Spiral plate load test probe based on soil layer pressure and settlement displacement test

Abstract

The utility model discloses a spiral plate load test probe based on soil layer pressure and settlement displacement test, which comprises a cylindrical load transmission rod connected with a probe rod, and a wire passing hole is arranged in the cylindrical load transmission rod; the rod body is sequentially provided with a probe rod connecting part, an upper torsion transmission part, a pressure sensing part, a lower torsion transmission part and a spiral plate shaft connecting part; the outer diameter of the pressure sensing part is small, and a resistance-type strain gauge is attached to the surface to measure soil layer pressure; the up-and-down torque transmission part is matched with an external torque sleeve through a spline to transmit torque; a displacement detection assembly is arranged between the lower torsion transmission part and the torsion sleeve and comprises a movable capacitor plate moving along with the rod and a fixed capacitor plate fixed to the torsion sleeve. The upper end and the lower end of the torsion sleeve are in threaded connection with the upper connector and the lower connector respectively to limit the axial movement range of the load transmission rod, and the movement amount is the displacement measurement range. The lower end of the spiral plate shaft connecting part is connected with a spiral plate assembly. The probe is high in integration level and can synchronously monitor soil layer pressure and settlement displacement.

Description

Technical Field

[0001] This utility model belongs to the field of spiral plate load testing technology, and in particular relates to a spiral plate load testing probe based on soil pressure and settlement displacement testing. Background Technology

[0002] Spiral plate load testing is a commonly used in-situ testing method in geotechnical engineering investigation. It can determine geotechnical parameters such as bearing capacity and deformation modulus of deep foundation soil, providing a basis for the design of deep foundations and pile foundations for high-rise buildings, high-speed railways and other projects.

[0003] The spiral plate load test involves using a probe as a force transmission rod to screw the spiral plate head into the stratum to a predetermined test depth. Then, loads are applied to the spiral bearing plate in stages through the probe. The settlement displacement of the soil under the spiral plate is recorded according to a certain time standard, thereby obtaining the load-settlement displacement-time relationship curve of the foundation soil. This allows us to obtain design parameters such as bearing capacity and deformation modulus of foundation soil at different depths.

[0004] The original spiral plate load test accurately measures the load through a pressure sensor installed on the underground spiral plate head. However, the settlement of the spiral plate head is assumed to be due to the probe not bending under load, and the settlement of the probe on the ground is considered to be the settlement displacement of the spiral plate. In reality, as the length of the probe increases and the load increases, the bending deformation of the probe becomes larger and larger, which will cause inaccurate displacement measurement. To avoid the error caused by the bending deformation of the probe under pressure in the spiral plate load test on the settlement displacement of the spiral plate, the invention patent CN105507226B "Method for eliminating the influence of bending of the force transmission rod on the accuracy of spiral plate load test and its displacement detector" and the utility model patent C205530200U disclose a technical solution. The displacement detector is placed at the bottom of the underground probe and a fixed sleeve is used. The settlement displacement of the spiral plate is determined by measuring the relative displacement between the sleeve and the probe, which ensures the accuracy of the displacement test of the spiral plate load test and greatly increases the test depth. This approach involves connecting a pressure detector to the hollow force transmission shaft of the displacement detector, which is structurally inefficient, has many sealing points, and is cumbersome to assemble. Therefore, a spiral plate load test probe based on soil pressure and settlement displacement testing was designed. Utility Model Content

[0005] To address the technical problems of existing spiral plate load test probes being insufficiently compact, having numerous sealing points, and being cumbersome to assemble, this invention provides a spiral plate load test probe based on soil pressure and settlement displacement testing.

[0006] This invention is implemented as follows: a spiral plate load test probe based on soil pressure and settlement displacement testing, characterized in that: it includes a cylindrical load transmission rod threadedly connected to a probe rod, the load transmission rod having a wire hole inside, the load transmission rod including an integrally formed probe rod connecting part, an upper torque transmission part, a pressure sensing part, a lower torque transmission part, and a spiral plate shaft connecting part, the outer diameter of the pressure sensing part being smaller than the outer diameter of other parts of the load transmission rod; the pressure sensing part is equipped with a resistive strain gauge for checking soil pressure.

[0007] The upper torque transmission part and the lower torque transmission part are provided with splines for transmitting rotational torque; the load transmission rod is fitted with a torque sleeve; the torque sleeve is provided with a spline groove that cooperates with the splines of the upper torque transmission part and the lower torque transmission part to transmit rotational torque.

[0008] A displacement detection assembly for detecting the relative displacement change between the load transmission rod and the torque sleeve is provided between the lower torque transmission part and the torque sleeve; the displacement detection assembly includes a movable capacitor plate that moves with the load transmission rod and is installed on the lower torque transmission part of the load transmission rod, and a fixed capacitor plate that cooperates with the movable capacitor plate on the inner wall of the torque sleeve.

[0009] The resistance strain gauge and displacement detection component are electrically connected to an external data acquisition device;

[0010] The upper end of the torque sleeve is threadedly connected to an upper connector to prevent the load transmission rod from disengaging from the torque sleeve. The inner wall of the upper connector slides against the outer wall of the probe connection part. The upper end of the upper connector is provided with an external thread for connecting the sleeve.

[0011] The lower end of the torque sleeve is threaded to prevent the load transmission rod from disengaging from the lower connector of the torque sleeve, and the inner wall of the lower connector slides in fit with the outer wall of the spiral plate shaft.

[0012] The lower end of the spiral plate shaft connection is connected to the spiral plate assembly;

[0013] The load transmission rod can move axially within the cavity formed by the upper connector, torque sleeve, and lower connector. The upper limit is when the upper end face of the spline of the upper torque transmission part abuts against the lower end face of the upper connector, and the lower limit is when the lower end face of the spline of the lower torque transmission part abuts against the end face of the inner ring platform of the lower connector. The maximum distance of movement is the displacement measurement range of the probe.

[0014] More preferably, the wall thickness of the pressure sensing part is 3-4 mm.

[0015] More preferably, the upper connector has a clamping part on the middle outer wall.

[0016] More preferably, O-rings are provided between the torque sleeve and the upper and lower connectors, between the upper connector and the probe rod connection, and between the lower connector and the spiral plate shaft connection.

[0017] More preferably, the spiral plate assembly includes a spiral plate connecting sleeve, which is threadedly connected to the lower end of the spiral plate shaft connecting part. The lower end of the spiral plate connecting sleeve is fitted with a spiral plate shaft through a square tenon. The spiral plate shaft is connected to the spiral plate connecting sleeve through a soft metal wire to prevent detachment. The upper end of the spiral plate shaft abuts against the spiral plate shaft connecting part. A spiral plate is welded to the lower part of the spiral plate shaft.

[0018] More preferably, the spiral plate assembly includes a spiral plate shaft, the spiral plate shaft includes a load transmission rod connecting part and a spiral plate sleeve connecting part, and an annular boss with an outer diameter larger than the outer diameter of the lower torque transmission part and the spiral plate sleeve connecting part and consistent with the outer diameter of the torque sleeve is provided between the load transmission rod connecting part and the spiral plate sleeve connecting part; a spiral plate head assembly is detachably fitted on the spiral plate sleeve connecting part;

[0019] The spiral plate head assembly includes a spiral plate sleeve that is detachably connected to the spiral plate sleeve connection part. The outer wall of the spiral plate sleeve is welded with a spiral plate. The spiral plate sleeve is provided with a spline groove inside. The spiral plate sleeve connection part is provided with a spline that mates with the spline groove. The upper and lower ends of the spiral plate sleeve are provided with damping rings between the spiral plate sleeve connection part and the spiral plate sleeve upper end to prevent the spiral plate sleeve from slipping off under its own weight.

[0020] More preferably, the annular boss of the spiral plate shaft is provided with a clamping part on its outer wall.

[0021] More preferably, a pore water pressure detection component is installed at the lower end of the spiral plate shaft for detecting pore water pressure in the soil layer.

[0022] More preferably, the pore water pressure detection assembly includes a cone head, which is threadedly connected to the pore water pressure detection cavity at the lower end of the spiral plate shaft. The outer circumference of the cone head is provided with a water inlet, which is connected to the pore water pressure detection cavity through a water inlet channel. A water pressure sensor is installed in the pore water pressure detection cavity, and the water pressure sensor is electrically connected to a pressure acquisition device.

[0023] More preferably, the water inlets are located on the same circumference, and a filter ring is installed on the circumferential surface of the water inlets.

[0024] Advantages and technical effects of this utility model: This utility model provides a spiral plate load test probe based on soil pressure and settlement displacement testing. Through a series of innovative designs, it realizes the synchronous and high-precision measurement of key parameters such as soil pressure, settlement displacement and pore water pressure, providing strong technical support for the evaluation of foundation soil bearing capacity and deformation characteristics in the field of civil engineering.

[0025] Firstly, regarding pressure measurement, the probe employs a specially designed load transfer rod, where the outer diameter of the pressure sensing section is smaller than the outer diameter of other parts of the load transfer rod. This structure makes pressure sensing more sensitive and able to more accurately capture changes in soil pressure. Combined with the use of resistance strain gauges, direct, real-time detection of soil pressure is achieved, providing a reliable basis for subsequent data acquisition and analysis.

[0026] Secondly, regarding torque transmission, the probe load transfer rod employs a two-segment spline structure to transmit rotational torque, ensuring efficient and accurate torque transfer between the torque sleeve and the load transfer rod. This guarantees the stability of the pressure sensing section structure between the upper and lower torque transmission parts, while also ensuring normal sliding of the load transfer rod within the torque sleeve during the load test. This design not only meets the process requirements of the spiral plate load test but also improves the structural strength of the probe, ensuring the smooth progress of the test.

[0027] Third, in terms of displacement measurement, the probe innovatively employs a displacement detection component, which detects the change in relative displacement between the load transfer rod and the torque sleeve through capacitance changes. This non-contact measurement method features high precision and stability, and can reflect the deformation of the soil layer under load in real time, providing important data for assessing the deformation characteristics of foundation soil.

[0028] Fourth, regarding multi-parameter testing, the probe incorporates a pore water pressure detection component, enabling simultaneous detection of pore water pressure within the soil layer. This design allows the probe to comprehensively acquire three key data points: soil pressure, displacement, and pore water pressure, providing strong support for a comprehensive assessment of the bearing capacity and deformation characteristics of foundation soil.

[0029] In particular, the design of the pore water pressure detection component is ingenious. The evenly distributed inlets ensure uniform inflow of pore water; the filter rings effectively block impurities, protecting the water pressure sensor from clogging and damage, thereby improving the accuracy of pore water pressure measurement.

[0030] Fifth, the overall design of the probe also takes into account the convenience and safety of actual operation. For example, the upper connector is equipped with a clamping part, which simplifies the installation and disassembly process; O-rings are provided between the torque sleeve and the upper and lower connectors, and between the upper and lower connectors and the load transmission rod, to enhance the sealing performance of the probe; the spiral plate assembly adopts a detachable design, which is convenient for replacement and maintenance; the annular boss of the spiral plate shaft is also equipped with a clamping part to ensure stable clamping and reliable connection.

[0031] In summary, the spiral plate load test probe provided by this utility model has significant technical advantages in terms of comprehensiveness, accuracy, and efficiency, providing strong technical support for the assessment of the bearing capacity and deformation characteristics of foundation soil in the field of civil engineering. Attached Figure Description

[0032] Figure 1a This is a schematic diagram of the initial working state structure of Embodiment 1 of this utility model;

[0033] Figure 1b This is a schematic diagram of the working state structure of Embodiment 1 of this utility model;

[0034] Figure 2 This is the sectional view AA in Figure 1;

[0035] Figure 3 This is a three-dimensional structural diagram of Embodiment 1 of this utility model;

[0036] Figure 4 This is a schematic diagram of a load transfer rod structure;

[0037] Figure 5 This is a schematic diagram of a half-section of the torsion sleeve structure;

[0038] Figure 6 This is a schematic diagram of the spiral plate shaft structure in Example 1;

[0039] Figure 7 This is a schematic diagram of the structure of Embodiment 2 of this utility model;

[0040] Figure 8 yes Figure 7 BB section view;

[0041] Figure 9 This is a three-dimensional structural diagram of Embodiment 2 of this utility model;

[0042] Figure 10 This is a schematic diagram of the load transfer rod structure in Embodiment 2 of this utility model;

[0043] Figure 11 This is a schematic diagram of the spiral plate shaft structure;

[0044] Figure 12 This is a schematic diagram of the three-dimensional structure of the spiral plate shaft;

[0045] Figure 13 This is a schematic diagram of the cone-shaped structure;

[0046] Figure 14 This is a schematic diagram of the spiral plate head assembly structure.

[0047] In the diagram: 1. Load transfer rod; 1-1. Probe connecting part; 1-2. Upper torque transmission part; 1-3. Pressure sensing part; 1-4. Lower torque transmission part; 1-5. Spiral plate shaft connecting part; 1-6. Spline; 2. Resistance strain gauge; 3. Torque sleeve; 3-1. Spline groove; 4. Upper connector; 4-1. Clamping part; 4-2. Lower connector;

[0048] 5. Spiral plate shaft; 5-1. Load transmission rod connecting part; 5-2. Spiral plate sleeve connecting part; 5-3. Annular boss; 5-4. Clamping part; 501. Spiral plate connecting sleeve; 502. Soft metal wire;

[0049] 6. Spiral plate head assembly; 6-1. Spiral plate sleeve; 6-2. Spiral plate; 6-3. Spline groove; 6-4. Spline; 7. Displacement detection assembly; 7-1. Moving capacitor plate; 7-2. Fixed capacitor plate; 8. Pore water pressure detection assembly; 8-1. Cone head; 8-2. Pore water pressure detection chamber; 8-3. Inlet; 8-4. Water pressure sensor; 8-5. Filter ring; 9. O-ring seal; 10. Damping ring. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model.

[0051] Example 1, please refer to Figures 1 to 12. Figure 6 A spiral plate load test probe based on soil pressure and settlement displacement testing includes a cylindrical load transfer rod 1 threadedly connected to a probe rod. The load transfer rod has a wire-passing hole. The load transfer rod includes an integrally formed probe rod connecting part 1-1, an upper torque transmission part 1-2, a pressure sensing part 1-3, a lower torque transmission part 1-4, and a spiral plate shaft connecting part 1-5. The outer diameter of the pressure sensing part is smaller than the outer diameter of other parts of the load transfer rod, making pressure sensing more sensitive and able to more accurately capture changes in soil pressure. A resistance strain gauge 2 is provided on the pressure sensing part for directly detecting soil pressure, facilitating subsequent data acquisition and analysis.

[0052] The upper and lower torque transmission parts are provided with splines 1-6 for transmitting rotational torque; a torque sleeve 3 is fitted over the load transmission rod; the torque sleeve is provided with a spline groove 3-1 that mates with the splines on the upper and lower torque transmission parts for transmitting rotational torque; the use of splines to transmit torque ensures efficient and accurate transmission of torque between the load transmission rod and the torque sleeve, maintains structural stability, allows the probe to rotate down to the test depth, and ensures that the load transmission rod and the torque sleeve slide together during the load test, accurately measuring the relative displacement between the load transmission rod and the torque sleeve.

[0053] A displacement detection component 7 is provided between the lower torque transmission part 1-4 and the torque sleeve 3 for detecting the displacement of the load transmission rod and the relative displacement change of the torque sleeve. The displacement detection component includes a movable capacitor plate 7-1 installed on the lower torque transmission part of the load transmission rod and moving with the load transmission rod, and a fixed capacitor plate 7-2 on the inner wall of the torque sleeve that cooperates with the movable capacitor plate. The relative displacement change between the load transmission rod and the torque sleeve is detected by the change in capacitance. This non-contact measurement method has high precision and high stability and can reflect the deformation of the soil layer under load in real time.

[0054] The upper end of the torque sleeve is threadedly connected to an upper connector 4 to prevent the load transfer rod from detaching from the torque sleeve. The inner wall of the upper connector slides in fit with the outer wall of the probe connection part. The upper connector is threadedly connected to the sleeve of the spiral plate load testing equipment. The lower end of the torque sleeve is threadedly connected to a lower connector 4-2 to prevent the load transfer rod from detaching from the torque sleeve. The inner wall of the lower connector slides in fit with the outer wall of the spiral plate shaft connection. This effectively prevents the load transfer rod from detaching from the torque sleeve during the test, enhancing the safety and stability of the entire probe.

[0055] The lower end of the spiral plate shaft connecting part 1-5 is connected to the spiral plate assembly 6. In this embodiment, the spiral plate assembly includes a spiral plate connecting sleeve 501. The spiral plate connecting sleeve is threaded to the lower end of the spiral plate shaft connecting part. The spiral plate shaft 5 is inserted into the lower end of the spiral plate connecting sleeve through a square tenon. The spiral plate shaft is connected to the spiral plate connecting sleeve through a soft metal wire 502 to prevent detachment. The upper end of the spiral plate shaft abuts against the spiral plate shaft connecting part. A spiral plate 6-2 is welded to the lower end of the spiral plate shaft.

[0056] The load transmission rod can move axially within the cavity formed by the upper connector, torque sleeve, and lower connector. The upper limit is when the upper end face of the spline of the upper torque transmission part abuts against the lower end face of the upper connector, and the lower limit is when the lower end face of the spline of the lower torque transmission part abuts against the end face of the inner ring platform of the lower connector. The maximum distance of movement is the displacement measurement range of the probe.

[0057] The resistance strain gauges and displacement detection components are electrically connected to external data acquisition equipment, enabling real-time data acquisition, transmission, and processing. The wiring harnesses of the resistance strain gauges and displacement detection components all extend from the wire passage holes of the load transfer rod.

[0058] In summary, this spiral plate load test probe, through a series of innovative technical features, achieves simultaneous measurement of soil pressure and settlement displacement. These technical features work together to form the foundation of the probe's high performance and high reliability, providing strong technical support for the assessment of foundation soil bearing capacity and deformation characteristics in the field of civil engineering.

[0059] Example 2: Based on Example 1, the load transfer rod of the test probe is axially extended through the wire hole. The external thread at the bottom end of the lower section of the spiral plate shaft connection is changed to an internal thread, and a pore water pressure sensor is added inside. Simultaneously, the structure of the spiral plate assembly is changed, such as changing the spiral plate from being welded to the spiral plate shaft to being welded to the spiral plate sleeve. This enables simultaneous detection of soil pressure, settlement displacement, and pore water pressure. The specific structure is as follows:

[0060] Please see Figures 7 to 14 A spiral plate load test probe based on soil pressure and settlement displacement testing includes a cylindrical load transfer rod 1 threadedly connected to a probe rod. The load transfer rod has a wire-passing hole. The load transfer rod includes an integrally formed probe rod connecting part 1-1, an upper torque transmission part 1-2, a pressure sensing part 1-3, a lower torque transmission part 1-4, and a spiral plate shaft connecting part 1-5. The outer diameter of the pressure sensing part is smaller than the outer diameter of other parts of the load transfer rod, making pressure sensing more sensitive and able to more accurately capture changes in soil pressure. A resistance strain gauge 2 is provided on the pressure sensing part for directly detecting soil pressure, facilitating subsequent data acquisition and analysis.

[0061] The upper and lower torque transmission parts are provided with splines 1-6 for transmitting rotational torque; the load transmission rod is fitted with a torque sleeve 3; the torque sleeve is provided with a spline groove 3-1 that mates with the splines on the upper and lower torque transmission parts for transmitting rotational torque.

[0062] The upper end of the torque sleeve is threadedly connected to an upper connector 4 to prevent the load transfer rod from detaching from the torque sleeve. The upper connector is threadedly connected to the sheath tube of the spiral plate load testing equipment. The upper end of the upper connector is provided with an external thread for connecting the sleeve. The lower end of the torque sleeve is threadedly connected to a lower connector 4-2 to prevent the load transfer rod from detaching from the torque sleeve. This effectively prevents the load transfer rod from detaching from the torque sleeve during the test, enhancing the safety and stability of the entire probe.

[0063] The lower end of the spiral plate shaft connecting part 1-5 is threadedly connected to the spiral plate shaft 5, and the spiral plate shaft is detachably provided with a spiral plate head assembly 6; the spiral plate shaft 5 includes a load transmission rod connecting part 5-1 and a spiral plate sleeve connecting part 5-2, and an annular boss 5-3 with an outer diameter larger than the outer diameter of the lower torque transmission part and the spiral plate sleeve connecting part is provided between the load transmission rod connecting part and the spiral plate sleeve connecting part. The design of the annular boss not only enhances the structural strength of the spiral plate shaft; the spiral plate assembly 6 is detachably fitted on the spiral plate sleeve connecting part; after the lower torque transmission part is threadedly connected to the spiral plate shaft, there is at least a certain gap between the lower end of the torque sleeve and the upper end face of the annular boss of the spiral plate shaft, to prevent the axial force received by the spiral plate assembly from being transmitted to the lower connector and improve the accuracy of measurement.

[0064] A displacement detection component 7 is provided between the lower torque transmission part 1-4 and the torque sleeve 3 for detecting the displacement change of the load transmission rod relative to the torque sleeve. The displacement detection component includes a movable capacitor plate 7-1 installed on the lower torque transmission part of the load transmission rod and moving with the load transmission rod, and a fixed capacitor plate 7-2 on the inner wall of the torque sleeve that cooperates with the movable capacitor plate. The displacement change of the load transmission rod is detected by the change of capacitance. This non-contact measurement method has high precision and high stability and can reflect the deformation of the soil layer under load in real time.

[0065] The lower end of the spiral plate shaft is equipped with a pore water pressure detection component 8, which is used to detect the pore water pressure in the soil layer. This design enables the probe to simultaneously acquire three key data points: soil pressure, displacement, and pore water pressure, providing strong support for a comprehensive assessment of the bearing capacity and deformation characteristics of the foundation soil.

[0066] The resistance strain gauge, displacement detection assembly, and pore water pressure detection assembly are electrically connected to external data acquisition equipment, enabling real-time data acquisition, transmission, and processing. The wiring harnesses for these components all extend from the wire passage holes of the load transfer rod.

[0067] In summary, this spiral plate load test probe, through a series of innovative technical design features, achieves simultaneous measurement of soil pressure, pore water pressure, and displacement, improving the comprehensiveness, accuracy, and efficiency of the test. These technical features work synergistically to form the foundation of the probe's high performance and high reliability, providing strong technical support for the assessment of foundation soil bearing capacity and deformation characteristics in the field of civil engineering.

[0068] The specific wall thickness of the pressure sensing element is usually determined based on actual design requirements, material properties, and the expected pressure, so there is no fixed range applicable to all situations. However, in helical load tests, when a hollow load transfer rod is used to collect soil pressure, the wall thickness of the pressure sensing element significantly affects its technical effectiveness. Generally, the wall thickness of the pressure sensing element is 3–4 mm.

[0069] Preferably, the outer wall of the upper connector is provided with a clamping part 4-1. This simplifies the installation and disassembly process, ensures stable clamping, and effectively improves the ease of operation and connection reliability.

[0070] More preferably, O-rings 9 are provided between the torque sleeve and the upper and lower connectors, between the upper connector and the probe connecting part, between the lower connector and the spiral plate shaft connecting part, and between the spiral plate shaft connecting part and the spiral plate shaft.

[0071] More preferably, the spiral plate assembly 6 includes a spiral plate sleeve 6-1 detachably connected to the spiral plate sleeve connecting part, and a spiral plate 6-2 welded to the outer wall of the spiral plate sleeve; a spline groove 6-3 is provided inside the spiral plate sleeve, and a spline 6-4 that mates with the spline groove is provided on the spiral plate sleeve connecting part; a damping ring 10 is provided between the inner and outer ends of the spiral plate sleeve and the spiral plate sleeve connecting part to prevent the spiral plate sleeve from slipping off under its own weight.

[0072] Preferably, the outer wall of the annular boss of the spiral plate shaft is provided with a clamping part 5-4. This ensures stable clamping and effectively improves the ease of operation and connection reliability.

[0073] More preferably, the pore water pressure detection component 8 includes a cone head 8-1, which is threadedly connected to the pore water pressure detection cavity 8-2 at the lower end of the spiral plate shaft. The outer circumference of the cone head is provided with a water inlet 8-3, which is connected to the pore water pressure detection cavity through a water inlet channel. A water pressure sensor 8-4 is installed in the pore water pressure detection cavity, and the water pressure sensor is electrically connected to a data acquisition device.

[0074] Preferably, the inlets are located on the same circumference, and filter rings 8-5 are installed on the circumferential surface of the inlets. This ingenious design greatly improves the accuracy and reliability of the test. The evenly distributed inlets ensure uniform inflow of pore water, while the filter rings effectively block impurities, protecting the water pressure sensor from clogging and damage, thereby improving the accuracy of pore water pressure measurement.

[0075] This invention plays a crucial role in the spiral plate load test. The following is a detailed description of the working process and force transmission path:

[0076] 1. Preparation stage

[0077] Connect the probe rod connector to the probe rod, and connect the upper connector of the probe to the sleeve. Pass the cable through the probe rod. Rotate the sleeve manually or mechanically to lower the entire probe (including the load transfer rod, torque sleeve, and spiral plate shaft) to the formation. Continuously add probe rods and sleeves until the probe reaches the predetermined test depth by 0.5–1.0 meters. During this process, the sleeve drives the upper connector, which in turn drives the torque sleeve. The torque sleeve, through its internal spline, engages with the splines of the upper and lower torque transfer parts on the load transfer rod, causing the load transfer rod to rotate. The spiral plate shaft connector on the load transfer rod drives the spiral plate connecting sleeve connected below it. The spiral plate connecting sleeve, through a square insert, drives the spiral plate shaft and its spiral plate to the predetermined test depth. Simultaneously, the probe rod connected to the probe rod connector on the load transfer rod rotates and moves downward synchronously with the test probe, ensuring that the advance per revolution equals the pitch of the spiral plate. This reduces the disturbance to the formation caused by the spiral plate load test.

[0078] 2. Installation and Debugging Phase

[0079] First, to eliminate the influence of the probe weight on the bearing spiral load test, the spinning of the sleeve was stopped when the test probe reached 0.5 to 1.0 meters above the predetermined test depth. A guide sleeve was then installed between the sleeve and the probe, and a friction sleeve was installed and clamped on the end face of the guide sleeve on the outer side of the probe. The spinning sleeve was then extended 0.5 to 1.0 meters to the predetermined test depth. Next, wooden blocks were installed on both sides of the sleeve on the ground, and sleeve clamps were placed on the wooden blocks and clamped with the sleeve clamps. Then, reaction frames and other reaction devices were installed, and a pressurizing device was installed at the upper end of the probe. The cables for testing pressure, displacement, and pore water pressure were connected to the main test control instrument. The operation of the load test probe was checked to ensure real-time data acquisition and recording.

[0080] 3. Loading and Observation Phase

[0081] The spiral bearing plate is loaded according to the expected loading level and loading standard using a probe. During loading, the load passes through the probe → load transfer rod → spiral plate; the resistance strain gauge on the pressure sensing part of the load transfer rod senses the change in pressure applied to the load plate; during loading, since the sleeve is locked on the ground and not subjected to vertical load, the load transfer rod of the test probe and the torsion sleeve generate relative displacement, and the moving capacitor plate and the fixed capacitor plate installed on it generate relative displacement synchronously, resulting in a change in capacitance between the two plates, which in turn senses the change in displacement.

[0082] During the loading process, the pore water pressure detection component also starts to work, collecting pore water in the soil layer through the water inlet and filter ring on the cone head, and the water pressure sensor measures the changes in pore water pressure in real time.

[0083] The electrical signals of pressure, displacement, and pore water pressure detected by the load test probe are transmitted to the external load test data acquisition and control instrument through the load transfer rod and the internal cable of the probe. The soil pressure, settlement displacement, and pore water pressure values ​​of the spiral bearing plate are recorded according to the load test standard.

[0084] Based on the settlement stability standard or observation time standard, apply the next level of load in a timely manner and continue to record data.

[0085] 4. Test Completion and Equipment Cleanup Phase

[0086] The spiral plate load test at that depth ends when all predetermined loading levels are completed or when soil failure is reached.

[0087] If the spiral plate load test continues at the next depth point in the borehole, the cable connecting the test control instrument and the reaction force and pressurization devices are disconnected. The probe and sleeve are then added, and assembly, debugging, and testing are performed according to the above three stages. If the spiral plate load test for this borehole is completed, the cable connecting the test control instrument and the reaction force and pressurization devices are disconnected without further assembly. Then, the probe and sleeve are lifted sequentially until the probe is removed. Initially, when lifting the probe, in Example 1, the spiral plate shaft detaches from the probe and remains in the formation at the test depth; in Example 2, the spiral plate sleeve and the spiral plate on it detach from the probe and remain in the formation at the test depth.

[0088] After the probe is removed from the hole, for Example 1, clean the dirt inside the spiral plate connecting sleeve, apply oil, and insert a new spiral plate shaft and its upper spiral plate for the next test; for Example 2, remove the pore water pressure detection component of the probe, clean the water passage and filter ring, and reinstall it. If the damping ring is damaged, replace it in time. Then, put a new spiral plate sleeve with a spiral plate on the spiral plate shaft for the next test.

[0089] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A spiral plate load test probe based on soil pressure and settlement displacement testing, characterized in that: The load transfer rod includes a cylindrical load transfer rod that is threadedly connected to a probe rod. The load transfer rod has a wire-passing hole inside. The load transfer rod includes an integrally formed probe rod connecting part, an upper torque transmission part, a pressure sensing part, a lower torque transmission part, and a spiral plate shaft connecting part. The outer diameter of the pressure sensing part is smaller than the outer diameter of other parts of the load transfer rod. The pressure sensing part is equipped with a resistive strain gauge for checking soil pressure. The upper torque transmission part and the lower torque transmission part are provided with splines for transmitting rotational torque; the load transmission rod is fitted with a torque sleeve; the torque sleeve is provided with a spline groove that cooperates with the splines of the upper torque transmission part and the lower torque transmission part to transmit rotational torque. A displacement detection assembly for detecting the relative displacement change between the load transmission rod and the torque sleeve is provided between the lower torque transmission part and the torque sleeve; the displacement detection assembly includes a movable capacitor plate that moves with the load transmission rod and is installed on the lower torque transmission part of the load transmission rod, and a fixed capacitor plate that cooperates with the movable capacitor plate on the inner wall of the torque sleeve. The resistance strain gauge and displacement detection component are electrically connected to an external data acquisition device; The upper end of the torque sleeve is threadedly connected to an upper connector to prevent the load transmission rod from disengaging from the torque sleeve. The inner wall of the upper connector slides against the outer wall of the probe connection part. The upper end of the upper connector is provided with an external thread for connecting the sleeve. The lower end of the torque sleeve is threaded to prevent the load transmission rod from disengaging from the lower connector of the torque sleeve, and the inner wall of the lower connector slides in fit with the outer wall of the spiral plate shaft. The lower end of the spiral plate shaft connection is connected to the spiral plate assembly; The load transmission rod can move axially within the cavity formed by the upper connector, torque sleeve, and lower connector. The upper limit is when the upper end face of the spline of the upper torque transmission part abuts against the lower end face of the upper connector, and the lower limit is when the lower end face of the spline of the lower torque transmission part abuts against the end face of the inner ring platform of the lower connector. The maximum distance of movement is the displacement measurement range of the probe.

2. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 1, characterized in that: The wall thickness of the pressure sensing element is 3-4 mm.

3. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 1, characterized in that: The upper connector has a clamping part on the middle outer wall.

4. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 1, characterized in that: O-rings are provided between the torque sleeve and the upper and lower connectors, between the upper connector and the probe rod connection, and between the lower connector and the spiral plate shaft connection.

5. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 1, characterized in that: The spiral plate assembly includes a spiral plate connecting sleeve, which is threaded to the lower end of the spiral plate shaft connecting part. The spiral plate shaft is inserted into the lower end of the spiral plate connecting sleeve through a square tenon. The spiral plate shaft is connected to the spiral plate connecting sleeve through a soft metal wire. The upper end of the spiral plate shaft abuts against the spiral plate shaft connecting part. A spiral plate is welded to the lower part of the spiral plate shaft.

6. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 1, characterized in that: The spiral plate assembly includes a spiral plate shaft, which includes a load transmission rod connecting part and a spiral plate sleeve connecting part. An annular boss with an outer diameter larger than the outer diameter of the lower torque transmission part and the spiral plate sleeve connecting part, and consistent with the outer diameter of the torque sleeve, is provided between the load transmission rod connecting part and the spiral plate sleeve connecting part. A spiral plate head assembly is detachably fitted onto the spiral plate sleeve connecting part. The spiral plate head assembly includes a spiral plate sleeve that is detachably connected to the spiral plate sleeve connection part. The outer wall of the spiral plate sleeve is welded with a spiral plate. The spiral plate sleeve is provided with a spline groove inside. The spiral plate sleeve connection part is provided with a spline that mates with the spline groove. The upper and lower ends of the spiral plate sleeve are provided with damping rings between the spiral plate sleeve connection part and the spiral plate sleeve upper end to prevent the spiral plate sleeve from slipping off under its own weight.

7. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 6, characterized in that: The spiral plate shaft has a clamping part on the outer wall of the annular boss.

8. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 6, characterized in that: A pore water pressure detection component is installed at the lower end of the spiral plate shaft to detect the pore water pressure in the soil layer.

9. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 8, characterized in that: The pore water pressure detection assembly includes a cone head, which is threadedly connected to the pore water pressure detection cavity at the lower end of the spiral plate shaft. The outer circumference of the cone head is provided with a water inlet, which is connected to the pore water pressure detection cavity through a water inlet channel. A water pressure sensor is installed inside the pore water pressure detection cavity, and the water pressure sensor is electrically connected to a pressure acquisition device.

10. The spiral plate load test probe based on soil pressure and settlement displacement testing according to claim 9, characterized in that: The water inlets are located on the same circumference, and a filter ring is installed on the circumferential surface of the water inlet.

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