In-situ dynamic detection system and method for three-dimensional stress field of underground engineering

Abstract

This invention discloses an in-situ dynamic detection system and method for three-dimensional stress fields in underground engineering. The detection system includes: a shell; a cavity in the middle of the shell, with an oil supply chamber and multiple mounting slots; the oil supply chamber is connected to an external oil supply device; the mounting slots are divided into an inner section, a middle section, and an outer section from the inside to the outside; multiple drive components, each corresponding to a mounting slot; each drive component includes a movable valve, a spring seat, and a piston; the movable valve is slidably disposed in the inner section of the mounting slot; the spring seat is fixedly disposed in the middle section of the mounting slot; a spring is disposed between the movable valve and the spring seat; the piston is slidably disposed in the outer section of the mounting slot; and multiple pressure sensing units, each corresponding to a drive component, connected to the side of the piston away from the movable valve. The detection system of this invention achieves multi-point dynamic continuous monitoring and active testing, shortening the testing time while ensuring testing accuracy.

Description

Technical Field

[0001] This invention relates to the field of stress detection technology, and in particular to an in-situ dynamic detection system and method for three-dimensional stress fields in underground engineering. Background Technology

[0002] As the development of shallow resources approaches saturation, the construction of major underground engineering projects, including transportation, water conservancy, and energy, is expanding into deeper spaces. Deep engineering rock masses exist in a complex mechanical environment characterized by high ground stress, high ground temperature, high osmotic pressure, and intense excavation disturbance—a "three-highs-one-disturbance" environment. Among these, the three-dimensional stress state and its dynamic evolution within the rock mass are the core determinants of the stability of the engineering rock mass. Its magnitude, direction, and spatiotemporal variations directly control the occurrence of engineering disasters such as rockbursts, rock bursts, and large deformations of the surrounding rock.

[0003] However, the field of rock mass stress detection and monitoring in engineering still faces pressing technical bottlenecks that need to be overcome. In-situ stress testing methods, primarily based on stress relief methods (such as borehole wall stress relief and borehole bottom stress relief), are mostly single-point, static, and passive in-situ testing techniques. These methods typically rely on field sampling or local disturbance testing, only obtaining the stress state at a specific instant at the measuring point, making it difficult to achieve long-term, uninterrupted continuous observation. Furthermore, while widely used strain and stress monitoring equipment in engineering, such as vibrating wire sensors and fiber Bragg gratings (FBGs), possess certain advantages in stability and durability, their measurement principles are mostly based on uniaxial stress or unidirectional strain sensing, only reflecting the mechanical response of the rock mass in a specific direction, and unable to comprehensively reconstruct the true three-dimensional stress field of the rock mass.

[0004] In addition, existing sensors that can measure the triaxial stress of rock mass passively apply force through contact with the rock mass until the force stabilizes. The measurement process of the sensor is from the initial zero point to the final stress state, which takes too long. The stabilization time can even exceed 180 days, making it difficult to provide timely data support for engineering design.

[0005] Therefore, developing a dynamic detection system capable of accurately analyzing the three-dimensional stress field of underground engineering has become a key technological requirement for achieving early warning of disasters. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides an in-situ dynamic detection system and method for three-dimensional stress fields in underground engineering. This system uses hydraulic pressure to drive multiple drive components on the casing, thereby enabling multiple pressure sensing units to actively monitor the stress distribution in the rock mass.

[0007] A first aspect of the present invention provides an in-situ dynamic detection system for three-dimensional stress fields in underground engineering. The in-situ dynamic detection system for three-dimensional stress fields in underground engineering includes:

[0008] The housing has a cavity in the middle, and the housing has an oil supply chamber that connects the cavity to the outside of the housing and multiple mounting slots; the oil supply chamber is connected to an external oil supply device to provide oil pressure to the cavity; the mounting slots are divided into an inner section, a middle section and an outer section from the inside to the outside.

[0009] Multiple drive components, each corresponding to a mounting slot; each drive component includes a movable valve, a spring seat, and a piston; the movable valve is slidably disposed in the inner section of the mounting slot, and is used to control the connection or disconnection between the inner section and the middle section; the spring seat is fixedly disposed in the middle section of the mounting slot; a spring is disposed between the movable valve and the spring seat; the piston is slidably disposed in the outer section of the mounting slot; and

[0010] Multiple pressure sensing units are connected to the drive components one by one. The pressure sensing units are connected to the side of the piston away from the active valve. All or part of the pressure sensing units are located on the outside of the housing. The pressure sensing units are connected to external measuring instruments to read the pressure sensing unit data.

[0011] Under hydraulic pressure, the drive assembly drives the pressure sensing unit to move outward, causing the pressure sensing unit to monitor a preset stress value.

[0012] According to the aforementioned three-dimensional stress field in-situ dynamic detection system for underground engineering, the piston has an annular notch on the side near the active valve; the piston has an exhaust port that penetrates the annular notch and the outside, and the piston has a sealing component connected to the exhaust port.

[0013] According to the aforementioned three-dimensional stress field in-situ dynamic detection system for underground engineering, the middle section wall has internal threads, and the side of the spring seat is provided with external threads that mate with the internal threads. The spring seat is connected to the middle section thread.

[0014] According to the aforementioned three-dimensional stress field in-situ dynamic detection system for underground engineering, the shell is divided into an upper hemisphere and a lower hemisphere; the number of pressure sensing units is equal in the upper and lower hemispheres; the pressure sensing units are evenly distributed on the same circumference of the outer wall of the upper hemisphere of the shell, and the pressure sensing units are evenly distributed on the same circumference of the outer wall of the lower hemisphere of the shell.

[0015] The angle between the normal of the pressure sensing unit in the upper hemisphere and the interface of the hemisphere is θ, 30°≤θ≤60°; the angle between the normal of the pressure sensing unit in the lower hemisphere and the interface of the hemisphere is ζ, 30°≤ζ≤60°.

[0016] Furthermore, both the upper and lower hemispheres have three pressure sensing units, and the angle between the projections of the normals of adjacent pressure sensing units in the upper and lower hemispheres onto the hemispherical interface is 60°.

[0017] According to the aforementioned three-dimensional stress field in-situ dynamic detection system for underground engineering, the movable valve has a partition and a first guide part and a second guide part located on both sides of the partition;

[0018] The first guide section is slidably connected to the inner sidewall.

[0019] The spring seat has a through guide hole, and the second guide part of the movable valve passes through the guide hole and is slidably connected;

[0020] The spring is sleeved on the second guide section.

[0021] Furthermore, a spring mounting groove is provided on the inner side of the spring seat, and the guide hole communicates with the spring mounting groove;

[0022] One end of the spring abuts against the spring mounting groove, and the other end abuts against the partition.

[0023] Furthermore, the first guide section is slidably connected to the inner section sidewall via a guide ring.

[0024] Furthermore, a first shoulder is formed between the inner section and the middle section, and a second shoulder is formed between the middle section and the outer section;

[0025] When there is no oil pressure in the cavity, the partition abuts against the first shoulder, and the piston abuts against the second shoulder; when there is oil pressure in the cavity, the partition disengages from the first shoulder.

[0026] A second aspect of the present invention provides a method for in-situ dynamic detection of three-dimensional stress fields in underground engineering, the method being based on the in-situ dynamic detection system for three-dimensional stress fields in underground engineering according to the first aspect of the present invention. The detection method includes the following steps:

[0027] S1. Drill a hole at the location where the stress state of the engineering rock mass is measured, install the in-situ dynamic detection system of the three-dimensional stress field of the underground engineering at the measurement location, and adjust it to the positive direction;

[0028] S2. Grouting is performed by injecting grout into the gap between the three-dimensional stress field in-situ dynamic detection system of the underground engineering and the borehole wall through the grouting pump. The grouting material is used to wrap the three-dimensional stress field in-situ dynamic detection system of the underground engineering and fill the cracks between it and the rock mass. Grouting is stopped when the preset grouting pressure value is reached.

[0029] S3. After the grout solidifies, use a hydraulic pump to apply hydraulic pressure to the cavity of the three-dimensional stress field in-situ dynamic detection system for underground engineering, and drive the pressure sensing unit to extend outward; when the pressure sensing unit monitors the value to the preset stress value, stop pressurizing.

[0030] S4. Continuously read the pressure sensing unit until it stabilizes, and calculate the three-dimensional stress state at the measuring point according to the analytical formula.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The detection system of the present invention achieves complete coverage and all-round perception of the three-dimensional stress field of the rock mass through multiple pressure sensing units distributed on the outside of the shell, providing a brand-new technical means for stress monitoring in fields such as rock engineering, underground space engineering, and mining engineering.

[0033] (2) The detection system of the present invention changes from the traditional passive test to the active test, which can shorten the test time while ensuring the test accuracy. Attached Figure Description

[0034] Figure 1 A schematic diagram of the three-dimensional dynamic detection system for the in-situ stress field of underground engineering in its initial state;

[0035] Figure 2 This is a top view of the in-situ dynamic detection system for the three-dimensional stress field of underground engineering in its initial state.

[0036] Figure 3 for Figure 2 Sectional view along the middle AA direction;

[0037] Figure 4 A cross-sectional view of an in-situ dynamic detection system for three-dimensional stress field in underground engineering under test conditions;

[0038] Figure 5 This is a schematic diagram of the three-dimensional structure of the shell;

[0039] Figure 6 This is a sectional view of the shell;

[0040] Figure 7 This is a three-dimensional structural diagram of the movable valve;

[0041] Figure 8 This is a three-dimensional structural diagram of the spring seat;

[0042] Figure 9 This is a sectional view of the spring seat;

[0043] Figure 10 This is a cross-sectional view of the piston;

[0044] Figure 11 This is a schematic diagram showing the distribution of the pressure sensing units on the housing.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1. Housing; 11. Cavity; 12. Oil supply chamber; 13. Mounting groove; 131. Inner section; 132. Middle section; 133. Outer section; 134. First shoulder; 135. Second shoulder;

[0047] 2. Drive assembly; 21. Active valve; 211. Separator; 212. First guide section; 213. Second guide section; 22. Spring seat; 221. Guide hole; 222. Spring mounting groove; 23. Piston; 231. Annular notch; 232. Exhaust port; 24. Spring; 25. Guide ring; 26. Sealing ring; 27. Sealing element;

[0048] 3. Pressure sensing unit. Detailed Implementation

[0049] To make the technical problem to be solved, the technical solution and advantages of the present invention clearer, the following description will be provided in conjunction with the accompanying drawings. Figures 1 to 11 The technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments.

[0050] This invention provides an in-situ dynamic detection system for three-dimensional stress fields in underground engineering, such as... Figures 1 to 4 As shown, the in-situ dynamic detection system for three-dimensional stress field in underground engineering includes a shell 1, multiple drive components 2, and multiple pressure sensing units 3, with each drive component 2 and pressure sensing unit 3 corresponding to another.

[0051] The structure of shell 1 is as follows Figure 5 and Figure 6 As shown, the housing 1 has a cavity 11 in the middle. The housing 1 has an oil supply chamber 12 connecting the cavity 11 to the outside of the housing 1, and multiple mounting slots 13. The oil supply chamber 12 is connected to an external oil supply device to provide oil pressure to the cavity 11. The mounting slots 13, from the inside to the outside, are an inner section 131, a middle section 132, and an outer section 133. The oil supply device delivers stable oil pressure to the cavity 11 through the oil supply chamber 12. This oil pressure, as the power source of the system, is evenly distributed inside the housing 1, providing power for the drive mechanism of the drive assembly 2.

[0052] The drive assembly 2 corresponds one-to-one with the mounting slot 13, and the drive assembly 2 slides along the mounting slot 13 of the housing 1. Figure 3 and Figure 4As shown, the drive assembly 2 includes a movable valve 21, a spring seat 22, and a piston 23. The movable valve 21 is slidably disposed in the inner section 131 of the mounting groove 13, and is used to control the connection or disconnection between the inner section 131 and the middle section 132. The spring seat 22 is fixedly disposed in the middle section 132 of the mounting groove 13. A spring 24 is disposed between the movable valve 21 and the spring seat 22. The piston 23 is slidably disposed in the outer section 133 of the mounting groove 13. The side wall of the piston 23 is slidably connected to the inner wall of the outer section 133 through a sealing ring 26, preventing hydraulic oil from passing through the side wall of the piston 23 and ensuring accurate oil pressure. When the oil supply device stops supplying oil to the cavity 11, the spring 24 rebounds and drives the movable valve 21 back to its original position, thereby disconnecting the inner section 131 and the middle section 132. The oil pressure between the outer section 133 and the piston 23 is stabilized, playing a pressure-holding role and ensuring that the detection system maintains high working stability and control accuracy in complex engineering environments for a long time.

[0053] The pressure sensing unit 3 is connected to the side of the piston 23 away from the movable valve 21, and all or part of the pressure sensing unit 3 is located on the outside of the housing 1. The pressure sensing unit 3 and the piston 23 can be fixedly connected by adhesive or by thread. The pressure sensing unit 3 is connected to an external measuring instrument to read the data from the pressure sensing unit 3. The mounting slots 13 are located in different directions of the housing 1, and multiple pressure sensing units 3 correspond to multiple drive components 2, which are installed in different directions of the housing 1, so that the detection system has multiple sensing points in three-dimensional space. The pressure sensing unit 3 is existing technology and will not be described in detail here. One model of the pressure sensing unit 3 is the SCYG315 dynamic earth pressure sensor, but other models are also available on the market.

[0054] The in-situ dynamic detection system for three-dimensional stress fields in underground engineering, as described in this invention, employs multiple independent driving components and pressure sensing units with different directions to simultaneously sense the stress state of rock mass in multiple directions. Through multiple pressure sensing units distributed on the outer side of the shell, complete coverage and all-round perception of the three-dimensional stress field of the rock mass are achieved, significantly overcoming the limitations of traditional unidirectional sensing and making the understanding of the complex stress field of the rock mass more comprehensive and accurate. The simultaneous operation of pressure sensing units in multiple directions allows for the acquisition of multi-dimensional stress information. Furthermore, through data processing and fusion, the true three-dimensional stress field distribution of the rock mass can be accurately reconstructed, enabling uninterrupted continuous monitoring of the stress state of the rock mass over long time series.

[0055] When the oil supply device stops supplying oil to the cavity 11, the spring 24 rebounds and drives the movable valve 21 back to its original position, thereby disconnecting the inner section 131 and the middle section 132, and stabilizing the oil pressure between the outer section 133 and the piston 23, which plays a role in maintaining pressure and ensuring that the detection system maintains a high degree of working stability and control accuracy in complex engineering environments for a long time.

[0056] In the detection system of this invention, oil pressure causes the drive assembly 2 to move the pressure sensing unit 3 outward, so that the pressure sensing unit 3 monitors a preset stress value. This invention transforms the traditional passive testing method into an active testing method, shortening the testing time while maintaining testing accuracy.

[0057] The detection system of this invention enables multi-point dynamic continuous monitoring, providing a brand-new technical means for stress monitoring in fields such as rock engineering, underground space engineering, and mining engineering, thereby improving the scientific nature of engineering design, the safety of construction, and the reliability of operation.

[0058] In some specific embodiments, such as Figure 10 As shown, the piston 23 has an annular notch 231 on the side near the movable valve 21, providing space for hydraulic oil and the movable valve 21. The piston 23 has an exhaust port 232 that penetrates the annular notch 231 and the outside, and the piston 23 has a sealing element 27 connected to the exhaust port 232. By setting the exhaust port 232 on the piston 23, air venting is achieved inside the three-dimensional stress field in-situ dynamic detection system for underground engineering. Specifically, hydraulic oil is input into the cavity 11 of the housing 1 through an external oil supply device to form oil pressure. During pressurization, the piston 23 is manually fixed in place. Once hydraulic oil flows out of the exhaust port 232 of the piston 23, the sealing element 27 is installed on the exhaust port 232, sealing the exhaust port 232 and venting the air inside the detection system, ensuring accurate stress monitoring. The sealing element 27 is a screw, and the inner wall of the exhaust port 232 has threads that mate with the screw. Figure 10 As shown. The sealing element 27 can also be a solenoid valve directly installed in the exhaust port 232.

[0059] In some specific embodiments, the wall surface of the middle section 132 has internal threads, and the side of the spring seat 22 is provided with external threads that mate with the internal threads, and the spring seat 22 is threadedly connected to the middle section 132.

[0060] In some specific embodiments, such as Figure 11 As shown in (a), the housing 1 is divided into an upper hemisphere and a lower hemisphere (the interface between the hemispheres is the XY plane). The number of pressure sensing units 3 is equal in the upper and lower hemispheres. The pressure sensing units 3 are evenly distributed on the same circumference of the outer wall of the upper hemisphere of the housing 1, and the pressure sensing units 3 are evenly distributed on the same circumference of the outer wall of the lower hemisphere of the housing 1. The angle between the normal of the pressure sensing unit 3 in the upper hemisphere and the interface between the hemispheres is θ, 30°≤θ≤60°; the angle between the normal of the pressure sensing unit 3 in the lower hemisphere and the interface between the hemispheres is ζ, 30°≤ζ≤60°, to avoid being too horizontal or vertical, which would result in low sensitivity for monitoring horizontal and vertical forces.

[0061] Furthermore, such as Figure 11As shown in (b), both the upper and lower hemispheres have three pressure sensing units 3. The angle between the projections of the normals of adjacent pressure sensing units 3 in the upper and lower hemispheres onto the hemispherical interface is 60°, ensuring that the pressure sensing units in the upper and lower hemispheres are staggered and evenly distributed on the hemispherical interface, which facilitates the analysis of the three-dimensional stress distribution.

[0062] In some specific embodiments, the movable valve 21 has a partition 211 and a first guide portion 212 and a second guide portion 213 located on both sides of the partition 211, respectively. The first guide portion 212 is slidably connected to the side wall of the inner section 131. The spring seat 22 has a through guide hole 221, and the second guide portion 213 of the movable valve 21 passes through the guide hole 221 and is slidably connected; the spring 24 is sleeved on the second guide portion 213. Figure 7 As shown, the partition 211 has a flat cylindrical structure, and the first guide portion 212 and the second guide portion 213 have cylindrical structures. The front end of the first guide portion 212 can also be a conical structure. The second guide portion 213 passes through the guide hole 221, and the guide hole 221 allows hydraulic oil to pass through and flow to the annular notch 231 of the piston 23.

[0063] Furthermore, such as Figure 8 and Figure 9 As shown, a spring mounting groove 222 is provided on the side of the spring seat 22 facing the inner section 131, and the guide hole 221 communicates with the spring mounting groove 222; one end of the spring 24 abuts against the spring mounting groove 222, and the other end abuts against the partition 211.

[0064] Furthermore, the first guide section 212 is slidably connected to the side wall of the inner section 131 via the guide ring 25, and the guide ring 25 allows hydraulic oil to pass through, so that the hydraulic oil flows from the inner section 131 of the mounting groove 13 to the middle section 132.

[0065] Furthermore, a first shoulder 134 is formed between the inner section 131 and the middle section 132, and a second shoulder 135 is formed between the middle section 132 and the outer section 133. When there is no oil pressure in the cavity 11, the partition 211 abuts against the first shoulder 134, and the piston 23 abuts against the second shoulder 135; when there is oil pressure in the cavity 11, the partition 211 disengages from the first shoulder 134; the oil pressure in the middle section 132 pushes the piston 23 disengage from the second shoulder 135, thereby pushing the pressure sensing unit 3 outward. When the pressurization in the cavity 11 stops, the spring 24 rebounds, the partition 211 abuts against the first shoulder 134, and the hydraulic oil that has entered the middle section 132 of the mounting groove 13 cannot flow back, thus playing a role in maintaining pressure.

[0066] Calibration method of in-situ dynamic detection system for three-dimensional stress field in underground engineering: The pressure sensing unit is numerically calibrated using diamond abrasive as the calibration medium. Calibration is completed by processing multiple sets of loading and unloading cycle test data. Specifically, diamond abrasive with a particle size of 0.5~1mm is used as the calibration medium. The pressure sensing unit 3 is loaded stepwise up to 6kN, with a loading step size of 0.3kN and a loading rate of 0.1kN / s, for a total of 20 loading levels. After each loading level stabilizes for 5 minutes, the next loading level is applied until full scale is reached. The accuracy levels and corresponding allowable errors of various calibration and inspection indicators such as linearity, repeatability, hysteresis, and sensitivity are classified. The calibration data is then processed to complete the calibration and verification of pressure sensing unit 3.

[0067] This invention also provides an in-situ dynamic detection method for three-dimensional stress fields in underground engineering, based on the aforementioned in-situ dynamic detection system for three-dimensional stress fields in underground engineering. The detection method includes the following steps:

[0068] S1. Drill a hole at the location where the stress state of the engineering rock mass is measured, install the in-situ dynamic detection system of the three-dimensional stress field of the underground engineering at the measurement location, and adjust it to the positive direction.

[0069] S2. Grouting is performed by injecting grout into the gap between the three-dimensional stress field in-situ dynamic detection system of underground engineering and the borehole wall through a grouting pump. The grouting material is used to wrap the three-dimensional stress field in-situ dynamic detection system of underground engineering and fill the cracks between it and the rock mass. Grouting is stopped when the preset grouting pressure value is reached.

[0070] S3. After the grout solidifies, hydraulic pressure is applied to the cavity 11 of the three-dimensional stress field in-situ dynamic detection system of underground engineering using a hydraulic pump, and the drive component 2 drives the pressure sensing unit 3 to extend outward; when the pressure sensing unit 3 monitors the value to the preset stress value, the pressurization is stopped.

[0071] S4. Continuously read the pressure sensing unit 3 until it stabilizes, and calculate the three-dimensional stress state at the measuring point according to the analytical formula.

[0072] Specifically, the analytical formula corresponding to the installation of six pressure sensing units 3 on the housing 1 is as follows:

[0073]

[0074] In the formula, σ a The stress value monitored by the a-th pressure sensing unit; l a Let m be the cosine of the angle between the normal of the a-th pressure sensing unit and the x-axis; a Let n be the cosine of the angle between the normal of the a-th pressure sensing unit and the y-axis; a Let be the cosine of the angle between the normal of the a-th pressure sensing unit and the z-axis; a is a value from 1 to 6.

[0075] Furthermore, in S2, the physical and mechanical properties of the grouting material are similar to those of the rock mass. The solidification shrinkage, creep, and mechanical properties of the grouting material match those of the rock mass, ensuring stable stress transmission and high reliability of the test data.

[0076] The in-situ dynamic detection system for three-dimensional stress fields in underground engineering of the present invention, during use, uses hydraulic pressure to drive the pressure sensing unit 3 to contact the test wall and reach a preset stress value, followed by a continuous testing process. This method overcomes the problem of stress test values ​​starting from zero and continuing until the normal test process, shortens the testing time, and provides data support for engineering design.

[0077] In the description of this invention, it should be understood that the terms "inner" and "outer," etc., indicating orientation or positional relationships, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0078] 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0079] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0080] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention.

Claims

1. An in-situ dynamic detection system for three-dimensional stress fields in underground engineering, characterized in that, include: The housing (1) has a cavity (11) in the middle. The housing (1) has an oil supply chamber (12) that connects the cavity (11) and the outside of the housing (1) and multiple mounting slots (13). The oil supply chamber (12) is connected to an external oil supply device to provide oil pressure to the cavity (11). The mounting slots (13) are, from the inside to the outside, an inner section (131), a middle section (132) and an outer section (133). Multiple drive components (2) correspond one-to-one with the mounting slots (13); each drive component (2) is equipped with a movable valve (21), a spring seat (22), and a piston (23); the movable valve (21) is slidably disposed in the inner section (131) of the mounting slot (13), and the movable valve (21) is used to control the connection or disconnection between the inner section (131) and the middle section (132); the spring seat (22) is fixedly disposed in the middle section (132) of the mounting slot (13); a spring (24) is disposed between the movable valve (21) and the spring seat (22); the piston (23) is slidably disposed in the outer section (133) of the mounting slot (13); and Multiple pressure sensing units (3) correspond one-to-one with the drive assembly (2). The pressure sensing unit (3) is connected to the side of the piston (23) away from the active valve (21). All or part of the pressure sensing unit (3) is located outside the housing (1). The pressure sensing unit (3) is connected to an external measuring instrument to read the data of the pressure sensing unit (3). Under the action of oil pressure, the drive component (2) drives the pressure sensing unit (3) to move outward, so that the pressure sensing unit (3) monitors the value of the preset stress value.

2. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 1, characterized in that, The piston (23) has an annular notch (231) on the side near the active valve (21); the piston (23) has an exhaust port (232) that passes through the annular notch (231) and the outside; the piston (23) has a sealing element (27) connected to the exhaust port (232).

3. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 1, characterized in that, The middle section (132) has an internal thread on its wall, and the side of the spring seat (22) has an external thread that matches the internal thread. The spring seat (22) is threadedly connected to the middle section (132).

4. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 1, characterized in that, The shell (1) is divided into an upper hemisphere and a lower hemisphere; the number of pressure sensing units (3) is equal in the upper hemisphere and the lower hemisphere; the pressure sensing units (3) are evenly distributed on the same circumference of the outer wall of the upper hemisphere of the shell (1), and the pressure sensing units (3) are evenly distributed on the same circumference of the outer wall of the lower hemisphere of the shell (1). The normal of the pressure sensing unit (3) in the upper hemisphere is at an angle of θ with the interface of the hemisphere, 30°≤θ≤60°; the normal of the pressure sensing unit in the lower hemisphere is at an angle of ζ with the interface of the hemisphere, 30°≤ζ≤60°.

5. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 4, characterized in that, Both the upper and lower hemispheres have three pressure sensing units (3), and the angle between the projections of the normals of adjacent pressure sensing units (3) on the hemispherical interface between the upper and lower hemispheres is 60°.

6. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 1, characterized in that, The active valve (21) has a partition (211) and a first guide (212) and a second guide (213) located on both sides of the partition (211); The first guide section (212) is slidably connected to the side wall of the inner section (131); The spring seat (22) has a through guide hole (221), and the second guide part (213) of the movable valve (21) passes through the guide hole (221) and is slidably connected; The spring (24) is sleeved on the second guide (213).

7. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 6, characterized in that, A spring mounting groove (222) is provided on the side of the spring seat (22) facing the inner section (131), and the guide hole (221) is connected to the spring mounting groove (222); One end of the spring (24) abuts against the spring mounting groove (222), and the other end abuts against the partition (211).

8. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 6, characterized in that, The first guide section (212) is slidably connected to the side wall of the inner section (131) via the guide ring (25).

9. The in-situ dynamic detection system for three-dimensional stress field in underground engineering according to claim 6, characterized in that, A first shoulder (134) is formed between the inner section (131) and the middle section (132), and a second shoulder (135) is formed between the middle section (132) and the outer section (133). When there is no oil pressure in the cavity (11), the partition (211) abuts against the first shoulder (134) and the piston (23) abuts against the second shoulder (135); when there is oil pressure in the cavity (11), the partition (211) disengages from the first shoulder (134).

10. A method for in-situ dynamic detection of three-dimensional stress field in underground engineering, characterized in that, Based on the in-situ dynamic detection system for three-dimensional stress fields in underground engineering as described in any one of claims 1 to 9; the detection method includes the following steps: S1. Drill a hole at the location where the stress state of the engineering rock mass is measured, install the in-situ dynamic detection system of the three-dimensional stress field of the underground engineering at the measurement location, and adjust it to the positive direction; S2. Grouting is performed by injecting grout into the gap between the three-dimensional stress field in-situ dynamic detection system of the underground engineering and the borehole wall through the grouting pump. The grouting material is used to wrap the three-dimensional stress field in-situ dynamic detection system of the underground engineering and fill the cracks between it and the rock mass. Grouting is stopped when the preset grouting pressure value is reached. S3. After the grout solidifies, hydraulic pressure is applied to the cavity (11) of the three-dimensional stress field in-situ dynamic detection system of underground engineering using a hydraulic pump, and the drive component (2) drives the pressure sensing unit (3) to extend outward; when the pressure sensing unit (3) monitors the value to the preset stress value, the pressurization is stopped. S4. Continuously read the pressure sensing unit (3) until it stabilizes, and calculate the three-dimensional stress state at the measuring point according to the analytical formula.

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