in the drilling holes; and monitoring the stress information of the coal rock mass in real time by using a wireless stress meter of the drilling three-way multipoint coal rock mass.
8. The coal rock mass stress monitoring method based on the drilling three-way multipoint coal rock mass wireless stress meter according to claim 7, wherein the manufacturing process of the unidirectional stress monitoring unit comprises the following steps: Configuring target concrete based on physical and mechanical characteristics of rock samples of stress monitoring points of on-site coal rock mass; And (3) selecting a polyvinylidene fluoride piezoelectric film with preset length and width, and pouring the target concrete on the upper surface and the lower surface of the polyvinylidene fluoride piezoelectric film to form an upper protective layer and a lower protective layer with length and width respectively larger than or equal to the preset length and width, thereby obtaining the unidirectional stress monitoring unit.
9. The coal rock mass stress monitoring method based on the drilling three-way multipoint coal rock mass wireless stress meter according to claim 8, wherein maintenance and uniaxial compression experiments are further required for the unidirectional stress monitoring unit after the unidirectional stress monitoring unit is manufactured.

Description

Drilling type three-way multipoint coal rock mass wireless stress meter and coal rock mass stress monitoring method Technical Field The disclosure relates to the safety fields of coal and rock mass, underground engineering and the like, in particular to a wireless stress meter for a drilling three-way multi-point coal and rock mass and a coal and rock mass stress monitoring method. Background The implementation of mining mineral resources, tunnel excavation or other geological engineering can change the stress distribution state originally existing in a coal rock body, different underground engineering has different requirements on project service life and deformation in the use process, for example, the service life of a stoping roadway in a coal mine is usually not more than 3 years, the service life of the stoping roadway is basically the same as that of a mine, the stoping roadway only needs to ensure that production is not influenced during stoping of a working face, a certain amount of roadway deformation convergence is allowed, and engineering such as a tunnel has strict requirements on the deformation, so that different underground engineering has the requirements on distinct deformation and service life for different purposes. The deformation of the underground engineering, namely the safety, can be mainly divided into three types of mechanical characteristics of rock stratum where the underground engineering is located, stress applied to the boundary of the underground engineering and manually applied supporting measures, wherein if the change condition of the stress applied to the boundary of the underground engineering can be timely and long-time monitored and perceived, corresponding measures can be better adopted to ensure the normal operation of the underground engineering, and the health and safety of staff are also ensured. At present, a borehole stress meter or a geophysical method is generally adopted for monitoring stress occurrence and evolution conditions of surrounding rocks in different deep parts from the surface of an underground engineering, the existing geophysical method represented by stress wave perception can realize abnormal monitoring within a certain range, but cannot well solve differences of conditions such as cavities, water and stress abnormality in monitored areas in waveform analysis, the borehole stress meter is generally of the type of hydraulic type, vibrating wire type, fiber bragg grating type, hollow inclusion type and the like, but the existing stress meter has certain defects such as complex installation process, single data amount and the like in the practical application process, and can not meet the requirements of higher precision and richer stress monitoring data to a certain extent, so that a new borehole stress meter needs to be developed to monitor the stress state of the underground engineering rock better. Disclosure of Invention The present disclosure aims to solve, at least to some extent, one of the technical problems in the related art. To this end, a first object of the present disclosure is to propose a borehole type three-way multi-point coal rock mass wireless stress meter to improve the accuracy of stress monitoring data. A second object of the present disclosure is to provide a coal rock mass stress monitoring method based on a borehole type three-way multi-point coal rock mass wireless stress meter. To achieve the above objective, an embodiment of a first aspect of the present disclosure provides a wireless stress meter for a drill hole type three-way multi-point coal rock mass, which includes a plurality of unidirectional stress monitoring units, a plurality of signal processing modules, a plurality of skeletons and a protective cap; the unidirectional stress monitoring unit comprises a polyvinylidene fluoride piezoelectric film, an upper protective layer and a lower protective layer which are respectively arranged on the upper surface and the lower surface of the polyvinylidene fluoride piezoelectric film, and a wire connected with the polyvinylidene fluoride piezoelectric film; The frames comprise a main frame and a secondary frame, one end of the main frame is connected with the protective cap, the other end of the main frame is connected with the secondary frame, the frames are tubular, a unidirectional stress monitoring unit which is axially arranged along the frames and is positioned in a hollow pipeline and a unidirectional stress monitoring unit which is radially arranged along the frames are embedded in the side, close to the protective cap, of the main frame, and at least two unidirectional stress monitoring units which are radially arranged along the frames and are perpendicular to each other are embedded in the side, close to the main frame, of the secondary frame, wherein a polyvinylidene fluoride piezoelectric film of the unidirectional stress monitoring unit which is radially arranged is coplanar with the outer wall of the