Deep rock mass three-dimensional ground stress measuring device and method

Abstract

The present disclosure provides a deep rock mass three-dimensional ground stress measuring device and method, and relates to the technical field of geological surveying. The device comprises: a stress gauge integrated with a distributed optical fiber sensor and a three-dimensional electronic compass is installed at a predetermined depth in a borehole; the azimuth and inclination of the borehole are automatically obtained through the three-dimensional electronic compass; the reflected wavelength data is collected through the distributed optical fiber sensor before and after the full stress release operation on the borehole wall surface; the wavelength data and the directional data are transmitted to a data processing unit, which automatically calculates and outputs the three-dimensional ground stress tensor and the principal stress in the geodetic coordinate system according to the principle of full stress release of the local borehole wall surface. Thus, the problems of low efficiency, large error and difficulty in realizing multi-point synchronous in-situ monitoring caused by the complicated manual installation, the dependence on external equipment for posture measurement and the limitations of single-point measurement in the traditional method are solved, and the full-process automatic, high-precision and expandable three-dimensional ground stress in-situ measurement is realized.

Description

Technical Field

[0001] This disclosure relates to the field of geological surveying technology, and in particular to a device and method for measuring three-dimensional geostress in deep rock masses. Background Technology

[0002] In-situ measurement of three-dimensional geostress in deep rock masses is crucial for ensuring the safety of underground engineering projects. The Borehole Wall Stress Relief Method (BWSRM) is an in-situ testing technique suitable for deep boreholes, but its engineering application still faces significant bottlenecks. Traditional strain gauge sensors are cumbersome to install, susceptible to interference, and struggle to achieve high-precision, distributed strain measurement in deep boreholes. Borehole attitude (azimuth and dip) largely relies on manual measurement, introducing errors and resulting in low efficiency. Furthermore, most existing devices perform single-point measurements, failing to meet the urgent need for simultaneous monitoring of three-dimensional geostress at multiple depths in deep, long boreholes. Therefore, there is an urgent need for a deep rock mass three-dimensional geostress measurement equipment capable of automated, high-precision, and multi-point synchronous measurement. Summary of the Invention

[0003] This disclosure aims to at least partially address one of the technical problems in the related art.

[0004] Therefore, the first aspect of this disclosure provides a three-dimensional geostress measurement device for deep rock masses, comprising:

[0005] At least one stress gauge, wherein the stress gauge has a cylindrical structure;

[0006] A distributed optical fiber sensing system includes at least one set of optical fiber sensors, which are disposed on the outer surface of the stress gauge. Each set includes at least multiple measurement points in different directions for acquiring reflected wavelengths and wavelengths affected by temperature.

[0007] A three-dimensional orientation system, integrated on the stress gauge, is used to automatically measure the orientation data of the stress gauge in the borehole;

[0008] The data processing unit is communicatively connected to the distributed optical fiber sensing system and the three-dimensional orientation system. It is used to receive the reflected wavelength, the temperature-affected wavelength, and the orientation data, and to determine the three-dimensional stress tensor and three-dimensional principal stress in the geodetic coordinate system based on the reflected wavelength, the temperature-affected wavelength, the orientation data, and the principle of the borehole local wall stress complete relief method.

[0009] In some embodiments of this disclosure, the distributed optical fiber sensing system includes at least three sets of optical fiber sensors arranged at equal intervals along the circumferential direction of the outer surface of the stress gauge cylinder, each set including at least three measurement points.

[0010] In some embodiments of this disclosure, the measurement points in each group of fiber optic sensors measure directions that are 0°, 45°, and 90° to the horizontal, respectively.

[0011] In some embodiments of this disclosure, the three-dimensional orientation system is a three-dimensional electronic compass, which is fixedly installed on one end face of the stress meter for real-time measurement of the orientation data. The orientation data includes yaw angle, pitch angle and roll angle, so as to obtain the azimuth and inclination angle of the borehole through coordinate transformation.

[0012] In some embodiments of this disclosure, the deep rock mass three-dimensional geostress measurement device includes: multiple stress gauges, which are arranged in series at different depths within the same borehole via a connecting structure, and the distributed optical fiber sensing system and three-dimensional orientation system of each stress gauge are communicatively connected to the data processing unit.

[0013] In some embodiments of this disclosure, the data processing unit is specifically used for:

[0014] The three-dimensional strain tensor of multiple measurement points on the borehole wall is determined by acquiring the reflected wavelength, the temperature-affected wavelength, and calibration parameters collected by the distributed optical fiber sensing system before and after stress relief.

[0015] Based on the principle of the method for complete relief of local wall stress in boreholes, the three-dimensional stress tensor in the borehole coordinate system is obtained by using the three-dimensional strain tensor and solving it by the least squares method.

[0016] Based on the orientation data measured by the three-dimensional orientation system, a transformation matrix from the borehole coordinate system to the geodetic coordinate system is constructed;

[0017] The three-dimensional stress tensor is transformed to a geodetic coordinate system using the transformation matrix.

[0018] The magnitude and direction of the three-dimensional principal stresses are determined based on the three-dimensional stress tensor in the geodetic coordinate system.

[0019] A second aspect of this disclosure provides a method for measuring three-dimensional geostress in deep rock masses, employing the measuring apparatus described in the first aspect above, comprising:

[0020] The stress gauge is integrated and calibrated in the factory, a distributed fiber optic sensing system is set on the surface of the stress gauge, and a three-dimensional electronic compass is installed.

[0021] Drilling target boreholes at the construction site;

[0022] Install the integrated stress gauge to the predetermined depth inside the borehole and ensure that it fits snugly against the borehole wall;

[0023] The three-dimensional electronic compass is activated to automatically acquire and record the orientation data of the stress gauge's location;

[0024] Before performing a full stress relief operation on the borehole wall, the initial reflection wavelength and the initial wavelength affected by temperature are collected by the distributed optical fiber sensing system.

[0025] The stress was completely relieved in a local area of ​​the borehole wall where the stress gauge was installed using a ring drill bit, and the reflected wavelength and temperature-affected wavelength after the stress was relieved were collected by the distributed optical fiber sensing system.

[0026] The collected orientation data, initial reflection wavelength, initial wavelength affected by temperature, reflection wavelength after removal, and wavelength affected by temperature after removal are transmitted to the data processing unit.

[0027] The data processing unit, based on the received directional data, initial reflection wavelength, initial wavelength of temperature influence, reflection wavelength after removal, and wavelength of temperature influence after removal, executes the geostress calculation steps of the aforementioned first aspect-related embodiments, and outputs the three-dimensional stress tensor and three-dimensional principal stress in the geodetic coordinate system.

[0028] In some embodiments of this disclosure, by connecting multiple stress gauges in series and arranging them at different depths in the same borehole, the three-dimensional geostress at multiple depth points can be measured simultaneously in a single operation.

[0029] The deep rock mass three-dimensional geostress measurement device disclosed herein directly mounts a distributed fiber optic sensing system onto the surface of a stress gauge and integrates a three-dimensional orientation system. This enables high-precision, distributed measurement of strain changes on the borehole wall, effectively improving the sensitivity of strain acquisition and its resistance to environmental interference. It automatically and in real-time acquires the azimuth and dip angles of the borehole, ensuring the accuracy of stress data conversion to the geodetic coordinate system and avoiding the errors and cumbersome operations associated with traditional manual measurements. The data processing unit synchronously receives strain and orientation data and automatically performs three-dimensional stress tensor calculation and coordinate transformation based on the principle of complete stress relief on the local borehole wall, directly outputting the magnitude and direction of the three-dimensional principal stresses in the geodetic coordinate system. This integrated device achieves full automation from in-situ data acquisition and attitude positioning to stress calculation, significantly improving the accuracy, efficiency, and reliability of deep rock mass geostress measurement.

[0030] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0031] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which:

[0032] Figure 1 A schematic diagram of a three-dimensional geostress measurement device for deep rock masses provided in an embodiment of this disclosure;

[0033] Figure 2 This is a schematic diagram of the geostress calculation process of a data processing unit provided in an embodiment of the present disclosure;

[0034] Figure 3 A schematic diagram illustrating the strain at any point on the borehole wall, provided as an embodiment of this disclosure;

[0035] Figure 4 This is a schematic diagram illustrating the relative relationship between the geodetic coordinate system and the borehole coordinate system. Detailed Implementation

[0036] Embodiments of this disclosure are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0037] Specifically, the following describes an embodiment of the deep rock mass three-dimensional geostress measurement device and method with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of a three-dimensional geostress measurement device for deep rock masses provided in an embodiment of this disclosure. Figure 1 As shown, the three-dimensional geostress measurement device for deep rock masses may include:

[0039] At least one stress gauge, which has a cylindrical structure;

[0040] A distributed fiber optic sensing system includes at least one set of fiber optic sensors, which are disposed on the outer surface of a stress gauge. Each set includes at least multiple measurement points in different directions for acquiring reflected wavelengths and wavelengths affected by temperature.

[0041] 3D Orientation System ( Figure 1 (not shown), integrated into the stress gauge, for automatically measuring the stress gauge's orientation data in the borehole;

[0042] The data processing unit communicates with the distributed fiber optic sensing system and the three-dimensional orientation system. It is used to receive reflected wavelength, temperature-affected wavelength and orientation data, and determine the three-dimensional stress tensor and three-dimensional principal stress in the geodetic coordinate system based on the reflected wavelength, temperature-affected wavelength and orientation data and the principle of the complete stress relief method for the local wall of the borehole.

[0043] In some embodiments of this disclosure, the distributed fiber optic sensing system includes at least three sets of fiber optic sensors evenly spaced along the circumferential surface of the stress gauge cylinder, each set including at least three measurement points. As an example, three sets of distributed fiber optic sensors can be wound or pasted at 120° intervals around the outer surface of the stress gauge cylinder. Replacing the traditional strain rosette with a fiber optic strain measurement system significantly improves the sensitivity, anti-interference capability, and spatial resolution of strain acquisition, while simplifying the on-site installation process.

[0044] In some embodiments of this disclosure, such as Figure 1 As shown, the measurement points in each group of fiber optic sensors measure directions φ that are 0°, 45° and 90° to the horizontal, respectively, and the axial spacing of the sensors can be minimized.

[0045] In some embodiments of this disclosure, the three-dimensional orientation system can be a three-dimensional electronic compass, which is fixedly installed on one end face of the stress meter for real-time measurement of orientation data. The orientation data includes yaw angle α, pitch angle β, and roll angle γ. The three angle data are transmitted back to the ground data processing terminal via wired or wireless means to calculate the azimuth angle of the borehole through coordinate transformation. D and tilt angle V The solution process is as follows:

[0046] The rotation matrices about the x, y, and z axes are:

[0047] (1)

[0048] (2)

[0049] (3)

[0050] The total rotation matrix is:

[0051] (4)

[0052] The drilling axis direction is the rotated z′ axis, i.e., the matrix. The third column:

[0053] (5)

[0054] inclination The angle between the axis and the horizontal plane:

[0055] (6)

[0056] Azimuth Let be the clockwise angle between the projection of the axis onto the horizontal plane and the direction of true north (y-axis), therefore:

[0057] (7)

[0058] In some embodiments of this disclosure, the deep rock mass three-dimensional geostress measurement device may include multiple stress gauges. The multiple stress gauges are arranged in series in different depth sections within the same borehole through a connecting structure. The distributed optical fiber sensing system and three-dimensional orientation system of each stress gauge are communicatively connected to the data processing unit, thereby realizing synchronous three-dimensional geostress measurement at multiple points and depths within the borehole.

[0059] Figure 2 This is a schematic diagram of the geostress calculation process of a data processing unit provided in an embodiment of this disclosure. Figure 2 As shown, the data processing unit can be used for:

[0060] Step 201: Obtain the reflected wavelength, temperature-affected wavelength, and calibration parameters collected by the distributed fiber optic sensing system before and after stress relief, and determine the three-dimensional strain tensor of multiple measurement points on the borehole wall.

[0061] Before the complete removal of the borehole wall, the initial value of the reflected wavelength of the fiber optic sensor is acquired. λ 0 and the initial wavelength affected by temperature λ T0 In one implementation, a toroidal drill bit with a wall thickness of 2 mm and an outer diameter of 34 mm can be used to completely relieve the stress on each local wall surface, and the reflected wavelength of the fiber optic sensor can be collected. λ Wavelength affected by temperature λ T The three-dimensional strain tensor is calculated using the following formula:

[0062] (8)

[0063] in, K λ It is the proportionality coefficient between strain and wavelength change. K T These are temperature compensation parameters, and the aforementioned data can be obtained through laboratory calibration.

[0064] Step 202: Based on the principle of the complete stress relief method for local borehole wall, the three-dimensional stress tensor in the borehole coordinate system is obtained by using the three-dimensional strain tensor and solving it by the least squares method.

[0065] like Figure 3 As shown, the angle between the hole wall and the circumferential direction is... The normal strain in the direction can be expressed as:

[0066] (9)

[0067] in, l and mThe measured values ​​are respectively The direction cosine of the circumferential and axial directions.

[0068] According to the theory of elasticity:

[0069] (10)

[0070] in,

[0071] (11)

[0072] Taking a stress gauge consisting of three sets of fiber optic sensors, each set including three measurement points in different directions, as an example, a single stress gauge can measure measurements in different directions (corresponding to different...) (Value) 9 points The value can be used to derive a set of equations:

[0073] (12)

[0074] in, ; and correspond Figure 1 The angle in the middle; They are different and The strain value measured at the measurement point; f ij They are different and The coefficient is obtained from formula (11).

[0075] The three-dimensional stress tensor can be obtained by solving equation (12) using the least squares method. ,Right now:

[0076] (13)

[0077] Step 203: Based on the orientation data measured by the three-dimensional orientation system, construct the transformation matrix from the borehole coordinate system to the geodetic coordinate system.

[0078] Figure 4 This is a schematic diagram illustrating the relative relationship between the geodetic coordinate system and the borehole coordinate system. (Example) Figure 4 As shown, the geodetic coordinate system is oxyz, with the z-axis perpendicular to the ground and pointing upwards, the x-axis pointing east, and the y-axis pointing north. The borehole coordinate system is ox′y′z′, where z′ is aligned with the borehole axis, the x′ axis lies in the xoy plane, and the direction of the y′ axis is determined using the right-hand screw rule. The transformation matrix between the geodetic and borehole coordinate systems is:

[0079] (14)

[0080] Step 204: Use the transformation matrix to transform the three-dimensional stress tensor to the geodetic coordinate system.

[0081] The stress tensor expressed in geodetic coordinates is:

[0082] (15)

[0083] Step 205: Determine the magnitude and direction of the three-dimensional principal stresses based on the three-dimensional stress tensor in the geodetic coordinate system.

[0084] Based on the stress characteristic equation, the eigenvalues ​​and eigenvectors are solved, and the magnitudes and principal directions of the three-dimensional principal stresses in the geodetic coordinate system are calculated. The calculation formulas are as follows:

[0085] (16)

[0086] Among them, the three roots obtained by solving formula (16) , and For three-dimensional principal stresses, J 1, J 2, J 3 can be calculated from equation (17):

[0087] (17)

[0088] Direction of principal stress l , m , n It can be calculated from equation (18):

[0089] (18)

[0090] By implementing the embodiments of this disclosure, a distributed fiber optic sensing system is directly mounted on the surface of the stress gauge and integrated with a three-dimensional orientation system. This achieves high-precision, distributed measurement of strain changes on the borehole wall, effectively improving the sensitivity of strain acquisition and its resistance to environmental interference. It automatically and in real-time acquires the azimuth and dip angles of the borehole, ensuring the accuracy of stress data conversion to the geodetic coordinate system and avoiding the errors and cumbersome operations associated with traditional manual measurements. The data processing unit synchronously receives strain and orientation data and automatically completes the three-dimensional stress tensor calculation and coordinate transformation based on the principle of complete stress relief on the local borehole wall, directly outputting the magnitude and direction of the three-dimensional principal stresses in the geodetic coordinate system. This integrated device achieves full automation from in-situ data acquisition and attitude positioning to stress calculation, significantly improving the accuracy, efficiency, and reliability of deep rock mass stress measurement.

[0091] This disclosure also proposes a method for measuring three-dimensional geostress in deep rock masses, which can employ the measuring device described in any of the above embodiments, and includes the following steps:

[0092] The stress gauge is integrated and calibrated in the factory, a distributed fiber optic sensing system is set on the surface of the stress gauge, and a three-dimensional electronic compass is installed.

[0093] Drilling target boreholes at the construction site;

[0094] Install the integrated stress gauge to the predetermined depth inside the borehole and ensure that it fits snugly against the borehole wall;

[0095] The three-dimensional electronic compass is activated to automatically acquire and record the orientation data of the stress gauge's location;

[0096] Before performing a full stress relief operation on the borehole wall, the initial reflection wavelength and the initial wavelength affected by temperature are collected by a distributed optical fiber sensing system.

[0097] The stress was completely relieved in a local area of ​​the borehole wall where the stress gauge was installed using a ring drill bit. At the same time, the reflected wavelength and the wavelength affected by temperature were collected by a distributed fiber optic sensing system.

[0098] The collected orientation data, initial reflection wavelength, initial wavelength affected by temperature, reflection wavelength after removal, and wavelength affected by temperature after removal are transmitted to the data processing unit.

[0099] The data processing unit, based on the received directional data, initial reflection wavelength, initial wavelength affected by temperature, reflection wavelength after removal, and wavelength affected by temperature after removal, performs the following operations: Figure 2 The geostress calculation steps of the illustrated embodiment output the three-dimensional stress tensor and three-dimensional principal stress in the geodetic coordinate system.

[0100] In some embodiments of this disclosure, multiple stress gauges can be connected in series and arranged at different depths of the same borehole to achieve simultaneous measurement of three-dimensional geostress at multiple depth points in a single operation.

[0101] The measurement method provided in this embodiment ensures the accuracy of the core sensing unit through standardized factory integration and calibration. In field operations, it combines automated drilling attitude acquisition and real-time data acquisition under full release operation. The integrated data processing unit directly completes the automatic calculation of the entire process from raw data to three-dimensional geostress, which significantly reduces manual operation and subjective intervention, and effectively improves the standardization, consistency and reliability of the entire measurement process.

[0102] In the foregoing descriptions of the embodiments, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0103] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0104] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of preferred embodiments of this disclosure includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as will be understood by those skilled in the art to which embodiments of this disclosure pertain.

[0105] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0106] It should be understood that various parts of this disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0107] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0108] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0109] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A three-dimensional geostress measurement device for deep rock masses, characterized in that, include: At least one stress gauge, wherein the stress gauge is a cylindrical structure, and multiple stress gauges are connected in series in different depth sections within the same borehole through a connecting structure; A distributed optical fiber sensing system includes at least one set of optical fiber sensors, which are disposed on the outer surface of the stress gauge. Each set includes at least multiple measurement points in different directions for acquiring reflected wavelengths and wavelengths affected by temperature. A three-dimensional orientation system, integrated on the stress gauge, is used to automatically measure the orientation data of the stress gauge in the borehole. The three-dimensional orientation system is a three-dimensional electronic compass, which is fixedly installed on one end face of the stress gauge and is used to measure the orientation data in real time. The orientation data includes yaw angle, pitch angle and roll angle, so as to obtain the azimuth angle and dip angle of the borehole through coordinate transformation. The data processing unit is communicatively connected to the distributed optical fiber sensing system and the three-dimensional orientation system. It is used to receive the reflected wavelength, the temperature-affected wavelength, and the orientation data, and to determine the three-dimensional stress tensor and three-dimensional principal stress in the geodetic coordinate system based on the reflected wavelength, the temperature-affected wavelength, the orientation data, and the principle of the borehole local wall stress complete relief method. The data processing unit is specifically used for: The three-dimensional strain tensor of multiple measurement points on the borehole wall is determined by acquiring the reflected wavelength, the temperature-affected wavelength, and calibration parameters collected by the distributed optical fiber sensing system before and after stress relief. Based on the principle of the method for complete relief of local wall stress in boreholes, the three-dimensional stress tensor in the borehole coordinate system is obtained by using the three-dimensional strain tensor and solving it by the least squares method. Based on the orientation data measured by the three-dimensional orientation system, a transformation matrix from the borehole coordinate system to the geodetic coordinate system is constructed; The three-dimensional stress tensor is transformed to a geodetic coordinate system using the transformation matrix. The magnitude and direction of the three-dimensional principal stresses are determined based on the three-dimensional stress tensor in the geodetic coordinate system.

2. The three-dimensional geostress measuring device for deep rock masses according to claim 1, characterized in that, The distributed fiber optic sensing system includes at least three sets of fiber optic sensors arranged at equal intervals along the circumferential direction of the outer surface of the stress gauge cylinder, each set including at least three measurement points.

3. The three-dimensional geostress measuring device for deep rock masses according to claim 2, characterized in that, The measurement points in each group of fiber optic sensors measure directions that are 0°, 45°, and 90° to the horizontal, respectively.

4. The three-dimensional geostress measuring device for deep rock masses according to claim 1, characterized in that, include: The distributed fiber optic sensing system and three-dimensional orientation system of each stress gauge are communicatively connected to the data processing unit.

5. A method for measuring three-dimensional geostress in deep rock masses, characterized in that, The method is based on the measuring device as described in any one of claims 1 to 4, and includes the following steps: The stress gauge is integrated and calibrated in the factory, a distributed fiber optic sensing system is set on the surface of the stress gauge, and a three-dimensional electronic compass is installed. Drilling target boreholes at the construction site; Install the integrated stress gauge to the predetermined depth inside the borehole and ensure that it fits snugly against the borehole wall; The three-dimensional electronic compass is activated to automatically acquire and record the orientation data of the stress gauge's location; Before performing a full stress relief operation on the borehole wall, the initial reflection wavelength and the initial wavelength affected by temperature are collected by the distributed optical fiber sensing system. The stress was completely relieved in a local area of ​​the borehole wall where the stress gauge was installed using a ring drill bit, and the reflected wavelength and temperature-affected wavelength after the stress was relieved were collected by the distributed optical fiber sensing system. The collected orientation data, initial reflection wavelength, initial wavelength affected by temperature, reflection wavelength after removal, and wavelength affected by temperature after removal are transmitted to the data processing unit. The data processing unit performs a ground stress calculation step based on the received directional data, initial reflection wavelength, initial wavelength of temperature influence, reflection wavelength after stress relief, and wavelength of temperature influence after stress relief. This includes: acquiring the reflection wavelength and wavelength of temperature influence collected by the distributed optical fiber sensing system before and after stress relief, as well as calibration parameters, and determining the three-dimensional strain tensor of multiple measurement points on the borehole wall. Based on the principle of the method for complete relief of local wall stress in boreholes, the three-dimensional stress tensor in the borehole coordinate system is obtained by using the three-dimensional strain tensor and solving it by the least squares method. Based on the orientation data measured by the three-dimensional orientation system, a transformation matrix from the borehole coordinate system to the geodetic coordinate system is constructed; The three-dimensional stress tensor is transformed to a geodetic coordinate system using the transformation matrix. The magnitude and direction of the three-dimensional principal stresses are determined based on the three-dimensional stress tensor in the geodetic coordinate system, and the three-dimensional stress tensor and three-dimensional principal stresses in the geodetic coordinate system are output.

6. The method for measuring three-dimensional geostress in deep rock masses according to claim 5, characterized in that, By connecting multiple stress gauges in series and arranging them at different depths in the same borehole, the three-dimensional geostress at multiple depth points can be measured simultaneously in a single operation.

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