AU2021102678A4 - Device for measuring radial displacement in small-diameter tunnel model test - Google Patents
Device for measuring radial displacement in small-diameter tunnel model test Download PDFInfo
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- AU2021102678A4 AU2021102678A4 AU2021102678A AU2021102678A AU2021102678A4 AU 2021102678 A4 AU2021102678 A4 AU 2021102678A4 AU 2021102678 A AU2021102678 A AU 2021102678A AU 2021102678 A AU2021102678 A AU 2021102678A AU 2021102678 A4 AU2021102678 A4 AU 2021102678A4
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- radial displacement
- small
- measuring
- cylindrical base
- spring steel
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- 238000006073 displacement reaction Methods 0.000 title claims abstract description 51
- 238000012360 testing method Methods 0.000 title claims abstract description 34
- 230000003068 static effect Effects 0.000 claims abstract description 9
- 229910000639 Spring steel Inorganic materials 0.000 claims description 29
- 229910000831 Steel Inorganic materials 0.000 claims description 14
- 239000010959 steel Substances 0.000 claims description 14
- 229910001220 stainless steel Inorganic materials 0.000 claims description 13
- 239000010935 stainless steel Substances 0.000 claims description 13
- 238000009826 distribution Methods 0.000 claims description 7
- 238000005259 measurement Methods 0.000 abstract description 25
- 238000000034 method Methods 0.000 description 9
- 238000012545 processing Methods 0.000 description 7
- 239000011435 rock Substances 0.000 description 5
- 238000009412 basement excavation Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 238000010146 3D printing Methods 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000917 particle-image velocimetry Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010297 mechanical methods and process Methods 0.000 description 1
- 238000012806 monitoring device Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000004379 similarity theory Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
- 238000004441 surface measurement Methods 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/08—Measuring arrangements characterised by the use of mechanical techniques for measuring diameters
- G01B5/12—Measuring arrangements characterised by the use of mechanical techniques for measuring diameters internal diameters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B5/00—Measuring arrangements characterised by the use of mechanical techniques
- G01B5/02—Measuring arrangements characterised by the use of mechanical techniques for measuring length, width or thickness
- G01B5/025—Measuring of circumference; Measuring length of ring-shaped articles
Abstract
The present disclosure relates to a device for measuring radial displacement in
small-diameter tunnel model test, and belongs to the technical field of geotechnical engineering
5 survey. The device comprises a magnetic base, a radial displacement meter and a static strain
indicator. By calibrating the relationship between the end strain and the displacement of the
elastic measuring heads with cantilever type structure, the heads are stuck into the
small-diameter tunnel to measure the radial absolute displacement with the measuring point.
The device can measure any circumferential position on the inner wall of the tunnel by rotating
0 the small diameter cylindrical base freely and it can adapt to the measurement of the radial
displacement of the small diameter tunnel within a certain diameter range by detachable
replacing the elastic measuring heads of different sizes which can rotate around the U-shaped
groove of the cylindrical base. The device is good at scene adaptability, simple to mount, simple
and convenient to operate and capable of conveniently and rapidly achieving measurement on
5 radial displacement of the small-diameter tunnel in the model test.
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Fig. 2
Description
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Fig. 2
Field
[0001] The present disclosure relates to a device for measuring radial displacement in small-diameter tunnel model test, and belongs to the technical field of geotechnical engineering survey.
Background
[0002] To respond to significant demands for energy sources, traffic and underground resources brought by rapid development of national economy, the construction of underground engineering is deepened continuously in company with great challenge.
[0003] With respect to mechanical response and deformation characteristic problems of a rock mass in the underground tunnel excavation process, not only intensive and systematic theoretical research and also laboratory model test study in combination with engineering practice and theories are required. Based on similarity theory, a model test implements operations such as loading, excavating and shoring model test samples with reduced dimensions in order to simulate primary rock stress states, excavation, shoring and the like of a tunnel on site, and obtains stress distribution and deformation displacement characteristics of the test samples by using corresponding monitoring devices to provide reference for engineering practice.
[0004] Fabrication of model test samples is the foundation of laboratory model tests. In recent years, dimensions of the model test samples are diversified as the model test samples are fabricated by diversified measures, and particularly novel technologies such as representative !5 3D printing are more and more applied in the fabrication of the model test samples. A model test sample fabricated by using a 3D printing technology usually has the characteristic of small dimension. A model test sample for model tests of tunnels generally has a centimeter-level hole diameter size (2-4 cm), and as radial displacement of tunnel feature points is a direct response of surrounding rack excavation or overloading and also is one of main bases for predicting, evaluating and controlling stability of surrounding rock of a single tunnel or security of partition walls in multiple tunnels, the radial displacement of tunnel feature points of surrounding rock usually needs to be monitored in relevant tests. For the reason of self sizes, a conventional radial displacement measuring device is barely capable of effectively measuring radial displacement of a small-diameter tunnel in laboratory model tests, and non-contact type surface measurement based on a digital image correlation method principle has limits such as measurement distortion when monitoring internal deformation of small holes, and therefore, higher demands are provided for laboratory small-dimension model displacement measurement.
[0005] At present, research on small hole radial displacement measurement in model tests in China is as follows.
[0006] (1) In the article "GroPIV Image Processing Technology and Application thereof in Rock and Soil Test" in Shanxi Architecture (Volume 43, Issue 4 in 2017), slope model test displacement is measured by means of a non-contact type measurement measure based on particle image velocimetry principle; however, because of the phenomenon that surface layers are liable to peel from inner sides in loading testing of tunnel models, the non-contact type measurement measure based on particle image velocimetry can only measure surface displacement, and can cause great deviation when applied in measurement on internal displacement of small-diameter tunnels, resulting in measurement result distortion.
[0007] (2) A Chinese patent application, with a publication number CN108981535A, published on December 11, 2018, has the invention name of "Contact Displacement Measuring Method and Measuring Device". Because of too large structure and size, the device is not applicable to radial displacement measurement on small-diameter tunnels, and is barely applicable to measurement demands for small holes having different diameters.
[0008] (3) A Chinese patent application, with an authorized publication number CN102721399B, published on January 28, 2015, has the invention name of "Wall-attached Type Shaft Radial Displacement Micrometer and Measuring Method thereof', and the device is cannot implement contact type measurement on inner walls of small-diameter tunnels and is not applicable to situations of too large deformation in small holes.
[0009] (4) A Chinese patent application, with an authorized publication number CN104501682B, published on November 21, 2017, has the invention name of "Device and !5 Method for Measuring Misalignment Quantity of Bolt Hole", besides the unsuitable size, the device can only acquire relative displacement of a hole wall, but cannot acquire absolute displacement of a specific measuring point of the hole wall.
[0010] Therefore, measurement on radial displacement in small holes in model tests is not well developed, and a device which is well applicable to measurement on displacement of small holes within a certain diameter range and is capable of acquiring radial displacement of a single small hole with great deformation is not available yet. In addition, a conventional mechanical method such as an extensometer can only acquire relative radial displacement of a tunnel wall, and cannot acquire absolute displacement of one specific feature point of a small-diameter tunnel.
Summary
[0011] With respect to the above problems, an objective of the present disclosure is to provide a simple and accurate contact type measuring device equipped with accessories with corresponding sizes, for measuring radial displacement of small-diameter tunnels in model tests.
[0012] To achieve the objective, the present disclosure is achieved through the following technical solution.
[0013] A device for measuring radial displacement in small-diameter tunnel model test, comprising:
[0014] a magnetic base, a radial displacement meter and a static strain indicator, wherein the radial displacement meter includes a round connecting rod, a cylindrical base and elastic measuring heads; each elastic measuring head includes an annular steel seat, a spring steel piece and a measuring head; four U-shaped grooves in annularly symmetric distribution are equipped in one end of the cylindrical base; stainless steel semicircular protractors are symmetrically arranged on inner walls of two sides of each U-shaped groove; the annular steel seat and the stainless steel semicircular protractors on the two sides of each U-shaped groove of the cylindrical base are connected through a screw rod; one end of the spring steel piece is fixedly connected with the annular steel seat; a strain gauge is adhered to the spring steel piece; the strain gauge is positioned on one side of the fixed connecting end; the measuring head is arranged at a free end of the spring steel piece and is in threaded connection with the spring steel piece; a positioning hole in an axial direction is formed in the surface center of the other end of the cylindrical base; two groups of through holes in orthogonally symmetric distribution in a radial direction are annularly formed in the cylindrical base; the through holes are positioned at one half of the length of the positioning hole; locking screw rods are arranged in the through holes; one end of the round connecting rod is fixedly sleeved with a stainless steel !5 whole circle protractor; an end of the same side is moveably inserted into the positioning hole; the other end is connected with a clamp on the magnetic base; and the strain gauge is in wire connection with the static strain indicator.
[0015] The U-shaped grooves of the cylindrical base are respectively equipped with rotary positioning rods.
[0016] A thickness of the spring steel piece ranges from 3 mm to 5 mm.
[0017] Due to the adoption of the technical solution, the device is capable of achieving measurement on radial displacement in laboratory small-diameter tunnel model tests, and mainly has the following advantages.
[0018] (1) By adopting a mode that the measuring device is fixed by using the magnetic base, the measuring device can flexibly adapt to a spatial position of a target point to be measured, and has better adaptability to the orientation structure of a model test sample.
[0019] (2) By adopting a mode that the cylindrical base may rotate freely around the round connecting rod and is linked and fixed through the locking screw rods around, measurement on radial absolute displacement of any annular target measuring point of the small-diameter tunnel may be achieved, and meanwhile, stability of the base in the measuring process is ensured.
[0020] (3) By adopting a mode that the detachable elastic measuring heads with different sizes are used and the elastic measuring heads rotate around the U-shaped grooves of the cylindrical base, one same base can adapt to measurement on radial absolute displacement of small holes in the certain diameter range.
[0021] (4) On the basis that the measuring device is fixed by the magnetic base, by adopting a mode that the measuring heads are separated by a cantilever type structure, absolute displacements of the target point measured by the measuring heads may be respectively acquired, and meanwhile, measurement demands for small holes with great deformation can be met.
[0022] (5) By adopting a mode that the measuring heads are regulated and controlled up and down freely, pre-pressing contact on a target measuring point can be achieved, and contact of contact type measurement in the whole process can be ensured.
[0023] The present disclosure provides the measuring device for radial displacement of the small-diameter tunnel in the model test. The device is good at scene adaptability, simple to mount, simple and convenient to operate and capable of conveniently and rapidly achieving measurement on radial displacement of the small-diameter tunnel in the model test.
Brief Description of the Drawings
[0024] Fig. 1 is a structural schematic diagram of the present disclosure; !5 [0025] Fig. 2 is a schematic diagram of working of the present disclosure;
[0026] Fig. 3 is a side view of Fig. 1; and
[0027] Fig. 4isanA-AviewofFig. 3.
Detailed Description of the Embodiments
[0028] The present disclosure is further described below in combination with Figs. 1, 2, 3 and 4.
[0029] A device for measuring radial displacement in small-diameter tunnel model test, comprising: a magnetic base 1, a radial displacement meter and a static strain indicator 14, wherein the radial displacement meter includes a round connecting rod 3, a cylindrical base 6 and elastic measuring heads; each elastic measuring head includes an annular steel seat 8, a spring steel piece 13 and a measuring head 12; four U-shaped grooves in annularly symmetric distribution are equipped in one end of the cylindrical base 6; stainless steel semicircular protractors 10 are symmetrically arranged on inner walls of two sides of each U-shaped groove; the annular steel seat 8 and the stainless steel semicircular protractors 10 on the two sides of each U-shaped groove of the cylindrical base 6 are connected through a screw rod 9; rotation constraint is applied; rotary positioning rods are respectively arranged in the U-shaped grooves to limit a maximum rotation angle of the annular steel seat 8 to be 45 degrees; one end of the spring steel piece 13 is fixedly connected with the annular steel seat 8; a strain gauge 11 is adhered to the spring steel piece 13; the strain gauge 11 is positioned on one side of the fixed connecting end; the measuring head 12 is arranged at a free end of the spring steel piece 13 and is in threaded connection with the spring steel piece 13; a positioning hole in an axial direction is formed in the surface center of the other end of the column base 6; two groups of through holes in orthogonally symmetric distribution in a radial direction are annularly formed in the cylindrical base 6; the through holes are positioned at one half of the length of the positioning hole; locking screw rods 7 are arranged in the through holes; one end of the round connecting rod 3 is fixedly sleeved with a stainless steel whole circle protractor 5 for implementing quantitative measurement on rotation of the cylindrical base 6; an end of the same side is moveably inserted into the positioning hole; a main rod on the magnetic base 1 is sleeved with a screw rod knob 2 for clamping and fixing; a chuck 4 is fixedly connected below the main rod; the other end of the round connecting rod 3 penetrates through the chuck 4 to be stably clamped; the static strain indicator 14 and the strain gauge 11 is in wire connection directly to acquire end strain data; a data processing computer 15 is connected with the static strain indicator 14 to acquire and process strain data; connection constraint of the screw rod 9 is removed; the annular steel seat 8 is capable of rotating around the screw rod 9; a rotation angle may be quantitatively !5 measured by two groups of stainless steel semicircular protractors 10 on the two sides; an opening radius of the spring steel piece 13 changes along with rotation so as to flexibly adapt to a target measuring tunnel diameter; and a round head screw of the measuring head 12 may be adjusted up and down freely along a screw hole of the spring steel piece 13 so that when the measuring head 12 is in contact with a target measuring point, the spring steel piece 13 slightly pre-bends to apply a counter force to achieve pre-pressing contact with the target measuring point, and contact between the measuring head and a measuring point in the whole measuring process is ensured.
[0030] The device of the present disclosure is used according to the following steps:
[0031] (1) calibrating a group of spring steel pieces specifically used for measurement, wherein the geometrical relationship of measuring head displacement o and end strain , is expressed as: co= [1+l(h)], wherein L is a length of an equal-thickness part of each spring steel piece, W is a width of a cross section of the equal-thickness part of each spring steel piece, H is a height of the cross section of the equal-thickness part of each spring steel piece, and a is a correction factor of measurement of each spring steel piece and is related to the length-width ratio of the equal-thickness part of each spring steel piece; recording an elasticity modulus E of each spring steel piece and the length L, the width W and the height H of the equal-thickness part, inputting into the data processing computer 15, performing five groups of calibrations on the spring steel pieces: oi=1 mm, 02=2 mm, 03=3mm, 04=4 mm and 0=5 mm, recording corresponding end strains si, 32, F,3, 4and, 5, importing the end strains into the data processing computer 15, and carrying out linear fitting so as to obtain the correction factor a;
[0032] (2) according to a spatial position of a model test sample tunnel, fixing the magnetic base on a side wall at a corresponding height for loading an instrument, connecting the main rod, clamping the round connecting rod 3, and carrying out horizontal alignment by using the stainless steel semicircular protractors 10;
[0033] (3) inserting the round connecting rod 3 into the positioning hole in the center of the end surface of the cylindrical base 6, carrying out horizontal alignment by the assistance of the locking screw rods around, rotating the cylindrical base to an appropriate position according to the position of the target measuring point, fastening the screws for linking by using the locking screw rods, applying constraint, reading the rotation angle P of the cylindrical base 6 by the stainless steel whole circle protractor 5, inputting the rotation angle into the data processing computer 15, resolving the radial displacement of the target measuring point into horizontal displacement ox=o-sins and vertical displacement oy=o-cosp, and performing output;
[0034] (4) connecting and mounting the elastic measuring heads in the U-shaped grooves of the cylindrical base 6 one by one through the screw rod, removing the constraint of the screw rod according to the diameter of a target measuring hole, rotating the annular steel seat 8, carrying out visual measurement to enable the opening radius of each spring steel piece to be slightly greater than the diameter of the target measuring hole, since the U-shaped grooves are respectively provided with the rotary positioning rods, enabling the maximum rotation angle of the annual steel seat 8 to be 45 degrees, fixing the annular steel seat 8, providing radial
displacement o={32[1+a( )]}-cosy for any rotation angle, reading respective rotation angles
71, 72, 73 and74by using the stainless steel semicircular protractors 10 on the two sides, and inputting the rotation angles into the data processing computer 15;
[0035] (5) adjusting the positions of the measuring heads 12 by screwing to make the measuring heads 12 be in contact with the target measuring point, slightly pre-bending the spring steel pieces 13 to apply the counter force to ensure pre-pressing contact of the round head screws of the measuring heads 12 and the measuring point, carrying out pre-calculation by using the computer, and calibrating a measurement start point; and
[0036] (6) loading a small-diameter tunnel model test sample by using relevant equipment, acquiring end strain data of the elastic measuring heads by using the static strain indicator 14, transmitting the end strain data to the data processing computer 15, and calculating and outputting radial displacements of measuring points in real time.
Claims (2)
1. A device for measuring radial displacement in small-diameter tunnel model test, comprising: a magnetic base (1), a radial displacement meter and a static strain indicator (14), wherein the radial displacement meter includes a round connecting rod (3), a cylindrical base (6) and elastic measuring heads; each elastic measuring head includes an annular steel seat (8), a spring steel piece (13) and a measuring head (12); four U-shaped grooves in annularly symmetric distribution are equipped in one end of the cylindrical base (6); stainless steel semicircular protractors (10) are symmetrically arranged on inner walls of two sides of each U-shaped groove; the annular steel seat (8) and the stainless steel semicircular protractors (10) on the two sides of each U-shaped groove of the cylindrical base (6) are connected through a screw rod (9); one end of the spring steel piece (13) is fixedly connected with the annular steel seat (8); a strain gauge (11) is adhered to the spring steel piece (13); the strain gauge (11) is positioned on one side of the fixed connecting end; the measuring head (12) is arranged at a free end of the spring steel piece (13) and is in threaded connection with the spring steel piece (13); a positioning hole in an axial direction is formed in the surface center of the other end of the column base (6); two groups of through holes in orthogonally symmetric distribution in a radial direction are annularly formed in the cylindrical base (6); the through holes are positioned at one half of the length of the positioning hole; locking screw rods (7) are arranged in the through holes; one end of the round connecting rod (3) is fixedly sleeved with a stainless steel whole circle protractor (5); an end of the same side is moveably inserted into the positioning hole; the other end is connected with a clamp on the magnetic base (1); and the strain gauge (11) is in wire connection with the static strain indicator (14).
2. The device of claim 1, wherein the U-shaped grooves of the cylindrical base (6) are respectively equipped with rotary positioning rods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102678A AU2021102678A4 (en) | 2021-05-19 | 2021-05-19 | Device for measuring radial displacement in small-diameter tunnel model test |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2021102678A AU2021102678A4 (en) | 2021-05-19 | 2021-05-19 | Device for measuring radial displacement in small-diameter tunnel model test |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2021102678A4 true AU2021102678A4 (en) | 2021-07-15 |
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|---|---|---|---|
| AU2021102678A Ceased AU2021102678A4 (en) | 2021-05-19 | 2021-05-19 | Device for measuring radial displacement in small-diameter tunnel model test |
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| Country | Link |
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| AU (1) | AU2021102678A4 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109916255A (en) * | 2019-03-28 | 2019-06-21 | 江苏核电有限公司 | A kind of reactor upper element surveyors' staff clamping device and its clamp method |
-
2021
- 2021-05-19 AU AU2021102678A patent/AU2021102678A4/en not_active Ceased
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109916255A (en) * | 2019-03-28 | 2019-06-21 | 江苏核电有限公司 | A kind of reactor upper element surveyors' staff clamping device and its clamp method |
| CN109916255B (en) * | 2019-03-28 | 2024-03-19 | 江苏核电有限公司 | Clamping device and clamping method for measuring scale of upper assembly of reactor |
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| FGI | Letters patent sealed or granted (innovation patent) | ||
| MK22 | Patent ceased section 143a(d), or expired - non payment of renewal fee or expiry |