A pressure gauge protection device for coarse-grained soil pressure test

Abstract

A pressure gauge protection device for a coarse-grained soil pressure gauge test includes a variable-diameter rigid protective armor installed on the outside of the pressure gauge cavity, the variable-diameter rigid protective armor consisting of a first metal armor in the middle and two second metal armors located at both ends; the first metal armor consists of a plurality of straight metal armor plates arranged in a ring along the tangential direction, and the second metal armor consists of a plurality of variable-diameter metal armor plates arranged in a ring along the tangential direction; the straight metal armor plates are of equal length along the axial direction of the pressure gauge cavity, and the variable-diameter metal armor plates are of smaller size as they are closer to the two ends along the axial direction of the pressure gauge cavity. The present invention can improve the tolerance and puncture resistance of the pressure gauge cavity in coarse-grained soil, and the installation and disassembly methods are simple. It can be used for large-sized pressure gauges and has strong applicability. At the same time, the variable-diameter armor design on the upper and lower sides of the present invention can make the lateral deformation of the test cavity in the middle of the pressure gauge more uniform, making the test results more accurate and effective.

Description

Technical Field

[0001] The invention belongs to the technical field of geotechnical engineering testing, and in particular relates to a pressure gauge protection device for a coarse-grained soil pressure gauge test. Background Art

[0002] Pressure gauge tests are widely used in in-situ geotechnical engineering to reveal the structural characteristics of soil layers. However, because in-situ soils often contain coarse-grained, porous, and angular soils, they can easily lead to uneven radial force application by the pressure gauge. Under high stress conditions in deeply buried soil layers, the pressure gauge test equipment can even be damaged, causing scratches or punctures in the pressure gauge cavity, compromising the proper conduct of the test and the accuracy of the results. Summary of the Invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a pressure gauge protection device for coarse-grained soil pressure gauge testing to solve the problems of insufficient tolerance and puncture resistance of the pressure gauge cavity, as well as the contact problem of the pressure gauge with porous and multi-angular coarse-grained soil, without affecting the test results.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] A pressure gauge protection device for a coarse-grained soil pressure test includes a variable-diameter rigid protective armor installed on the outside of the pressure gauge cavity, the variable-diameter rigid protective armor consisting of a first metal armor in the middle and two second metal armors located at both ends; the first metal armor consists of a plurality of straight metal armor sheets arranged in a ring along the tangential direction, and the second metal armor consists of a plurality of variable-diameter metal armor sheets arranged in a ring along the tangential direction; the straight metal armor sheets are of equal length along the axial direction of the pressure gauge cavity, and the variable-diameter metal armor sheets are of smaller size along the axial direction of the pressure gauge cavity as they approach the two ends.

[0006] In one embodiment, the straight metal armor plate is a straight metal sub-armor plate or is composed of multiple straight metal sub-armor plates connected in series along the axial direction. Each straight metal sub-armor plate has the same shape and size, and has a first assembly hole A at one end along the axial direction and a second assembly hole A at the other end. The first assembly hole A and the second assembly hole A are located in the same straight line. Two circumferentially adjacent straight metal sub-armor plates are overlapped and arranged in a ring in sequence along the tangential direction. That is, the edge of one straight metal sub-armor plate presses on the edge of its circumferentially adjacent straight metal sub-armor plate, so that the two can produce relative displacement along the circumferential direction. When multiple straight metal sub-armor plates are connected in series, the two axially adjacent straight metal sub-armor plates are assembled by fixing buckles to enable limited sliding.

[0007] In one embodiment, the straight metal sub-armor is arc-shaped along a cross section perpendicular to the axial direction, and the shape and size of the arc are the same from one end to the other end, and the curvature thereof fits the outer side of the pressure relief device cavity.

[0008] In one embodiment, the variable diameter metal armor plate is composed of a plurality of serially connected variable diameter metal sub-armor plates along the axial direction. The length of each variable diameter metal sub-armor plate along the axial cross-section gradually decreases toward the axial end, and the variable diameter metal sub-armor plates in the same circumferential direction have the same shape and size. A first assembly hole B is provided at one axial end of the variable diameter metal sub-armor plate, and a second assembly hole B is provided at the other end. The first assembly hole B and the second assembly hole B are located on the same straight line. Two axially adjacent variable diameter metal sub-armor plates are assembled by fixing buckles to enable limited sliding. Two circumferentially adjacent variable diameter metal sub-armor plates are tangentially overlapped, that is, the edge of one variable diameter metal sub-armor plate presses against the edge of its circumferentially adjacent variable diameter metal sub-armor plate, enabling relative displacement between the two circumferentially.

[0009] In one embodiment, the variable diameter metal sub-armor sheet is arc-shaped along a cross section perpendicular to the axial direction. The arc has the same curvature and gradually decreases in length in a direction away from the first metal armor, and the arc fits the outer side of the pressure relief device cavity.

[0010] In one embodiment, the first metal armor and the second metal armor are connected by connecting corresponding assembly holes through fixing buckles, and the second metal armor is fixed to the end of the bypass pressure device cavity by a fixing device at the end away from the first metal armor.

[0011] In one embodiment, the fixing device is an adhesive device, a bolt device, a screw device or a snap-fit ​​device.

[0012] In one embodiment, the shaft diameter of the fixing buckle is smaller than the hole diameter of each mounting hole, and the difference range is the movement range of adjacent sub-armor panels.

[0013] In one embodiment, the axial length of the first metal armor is consistent with the length of the pressure regulator cavity, and the axial length of the second metal armor is half of the difference between the entire length of the pressure regulator and the axial length of the first metal armor.

[0014] The present invention also proposes a pressure relief test method for a pressure relief device using the coarse-grained soil pressure relief test. The method first calibrates the restraining effect of the protection device on the pressure relief device, then performs the pressure relief test, and corrects the test results based on the calibration. The steps of the calibration and test result correction are as follows:

[0015] (1) After the protection device is installed, under the condition of no other lateral constraints, the lateral pressure gauge is pressurized in stages based on the test cavity volume change. The volume change of each stage and its corresponding lateral pressure are recorded, and the lateral pressure-volume change calibration curve is drawn;

[0016] (2) After the test is completed and the lateral pressure-volume change test curve is obtained, the test curve and the calibration curve are aligned based on the volume change, and the lateral pressure of the test curve is deducted from the lateral pressure of the corresponding calibration curve to complete the correction.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] 1) It can improve the tolerance and puncture resistance of the pressure relief device cavity in coarse-grained soil.

[0019] 2) The installation and disassembly methods are simple and can be used for large-sized bypass pressure transmitters, with strong applicability.

[0020] 3) The design of the variable diameter armor on the upper and lower sides can make the lateral deformation of the test cavity in the middle of the pressure gauge more uniform, making the test results more accurate and effective. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention (original state).

[0022] Figure 2 Schematic diagram of the structure of the present invention (expanded state).

[0023] Figure 3 It is a schematic structural diagram of a single straight metal sub-armor sheet of the present invention.

[0024] Figure 4 It is a cross-sectional view of the overlap of circumferentially adjacent straight metal sub-armor sheets (variable diameter metal sub-armor sheets) of the present invention.

[0025] Figure 5 It is a schematic diagram of the second metal armor structure of the present invention (assembly).

[0026] Figure 6 It is a schematic diagram of the second metal armor structure of the present invention (bulk).

[0027] Figure 7 It is a schematic diagram of the structure of a single second metal armor assembled with a fixing buckle according to the present invention.

[0028] Figure 8 It is a schematic diagram of the structure of a single variable diameter rigid protective armor assembled with fixing buckles according to the present invention.

[0029] Figure 9 It is a schematic diagram of the fixing buckle structure of the present invention. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings and examples.

[0031] The present invention relates to a pressure gauge protection device for a coarse-grained soil pressure gauge test. The main body of the device is a variable-diameter rigid protective armor, which is installed on the outside of the pressure gauge cavity to wrap the pressure gauge cavity and is used to protect the pressure gauge during the pressure gauge test to prevent the pressure gauge cavity from being punctured.

[0032] like Figure 1 and Figure 2 As shown, the variable diameter rigid protective armor is roughly in the shape of a hollow cylinder, consisting of a first metal armor 1 in the middle and two second metal armors 2 located at both ends. It is installed on the outside of the pressure relief device cavity and fits with it. Among them, the first metal armor 1 is composed of a plurality of straight metal armor sheets arranged in a ring along the tangent direction, and the second metal armor 2 is composed of a plurality of variable diameter metal armor sheets arranged in a ring along the tangent direction. Straight metal armor sheets refer to those with the same length along the axial direction of the pressure relief device cavity, while variable diameter metal armor sheets refer to those with smaller dimensions as they approach the two ends along the axial direction of the pressure relief device cavity. One end of the second metal armor 2 is connected to the first metal armor 1, and the other end is fixed to the end outside the pressure relief device cavity by a fixing device 3.

[0033] Therefore, according to Figure 1 and Figure 2 In its original, pre-tested state, the variable-diameter rigid protective armor was cylindrical. However, during testing, it expanded, and the structures of the first and second metal armors 1 and 2 resulted in different shapes after expansion. Specifically, after expansion, the first metal armor 1 remained cylindrical, while the second metal armor 2, after expansion, had a smaller cross-section toward the ends and a larger cross-section toward the center.

[0034] The principle is:

[0035] During the test, air pressure was applied to the pressure gauge cavity, causing the pressure diaphragm in the pressure gauge cavity to expand. Since the two ends of the pressure diaphragm are fixed and cannot produce volume changes, the middle part of the pressure diaphragm expands significantly, while the two ends expand less significantly.

[0036] During the expansion process of the second metal armor 2, the variable diameter metal armor pieces connected by the fixing buckles will rotate relative to each other at the fixing buckle position, so that the variable diameter metal armor pieces are connected at a certain angle, thereby achieving the effect of making the second metal armor 2 as a whole achieve a near bending deformation.

[0037] In combination with the above structure, the present invention protects the lateral pressure chamber from being scratched or punctured by sharp soil particles by adding a variable diameter rigid protective armor to the outside of the lateral pressure chamber that can expand and deform in coordination with the lateral pressure chamber, thereby reducing the loss of the lateral pressure chamber and extending the service life of the lateral pressure chamber. Compared with the contact conditions between the lateral pressure chamber and the coarse sand and gravel soil layer, the contact surface between the lateral pressure chamber and the protective device of the present invention fits well, and the metal protective armor can evenly transmit the pressure of the lateral pressure chamber to the soil layer. The variable diameter design of the protective armor makes the deformation of the lateral pressure chamber more uniform and the test results more stable. The device provides a solution to the tolerance and puncture resistance problems of the lateral pressure chamber of coarse-grained soils such as gravel and rockfill materials, as well as the contact problem with porous and multi-angular coarse-grained soils. It can be used for large-scale, high-stress lateral pressure tests on coarse-grained soils.

[0038] In the embodiment of the present invention, reference Figure 3As shown, the straight metal armor plate can consist of a single straight metal sub-plate 11, or it can be composed of multiple straight metal sub-plates 11 connected in series along the axial direction of the pressure relief chamber. Each straight metal sub-plate 11 has the same shape and size, and has a first assembly hole A12 at one axial end and a second assembly hole A13 at the other end. The line connecting the first assembly hole A12 and the second assembly hole A13 is parallel to the axial direction.

[0039] Thus, when multiple straight metal sub-armor sheets 11 are connected in series, two axially adjacent straight metal sub-armor sheets 11 are assembled together using the fixing buckle 14. Specifically, the fixing buckle 14 is inserted into the first assembly hole A12 of one straight metal sub-armor sheet 11 and the second assembly hole A13 of the adjacent straight metal sub-armor sheet 11 to achieve axial assembly of the two straight metal sub-armor sheets 11. The assembly of the fixing buckle 14 with the assembly holes allows limited sliding of the two axially adjacent straight metal sub-armor sheets 11.

[0040] At the same time, two circumferentially adjacent straight metal sub-armor sheets 11 are overlapped and arranged in a ring in the tangential direction. That is, the edge of one straight metal sub-armor sheet 11 is pressed on the edge of its circumferentially adjacent straight metal sub-armor sheet 11. The straight metal sub-armor sheets 11 in the same circumferential direction are pressed against each other in sequence. Figure 4 As shown, by combining the fixing buckle 14 with the assembly hole, two circumferentially adjacent straight metal sub-armor sheets 11 can produce relative displacement along the circumferential direction.

[0041] Furthermore, in an embodiment of the present invention, the front view of the straight metal sub-armor 11 is rectangular, while the cross-section perpendicular to the axial direction is arc-shaped. Moreover, the shape and size of the arc are exactly the same from one end to the other end along the axial direction, and the arc can fit on the outside of the pressure relief device cavity. This fit can have a certain gap without affecting the test application.

[0042] For example, the width (dimension perpendicular to the axial direction) of a single straight metal sub-armor sheet 11 of the present invention is generally 20 mm, and the length (dimension along the axial direction) is generally 300 mm. When used, the circumferential number is determined according to the size of the pressure gauge, and the size of the straight metal armor can be adjusted according to the size of the pressure gauge measuring cavity.

[0043] In the embodiment of the present invention, reference Figure 5 and Figure 6 As shown, the variable diameter metal armor plate is composed of multiple variable diameter metal sub-plates 21 connected in series along the axial direction of the pressure relief chamber. The length of each variable diameter metal sub-plate 21 along the axial cross-section gradually decreases toward the axial end. The variable diameter metal sub-plates 21 in the same circumferential direction can have the same shape and dimensions. A first assembly hole B21 is defined at one axial end of the variable diameter metal sub-plate 21, and a second assembly hole B23 is defined at the other end. The line connecting the first assembly hole B22 and the second assembly hole B23 is parallel or approximately parallel to the axial direction.

[0044] Thus, two axially adjacent variable-diameter metal armor sub-pieces 21 are assembled together using the fixing buckle 14. Specifically, the fixing buckle 14 is inserted through the first assembly hole B22 of one variable-diameter metal armor sub-piece 21 and the second assembly hole B23 of the adjacent variable-diameter metal armor sub-piece 21. This allows for axial assembly of the two variable-diameter metal armor sub-pieces 21. This assembly of the fixing buckle 14 and the assembly holes allows limited sliding movement of the two axially adjacent variable-diameter metal armor sub-pieces 21.

[0045] At the same time, two circumferentially adjacent variable diameter metal sub-armor sheets 21 are overlapped and arranged in a ring in the tangential direction. That is, the edge of one variable diameter metal sub-armor sheet 21 is pressed on the edge of its circumferentially adjacent variable diameter metal sub-armor sheet 21. The variable diameter metal sub-armor sheets 21 in the same circumferential direction are pressed against each other in turn. Similarly, Figure 4 As shown, by combining the fixing buckle 14 with the assembly hole, two circumferentially adjacent variable-diameter metal sub-armor sheets 21 can produce relative displacement along the circumferential direction.

[0046] Furthermore, in an embodiment of the present invention, the front view of the variable diameter metal sub-armor piece 21 is an isosceles trapezoid, while the cross section perpendicular to the axial direction is an arc. Moreover, from the end close to the first metal armor 1 along the axial direction to the end away from the first metal armor 1, the shape and curvature of the arc are the same, but the size gradually decreases. The curvature can fit the outside of the side pressure device cavity. This fit can have a certain gap without affecting the test application.

[0047] For example, the maximum width (dimension perpendicular to the axial direction) of a single variable diameter metal sub-armor piece 21 of the present invention is generally 20 mm, and the length (dimension along the axial direction) is generally 15 mm. When in use, the circumferential installation quantity and the minimum width are determined based on the overall length of the pressure gauge. The size of the variable diameter metal armor can be adjusted according to the size of the pressure gauge measuring cavity.

[0048] For example, the axial length of the first metal shield 1 matches the length of the pressure gauge test chamber, while the axial length of each second metal shield 2 is half the difference between the overall pressure gauge length and the axial length of the first metal shield 1. Typically, a single straight metal shield is 300 mm long, and a single variable-diameter metal shield is 15 mm long, with a ratio of 20:1. This ratio can be adjusted based on actual conditions.

[0049] In the second metal armor 2 of the present invention, the metal sub-armor pieces 21 with variable diameters on the same axial direction are fixed with the fixing buckles 14, and the effect is as follows: Figure 7 As shown, it can be seen that the closer it is to the end of the pressure relief device cavity, the smaller the transverse dimension. In the overall variable diameter rigid protective armor of the present invention, after the straight metal sub-armor sheet 11 and the variable diameter metal sub-armor sheet 21 on the same axial direction are fixed with the fixing buckle 14, the effect is referenced. Figure 8As shown, it can be seen that the closer it is to the end of the pressure relief chamber, the smaller the lateral dimension is, and in the middle of the pressure relief chamber, the lateral dimension is the largest and equal.

[0050] Among them, at the junction of the first metal armor 1 and the second metal armor 2, Figure 3 and Figure 6 Taking the structure shown as an example, the first assembly hole A12 at the end of the first metal armor 1 is connected to the second assembly hole B23 at the end of the second metal armor 2 via a fixing buckle 14, thereby achieving the connection between the first metal armor 1 and the second metal armor 2. The connection of the second metal armor 2 is similar.

[0051] The second metal armor 2 of the present invention is fixed to the end of the pressure relief chamber at the end away from the first metal armor 1 by a fixing device 3. The fixing device 3 can be an adhesive device, a bolt device, a screw device or a clamping device, etc. In practice, adhesive tape can be used for fixing.

[0052] In some embodiments of the present invention, reference Figure 9 As shown, the fixing buckle 14 is assembled from a sub-buckle 141 and a female buckle 142. The sub-buckle 141 is an externally threaded shaft with a cap at its end, while the female buckle 142 is an internally threaded shaft with a cap at its end. They are connected by inserting them into corresponding assembly holes. The shaft diameter of the fixing buckle 14 is smaller than the diameter of each mounting hole; the difference between the two defines the range of movement of adjacent sub-armor panels.

[0053] The pressure gauge protection device for the coarse-grained soil pressure test of the present invention lays the foundation for conducting large-scale, high-stress pressure tests on coarse-grained soil. The coarse-grained soil pressure test method of the present invention includes:

[0054] First, install the protection device on the existing bypass pressure gauge. The specific installation steps are as follows:

[0055] (1) Arrange a group of variable diameter metal sub-armor sheets 21 in order of size, align the corresponding assembly holes according to the principle of placing the smaller metal sub-armor sheets at both ends, and install the fixing buckles 14 to ensure that the variable diameter metal sub-armor sheets 21 can slide within a limited range after the fixing buckles 14 are installed.

[0056] (2) Repeat step (1) to obtain two upper and lower variable diameter metal armor plates, and connect the widest sides of the two variable diameter metal armor plates to a straight metal armor plate through a fixing buckle 14, with the variable diameter metal armor plate on top, to ensure that limited sliding can be performed between the metal armor plates after the fixing buckle 14 is installed.

[0057] (3) Repeat steps (1) and (2) to assemble all the metal armor plates. Lap all the strip metal armor plates in sequence to form a ring.

[0058] (4) Put the assembled metal armor protection device on the lateral pressure device, and use the fixing device 3 to fix the upper and lower ends. The coarse-grained soil lateral pressure test device is assembled.

[0059] Before using this device to conduct a pressure gauge test, it is necessary to calibrate the restraint effect of the protection device on the pressure gauge. Then, conduct the pressure gauge test and correct the test results based on the calibration. The steps for calibration and test result correction are as follows:

[0060] (1) After the protection device is installed, under the condition of no other lateral constraints, the lateral pressure gauge is pressurized in stages based on the test cavity volume variation (the specific pressurization stages are adjusted according to the needs of subsequent tests), the volume variation of each stage and its corresponding lateral pressure are recorded, and the lateral pressure-volume variation calibration curve is drawn;

[0061] (2) After the test is completed and the lateral pressure-volume change test curve is obtained, the test curve and the calibration curve are aligned based on the volume change, and the lateral pressure of the test curve is deducted from the lateral pressure of the corresponding calibration curve to complete the correction.

[0062] It is worth noting that during the test, pressure was applied inside the plenum chamber, and the metal armor was tightly fitted to the outer wall of the plenum chamber. Only a small amount of small soil particles could enter the gap between the metal armor and the plenum chamber through the gap between the metal armor, and their influence on the test results can be ignored.

Claims

1. A pressure gauge protection device for a coarse-grained soil pressure test, characterized in that: The invention comprises a variable diameter rigid protective armor installed on the outside of the pressure relief chamber, wherein the variable diameter rigid protective armor is composed of a first metal armor (1) in the middle and two second metal armors (2) located at both ends; the first metal armor (1) is composed of a plurality of straight metal armor sheets arranged in a ring along a tangential direction, and the second metal armor (2) is composed of a plurality of variable diameter metal armor sheets arranged in a ring along a tangential direction; the straight metal armor sheets are of equal length along the axial direction of the pressure relief chamber, and the variable diameter metal armor sheets are of smaller size as they are closer to the two ends along the axial direction of the pressure relief chamber; The straight metal armor plate is a straight metal sub-armor plate (11) or is composed of a plurality of straight metal sub-armor plates (11) connected in series along the axial direction. Each straight metal sub-armor plate (11) has the same shape and size, and has a first assembly hole A (12) at one end along the axial direction and a second assembly hole A (13) at the other end. The first assembly hole A (12) and the second assembly hole A (13) are located in the same straight line. Two circumferentially adjacent straight metal sub-armor plates (11) are overlapped and arranged in a ring in sequence along the tangential direction, that is, the edge of one straight metal sub-armor plate (11) is pressed on the edge of its circumferentially adjacent straight metal sub-armor plate (11) so that the two can generate relative displacement along the circumferential direction. When multiple straight metal sub-armor plates are connected in series, the two axially adjacent straight metal sub-armor plates (11) are assembled by fixing buckles (14) so ​​that limited sliding can be performed. The variable diameter metal armor plate is composed of a plurality of variable diameter metal sub-armor plates (21) connected in series along the axial direction. The length of each variable diameter metal sub-armor plate (21) along the axial cross section gradually decreases toward the axial end. The variable diameter metal sub-armor plates (21) in the same circumferential direction have the same shape and size. A first assembly hole B (21) is provided at one axial end of the variable diameter metal sub-armor plate (21), and a second assembly hole B (23) is provided at the other end. The first assembly hole B (22) and the second assembly hole B (23) are located on the same straight line. Two axially adjacent variable diameter metal sub-armor plates (21) are assembled by fixing buckles (14) so ​​as to enable limited sliding. Two circumferentially adjacent variable diameter metal sub-armor plates (21) are overlapped along the tangential direction, that is, the edge of one variable diameter metal sub-armor plate (21) is pressed against the edge of its circumferentially adjacent variable diameter metal sub-armor plate (21), so that the two can generate relative displacement along the circumferential direction.

2. The pressure gauge protection device for the coarse-grained soil pressure test according to claim 1, characterized in that: The straight metal sub-armor sheet (11) is arc-shaped along a cross section perpendicular to the axial direction, and the shape and size of the arc are the same from one end to the other end, and the arc fits the outer side of the pressure relief device cavity.

3. The pressure gauge protection device for the coarse-grained soil pressure test according to claim 1, characterized in that: The variable diameter metal sub-armor piece (21) is arc-shaped along a cross section perpendicular to the axial direction, and has a constant arc angle and a gradually decreasing arc length in a direction away from the first metal armor (1), and the arc angle fits the outer side of the pressure relief device cavity.

4. The pressure gauge protection device for the coarse-grained soil pressure test according to claim 1, characterized in that: The first metal armor (1) and the second metal armor (2) are connected by connecting corresponding assembly holes through fixing buckles (14); the second metal armor (2) is fixed to the end of the bypass pressure chamber through a fixing device (3) at an end away from the first metal armor (1).

5. The pressure gauge protection device for the coarse-grained soil pressure test according to claim 4, characterized in that: The fixing device (3) is an adhesive device, a bolt device, a screw device or a clamping device.

6. The pressure gauge protection device for the coarse-grained soil pressure test according to any one of claims 2 to 5, characterized in that: The shaft diameter of the fixing buckle (14) is smaller than the aperture of each mounting hole, and the difference range is the movement range of adjacent sub-armor sheets.

7. The pressure gauge protection device for the coarse-grained soil pressure test according to claim 1, characterized in that: The axial length of the first metal armor (1) is consistent with the length of the pressure gauge test chamber, and the axial length of the second metal armor (2) is half the difference between the overall length of the pressure gauge and the axial length of the first metal armor (1).

8. A pressure test method for a pressure transmitter protection device for a coarse-grained soil pressure test according to claim 1, wherein the restraining effect of the protection device on the pressure transmitter is first calibrated, and then the pressure test is performed, and the test results are corrected based on the calibration, characterized in that: The steps of calibration and test result correction are as follows: (1) After the protection device is installed, under the condition of no other lateral constraints, the lateral pressure gauge is pressurized in stages based on the test cavity volume change. The volume change of each stage and its corresponding lateral pressure are recorded, and the lateral pressure-volume change calibration curve is drawn; (2) After the test is completed and the lateral pressure-volume change test curve is obtained, the test curve and the calibration curve are aligned based on the volume change, and the lateral pressure of the test curve is deducted from the lateral pressure of the corresponding calibration curve to complete the correction.

Images