A three-compartment lateral pressure probe differential pressure self-balancing control box device and application method

Abstract

This invention discloses a control box device and application method for a three-compartment pressure slack probe differential pressure self-balancing, including a pressure slack probe control box, a three-compartment pressure slack probe, and a nitrogen power source. The pressure slack probe control box contains a first gas compartment, a water compartment, and a second gas compartment. Adjacent compartments are connected by a deformable partition, springs, and a transmission rod, forming a mechanical differential pressure self-balancing mechanism. When a pressure difference occurs between the water compartment and any gas compartment, the deformable partition displaces under the pressure difference, changing the compartment volume, and the springs provide a reverse elastic force, achieving self-regulating balance between water and gas pressure. This invention solves the problems of complex differential pressure adjustment operation, measurement distortion caused by pressure imbalance, and instability during the pressure slack membrane adhesion process in traditional pressure slack probes, providing continuous and stable control throughout the testing process.

Description

Technical Field

[0001] This invention belongs to the technical field of in-situ testing instruments for geotechnical engineering, specifically relating to a control box device and application method for a three-compartment pressuremeter probe with self-balancing pressure difference, used to achieve dynamic balance of pressure difference between the water bladder and the two side air bladders in a pressuremeter test, thereby accurately measuring the lateral pressure and deformation characteristics of the soil. Background Technology

[0002] A pressuremeter is a commonly used in-situ testing device in geotechnical engineering, used to determine the deformation modulus, ultimate bearing capacity, and stress-strain relationship of soil in the horizontal direction. When the pressuremeter probe is placed into a pre-drilled borehole, an initial gap exists between the probe and the borehole wall. A certain initial pressure needs to be applied to bring the probe-soil lateral pressure to the initial horizontal stress level, establishing a reference zero point for subsequent formal loading tests. To accurately measure the mechanical response of the soil in a "zero initial strain" state, this process needs to be achieved through differential pressure adjustment. Without differential pressure adjustment, the recorded initial pressure-volume curve will include a "gap-filling" stage. This data is unrelated to the mechanical properties of the soil itself and affects the accuracy of the test results.

[0003] A conventional three-chamber pressure gauge typically consists of three concentric chambers: a central water chamber for measurement and upper and lower air chambers for protection. This design ensures that the pressure exerted on the borehole wall by the central measuring chamber and the upper and lower protective chambers remains consistent, resulting in an ideal, uniform cylindrical deformation of the probe along the measuring chamber. During the experiment, by activating the air circuit control, the air source drives the water tank's water circuit pressure to inject water into the flexible pressure gauge diaphragm, causing the water chamber to expand. A constant water chamber pressure is then maintained, and the air circuit control activates the air circuit pressure to expand the upper and lower air chambers, always keeping the expansion of the air chambers slightly less than that of the water chamber. Finally, the pressure and water level data are manually read and recorded using a mechanical dial. However, because the borehole groundwater level is connected to the atmospheric environment, a pressure difference exists between the water pressure inside the pressure gauge diaphragm and the pressure outside the borehole. Especially when the pressure gauge probe is lowered to a depth exceeding 10m, pressure imbalance and significant hysteresis occur in the water and air pipelines during the experiment. Traditional pressure gauges address this pressure imbalance by manually adjusting the "differential pressure regulating valve" on the control unit. However, due to differences in air and water pressure balancing parameters under varying elevations, there is a time lag between the air circuit drive process and the water pressure increase, causing discrepancies between the pressure gauge data read in the experiment and the actual pressure, resulting in insufficient accuracy of the experimental data. Simultaneously, the manually adjusted pressure balancing valve is prone to over- or under-pressurization. Repeated adjustments within the limited testing time further exacerbate experimental errors. The entire balancing process relies on the operator's experience, manually adjusting the differential pressure control valve by visually observing the two pressure gauges. If the pressure is unbalanced, the measuring chamber, when pressurized, will exhibit a "candied hawthorn" effect, with both ends restricted and the middle excessively bulging, causing deformation that does not conform to the theoretical assumption of "uniform cylindrical expansion," thus distorting parameters such as the measured pressure modulus.

[0004] In addition, the upper and lower air bladders of the traditional three-compartment side-pressure membrane use the same air path, and there is a slight difference in air pressure, which causes different side expansion of the air bladders. This results in different stress states at the upper and lower ends of the water bladders, affecting the identification and data accuracy during the wall adhesion stage.

[0005] The publicly available GEOSPAD data acquisition device uses two built-in pressure sensors and an ultrasonic level sensor to simultaneously and continuously collect real-time pressure data from the measuring chamber (water chamber) and two protective chambers (air chambers), as well as the volume change of the measuring chamber. The acquired data is transmitted in real-time to the main control unit, GeoBOX, via wireless or wired connection. The software on GeoBOX displays and guides the test procedures in real time, while automatically and accurately recording all test data. It can calculate and display the pressure difference between the measuring chamber and the protective chambers in real time. Based on this continuously updated and accurate difference, the operator manually adjusts the original differential pressure regulating valve on the control unit to bring the pressure difference to zero. It is evident that although this intelligent pressure gauge introduces electronic control, it only achieves automated data acquisition and does not fundamentally solve the core drawbacks of pressure imbalance and cumbersome manual adjustment.

[0006] This invention uses a water tank and a gas tank as intermediaries to transmit the underground pressure difference to the surface, and balances the pressure difference using springs, significantly reducing operational difficulty. It fundamentally solves the problem of pressure hysteresis due to water-gas pressure differences, offering fast response, high precision, full automation, and independence from operator experience. Summary of the Invention

[0007] The purpose of this invention is to provide a control box device and application method for self-balancing differential pressure of a three-compartment pressure-side probe. By constructing a three-compartment pressure system corresponding one-to-one with the three chambers of the probe in the control box, the complex pressure balance problem at the underground probe is transferred to the ground control box by introducing a passive mechanical feedback mechanism composed of deformable partition, spring and transmission rod, and automatic adjustment is achieved through mechanical structure.

[0008] The technical problem to be solved by the present invention is achieved through the following technical solution:

[0009] A control box device for self-balancing differential pressure of a three-compartment pressure bypass probe includes:

[0010] The pressure gauge control box contains an independent first air chamber, a water chamber, and a second air chamber; the water chamber is located between the first air chamber and the second air chamber.

[0011] A mechanical differential pressure self-balancing mechanism includes: a first deformable partition disposed between the first air chamber and the water chamber; a second deformable partition disposed between the water chamber and the second air chamber; a linkage transmission rod connecting the first deformable partition and the second deformable partition; and a first spring and a second spring respectively connected to the first deformable partition and the second deformable partition. When a pressure difference occurs between the water chamber and the first air chamber and the water chamber, the mechanical differential pressure self-balancing mechanism drives the corresponding deformable partition to shift, and provides a reverse force through the springs to automatically adjust the volume of the corresponding air chamber until the pressure difference tends to balance.

[0012] The three-compartment pressure slack probe is connected to the pressure slack instrument control box via a pipeline; the three-compartment pressure slack probe includes a first air bladder, a water bladder and a second air bladder arranged in sequence, the first air bladder is connected to the first air chamber, the water bladder is connected to the water chamber and the second air bladder is connected to the second air chamber.

[0013] A nitrogen power source is used to provide a pressurized medium for the control box device.

[0014] Furthermore, the pressure gauge control box also includes a first air pressure sensor, a water pressure sensor, and a second air pressure sensor, which are used to monitor the pressure of the first air chamber, the water chamber, and the second air chamber in real time, respectively.

[0015] Furthermore, the water tank is connected to an external water tank via a water pipe to compensate for the water demand caused by changes in the volume of the water bladder, and at the same time to buffer and stabilize the basic pressure of the water tank.

[0016] Furthermore, the pressure gauge control box is also equipped with a controller, which is electrically connected to the first air pressure sensor, the water pressure sensor, the second air pressure sensor, and the pipeline control valves connecting each compartment, and is used to receive pressure data and control the on / off state of each pipeline.

[0017] An application method for a control box device with a three-compartment pressure septum probe differential pressure self-balancing as described above includes the following steps:

[0018] S1. Initial placement and data recording: Place the three-compartment pressure gauge probe at the predetermined test depth in the borehole; inject water into the water bladder to make it initially adhere to the borehole wall, and record the initial pressure values ​​of the first air chamber, water chamber, and second air chamber in the pressure gauge control box at this time;

[0019] S2, Pressure difference balance adjustment: According to the initial pressure value recorded in step S1, turn on the nitrogen power source, and adjust the gas path pressure to make the pressure of the first and second gas chambers reach the initial balance state with the pressure of the water chamber; at this time, the radial pressure of the first air bladder, water bladder and second air bladder of the three-chamber pressure-side probe on the orifice wall is equal.

[0020] S3. Staged loading and monitoring: Based on the initial equilibrium state established in step S2, the water tank is pressurized in stages according to the preset pressure level through the nitrogen power source, and the pressure value of the water tank and the pressure values ​​of the first and second gas tanks at each pressure level are monitored and recorded simultaneously.

[0021] S4. Dynamic pressure differential self-balancing: During the graded loading process in step S3, when the internal pressure of the water bladder becomes unbalanced with the pressure of any air bladder due to the action of the soil, the pressure difference will be transmitted to the control box of the pressure gauge; the mechanical pressure differential self-balancing mechanism will then respond, driving the corresponding deformable partition to displace and compress or stretch the spring, thereby automatically adjusting the volume and pressure of the corresponding air chamber, so that the pressure difference between the water chamber and the air chamber is restored to a balanced state;

[0022] S5. Test End and Reset: After the loading test is completed, the pressure of the nitrogen power source is released, causing the air bladder and water bladder of the three-compartment pressure bypass probe to contract. The mechanical differential pressure self-balancing mechanism is reset under the action of the spring, and the system returns to its initial state.

[0023] Furthermore, in step S3, the staged pressurization process is automatically executed by the controller according to a preset program, controlling the nitrogen power source and related pipeline control valves.

[0024] Furthermore, in step S4, the dynamic differential pressure self-balancing process is carried out in real time and automatically, and its balance response is determined by the mechanical relationship between the displacement of the deformable partition, the elastic force of the spring, and the change in chamber pressure.

[0025] Furthermore, the steady-state equilibrium condition of the dynamic differential pressure self-balancing process is described by the following formula:

[0026] ;

[0027] In the formula, , These are the real-time pressures of the water tank and the regulated gas tank, respectively. This corresponds to the stiffness coefficient of the spring. This represents the amount of deformation of the spring from its equilibrium position. This refers to the effective pressure-bearing area of ​​the deformable partition.

[0028] The present invention proposes a control box device and application method for self-balancing differential pressure of a three-compartment pressure bypass probe, which has the following improvements and advantages over previous technologies:

[0029] By shifting the pressure balancing process from long underground pipelines to a sealed surface chamber, media transmission lag is eliminated. The system response is determined by the mechanical behavior of the structure, resulting in a fast response time and pressure compensation that is almost synchronous with soil deformation. This leads to more uniform deformation of the pressure-side membrane, accurate identification of the adhesion stage, and improved data reading accuracy.

[0030] Passive dynamic stability compensation means that any pressure disturbance that deviates from the equilibrium will immediately trigger a restoring force in the opposite direction and proportional in magnitude, forcing the system to return to equilibrium.

[0031] It is suitable for various strata such as soft soil, sand, and clay, with a range of 0~5.0 MPa, meeting the needs of engineering survey. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the control box device for the differential pressure self-balancing of a three-compartment pressure bypass probe according to the present invention;

[0033] Figure 2 This is a schematic diagram of the internal structure of the pressure gauge control box of this invention;

[0034] Figure 3 This is the computer control flowchart of the present invention.

[0035] In the diagram: 1—Pressure shunting instrument control box; 2—Three-compartment pressure shunting probe; 3—PC control program; 4—Nitrogen power source; 101—First pressure sensor; 102—Water pressure sensor; 103—Second pressure sensor; 104—Controller; 105—Water tank; 106—First air chamber; 107—First deformable partition; 108—First spring; 109—Water chamber; 110—Second deformable partition; 111—Second air chamber; 112—Deformable partition; 113—Second spring; 114—First transmission rod; 115—Second transmission rod; 116—Water pipe; 201—Probe main rod; 202—First airbag; 203—Water bag; 204—Second airbag; 205—Water pipe; 206—Air pipe. Detailed Implementation

[0036] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings.

[0037] like Figure 1 As shown, this embodiment of the invention provides a control box device for self-balancing differential pressure of a three-compartment pressure bypass probe, including a pressure bypass instrument control box 1, a three-compartment pressure bypass probe 2, a PC control program 3, and a nitrogen power source 4. The nitrogen power source 4 provides a stable gas supply, and the PC control program 3 communicates with the MCU controller 104 via serial port or wireless means to realize human-machine interaction, parameter setting, data storage, and curve plotting.

[0038] like Figure 2 and Figure 3 As shown, the inside of the pressure gauge control box 1, from left to right, consists of a first air chamber 106, a water chamber 109, and a second air chamber 111. The first air chamber 106 and the water chamber 109 are separated by a first deformable partition 107. A first spring 108 is connected to the left side of the partition, and the right side is linked to a second deformable partition 110 via a first transmission rod 114. The water chamber 109 and the second air chamber 111 are separated by a second deformable partition 110, with a second spring 113 connected to its right side.

[0039] Three pressure sensors (first air pressure sensor 101, water pressure sensor 102, and second air pressure sensor 103) are respectively installed inside the first air chamber 106, water chamber 109, and second air chamber 111 to monitor the pressure in real time. The MCU controller 104 drives the solenoid valve according to a preset algorithm such as PID control to control nitrogen to enter the air chamber or water to flow from the water tank 105 into the water chamber 109.

[0040] After the three-compartment pressure-side probe 2 is lowered into the well, the first airbag 202, waterbag 203, and second airbag 204 correspond to the upper, middle, and lower regions of the soil, respectively. When the waterbag 203 experiences increased pressure due to soil resistance, the pressure in the water compartment 109 rises synchronously, pushing the second deformable partition 110 to the right and compressing the second spring 113. This causes the volume of the second air compartment 111 to decrease and the air pressure to increase until the pressure differential... The system reaches a new equilibrium at a pressure ≤0.01MPa. This process requires no external energy and has a fast response time.

[0041] The aforementioned mechanical differential pressure self-balancing mechanism is essentially a negative feedback system based on force balance. When the water tank pressure... Higher than the pressure in the right-side gas chamber At this time, the difference ΔP acts on the second deformable partition 110, generating a net force to the left. This force causes the partition to shift to the left, compressing the second spring 113 via the second transmission rod 115. The spring generates a reverse elastic force. k is the spring stiffness coefficient, and Δx is the compression amount, which increases until it balances the force generated by the pressure difference, at which point the partition stops moving. At this new position, the volume of the second air chamber 111 decreases, and according to Boyle's law, its air pressure... The corresponding increase leads to an automatic decrease and eventual stabilization with... The difference. The design of spring stiffness k needs to comprehensively consider the system response speed and balance accuracy, and is usually determined through experiments.

[0042] At the start of the test or during a certain stable pressurization phase, the system is pre-set to have equal pressure in the water tank 109 and the two air tanks (106, 111) (i.e.) = = At this point, the forces acting on both sides of the two deformable partitions are equal in magnitude and opposite in direction, the partitions are in a static equilibrium position, and the springs (108, 113) remain in their initial pre-compressed or free state.

[0043] When probe 2 expands in the soil, due to the non-uniformity or anisotropy of the soil distribution, the soil reaction force on the middle water bladder (203) may differ from that on the upper and lower air bladders (202, 204). This difference is instantaneously transmitted to the ground control box 1 through the incompressible water medium and air pipelines (205, 206), manifesting as a pressure difference between the water chamber 109 and any of the air chambers. .

[0044] The feedback response process is as follows: pressure difference Effective working area of ​​the second deformable partition 110 A net force is generated on it. This force pushes the partition to move towards the side with lower pressure (i.e., towards the second air chamber 111). The movement of the partition compresses (or stretches) the second spring 113 via the second transmission rod 115. According to Hooke's Law, the spring immediately generates an elastic restoring force in the opposite direction. ,in Let be the stiffness coefficient of the spring. This represents the amount of deformation of the spring. As the partition moves It increases linearly with the increase of . When Growth to When the magnitudes are equal, the net force on the partition is zero, the movement stops, and the system reaches a new force equilibrium position.

[0045] The automatic pressure adjustment process is as follows: During the aforementioned displacement, the volume of the second gas chamber (111) decreases due to the movement of the partition. According to Boyle's law, the gas inside the chamber is compressed, and its pressure... The pressure then rises. This change directly affects the probe's second airbag (204). This process continues until... Rise to The difference Approaching zero, at this point... The driving force generated The pressure also approaches zero, and the system completes an automatic balancing adjustment. The entire process is completed within milliseconds, achieving dynamic tracking and balancing of pressure.

[0046] The steady-state equilibrium condition of the above-mentioned mechanical negative feedback system can be described by the following formula:

[0047]

[0048] In the formula, , These are the real-time pressures of the water tank and the regulated gas tank, respectively. This is the stiffness coefficient (N / mm) of the corresponding spring. This represents the amount of deformation (mm) of the spring from its equilibrium position. The effective bearing area (mm²) of the deformable partition.

[0049] After the test, the MCU controller (104) closes all solenoid valves and opens the pressure relief channel. The air bladder and water bladder contract under the spring return force and soil rebound, and the system returns to its initial state, ready for the next test.

[0050] This invention also provides an application method for the control box device for differential pressure self-balancing of the three-compartment pressure-spotting probe as described above, comprising the following steps:

[0051] S1. Initial placement and data recording: Place the three-compartment pressure gauge probe 2 at the predetermined test depth in the borehole; inject water into the water bladder 203 so that it initially adheres to the borehole wall, and record the initial pressure values ​​of the first air chamber 106, water chamber 109 and second air chamber 111 in the pressure gauge control box 1 at this time.

[0052] S2, Pressure difference balance adjustment: According to the initial pressure value recorded in step S1, the nitrogen power source 4 is turned on, and the pressure of the first air chamber 106 and the second air chamber 111 is adjusted to achieve an initial balance with the pressure of the water chamber 109; at this time, the radial pressure of the first air chamber 202, the water chamber 203 and the second air chamber 204 of the three-chamber pressure-side probe 2 on the borehole wall is equal.

[0053] S3. Staged loading and monitoring: Based on the initial equilibrium state established in step S2, the water tank 109 is pressurized in stages according to the preset pressure levels through the nitrogen power source 4, and the pressure values ​​of the water tank 109 and the first gas tank 106 and the second gas tank 111 at each pressure level are monitored and recorded simultaneously; wherein, the staged pressurization process is automatically executed by the controller 104 according to the preset program, controlling the nitrogen power source 4 and related pipeline control valves.

[0054] S4. Dynamic Pressure Difference Self-Balancing: During the graded loading process in step S3, when the internal pressure of the water bladder 203 becomes unbalanced with the pressure of any of the air bladders 202 and 204 due to the action of the soil, the pressure difference will be transmitted to the pressure gauge control box 1; the mechanical pressure difference self-balancing mechanism will then respond, driving the corresponding deformable partition to displace and compress or stretch the spring, thereby automatically adjusting the volume and pressure of the corresponding air chamber, so that the pressure difference between the water chamber 109 and the first air chamber 106 and the second air chamber 111 is restored to a balanced state; wherein, the dynamic pressure difference self-balancing process is carried out in real time and automatically, and its balance response is determined by the mechanical relationship between the displacement of the deformable partition, the elastic force of the spring and the change of chamber pressure.

[0055] S5. Test End and Reset: After the loading test is completed, the pressure of the nitrogen power source 4 is released, causing the air bladder and water bladder of the three-compartment pressure bypass probe 2 to contract. The mechanical differential pressure self-balancing mechanism is reset under the action of the spring, and the system returns to its initial state.

[0056] This invention has the following features and effects:

[0057] 1. Achieves automatic, real-time pressure differential balancing with simple operation and high precision: Based on the core innovation of this invention—a mechanical pressure differential self-balancing mechanism composed of deformable baffles, linkage transmission rods, and springs—this invention transforms the physical process of pressure balancing from relying on human experience and manual adjustment to being automatically completed by the mechanical relationship of the mechanical structure. Any water-air pressure difference generated at any probe will immediately cause the baffle to shift and compress the spring. The counterforce generated by the spring drives changes in the volume and pressure of the air chamber until the pressure differential returns to zero. This process has a rapid response (millisecond level), achieving pressure compensation almost synchronous with soil deformation, completely eliminating the lag and errors caused by traditional long pipeline transmission and manual adjustment, and significantly improving testing accuracy, especially the identification accuracy during the wall-attaching stage.

[0058] 2. Reliable structure and strong adaptability, improving test stability and success rate: The mechanical differential pressure self-balancing mechanism, as a passive negative feedback system, has its equilibrium state determined by inherent parameters such as spring stiffness and diaphragm area. It does not rely on external continuous energy or complex electronic control, has strong anti-interference capabilities, and operates stably and reliably. This design enables the system to automatically adapt to changes in soil reaction force in different strata such as soft soil, sand, and clay, as well as pressure environments at different depths. This ensures that the pressure in the three chambers of the probe remains dynamically balanced throughout the entire loading process (from wall adhesion to lateral expansion failure), thereby obtaining deformation data that conforms to the assumption of uniform cylindrical expansion, improving the reliability of test results and applicability under different geological conditions.

[0059] 3. Shifting the balancing process to the ground simplifies the system and reduces operational complexity: By using a ground-based pressure gauge control box and its internal compartments that correspond one-to-one with the probe's three chambers, this invention moves the core functions of pressure sensing and balancing adjustment from the probe inside the underground borehole to the ground-based control box. This avoids the adverse effects of the complex underground environment on the precision adjustment mechanism; furthermore, it allows operators to centrally monitor and set parameters on the ground, greatly simplifying the operation process, reducing reliance on operator experience, minimizing human error, and improving the convenience and efficiency of engineering applications.

[0060] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control box device for self-balancing differential pressure of a three-compartment pressure bypass probe, characterized in that, include: The pressure gauge control box (1) has an independent first air chamber (106), a water chamber (109), and a second air chamber (111); the water chamber (109) is located between the first air chamber (106) and the second air chamber (111); The mechanical differential pressure self-balancing mechanism includes: a first deformable partition (107) disposed between the first air chamber (106) and the water chamber (109); a second deformable partition (110) disposed between the water chamber (109) and the second air chamber (111); a linkage transmission rod (114, 115) connecting the first deformable partition (107) and the second deformable partition (110); and a first spring (108) and a second spring (113) respectively connected to the first deformable partition (107) and the second deformable partition (110). The mechanical differential pressure self-balancing mechanism is used to drive the corresponding first deformable partition (107) and second deformable partition (110) to move when a pressure difference occurs between the water chamber (109) and the first air chamber (106) and the water chamber (109), and to provide a reverse force through the springs (108, 113) to automatically adjust the volume of the corresponding air chamber until the pressure difference tends to be balanced. The three-compartment pressure bypass probe (2) is connected to the pressure bypass instrument control box (1) via a pipeline; the three-compartment pressure bypass probe (2) includes a first airbag (202), a water bag (203), and a second airbag (204) arranged in sequence. The first airbag (202) is connected to the first air chamber (106), the water bag (203) is connected to the water chamber (109), and the second airbag (204) is connected to the second air chamber (111). A nitrogen power source (4) is used to provide a pressurizing medium for the control box device.

2. The apparatus according to claim 1, characterized in that, The pressure gauge control box (1) also includes a first air pressure sensor (101), a water pressure sensor (102), and a second air pressure sensor (103), which are used to monitor the pressure of the first air chamber (106), the water chamber (109), and the second air chamber (111) in real time, respectively.

3. The apparatus according to claim 1, characterized in that, The water tank (109) is connected to an external water tank (105) via a water pipe (116) to compensate for the water demand caused by changes in the volume of the water tank, and at the same time to buffer and stabilize the basic pressure of the water tank.

4. The apparatus according to claim 2, characterized in that, The pressure gauge control box (1) is also equipped with a controller (104). The controller (104) is electrically connected to the first air pressure sensor (101), the water pressure sensor (102), the second air pressure sensor (103), and the pipeline control valves connecting each compartment. It is used to receive pressure data and control the on / off state of each pipeline.

5. An application method of a control box device for differential pressure self-balancing of a three-compartment pressure-spotting probe as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Initial placement and data recording: Place the three-compartment pressure gauge probe (2) at the predetermined test depth in the borehole; inject water into the water bladder (203) so that it initially adheres to the borehole wall, and record the initial pressure values ​​of the first air chamber (106), water chamber (109), and second air chamber (111) in the pressure gauge control box (1) at this time; S2, Pressure difference balance adjustment: According to the initial pressure value recorded in step S1, turn on the nitrogen power source (4), and adjust the gas path pressure to make the pressure of the first gas chamber (106) and the second gas chamber (111) reach the initial balance state with the pressure of the water chamber (109); at this time, the radial pressure of the first air bladder (202), water bladder (203) and the second air bladder (204) of the three-chamber pressure probe (2) on the borehole wall is equal; S3. Gradual loading and monitoring: Based on the initial equilibrium state established in step S2, the water tank (109) is pressurized in stages according to the preset pressure level through the nitrogen power source (4), and the pressure value of the water tank (109) and the pressure values ​​of the first gas tank (106) and the second gas tank (111) under each pressure level are monitored and recorded simultaneously. S4. Dynamic pressure differential self-balancing: During the graded loading process in step S3, when the internal pressure of the water bladder (203) becomes unbalanced with the pressure of any air bladder (202, 204) due to the action of the soil, the pressure difference will be transmitted to the pressure gauge control box (1); the mechanical pressure differential self-balancing mechanism will then respond, drive the corresponding deformable partition to move and compress or stretch the spring, thereby automatically adjusting the volume and pressure of the corresponding air chamber, so that the pressure difference between the water chamber (109) and the first air chamber (106) and the second air chamber (111) is restored to a balanced state; S5. End of test and reset: After the loading test is completed, the pressure of the nitrogen power source (4) is removed, causing the air bladder and water bladder of the three-compartment pressure probe (2) to contract. The mechanical differential pressure self-balancing mechanism is reset under the action of the spring, and the system returns to the initial state.

6. The method according to claim 5, characterized in that, In step S3, the staged pressurization process is automatically executed by the controller (104) according to a preset program, controlling the nitrogen power source (4) and related pipeline control valves.

7. The method according to claim 5, characterized in that, In step S4, the dynamic differential pressure self-balancing process is carried out in real time and automatically, and its balance response is determined by the mechanical relationship between the displacement of the deformable partition, the elastic force of the spring, and the change in chamber pressure.

8. The method according to claim 7, characterized in that, The steady-state equilibrium condition of the dynamic differential pressure self-balancing process is described by the following formula: ； In the formula, , These are the real-time pressures of the water tank and the regulated gas tank, respectively. This corresponds to the stiffness coefficient of the spring. This represents the amount of deformation of the spring from its equilibrium position. This refers to the effective pressure-bearing area of ​​the deformable partition.

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