Rock mass multi-physics field sensing and supporting integrated device and method

Abstract

The invention provides a rock mass multi-physics field sensing and supporting integrated device and method, and particularly relates to the field of rock mass supporting and monitoring, and the device comprises an anchor rod, an iron pipe, an optical fiber sensor and a temperature compensation optical fiber; the anchor rod comprises a sensing head and a hollow rod body, the sensing head is installed at the first end of the hollow rod body, the anchor rod is driven into a rock mass to enable the sensing head to be embedded into the rock mass, the sensing head comprises a distributed optical fiber, a strain sensor, a temperature sensor and a fiber bragg grating sensor, and the strain sensor, the temperature sensor and the fiber bragg grating sensor are connected with the distributed optical fiber. The distributed optical fiber penetrates through the hollow rod body and penetrates out of the second end of the hollow rod body; the iron pipe is a hollow cylinder fixed on the outer surface of the anchor rod in a sleeving manner; the optical fiber sensor is fixed on the surface of the iron pipe; the distributed optical fiber is connected with the optical fiber sensor; the temperature compensation fiber is fixed on the surface of the iron pipe; the problems that in the prior art, rock mass strain monitoring sensitivity is insufficient, sensing information is single, and a monitoring system is complex are solved, and therefore the effect of accurately and comprehensively sensing multiple kinds of physical field information in real time is achieved.

Description

Technical Field

[0001] The present invention relates to the field of rock mass support monitoring, and in particular to a rock mass multi-physical field sensing support integrated device and method. Background Art

[0002] Rock mass is composed of various rocks and is heterogeneous due to the cutting of structural surfaces such as joints and faults and the influence of groundwater. When the rock mass is subjected to force, the different directions, distributions and densities of its structural surfaces lead to differences in mechanical properties. Rock mass fracture and deformation will produce physical effects such as acoustic emission, temperature, and stress. Monitoring can be carried out through monitoring means, so as to analyze data information, improve the reliability of identifying precursor information of rock mass damage, and support the rock mass in time.

[0003] Most of the current research focuses on describing the regular changes in parameters such as acoustic emission, infrared radiation, and strain of rock masses. Acoustic emission technology is greatly affected by geological conditions and has limited positioning accuracy, making it difficult to predict large-scale disasters such as rock collapse and landslides; infrared radiation technology has a short monitoring distance and low imaging resolution, making it difficult to achieve fine identification of small targets; full-field strain technology has insufficient monitoring sensitivity for tiny strains, and the amount of data generated after monitoring is huge, making data processing complex. In addition, a long time is required to complete data collection and processing during monitoring, making it impossible to monitor the strain state of the rock mass in real time.

[0004] In response to the above problems, how to comprehensively detect the physical changes caused by rock fracture and enhance the sensitivity of monitoring technology are issues that need to be addressed. Summary of the invention

[0005] The main purpose of the present invention is to provide an integrated device and method for rock multi-physical field sensing and support, so as to at least solve the problems of insufficient sensitivity of rock strain monitoring, single sensing information and complex monitoring system in the prior art, so as to achieve the effect of accurate and real-time comprehensive perception of multiple physical field information.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a rock multi-physical field sensing integrated device is provided, comprising: an anchor rod, the anchor rod comprising: a sensing head, a hollow rod body, the sensing head is a hollow cylinder, and is sleeved on the outer surface of the first end of the hollow rod body, the anchor rod is driven into the rock mass so that the sensing head is buried in the rock mass, the sensing head comprises: a distributed optical fiber, a strain sensor, a temperature sensor and a fiber grating sensor, the strain sensor, the temperature sensor and the fiber grating sensor are connected with the distributed optical fiber, and the distributed optical fiber penetrates the hollow rod body and passes out from the second end of the hollow rod body; an iron pipe, the iron pipe is a hollow cylinder, and the iron pipe is sleeved and fixed on the outer surface of the anchor rod; an optical fiber sensor, the optical fiber sensor is fixed on the surface of the iron pipe, and the distributed optical fiber is connected to the optical fiber sensor; a temperature compensation optical fiber, the temperature compensation optical fiber is fixed on the surface of the iron pipe; wherein the sensing head is used to sense changes in physical information inside the rock mass, the iron pipe is used to protect the internal anchor rod, the optical fiber sensor is used to transmit monitoring data, the temperature compensation optical fiber is used to monitor temperature changes, and the hollow rod body is used to lay distributed optical fibers and pour slurry.

[0007] Furthermore, the anchor rod also includes: an oil cylinder, which is in the shape of a hollow ring and is connected to the hollow rod body, and is used to push the anchor rod to fit tightly into the rock mass.

[0008] Furthermore, the distributed optical fiber is arranged at the center of the sensing head, and the strain sensor, the temperature sensor and the fiber grating sensor are evenly arranged around the distributed optical fiber.

[0009] Furthermore, the sensing head also includes: reinforcing ribs, the number of which is greater than two, and the reinforcing ribs are tightly arranged around the distributed optical fiber in the center of the sensing head; a composite rubber protective cover, which is a hollow cylinder and tightly wraps the distributed optical fiber, the reinforcing ribs, the strain sensor, the temperature sensor and the fiber grating sensor; wherein the reinforcing ribs are used to increase the structural strength and stability of the distributed optical fiber, and the composite rubber protective cover is used to protect the inside of the sensing head from damage during the monitoring process.

[0010] Furthermore, the oil cylinder includes: an end cover, which is in a circular ring shape and is located at the top of the oil cylinder; a piston, which is located inside the oil cylinder and fits tightly with the inner wall of the oil cylinder, and the piston can slide axially along the inner wall of the oil cylinder; a sealing ring, which fits tightly with the end cover and the piston; wherein the end cover is used to protect the oil cylinder and prevent leakage of the hydraulic oil in the oil cylinder, the piston is used to control the extension and retraction of the anchor rod, and the sealing ring is used to prevent leakage of the hydraulic oil in the oil cylinder between the end cover and the piston, so as to maintain liquid pressure for the oil cylinder.

[0011] According to another aspect of the present invention, a method for integrated perception of multi-physical fields of rock mass is provided. The method is implemented based on an integrated device for sensing multi-physical fields of rock mass, and the method comprises the following steps:

[0012] Step S1: obtaining the rock mass multi-physics field sensing integrated device, the rock mass multi-physics field sensing integrated device comprising: an anchor rod, the anchor rod comprising: a sensing head, a hollow rod body, and an oil cylinder, installing the anchor rod, installing the sensing head at the first end of the hollow rod body, and installing the oil cylinder at the second end;

[0013] Step S2: drilling a hole on the rock surface, inserting the installed anchor rod into the hole and pouring grout into the hollow rod body for anchoring;

[0014] Step S3: the rock mass multi-physical field sensing integrated device further includes: an optical fiber sensor and a temperature compensation optical fiber, the anchor rod is connected to the optical fiber sensor, the temperature compensation optical fiber is installed, and the optical fiber sensor and the temperature compensation optical fiber are connected to the demodulator;

[0015] Step S4: Collect monitoring data, transmit the data to the backend server for storage, analysis and processing, and generate monitoring reports and early warning information;

[0016] Step S5: Perform intelligent support control based on the physical state changes in the rock mass obtained through monitoring and analysis, and take countermeasures to abnormal situations to achieve precise support and control of the rock mass.

[0017] Further, step S1 includes:

[0018] Step S101: the sensing head includes: a distributed optical fiber, a strain sensor, a temperature sensor, a fiber Bragg grating sensor, a reinforcing rib and a composite rubber protective cover, and the strain sensor, the temperature sensor and the fiber Bragg grating sensor are respectively connected to the distributed optical fiber;

[0019] Step S102: installing reinforcing ribs circumferentially with the distributed optical fiber as the center, the number of the reinforcing ribs being greater than two, and surrounding the strain sensor, the temperature sensor, and the fiber grating sensor at equal intervals on the outside of the reinforcing ribs;

[0020] Step S103: tightly wrap the distributed optical fiber, the reinforcing ribs, the strain sensor, the temperature sensor and the fiber grating sensor with a composite rubber protective cover, install the sensing head at the first end of the hollow rod body, and the distributed optical fiber enters the hollow rod body from the sensing head and exits from the second end of the hollow rod body;

[0021] Step S104: installing an oil cylinder at the second end of the hollow rod body, wherein the oil cylinder comprises an end cover, a piston, and a sealing ring.

[0022] Further, step S3 includes:

[0023] Step S201: the rock mass multi-physical field sensing integrated device further includes: an iron pipe, which is sleeved on the outer surface of the anchor rod to fix the anchor rod and the iron pipe;

[0024] Step S202: installing an optical fiber sensor on the surface of the iron pipe, and connecting the distributed optical fiber passing through the second end of the hollow rod body to the optical fiber sensor;

[0025] Step S203: installing a temperature compensating optical fiber on the surface of the iron pipe, and connecting the optical fiber sensor and the temperature compensating optical fiber to a demodulator.

[0026] The invention provides a rock mass multi-physical field sensing support integrated device and method, the device comprises: an anchor rod, an iron pipe, an optical fiber sensor, and a temperature compensation optical fiber; the anchor rod comprises: a sensing head, a hollow rod body, the sensing head is installed at the first end of the hollow rod body, the anchor rod is driven into the rock mass so that the sensing head is buried in the rock mass, the sensing head comprises: a distributed optical fiber, a strain sensor, a temperature sensor and an optical fiber grating sensor, the strain sensor, the temperature sensor and the optical fiber grating sensor are connected with the distributed optical fiber, the distributed optical fiber penetrates the hollow rod body and passes out from the second end of the hollow rod body; the iron pipe is a hollow cylinder sleeved and fixed on the outer surface of the anchor rod; the optical fiber sensor is fixed on the surface of the iron pipe, the distributed optical fiber is connected with the optical fiber sensor; the temperature compensation optical fiber is fixed on the surface of the iron pipe; thereby, comprehensive sensing of various physical field information of the rock mass is performed, and the problems of insufficient sensitivity of rock mass strain monitoring, single sensing information and complex monitoring system in the prior art are solved, thereby achieving the effect of accurate and real-time comprehensive sensing of various physical field information. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 It is a structural schematic diagram of an optional rock mass multi-physical field sensing integrated device according to an embodiment of the present invention;

[0029] Figure 2 1 is a schematic diagram of an anchor structure of an optional rock mass multi-physical field sensing integrated device according to an embodiment of the present invention;

[0030] Figure 3 is a schematic diagram of the interior of an anchor rod of a rock mass multi-physical field sensing integrated device that can be selected according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of a sensing head of a rock mass multi-physical field sensing integrated device that can be selected according to an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of the oil cylinder structure of an optional rock mass multi-physical field sensing integrated device according to an embodiment of the present invention;

[0033] Figure 6is a schematic diagram of a framework of a rock mass multi-physical field sensing integrated device that can be selected according to an embodiment of the present invention;

[0034] Figure 7 It is a schematic flow chart of the steps of an optional integrated method for multi-physical field perception of rock mass according to an embodiment of the present invention.

[0035] The above drawings include the following reference numerals:

[0036] 10. Anchor rod; 11. Sensing head; 111. Distributed optical fiber; 112. Strain sensor; 113. Temperature sensor; 114. Fiber Bragg grating sensor; 115. Reinforcement rib; 116. Composite rubber protective cover; 12. Hollow rod body; 13. Oil cylinder; 131. End cover; 132. Piston; 133. Sealing ring; 20. Iron pipe; 30. Optical fiber sensor; 40. Temperature compensation optical fiber. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0038] The present invention provides a rock mass multi-physical field sensing integrated device, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, it includes: an anchor rod 10, an iron pipe 20, an optical fiber sensor 30, and a temperature compensation optical fiber 40; the anchor rod 10 includes: a sensing head 11, a hollow rod body 12, the sensing head 11 is a hollow cylinder, and is sleeved on the outer surface of the first end of the hollow rod body 12. The anchor rod 10 is driven into the rock mass so that the sensing head 11 is buried in the rock mass. The sensing head 11 includes: a distributed optical fiber 111, a strain sensor 112, a temperature sensor 113 and a fiber grating sensor 114, and the strain sensor 112, the temperature sensor 113 and the fiber grating sensor 114 are connected to the distributed optical fiber 111. The distributed optical fiber 111 is connected, and the distributed optical fiber 111 penetrates the hollow rod body 12 and passes through the second end of the hollow rod body 12; the iron pipe 20 is a hollow cylinder, and the iron pipe 20 is sleeved and fixed on the outer surface of the anchor rod 10; the optical fiber sensor 30 is fixed on the surface of the iron pipe 20, and the distributed optical fiber 111 is connected to the optical fiber sensor 30; the temperature compensation optical fiber 40 is fixed on the surface of the iron pipe 20; thereby, a comprehensive perception of various physical field information of the rock mass is performed to solve the problems of insufficient sensitivity of rock mass strain monitoring, single perception information and complex monitoring system in the prior art.

[0039] Specifically, the hollow rod body 12 can withstand the complex stress environment inside the rock mass. The hollow design is used for laying distributed optical fibers 111 and pouring slurry. The sensing head 11 is used to sense changes in physical information inside the rock mass. The iron pipe 20 is used to protect the inside of the anchor rod 10 and buffer external shocks and vibrations. The distributed optical fiber 111 is connected to the optical fiber sensor 30. Through the highly sensitive optical fiber transmission technology, the strain and temperature change data inside the rock mass are transmitted to the monitoring system in real time to ensure the timeliness and accuracy of the data. The temperature compensation optical fiber 40 is used to monitor temperature changes in real time, and the change data is recorded to compensate for errors caused by temperature, thereby ensuring the accuracy of the data measured by the sensing head 11.

[0040] Furthermore, if Figure 2 As shown, the anchor rod 10 also includes: a cylinder 13, which is a hollow ring shape and is connected to the hollow rod body 12. The cylinder 13 pushes the anchor rod 10 through hydraulic pressure so that it can contact the rock more closely, thereby improving the monitoring accuracy of the anchor rod 10. The distributed optical fiber 111 enters the hollow rod body 12 from the sensing head 11 and passes through the second end of the hollow rod body 12.

[0041] Furthermore, if Figure 3 As shown, epoxy resin and curing agent are used to fix the distributed optical fiber 111 inside the hollow rod body 12. This fixing method can maximize the protection of the distributed optical fiber 111, allowing it to be completely embedded in the hollow rod body 12, and through complete coupling, reduce the impact of various external complex factors in the surrounding rock tunnel on the optical fiber.

[0042] In the specific implementation, the anchor rod 10 is installed by anchor support technology. For the tunnel position that needs to be supported, a professional drilling rig or other hole drilling equipment is used to drill holes of a certain diameter and depth in the rock mass. The position, number and spacing of the holes are determined according to the engineering design and actual geological conditions. The gravel, mud and other debris in the drilled holes are cleaned to improve the installation efficiency and support effect of the subsequent anchor rod 10, and ensure that the anchor rod 10 can be firmly embedded in the hole and form a good combination with the surrounding rock and soil. When burying the anchor rod 10 in the hole, threaded steel bars or steel pipes with good strength and durability are usually selected as anchor rod materials. The length of the anchor rod 10 generally needs to be determined according to the geological conditions and support design. When burying, it is necessary to ensure that one end of the anchor rod 10 can be firmly fixed deep in the hole to ensure the firmness and stability of the support; and the other end needs to be exposed to the ground for subsequent tensioning and connection operations. When the anchor rod 10 is tensioned, the anchor rod 10 is subjected to a certain tensile force to form a closer bond with the surrounding rock and soil, thereby increasing the force bearing capacity and support effect of the anchor rod 10. The special tensioning equipment will apply force to cause the anchor rod 10 to produce a certain tensile deformation, so that it can ensure that a close friction or bonding force is formed between the anchor rod 10 and the surrounding rock and soil, thereby enhancing the stability and bearing capacity of the anchor rod 10. Then the anchor rod 10 is connected to a solid body, which is usually a steel beam, a concrete wall or other structure with a certain strength and stability to enhance the support effect. The anchor rod 10 is tightly connected to the solid body by threaded connection or welding, and the force of the anchor rod 10 is effectively transferred to the solid body. Finally, the anchor support system is regularly monitored and maintained, problems are discovered in time, and corresponding repair and reinforcement measures are taken to ensure that the anchor support system is always in a good working condition, which is conducive to improving the safety and stability of the tunnel and ensuring the normal operation of the mine production.

[0043] Furthermore, if Figure 4 As shown, the distributed optical fiber 111 is disposed at the center of the sensing head 11 , and the strain sensor 112 , the temperature sensor 113 and the fiber grating sensor 114 are evenly arranged around the distributed optical fiber 111 .

[0044] Furthermore, the sensing head 11 also includes: reinforcing ribs 115, the number of the reinforcing ribs 115 is greater than two, and the reinforcing ribs 115 are tightly arranged around the distributed optical fiber 111 in the center of the sensing head 11; a composite rubber protective cover 116, the composite rubber protective cover 116 is a hollow cylinder, tightly wrapping the distributed optical fiber 111, the reinforcing ribs 115, the strain sensor 112, the temperature sensor 113 and the fiber grating sensor 114; wherein the reinforcing ribs 115 are used to increase the structural strength and stability of the distributed optical fiber 111, the composite rubber protective cover 116 is used to protect the inside of the sensing head 11 from damage during the monitoring process, the reinforcing ribs 115 are made of high-strength material, which can effectively prevent the distributed optical fiber 111 in the center of the sensing head 11 from deformation or damage during installation and use, and the composite rubber protective cover 116 has good flexibility and wear resistance, and can protect the internal sensor from external factors in harsh environments.

[0045] Furthermore, if Figure 5 As shown, the oil cylinder 13 includes: an end cover 131, which is annular and located at the top of the oil cylinder 13; a piston 132, which is located inside the oil cylinder 13 and fits tightly with the inner wall of the oil cylinder 13, and the piston 132 can slide axially along the inner wall of the oil cylinder 13; a sealing ring 133, which fits tightly with the end cover 131 and the piston 132; wherein the end cover 131 is used to protect the oil cylinder 13 and prevent the hydraulic oil in the oil cylinder 13 from leaking, the piston 132 is used to accurately control the extension and retraction of the anchor rod 10, and the sealing ring 133 is made of high-strength material and is used to prevent the hydraulic oil in the oil cylinder 13 from leaking between the end cover 131 and the piston 132, so as to maintain liquid pressure for the oil cylinder 13.

[0046] Specifically, the strain sensor 112 is used to monitor the stress changes of the rock mass to ensure accurate perception of the stress and strain state inside the rock mass. The temperature sensor 113 is used to monitor the temperature changes inside the rock mass and provide real-time temperature data. The fiber grating sensor 114 is used to perform high-precision stress and temperature perception to provide more accurate data for rock mass monitoring. The distributed optical fiber 111 is arranged at the center of the sensing head 11, and the reinforcement ribs 115 are closely arranged around the distributed optical fiber 111, so that the distributed optical fiber 111 has better structural strength and stability, and can still work normally when the three peripheral sensors are damaged, thereby providing guarantee for monitoring work.

[0047] In specific implementation, the strain sensor 112 and the distributed optical fiber 111 both use stimulated Brillouin optical time-domain scattering technology or stimulated Brillouin optical time-domain reflection technology in the distributed optical fiber sensing technology for monitoring.

[0048] Specifically, the stimulated Brillouin optical time-domain scattering technology uses the optical fiber itself as a sensing element. When the optical fiber under test is subjected to external force or temperature changes, backward stimulated Brillouin scattering excites longitudinal acoustic waves in the optical fiber. The frequency difference between the scattered light and the incident light is defined as the Brillouin frequency shift. The Brillouin frequency shift is a function of the temperature and strain of the optical fiber. The temperature and strain changes inside the rock mass are detected by measuring the changes in the Brillouin frequency shift.

[0049] The change in Brillouin frequency shift with temperature and strain is:

[0050] Δε=[ΔV B -C1ΔT] / C2

[0051] Where Δε is the strain change; ΔV B is the Brillouin frequency shift, MHz; C1 is the temperature sensitivity coefficient, MHz / ℃; ΔT is the temperature change, ℃; C2 is the strain sensitivity coefficient, 103GHz. For single-mode optical fiber, the temperature and stress coefficients are approximately 1.07MHz / ℃ and 0.05MHz / με, respectively.

[0052] Specifically, stimulated Brillouin optical time-domain reflectometry utilizes the property that the frequency and power of Brillouin spontaneous scattered light are proportional to the temperature and strain in the optical fiber. By measuring the frequency drift of the back-scattered spontaneous Brillouin light in the optical fiber, the distribution information of temperature and strain along the optical fiber is obtained.

[0053] In specific implementation, the temperature sensor 113 uses optical frequency domain reflection technology, which can obtain the Rayleigh scattering information of the entire optical fiber, and invert the temperature distribution of each position of the optical fiber by measuring the position and intensity change of the scattered signal. The optical fiber sensor is arranged in the structure to be tested, and the optical fiber and the object to be tested are bonded to make them deform in coordination. The temperature distribution of the test optical fiber can reflect the temperature distribution of the object to be tested to realize sensing measurement. During measurement, the laser based on the coherent detection technology of optical continuous frequency modulated wave emits linear frequency sweep light, which is divided into two paths through the coupler: one path enters the measuring optical fiber and generates Rayleigh scattered light to return; the other path enters the reference optical fiber and returns through the reflector. The two backscattered lights are combined by the coupler and enter the photodetector to meet the coherence condition, realizing the conversion of optical signal to electrical signal.

[0054] The frequency of the laser can be expressed as υ=υ0+γt, where υ0 is the starting optical frequency and γ is the frequency sweep slope. Then the phase of the laser output optical signal is:

[0055]

[0056] in is the initial phase of the light source.

[0057] The light signal emitted by the light source can be expressed as:

[0058]

[0059] Where E0 is the light signal intensity of the light source.

[0060] The beat frequency of the Rayleigh scattered light signal at the distance coupler on the test fiber can be expressed as:

[0061]

[0062] Where t0 is the time delay of the measured signal returning from x0 to the coupler, and n is the refractive index of the test fiber.

[0063] Assuming the Rayleigh scattering coefficient of the test fiber is α0, the current obtained after mixing in the photodetector can be expressed as:

[0064]

[0065] The phase difference The beat frequency is ω b =2πf b =2πγt. From the beat frequency formula, we know that the frequency f b The delay is proportional to the scattering position on the test optical fiber. By using a spectrum analyzer to analyze the beat frequency signal spectrum, the position and intensity information of the optical signal in the optical fiber can be directly obtained, thereby obtaining the optical frequency domain reflection distance domain and reflectivity curve.

[0066] In specific implementation, the fiber grating sensor 114 uses fiber grating technology, which forms a micro-nano periodic structure in the fiber core, generates a periodic refractive index distribution through ultraviolet exposure, and forms a narrow-band reflection filter of a specific wavelength. When the external temperature or stress changes, the grating area length or effective refractive index of the fiber grating will change, causing the central wavelength to move, thereby reflecting the changes in external strain and temperature by measuring the translation of the central wavelength.

[0067] According to the optical waveguide mode coupling theory, the reflection wavelength of the fiber grating satisfies the following relationship with the effective refractive index of the fiber core and the grating period:

[0068] λ B =2Λn eff

[0069] Where: n eff is the effective refractive index of the fiber core, and Λ is the fiber grating period. Fiber gratings are sensitive to both temperature and strain. Therefore, when the temperature changes, the effect of the temperature change ΔT and the effect caused by the thermal expansion effect in the grating area, n eff and Λ will change accordingly, and then the central wavelength of the fiber Bragg grating will change. The change is:

[0070] Where: α represents the thermal expansion coefficient of the optical fiber, α = 5.5 × 10 -7 / ℃; ε is the thermo-optical coefficient of the optical fiber material, ε=6.4×10 -6 / ℃.

[0071] Therefore, the temperature sensitivity K of the fiber Bragg grating is t for:

[0072]

[0073] Since fiber Bragg gratings are sensitive to both temperature and strain, if they are not packaged properly, long-distance distributed fiber Bragg grating arrays are prone to fiber Bragg grating stress. For strain effects, the reflection wavelength of the fiber Bragg grating changes as follows:

[0074]

[0075] Δò=(α s -α)ΔT

[0076] Where P e is the effective elastic-optical coefficient of the fiber Bragg grating, P e =0.22; Δò is the axial strain of the fiber Bragg grating; α s is the thermal expansion coefficient of the metal capillary, α s =17.2×10 -6 / ℃. At this time, the fiber Bragg grating is a component that is sensitive to both strain and temperature. The formula for the change of the Bragg grating reflection wavelength with temperature is:

[0077]

[0078] In specific implementation, the optical fiber sensor and the temperature compensation optical fiber will be connected to the demodulator for monitoring data analysis. The stimulated Brillouin optical time-domain scattering analyzer adopts pre-pumped Brillouin optical time-domain analysis technology, with a spatial resolution of 0.05-1m and a spatial sampling distance of 1cm. It uses ordinary single-mode optical fiber for strain and temperature measurement with an accuracy of 15με / 0.75℃. The stimulated Brillouin optical time-domain reflectometer has a spatial resolution of 1m, a test range of 0.5-128Km, a minimum sampling interval of 5cm, a strain accuracy of ±50εμ, a range of -3-4%, supports single-ended measurement, and has strong adaptability.

[0079] Fiber Bragg Grating data acquisition uses a portable high-frequency dynamic fiber Bragg grating demodulator, which has static and dynamic full-spectrum analysis functions, a maximum of 4 channels, and a bandwidth of 160nm, suitable for connecting hundreds of sensors. Its high-power, low-noise scanning laser light source ensures wavelength accuracy, with a maximum test accuracy of 1pm, a scanning frequency of 5KHz, and a measurement range of 1500-1580nm, suitable for data acquisition on engineering sites.

[0080] Distributed temperature data acquisition uses a distributed fiber optic test system with optical frequency domain reflection technology. The spatial resolution can reach up to 0.64mm and the maximum measurement length is 120m. It has short-distance and high-precision measurement capabilities and can achieve fully distributed millimeter-level high-precision strain measurement.

[0081] Figure 6 It is a schematic diagram of the framework of an optional integrated device for multi-physical field sensing of rock mass according to an embodiment of the present invention. During support and sensing, the temperature sensor 113 monitors the temperature change inside the rock mass through optical frequency domain reflection technology and provides real-time temperature data. The strain sensor 112 monitors the stress change of the rock mass through stimulated Brillouin time-domain scattering / reflection technology and accurately senses the stress and strain state inside the rock mass. The fiber grating sensor 114 performs high-precision stress and temperature sensing through fiber grating technology and provides more accurate data for rock mass monitoring.

[0082] Furthermore, after the temperature sensor 113, strain sensor 112 and fiber Bragg grating sensor 114 sense the signal data, they are demodulated by a demodulator, and then the demodulated data is transmitted to a dedicated data acquisition and processing system to collect, process and analyze the data of the fiber optic sensor in real time. The monitoring data is transmitted to the background server through the data acquisition and processing unit for storage and analysis, and a monitoring report and early warning information are generated. The system integrates multi-physical field information display and is equipped with an intelligent support control system to automatically adjust and control the support equipment according to the monitored physical information.

[0083] Furthermore, through the intelligent analysis algorithm developed based on the perception data, real-time monitoring, analysis and early warning of the multi-physical field parameters of the rock mass can be achieved. When the optical fiber senses the strain or temperature change, it will feedback the information to the intelligent support system, detect the abnormality in time and take corresponding measures, so as to achieve accurate support and control of the surrounding rock.

[0084] Furthermore, the intelligent support system can be monitored and managed through a user-friendly human-computer interaction interface, providing intuitive data display, intelligent analysis results and early warning information. Users can view environmental monitoring data in real time through this interface, which facilitates real-time monitoring and operation by personnel on the well, and improves the guidance ability of coal mine safety production.

[0085] This implementation scheme achieves efficient management and regulation of the environment through comprehensive monitoring and intelligent analysis of temperature, light and response signals, provides a convenient user interaction experience, and is suitable for smart homes, offices and other places that require environmental monitoring.

[0086] Figure 7is a flow chart of a method for integrated perception of multiple physical fields of rock mass which can be selected according to an embodiment of the present invention. The present invention also provides a method for integrated perception of multiple physical fields of rock mass, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the method includes:

[0087] Step S1: obtaining the rock mass multi-physical field sensing integrated device, the rock mass multi-physical field sensing integrated device comprising: an anchor rod 10, the anchor rod 10 comprising: a sensing head 11, a hollow rod body 12, and an oil cylinder 13, installing the anchor rod 10, installing the sensing head 11 at the first end of the hollow rod body 12, and installing the oil cylinder 13 at the second end;

[0088] Among them, the sensing head 11 is used to sense the multi-physical field of the rock mass, the hollow rod body 12 is used to place the distributed optical fiber and inject grout, and the oil cylinder 13 is used to push the anchor rod 10 through hydraulic pressure so that it can be in closer contact with the rock mass, thereby improving the monitoring accuracy of the anchor rod 10;

[0089] Step S2: drilling a hole on the surface of the rock mass, inserting the installed anchor rod 10 into the hole and pouring grout into the hollow rod body 12 for anchoring;

[0090] The borehole provides an embedding space for the anchor rod 10, so that it can penetrate into the rock mass. The anchor rod 10 can be firmly fixed in the borehole by pouring grout into the hollow anchor rod 10, ensuring that the anchor rod 10 will not move during the monitoring process, thereby providing a stable working environment for the sensing head 11.

[0091] Step S3: the integrated rock mass multi-physical field sensing device further includes: an optical fiber sensor 30, a temperature compensation optical fiber 40, connecting the anchor rod 10 with the optical fiber sensor 30, installing the temperature compensation optical fiber 40, and connecting the optical fiber sensor 30 and the temperature compensation optical fiber 40 with a demodulator;

[0092] The optical fiber sensor 30 is used to transmit the monitored physical changes such as stress and temperature inside the rock mass, and the temperature compensation optical fiber 40 is used to compensate for the data error caused by temperature change to ensure the accuracy of the data. The optical fiber sensor 30 and the temperature compensation optical fiber 40 are connected to the demodulator to collect and analyze the monitored data, providing a basis for subsequent support decisions.

[0093] Step S4: Collect monitoring data, transmit the data to the backend server for storage, analysis and processing, and generate monitoring reports and early warning information;

[0094] The system continuously collects and transmits monitoring data from inside the rock mass, generates monitoring reports after storing and analyzing the data through the backend server, and issues warning information when the data is abnormal, so as to timely discover potential safety hazards;

[0095] Step S5: Perform intelligent support control according to the physical state changes in the rock mass obtained through monitoring and analysis, and take countermeasures for abnormal situations to achieve accurate support and control of the rock mass;

[0096] Among them, intelligent support control can take corresponding support measures after discovering safety hazards to prevent the rock structure from becoming unstable or collapsing, thereby ensuring the safety of the project and personnel.

[0097] Further, step S1 includes:

[0098] Step S101: the sensing head 11 comprises: a distributed optical fiber 111, a strain sensor 112, a temperature sensor 113, a fiber Bragg grating sensor 114, a reinforcing rib 115, and a composite rubber protective cover 116, and the strain sensor 112, the temperature sensor 113 and the fiber Bragg grating sensor 114 are connected to the distributed optical fiber 111 respectively;

[0099] Among them, connecting multiple sensors to the distributed optical fiber 111 can simplify the structure, reduce the complexity of wiring, and improve the efficiency and accuracy of data transmission;

[0100] Step S102: installing reinforcing ribs 115 circumferentially around the distributed optical fiber 111, the number of reinforcing ribs 115 being greater than two, and surrounding and arranging the strain sensor 112, the temperature sensor 113, and the fiber grating sensor 114 at equal intervals on the outside of the reinforcing ribs 115;

[0101] Among them, the structural strength of the distributed optical fiber 111 is improved by closely arranging the reinforcing ribs 115 in the circumferential direction. Even if the three peripheral sensors are damaged, the central distributed optical fiber 111 can still monitor normally, providing guarantee for the monitoring of the physical state of the rock mass and improving the continuity and reliability of data monitoring.

[0102] Step S103: tightly wrap the distributed optical fiber 111, the reinforcing rib 115, the strain sensor 112, the temperature sensor 113 and the fiber grating sensor 114 with the composite rubber protective cover 116, install the sensing head 11 at the first end of the hollow rod body 12, and the distributed optical fiber 111 enters the hollow rod body 12 from the sensing head 11 and passes through the second end of the hollow rod body 12;

[0103] The composite rubber protective sleeve 116 is used to tightly wrap the sensing head 11 to strengthen the protection of the internal components. It effectively prevents the external environment from damaging the sensor and optical fiber, such as moisture, corrosion and mechanical damage. The distributed optical fiber 111 is not only a guarantee for data monitoring, but also a channel for data transmission. By connecting the three sensors, the monitoring data is transmitted to the optical fiber sensor 30;

[0104] Step S104: installing the oil cylinder 13 at the second end of the hollow rod body 12, the oil cylinder 13 comprising: an end cover 131, a piston 132, and a sealing ring 133;

[0105] Among them, the end cover 131, the piston 132 and the sealing ring 133 are key components of the oil cylinder 13, which are respectively used to close the oil cylinder 13, provide hydraulic power and prevent leakage.

[0106] Further, step S3 includes:

[0107] Step S301: the rock mass multi-physical field sensing integrated device further includes: an iron pipe 20, the iron pipe 20 is sleeved on the outer surface of the anchor rod 10, and the anchor rod 10 and the iron pipe 20 are fixed;

[0108] The iron pipe 20 provides additional protection for the anchor rod 10, protecting it from the influence of external environment such as mechanical damage and corrosion, and enhancing the durability of the anchor rod 10. Fixing the anchor rod 10 to the iron pipe 20 ensures that it will not loosen or shift during the working process, providing a reliable guarantee for the subsequent monitoring work.

[0109] Step S302: Install the optical fiber sensor 30 on the surface of the iron pipe 20, and connect the distributed optical fiber 111 passing through the second end of the hollow rod body 12 to the optical fiber sensor 30;

[0110] The distributed optical fiber 111 is connected with the optical fiber sensor 30 to establish a data transmission channel, which can timely and accurately transmit the data of the change of the physical state of the rock mass monitored by the three sensors in the sensing head 11;

[0111] Step S303: installing the temperature compensation optical fiber 40 on the surface of the iron pipe 20, and connecting the optical fiber sensor 30 and the temperature compensation optical fiber 40 to the demodulator;

[0112] The temperature compensation optical fiber 40 can compensate for the influence of temperature change on data measurement and ensure the accuracy of the measured data. The optical fiber sensor 30 and the temperature compensation optical fiber 40 are connected to the demodulator to process and analyze the collected data to provide accurate data support for rock mass monitoring.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A rock mass multi-physical field sensing integrated device, characterized in that: The device comprises: An anchor rod (10), the anchor rod (10) comprising: a sensing head (11) and a hollow rod body (12), the sensing head (11) being a hollow cylinder and sleeved on the outer surface of the first end of the hollow rod body (12), the anchor rod (10) being driven into a rock mass so that the sensing head (11) is buried in the rock mass, the sensing head (11) comprising: a distributed optical fiber (111), a strain sensor (112), a temperature sensor (113) and a fiber grating sensor (114), the strain sensor (112), the temperature sensor (113) and the fiber grating sensor (114) being connected to the distributed optical fiber (111), and the distributed optical fiber (111) passing through the hollow rod body (12) and passing out from the second end of the hollow rod body (12); An iron pipe (20), wherein the iron pipe (20) is a hollow cylinder and is sleeved and fixed on the outer surface of the anchor rod (10); An optical fiber sensor (30), the optical fiber sensor (30) being fixed to the surface of the iron pipe (20), and the distributed optical fiber (111) being connected to the optical fiber sensor (30); A temperature compensation optical fiber (40), wherein the temperature compensation optical fiber (40) is fixed to the surface of the iron pipe (20); The sensing head (11) is used to sense changes in physical information inside the rock mass, the iron pipe (20) is used to protect the anchor rod (10), the optical fiber sensor (30) is used to transmit monitoring data, the temperature compensation optical fiber (40) is used to monitor temperature changes, and the hollow rod body (12) is used to lay the distributed optical fiber (111) and inject grout.

2. The rock mass multi-physical field sensing integrated device according to claim 1 is characterized in that: The anchor rod (10) further comprises: The oil cylinder (13) is in the shape of a hollow ring and is connected to the hollow rod body (12) and is used to push the anchor rod (10) to fit tightly into the rock mass.

3. The rock mass multi-physical field sensing integrated device according to claim 1 is characterized in that: The distributed optical fiber (111) is arranged at the center of the sensing head (11), and the strain sensor (112), the temperature sensor (113) and the fiber grating sensor (114) are evenly arranged around the distributed optical fiber (111).

4. The rock mass multi-physical field sensing integrated device according to claim 1 is characterized in that: The sensing head (11) further comprises: Reinforcing ribs (115), the number of the reinforcing ribs (115) being greater than two, and the reinforcing ribs being closely arranged around the distributed optical fiber (111) at the center of the sensing head (11); A composite rubber protective sleeve (116), wherein the composite rubber protective sleeve (116) is in the form of a hollow cylinder and tightly wraps the distributed optical fiber (111), the reinforcing rib (115), the strain sensor (112), the temperature sensor (113), and the fiber grating sensor (114); The reinforcing ribs (115) are used to increase the structural strength and stability of the distributed optical fiber (111), and the composite rubber protective sleeve (116) is used to protect the interior of the sensing head (11) from damage during the monitoring process.

5. The rock mass multi-physical field sensing integrated device according to claim 2, characterized in that: The oil cylinder comprises: An end cover (131), the end cover (131) is annular and is located at the top of the oil cylinder (13); A piston (132), wherein the piston (132) is located inside the oil cylinder (13) and is tightly fitted to the inner wall of the oil cylinder (13), and the piston (132) is capable of axially sliding along the inner wall of the oil cylinder (13); A sealing ring (133), wherein the sealing ring (133) is tightly fitted with the end cover (131) and the piston (132); The end cover (131) is used to protect the oil cylinder (13) and prevent the hydraulic oil in the oil cylinder (13) from leaking; the piston (132) is used to control the extension and retraction of the anchor rod (10); and the sealing ring (133) is used to prevent the hydraulic oil in the oil cylinder (13) from leaking between the end cover (131) and the piston (132), thereby maintaining liquid pressure for the oil cylinder (13).

6. A method for integrated perception of rock mass multi-physical fields, characterized in that: The method is applied to the device according to any one of claims 1 to 5, comprising the following steps: Step S1: obtaining the rock mass multi-physical field sensing integrated device, the rock mass multi-physical field sensing integrated device comprising: an anchor rod (10), the anchor rod (10) comprising: a sensing head (11), a hollow rod body (12), and an oil cylinder (13), installing the anchor rod (10), installing the sensing head (11) at the first end of the hollow rod body (12), and installing the oil cylinder (13) at the second end; Step S2: drilling a hole on the surface of the rock mass, inserting the installed anchor rod (10) into the hole and pouring grout into the hollow rod body (12) for anchoring; Step S3: the rock mass multi-physical field sensing integrated device further comprises: an optical fiber sensor (30) and a temperature compensation optical fiber (40); the anchor rod (10) is connected to the optical fiber sensor (30); the temperature compensation optical fiber (40) is installed; and the optical fiber sensor (30) and the temperature compensation optical fiber (40) are connected to a demodulator; Step S4: Collect monitoring data, transmit the data to the backend server for storage, analysis and processing, and generate monitoring reports and early warning information; Step S5: Perform intelligent support control based on the physical state changes in the rock mass obtained through monitoring and analysis, and take countermeasures to abnormal situations to achieve precise support and control of the rock mass.

7. The rock mass multi-physical field sensing integrated method according to claim 6 is characterized in that: The step S1 comprises: Step S101: the sensing head (11) comprises: a distributed optical fiber (111), a strain sensor (112), a temperature sensor (113), a fiber Bragg grating sensor (114), a reinforcing rib (115) and a composite rubber protective cover (116), and the strain sensor (112), the temperature sensor (113) and the fiber Bragg grating sensor (114) are respectively connected to the distributed optical fiber (111); Step S102: The reinforcing ribs (115) are installed circumferentially with the distributed optical fiber (111) as the center, the number of the reinforcing ribs (115) is greater than two, and the strain sensor (112), the temperature sensor (113) and the fiber grating sensor (114) are arranged on the outside of the reinforcing ribs (115) at equal intervals to surround each other; Step S103: tightly wrapping the distributed optical fiber (111), the reinforcing rib (115), the strain sensor (112), the temperature sensor (113) and the fiber grating sensor (114) with the composite rubber protective sleeve (116), installing the sensing head (11) on the first end of the hollow rod body (12), and the distributed optical fiber (111) enters the hollow rod body (12) from the sensing head (11) and passes through the second end of the hollow rod body (12); Step S104: installing the oil cylinder (13) at the second end of the hollow rod body (12), wherein the oil cylinder (13) comprises an end cover (131), a piston (132), and a sealing ring (133).

8. The rock mass multi-physical field perception integrated method according to claim 6, characterized in that: The step S3 comprises: Step S301: the rock mass multi-physical field sensing integrated device further comprises: an iron pipe (20), the iron pipe (20) is sleeved on the outer surface of the anchor rod (10), and the anchor rod (10) and the iron pipe (20) are fixed; Step S302: installing the optical fiber sensor (30) on the surface of the iron pipe (20), and connecting the distributed optical fiber (111) extending from the second end of the hollow rod body (12) to the optical fiber sensor (30); Step S303: installing the temperature compensating optical fiber (40) on the surface of the iron pipe (20), and connecting the optical fiber sensor (30) and the temperature compensating optical fiber (40) to a demodulator.

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