CN113483934A - Tunnel contact pressure testing device and method - Google Patents
Tunnel contact pressure testing device and method Download PDFInfo
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- CN113483934A CN113483934A CN202110562848.3A CN202110562848A CN113483934A CN 113483934 A CN113483934 A CN 113483934A CN 202110562848 A CN202110562848 A CN 202110562848A CN 113483934 A CN113483934 A CN 113483934A
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- pressure
- testing
- panel
- contact pressure
- pressure sensor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F17/18—Special adaptations of signalling or alarm devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
- G01L5/161—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force using variations in ohmic resistance
Abstract
The invention provides a testing device and a testing method for tunnel contact pressure, the testing device comprises an impact panel, a diaphragm type pressure sensor and a substrate panel which are stacked from top to bottom, the impact panel and the substrate panel jointly wrap the diaphragm type pressure sensor and encapsulate the impact panel, the diaphragm type pressure sensor and the substrate panel together, the impact panel is used for transmitting the contact pressure to the diaphragm type pressure sensor uniformly, and the diaphragm type pressure sensor is used for converting the contact pressure into a resistance signal. The testing device is formed by packaging a force application panel, a diaphragm type pressure sensor and a substrate panel in a three-layer structure, wherein the force application panel uniformly transmits contact pressure to the diaphragm type pressure sensor, and the diaphragm type pressure sensor directly converts the pressure into an electric signal, so that errors caused by multiple signal conversion of a traditional rigid pressure box are avoided; the device's whole thickness can be accomplished to be less than 2mm, and has advantages such as simple to operate, pass power reliable, strong durability, precision height.
Description
Technical Field
The invention relates to the field of tunnel engineering, in particular to a device and a method for testing tunnel contact pressure.
Background
The traditional rigid soil pressure cell has the influence of factors such as embedding effect, interaction influence of the cell and soil, filling influence, influence of different environments and the like on the testing precision in geotechnical engineering tests, but if the rock-soil body is soft, particularly in the stratum such as sandy soil, clay and the like, the surrounding rock deformation capacity is strong, and the testing precision can meet the requirement by adopting the mode of embedding the rigid soil pressure cell for testing the soil pressure.
However, in tunnel engineering, especially in mine method tunnels, the rigidity of the contact surface between the primary support and the surrounding rock, between the sprayed layer and the secondary lining is large, and if the rigid soil pressure cell used in the field of geotechnical engineering is directly carried, the problem obviously exists, which is specifically as follows:
(1) influence of measured Medium stiffness
Because the pressure cell rate is timed, the relation between the oil pressure and the steel string frequency is established, when the rigidity of the measured medium is lower, the medium does not restrict the deformation response of the bearing plate, at the moment, the stress condition of the bearing plate is more consistent with the stress condition of the oil pressure rate timing, the actual stress can be completely induced by the pressure cell, so the difference value between the actual stress and the measured stress is lower, and the precision can generally meet the engineering requirements. However, when the rigidity of the measured medium is high, the medium has high self-supporting capacity and small deformation, so that the deformation response of the bearing plate is restricted, and the stress of the bearing plate cannot be completely sensed by the sensitive element of the pressure box. From the analysis of the static balance angle, a part of the compressive stress is born by the side wall of the pressure box, so that the deformation of the bearing plate is smaller, and the actual stress is smaller than the actual stress. With the increase of the rigidity of the measured medium, the phenomenon that the measured stress is smaller is aggravated.
(2) Influence of the structural dimensions of the pressure cell
In order to adapt to severe working environment, the pressure box adopts a steel structure. In order to ensure the stable performance of the pressure cell, the integral strength and the rigidity of the pressure cell need to meet certain requirements, so that the side walls of the pressure cell are thicker, the larger the measuring range of the pressure cell is, the larger the thickness is, and the smaller the actually measured stress is obviously. The stress of the measured medium needs to be transmitted to the steel string through the bearing plate, so the diameter of the bearing plate of the pressure box also influences the measured value. The larger the diameter is, the more sensitive the steel string is to deformation of the bearing plate, and the closer the obtained measured value is to the actual stress. However, the diameter of the pressure cell is generally only 10 to 20cm, depending on the embedding conditions.
(3) Influence of the buried state of the pressure cell
The embedding of the pressure cell is one of the most important links in the monitoring work. Because the rigid soil pressure cell is not provided with a special installation hanging structure, the field installation mode is five-door and eight-door, most of the rigid soil pressure cells are directly supported on the wall of the hole by steel bars or are placed behind the wall of a steel frame, so that the stress surface of the pressure cell is not closely attached to surrounding rocks or even stress concentration is obvious, when sprayed concrete is applied, the pressure cell is directly wrapped, so that the stress on the side surface of the pressure cell is caused, the test panel is reversely stressed, and a negative value often appears in the test result; meanwhile, after the concrete is hardened, the pressure box wrapped in the cavity is often separated from the wall surface, and the actual stress state cannot be truly reflected.
In summary, the contact pressure monitoring of the tunnel is an important component of the structural health monitoring, but the traditional monitoring means has a large error, so that the measurement result cannot effectively guide the design and construction of the tunnel, and therefore, the development of a contact pressure testing device and a corresponding testing method suitable for tunnel engineering is urgently needed.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a device and a method for testing tunnel contact pressure.
The invention is realized by the following steps:
in one aspect, the invention provides a testing device for tunnel contact pressure, which comprises a force application panel, a diaphragm type pressure sensor and a substrate panel which are stacked from top to bottom, wherein the force application panel and the substrate panel jointly wrap the diaphragm type pressure sensor and encapsulate the diaphragm type pressure sensor, the force application panel, the diaphragm type pressure sensor and the substrate panel together, the force application panel is used for uniformly transmitting the contact pressure to the diaphragm type pressure sensor, and the diaphragm type pressure sensor is used for converting the contact pressure into a resistance signal.
Further, the diaphragm type pressure sensor comprises a base film, pressure-sensitive materials and a lead assembly, wherein the pressure-sensitive materials are uniformly distributed on the base film, when the pressure-sensitive materials are under pressure, a power function relation is formed between a pressure value and a resistance value, and the lead assembly is used for transmitting resistance signals of the pressure-sensitive materials to resistance value monitoring equipment.
Further, the wire assembly comprises an internal connecting wire, wiring terminals and an external connecting wire, the internal connecting wire is connected with adjacent pressure-sensitive materials and is used for connecting each pressure-sensitive material to the wiring terminals, and the external connecting wire is connected with the wiring terminals and external resistance value monitoring equipment.
Further, the pressure-sensitive material and the inner conductor line are both printed on the base film.
Further, the force application panel comprises a rubber plate and rigid force bearing blocks, wherein the rigid force bearing blocks are regularly arranged on the rubber plate and fully cover the pressure-sensitive material.
Furthermore, the hardness of the rubber plate is within the range of 60-70 HA, the hardness of the rigid stress blocks is within the range of 90-95 HD, and the gap between every two adjacent rigid stress blocks is smaller than 0.5 mm.
Furthermore, the base panel is of a homogeneous flat plate structure, and fixing holes are additionally formed in corners.
Further, the hardness of the substrate panel is within the range of 90-95 HD.
Further, inert lubricating grease is filled among three layers of the force application panel, the diaphragm type pressure sensor and the base panel, and the three layers of panels are in closed lap joint in an edge heat welding mode.
In another aspect, the present invention further provides a method for testing a tunnel contact pressure, which uses the apparatus for testing a tunnel contact pressure as described above, and the method includes:
s1: calibrating the testing device of the tunnel contact pressure through a loading test, and acquiring a pressure-resistance curve of each characteristic point;
s2: leveling the wall surface of the test point, tightly attaching an impact panel of the test device to the wall surface of the tunnel, and fixing the test device at the preset test point position;
s3: according to the tunnel construction steps, spraying concrete to completely cover the testing device, recording initial data, testing the resistance values omega 1 and omega 1 … omega n of each characteristic point of the testing device, and obtaining initial pressure values P1 and P2 … Pn of each characteristic point through the pressure-resistance curve determined in the step S1;
s4: testing the contact pressure according to a test plan to obtain resistance values omega t1 and omega t1 … omega tn of each characteristic point of the testing device at any moment, and obtaining initial pressure values Pt1 and Pt2 … Ptn of each characteristic point through the pressure-resistance curve determined in the step S1;
s5: and acquiring a pressure change difference value (delta Pn = Ptn-Pn) of each test characteristic point of the test device, discarding the obviously deviated data, and then taking an arithmetic average value as a contact pressure test value at the moment.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a device and a method for testing tunnel contact pressure, wherein the testing device is formed by packaging a force panel, a diaphragm type pressure sensor and a substrate panel in a three-layer structure; the device's whole thickness can be accomplished to be less than 2mm, and has advantages such as simple to operate, pass power reliable, strong durability, precision height.
Drawings
Fig. 1 is a schematic structural diagram of a testing apparatus for tunnel contact pressure according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a diaphragm type pressure sensor provided in an embodiment of the present invention;
FIG. 3 is a graph showing a relationship between a pressure value and a resistance value of a pressure sensitive material according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of an impact panel according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a substrate panel according to an embodiment of the present invention.
Description of reference numerals: 1: a diaphragm type pressure sensor; 1-1: a pressure sensitive material; 1-2: an internal connection lead; 1-3: a base film; 1-4: a binding post; 1-5: connecting a lead externally; 2: a force application panel; 2-1: a rubber plate; 2-2: a rigid stress block; 3: a base panel; 3-1: homogenizing the plate; 3-2: and (7) fixing holes.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, an embodiment of the present invention provides a testing apparatus for testing a contact pressure of a tunnel supporting structure, the testing apparatus includes an acting panel 2, a diaphragm type pressure sensor 1 and a substrate panel 3 stacked from top to bottom, the acting panel 2 and the substrate panel 3 together wrap the diaphragm type pressure sensor 1, and the three are packaged and fixed together, so as to protect the diaphragm type pressure sensor 1, and achieve convenient and fast installation and fixation of the testing apparatus. The force application panel 2 is used for uniformly transmitting the contact pressure to the diaphragm type pressure sensor 1, so that stress concentration caused by local unevenness is avoided; the diaphragm type pressure sensor 1 is used for converting contact pressure into resistance signals, corresponding contact pressure test values can be obtained by analyzing the resistance signals, and errors caused by multiple signal conversion of a traditional rigid pressure box are avoided.
In detail, as shown in fig. 2, the diaphragm type pressure sensor 1 includes a base film 1-3, a pressure sensitive material 1-1, and a wire assembly, wherein the pressure sensitive material 1-1 is uniformly arranged on the base film 1-3, and when the pressure sensitive material 1-1 is subjected to pressure, a power function relationship is formed between a pressure value and a resistance value, as shown in fig. 3, the pressure applied to the sensor can be calculated by monitoring the resistance value of the sensor; the lead assembly is used for transmitting the resistance signal of each pressure-sensitive material 1-1 to the resistance value monitoring equipment. Specifically, the wire assembly comprises an internal connecting wire 1-2, a binding post 1-4 and an external connecting wire 1-5, the internal connecting wire 1-2 is connected with adjacent pressure-sensitive materials 1-1 and connects each pressure-sensitive material 1-1 to the binding post 1-4, the external connecting wire 1-5 is connected with the binding post 1-4 and external resistance value monitoring equipment, and the connection mode is simple and convenient. Furthermore, the pressure-sensitive material 1-1 and the internal connection lead 1-2 are printed on the base film 1-3, so that the pressure-sensitive material is convenient to manufacture, firm to fix and good in stability. In the preferred embodiment, the diaphragm type pressure sensor 1 has a square structure of 20cm × 20cm, and the thickness of the base film 1-3 is preferably 0.2 mm.
Further, as shown in fig. 4, the size of the force application panel 2 is the same as that of the diaphragm type pressure sensor 1, the force application panel 2 includes a rubber plate 2-1 and rigid force application blocks 2-2, the rigid force application blocks 2-2 are regularly arranged on the rubber plate 2-1, and the arrangement mode of the rigid force application blocks 2-2 is related to the arrangement of the pressure sensitive materials 1-1 in the diaphragm type pressure sensor 1, so that the pressure sensitive materials 1-1 are fully covered, uniform pressure is transmitted to the pressure sensitive materials 1-1, and stress concentration is prevented. The hardness of the rubber plate 2-1 is within the range of 60-70 HA, ethylene propylene diene monomer or chloroprene rubber is preferred, and the thickness is 0.5mm preferably; the rigidity of the rigid stress blocks 2-2 is within the range of 90-95 HD, the rigidity is preferably PC material, the thickness is preferably 0.5mm, and the gap between every two adjacent rigid stress blocks 2-2 is smaller than 0.5 mm.
Further elaborately, as shown in fig. 5, the size of the substrate panel 3 is the same as that of the diaphragm type pressure sensor 1, the substrate panel 3 is constructed by a homogeneous flat plate 3-1, and fixing holes 3-2 are additionally formed in corners, so that the substrate panel is convenient to mount, preferably, the hardness of the substrate panel 3 is in a range of 90-95 HD, preferably, a PC plate is adopted, and the thickness is preferably 0.5 mm.
The embodiment is optimized, inert lubricating grease is filled among three layers of the force application panel 2, the diaphragm type pressure sensor 1 and the base panel 3, the local shearing of the diaphragm type pressure sensor 1 is prevented, the three layers of panels are in closed lap joint in a mode of edge thermal welding, and the packaging is simple and firm.
The whole thickness of the testing device for the tunnel contact pressure provided by the embodiment of the invention is less than 2mm, so that the influence or change of a stress field of a contact surface in a testing process can be effectively avoided, and the accuracy of the contact pressure test is improved.
The embodiment of the invention also provides a testing method of the tunnel contact pressure, which adopts the testing device of the tunnel contact pressure, and the method comprises the following steps:
s1: calibrating the testing device of the tunnel contact pressure through a loading test, and acquiring a pressure-resistance curve of each characteristic point;
s2: leveling the wall surface of the test point, tightly attaching the force application panel 2 of the test device to the wall surface of the tunnel, and fixing the test device at the preset test point position; specifically, when the contact pressure of surrounding rock and sprayed concrete is tested, after tunnel excavation is completed, the wall surface of a test point is leveled, an impact panel 2 of the test device is attached to the wall surface of the tunnel, a small-sized nail gun penetrates through a fixing hole 3-2 of a base panel 3 of the test device, and the test device is fixed at a preset test point position; arranging and fixing the lead assemblies along the wall surface of the tunnel, and taking protective measures;
s3: according to the tunnel construction steps, spraying concrete to completely cover the testing device, recording initial data, testing the resistance values omega 1 and omega 1 … omega n of each characteristic point of the testing device, and obtaining initial pressure values P1 and P2 … Pn of each characteristic point through the pressure-resistance curve determined in the step S1;
s4: testing the contact pressure according to a test plan to obtain resistance values omega t1 and omega t1 … omega tn of each characteristic point of the testing device at any moment, and obtaining initial pressure values Pt1 and Pt2 … Ptn of each characteristic point through the pressure-resistance curve determined in the step S1;
s5: and acquiring a pressure change difference value (delta Pn = Ptn-Pn) of each test characteristic point of the test device, discarding the obviously deviated data, and then taking an arithmetic average value as a contact pressure test value at the moment.
In summary, the testing device and the method for the tunnel contact pressure provided by the invention are formed by packaging three-layer structures of the force panel 2, the diaphragm type pressure sensor 1 and the substrate panel 3, the force panel 2 uniformly transmits the contact pressure to the diaphragm type pressure sensor 1, and the diaphragm type pressure sensor 1 directly converts the pressure into an electric signal, so that errors caused by multiple signal conversion of a traditional rigid pressure box are avoided; the device's whole thickness can be accomplished to be less than 2mm, and has advantages such as simple to operate, pass power reliable, strong durability, precision height.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A testing device for tunnel contact pressure is characterized in that: the film type pressure sensor comprises a force application panel, a film type pressure sensor and a substrate panel which are stacked from top to bottom, wherein the force application panel and the substrate panel jointly wrap the film type pressure sensor and are packaged and fixed together, the force application panel is used for transmitting contact pressure to the film type pressure sensor uniformly, and the film type pressure sensor is used for converting the contact pressure into a resistance signal.
2. The apparatus for testing tunnel contact pressure of claim 1, wherein: the diaphragm type pressure sensor comprises a base film, pressure-sensitive materials and a lead assembly, wherein the pressure-sensitive materials are uniformly distributed on the base film, when the pressure-sensitive materials are subjected to pressure, a pressure value and a resistance value are in a power function relationship, and the lead assembly is used for transmitting resistance signals of the pressure-sensitive materials to resistance value monitoring equipment.
3. The apparatus for testing tunnel contact pressure of claim 2, wherein: the wire assembly comprises an internal connecting wire, wiring terminals and an external connecting wire, wherein the internal connecting wire is connected with adjacent pressure-sensitive materials and is used for connecting each pressure-sensitive material to the wiring terminals, and the external connecting wire is connected with the wiring terminals and external resistance value monitoring equipment.
4. The apparatus for testing tunnel contact pressure of claim 3, wherein: the pressure sensitive material and the inner connecting lead are both printed on the base film.
5. The apparatus for testing tunnel contact pressure of claim 1, wherein: the force application panel comprises a rubber plate and rigid force bearing blocks, wherein the rigid force bearing blocks are regularly distributed on the rubber plate and fully cover the pressure-sensitive material.
6. The apparatus for testing tunnel contact pressure of claim 5, wherein: the hardness of the rubber plate is within the range of 60-70 HA, the hardness of the rigid stress blocks is within the range of 90-95 HD, and the gap between every two adjacent rigid stress blocks is smaller than 0.5 mm.
7. The apparatus for testing tunnel contact pressure of claim 1, wherein: the base panel is of a homogeneous flat plate structure, and fixing holes are additionally formed in corners.
8. The apparatus for testing tunnel contact pressure of claim 7, wherein: the hardness of the substrate panel is within the range of 90-95 HD.
9. The apparatus for testing tunnel contact pressure of claim 1, wherein: inert lubricating grease is filled among the three layers of the force application panel, the diaphragm type pressure sensor and the base panel, and the three layers of the panels are in closed lap joint in an edge heat welding mode.
10. A method for testing a tunnel contact pressure, which employs the tunnel contact pressure testing apparatus according to any one of claims 1 to 9, the method comprising:
s1: calibrating the testing device of the tunnel contact pressure through a loading test, and acquiring a pressure-resistance curve of each characteristic point;
s2: leveling the wall surface of the test point, tightly attaching an impact panel of the test device to the wall surface of the tunnel, and fixing the test device at the preset test point position;
s3: according to the tunnel construction steps, spraying concrete to completely cover the testing device, recording initial data, testing the resistance values omega 1 and omega 1 … omega n of each characteristic point of the testing device, and obtaining initial pressure values P1 and P2 … Pn of each characteristic point through the pressure-resistance curve determined in the step S1;
s4: testing the contact pressure according to a test plan to obtain resistance values omega t1 and omega t1 … omega tn of each characteristic point of the testing device at any moment, and obtaining initial pressure values Pt1 and Pt2 … Ptn of each characteristic point through the pressure-resistance curve determined in the step S1;
s5: and acquiring a pressure change difference value (delta Pn = Ptn-Pn) of each test characteristic point of the test device, discarding the obviously deviated data, and then taking an arithmetic average value as a contact pressure test value at the moment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110562848.3A CN113483934A (en) | 2021-05-24 | 2021-05-24 | Tunnel contact pressure testing device and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110562848.3A CN113483934A (en) | 2021-05-24 | 2021-05-24 | Tunnel contact pressure testing device and method |
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| Publication Number | Publication Date |
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| CN113483934A true CN113483934A (en) | 2021-10-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202110562848.3A Pending CN113483934A (en) | 2021-05-24 | 2021-05-24 | Tunnel contact pressure testing device and method |
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| CN (1) | CN113483934A (en) |
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2021
- 2021-05-24 CN CN202110562848.3A patent/CN113483934A/en active Pending
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