CN109556563B - Radial displacement measuring device for small-aperture tunnel model test - Google Patents
Radial displacement measuring device for small-aperture tunnel model test Download PDFInfo
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- CN109556563B CN109556563B CN201910017195.3A CN201910017195A CN109556563B CN 109556563 B CN109556563 B CN 109556563B CN 201910017195 A CN201910017195 A CN 201910017195A CN 109556563 B CN109556563 B CN 109556563B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/32—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring the deformation in a solid
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
- G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
- G01M5/0041—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress
- G01M5/005—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings by determining deflection or stress by means of external apparatus, e.g. test benches or portable test systems
Abstract
The invention relates to a radial displacement measuring device for a small-aperture tunnel model test, belonging to the technical field of geotechnical engineering measurement; the device consists of a magnetic base, a radial displacement meter and a static strain gauge; by calibrating the relation between the strain of the end part of the elastic measuring head with a cantilever type structure and the displacement of the measuring head, the measuring head extends into the inner wall of the small-aperture tunnel to carry out contact measurement with a target measuring point to obtain radial absolute displacement, and the device can realize the measurement of the target measuring point at any annular position on the inner wall of the tunnel through the free rotation of the small-diameter cylindrical base; the device can adapt to the measurement of the radial displacement of the small-aperture tunnel within a certain diameter range by the detachable elastic measuring heads with different sizes and the rotation of the elastic measuring heads around the U-shaped groove of the cylindrical base; the device simple structure, it is easy and simple to handle, can directly acquire the absolute displacement of measurement station, can conveniently be applied to the measurement of the small-bore tunnel radial displacement of indoor model test.
Description
Technical Field
The invention relates to a radial displacement measuring device for a small-aperture tunnel model test, and belongs to the technical field of geotechnical engineering measurement.
Background
In order to respond to the great demand of rapid development and growth promotion of national economy on energy, traffic and underground resources, the construction of underground engineering is continuously developed towards deep parts. The construction of a large number of deep and long tunnel (underground chamber, tunnel and roadway) projects is accompanied, for example, a plurality of ultra-deep and ultra-long tunnels with the buried depth of more than 1000 meters and the length of more than 20 kilometers appear on the built Sichuan railway. Under deep conditions such as high ground stress, the mechanical characteristics and engineering response of the underground tunnel surrounding rock structure show new subject phenomena and rules, and the traditional underground engineering theoretical system faces huge challenges when solving the problem of deep underground engineering. Therefore, the mechanical characteristics and engineering response of the deep rock mass are systematically researched, and a new system of the deep rock mass mechanical theory is established inevitably.
Aiming at the problems of mechanical response and deformation characteristics of rock masses in the excavation process of underground tunnels, both deep and systematic theoretical research and indoor model test research by combining engineering practice and theory are required. The model test is based on a similar theory, the operations of loading, excavating, supporting and the like are carried out on a model sample with reduced size so as to simulate the original rock stress state, excavating, supporting and the like of a field tunnel, and the stress distribution and deformation displacement characteristics of the sample are obtained through a corresponding monitoring device, so that reference and reference are provided for engineering practice.
The preparation of model samples is the basis for the indoor model test, and in recent years, with the diversification of model test sample preparation means, particularly, new technologies represented by 3D printing are increasingly applied to the preparation of model samples, and the scale of the model samples is diversified. Model samples manufactured by using a 3D printing technology generally have small-scale characteristics, wherein for a model test of a tunnel, the diameter size of a hole of the model sample is usually in the centimeter level (2-4cm), and when a relevant test is performed, the radial displacement of a feature point of tunnel surrounding rock is often required to be monitored, because the radial displacement of the feature point of the tunnel is a direct response quantity of surrounding rock excavation or overload and is also one of main bases for predicting, evaluating and controlling the stability of the surrounding rock of a single tunnel or the safety of a partition wall in multiple tunnels. Therefore, monitoring and acquiring the radial displacement of the small-aperture tunnel in the model test puts higher demands on the displacement measurement of the indoor small-scale model.
At present, the current domestic research situation on the measurement of the radial displacement of the small hole in the model test is as follows:
(1) in the article of GeoPIV image processing technology and application thereof in geotechnical tests, a non-contact measurement means based on the principle of a particle image velocimetry method is used for measuring displacement of a slope model test in Shanxi building (2017, volume 43, No. 4); however, the phenomenon that the surface layer is peeled off from the inner side is easy to occur when the tunnel model is subjected to a loading test, and the non-contact surface measurement means based on the digital image correlation method can only measure the surface displacement, so that the large deviation can occur when the non-contact surface measurement means is applied to the displacement measurement in the small-aperture tunnel, and the measurement result is distorted.
(2) The invention discloses a passive magnetoelectric radial displacement sensor, which is a Chinese patent with the granted publication number of CN102607396B and publication date of 2015.04.15 and is named as a radial displacement sensor; but the device is only used for measuring the radial displacement of the rotating component, and is not suitable for static bearing tests of tunnel models.
(3) The Chinese patent application publication No. CN108981535A, publication No. 2018.12.11, entitled "contact displacement measuring method and measuring device thereof", discloses a measuring device which amplifies and transmits the movement stroke of a contact to an outer side displacement output end by utilizing a lever principle; but because the structure and the size of the device are too big, the device is not suitable for the radial displacement measurement of the tunnel with small aperture, and is difficult to adapt to the small aperture measurement requirements in different aperture ranges.
(4) The invention discloses a device for measuring the radial displacement by fixing a displacement sensor on the inner wall of a shaft through a propeller strut, and the device is characterized in that Chinese patent granted publication No. CN102721399B, publication No. 2015.01.28, entitled "wall-attached shaft radial displacement micrometer and a measuring method thereof"; however, the device cannot perform contact measurement on the inner wall of the tunnel with the small aperture due to the overlarge size of the fixing device, and is also not suitable for the situation of overlarge deformation inside the small aperture.
(5) The invention discloses a device and a method for measuring the dislocation quantity of bolt holes, which is entitled as a device and a method for measuring the dislocation quantity of bolt holes, wherein the Chinese patent is granted with publication number CN104501682B and publication number 2017.11.21, and discloses a device for measuring the radial displacement of a tubular body by arranging a telescopic measuring rod on the inner wall of a tube hole; but besides the unsuitable size, the device can only obtain the relative displacement of the hole wall, and cannot obtain the absolute displacement of a specific measuring point of the hole wall. Because the tunnel model hole size that the new technology that takes 3D printing as the representative made is less than traditional system appearance model, its diameter yardstick is usually at centimetre level, and current radial displacement measuring device is mostly because self size reason, hardly carries out effectual measurement to the small aperture tunnel radial displacement of indoor model test, and non-contact surface measurement based on digital image correlation method principle has limitations such as measurement distortion when monitoring the inside deformation of aperture.
Therefore, the measurement of the radial displacement of the inner part of the small hole used in the model test is not mature, and meanwhile, the measurement device is lack of good adaptability to the measurement of the displacement of the small hole in a certain aperture range, and the radial displacement of large deformation of a single small hole can be obtained. In addition, the traditional mechanical method such as extensometer or extensometer can only obtain the radial relative displacement of the tunnel wall, and can not obtain the absolute displacement of a specific characteristic point of the small-aperture tunnel.
Disclosure of Invention
Aiming at the problems, the invention aims to provide a simple and accurate contact type measuring device which is matched with accessories with corresponding sizes to realize the measurement of the radial displacement of the small-aperture tunnel in a model test.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a radial displacement measuring device for a small-aperture tunnel model test comprises a magnetic base, a radial displacement meter and a static strain gauge, wherein the radial displacement meter comprises a circular connecting rod, a cylindrical base and an elastic measuring head, the elastic measuring head consists of an annular steel seat, a spring steel sheet and the measuring head, one end of the cylindrical base is provided with four U-shaped grooves which are distributed annularly and symmetrically, the inner walls of two sides of each U-shaped groove are symmetrically provided with stainless steel semicircular protractors, the annular steel seat is connected with the stainless steel semicircular protractors on two sides of the U-shaped groove of the cylindrical base through a screw rod, one end of the spring steel sheet is fixedly connected with the annular steel seat, a strain gauge is pasted on the spring steel sheet and is positioned on one side of a fixed connecting end, the free end of the spring steel sheet is provided with the measuring head, the measuring head is connected with the spring steel sheet through a thread, the center of the end face of the other end, the through hole is positioned at one half of the length of the positioning hole, a locking screw is arranged in the through hole, one end of the circular connecting rod is fixedly sleeved with a stainless steel full-circle protractor, the end head at the same side is movably inserted into the positioning hole, the other end of the circular connecting rod is connected with a clamp on the magnetic base, and the strain gauge is connected with the static strain gauge through a wire.
The U-shaped grooves of the cylindrical bases are respectively provided with a rotary positioning rod.
The thickness of the spring steel sheet ranges from 3mm to 5 mm.
Due to the adoption of the technical scheme, the method can realize the measurement of the radial displacement of the indoor small-aperture tunnel model test, and mainly has the following advantages:
(1) through adopting the fixed mode of magnetic base with measuring device for it can adapt to the spatial position of the target point that awaits measuring in a flexible way, has stronger adaptability to the range overall arrangement of tunnel model sample.
(2) By adopting the mode that the cylindrical base can freely rotate around the connecting circular connecting rod and is fixedly connected through the locking screw rods around, the measurement of the radial absolute displacement of the small-aperture tunnel ring to any target measurement point can be realized, and the stability of the base in the measurement process is ensured.
(3) Through adopting the elastic measuring head of detachable not unidimensional and the rotatory mode of elastic measuring head around cylinder base U type recess, can realize that same base can adapt to the radial absolute displacement measurement of certain aperture range aperture.
(4) The measuring head is separated by adopting the cantilever type structure on the basis that the magnetic base fixes the radial displacement meter, so that the absolute displacement of each measuring head measuring target point can be acquired respectively, and the measuring requirement of large deformation of the small hole can be met.
(5) By adopting a mode that the measuring head is freely regulated and controlled up and down, the prepressing contact of a target measuring point can be realized, and the fitting performance of the whole contact type measuring process is ensured.
The invention provides a measuring device for the radial displacement of the small-aperture tunnel in the model test, and the device has strong scene adaptability, simple installation and simple and convenient operation, and can conveniently and quickly realize the measurement of the radial displacement of the small-aperture tunnel in the model test.
Description of the drawings:
FIG. 1 is a schematic structural diagram of the present invention.
Fig. 2 is a schematic diagram of the operation of the present invention.
Fig. 3 is a side view of fig. 1.
3 fig. 3 4 3 is 3 a 3 view 3 a 3- 3 a 3 of 3 fig. 3 3 3. 3
The specific implementation mode is as follows:
the invention will be further described with reference to fig. 1, 2, 3 and 4.
The radial displacement measuring device for the small-aperture tunnel model test is formed by combining a magnetic base 1, a radial displacement meter and a static strain gauge 14, wherein the radial displacement meter comprises a circular connecting rod 3, a cylindrical base 6 and an elastic measuring head, and the elastic measuring head consists of an annular steel base 8, a spring steel sheet 13 and a measuring head 12; one end of a cylindrical base 6 is provided with four U-shaped grooves which are circumferentially and symmetrically distributed, the inner walls of two sides of each U-shaped groove are symmetrically provided with stainless steel semicircular protractors 10, an annular steel seat 8 is connected with the stainless steel semicircular protractors 10 on two sides of the U-shaped groove of the cylindrical base 6 through a screw 9, rotation constraint is exerted, the U-shaped grooves are respectively provided with a rotation positioning rod, the maximum rotation angle of the annular steel seat 8 is limited to be 45 degrees, one end of a spring steel sheet 13 is fixedly connected with the annular steel seat 8, a strain gauge 11 is pasted on the spring steel sheet, the strain gauge 11 is in half-bridge connection, the strain gauge 11 is positioned on one side of a fixed connection end, the free end of the spring steel sheet 13 is provided with a measuring head; the center of the end face of the other end of the cylindrical base 6 is provided with an axial positioning hole, the cylindrical base 6 is annularly provided with two groups of through holes which are orthogonally and symmetrically distributed along the radial direction, the through holes are positioned at the half part of the length of the positioning hole, a locking screw 7 is arranged in the through holes, one end of the circular connecting rod 3 is fixedly sleeved with a stainless steel full-circle protractor 5, the rotation of the cylindrical base 6 is quantitatively measured, the end heads at the same side are movably inserted into the positioning hole, the main rod on the magnetic base 1 is sleeved with a screw knob 2 to be clamped and fixed, the lower part of the main rod is fixedly connected with a chuck 4; the static strain gauge 14 is directly connected with the strain gauge 11 by a line to acquire end strain data, and the data processing computer 15 is connected with the static strain gauge 14 to acquire and process the strain data; the connection constraint of the screw rod 9 is removed, the annular steel seat 8 can rotate around the screw rod 9, the rotation angle can be quantitatively measured by two groups of stainless steel semicircular protractors 10 on two sides, the opening radius of the spring steel sheet 13 changes along with rotation, the flexible adaptation to the target measuring hole diameter is realized, the round head screw of the measuring head 12 can be freely adjusted up and down along the screw hole of the spring steel sheet 13, when the measuring head 12 is in contact with a target measuring point, the spring steel sheet 13 is slightly pre-bent to apply counter force, the pre-pressing contact with the target measuring point is realized, the fitting performance of the measuring head and the measuring point in the whole measuring process is ensured, and the diameter range of a small-hole tunnel model adapted by.
The invention relates to a measuring device for the radial displacement of a small-aperture tunnel in a model test, which is specifically carried out by the following steps:
(1) a group of spring steel sheets used for measurement are calibrated, and the relationship between the measuring head displacement omega and the end strain epsilon is expressed by the geometrical relationship:
wherein L is the length of the equal thickness part of the spring steel sheet, α is the width of the section of the equal thickness part of the spring steel sheet, H is the height of the section of the equal thickness part of the spring steel sheet, and alpha is the correction coefficient measured by the spring steel sheet and is related to the length-width ratio of the equal thickness part of the spring steel sheet, the elastic modulus E of each spring steel sheet and the length L, the width α and the height H of the equal thickness part of the spring steel sheet are recorded and input into a data processing computer 15, and omega is carried out on the spring steel sheet1＝1mm、ω2＝2mm、ω3＝3mm、ω44mm and omega5Calibrated for five groups of 5mm and recording the corresponding end strain epsilon1、ε2、ε3、ε4And epsilon5the correction coefficient α is obtained by linear fitting by the lead-in data processing computer 15.
(2) According to the space position of the model sample tunnel, the magnetic base 1 is fixed on the side wall of the corresponding height loading instrument, connected with the main rod, used for clamping the circular connecting rod 3, and horizontally calibrated by using the stainless steel full-circle protractor 10.
(3) inserting the circular connecting rod 3 into a positioning hole in the center of the end face of the cylindrical base 6, performing horizontal calibration by means of locking screws on the periphery, rotating the cylindrical base to a proper position according to a target measuring point position, performing locking screw connection by using the locking screws, applying constraint, reading the rotation angle β of the cylindrical base 6 through the stainless steel full-circle protractor 10, and inputting the rotation angle β into a data processing meterComputer 15, the radial displacement of the target measurement point can be decomposed into horizontal displacement omegaxω sin β and vertical displacement ωyω · cos β output.
(4) The elastic measuring heads are connected and installed in the U-shaped groove of the cylindrical base 6 one by one through the screw rods, the screw rod constraint is removed according to the aperture size of a target measuring hole, the annular steel base 8 is rotated, the opening radius of the spring steel sheet is slightly larger than the aperture size of the target measuring hole through visual inspection, the U-shaped groove is respectively provided with the rotating positioning rod, the maximum rotating angle of the annular steel base 8 is 45 degrees, the annular steel base 8 is fixed, and the radial displacement is realized for any rotating angle gamma
The angle gamma of each rotation is read through the stainless steel semicircle protractors 10 at the two sides1、γ2、γ3And gamma4And input to the data processing computer 15.
(5) The position of the measuring head 12 is adjusted through screwing and is in contact with a target measuring point, so that the spring steel sheet 13 is slightly pre-bent, counter force is applied to ensure the round head screw of the measuring head 12 to be in pre-pressing contact with the measuring point, pre-calculation is carried out through a computer, and a measuring initial point is calibrated.
(6) And (3) loading the small-aperture tunnel model sample by using related equipment, acquiring strain data of the end part of the elastic measuring head in real time by the static strain gauge 14, transmitting the strain data to the data processing computer 15, and calculating and outputting the radial displacement of each measuring point in real time.
Claims (2)
1. The utility model provides a radial displacement measuring device of small aperture tunnel model test, includes magnetic base (1), radial displacement meter and static strain gauge (14), its characterized in that: the radial displacement meter comprises a circular connecting rod (3), a cylindrical base (6) and an elastic measuring head, wherein the elastic measuring head consists of an annular steel seat (8), a spring steel sheet (13) and a measuring head (12);
one end of the cylindrical base (6) is provided with four U-shaped grooves which are circumferentially and symmetrically distributed, the inner walls of two sides of each U-shaped groove are symmetrically provided with stainless steel semicircular protractors (10), the annular steel base (8) is connected with the screw rods (9) between the stainless steel semicircular protractors (10) on two sides of the U-shaped groove of the cylindrical base (6), one end of a spring steel sheet (13) is fixedly connected with the annular steel base (8), a strain gauge (11) is pasted on the spring steel sheet, the strain gauge (11) is positioned on one side of the fixed connecting end, the free end of the spring steel sheet (13) is provided with a measuring head (12), and the measuring head (12) is in threaded connection with the spring steel sheet (;
the center of the end face of the other end of the cylindrical base (6) is provided with a positioning hole along the axial direction, the cylindrical base (6) is annularly provided with two groups of through holes which are orthogonally and symmetrically distributed along the radial direction, the through holes are positioned at the half of the length of the positioning hole, locking screw rods (7) are arranged in the through holes, one end of a circular connecting rod (3) is fixedly sleeved with a stainless steel full-circle protractor (5), the end heads at the same side are movably inserted into the positioning hole, the other end of the circular connecting rod is connected with a clamp on a magnetic base, and a strain gauge (11) is in.
2. The small-aperture tunnel model test radial displacement measuring device of claim 1, wherein: and the U-shaped grooves of the cylindrical base (6) are respectively provided with a rotary positioning rod.
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| CN201910017195.3A CN109556563B (en) | 2019-01-08 | 2019-01-08 | Radial displacement measuring device for small-aperture tunnel model test |
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| CN201910017195.3A CN109556563B (en) | 2019-01-08 | 2019-01-08 | Radial displacement measuring device for small-aperture tunnel model test |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113983916B (en) * | 2021-10-29 | 2022-04-26 | 安徽建筑大学 | Tunnel deformation testing device |
| CN114278309A (en) * | 2021-12-06 | 2022-04-05 | 绍兴文理学院 | Tunnel position adjusting and positioning device in tunnel physical model |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS6247529A (en) * | 1985-08-27 | 1987-03-02 | Ishikawajima Harima Heavy Ind Co Ltd | Shape detector |
| AU7616787A (en) * | 1986-07-29 | 1988-02-04 | Unisearch Limited | Optical strain gauge |
| CN2305265Y (en) * | 1997-10-16 | 1999-01-27 | 王大维 | Magnetic based hole driller |
| CN2878671Y (en) * | 2006-01-10 | 2007-03-14 | 山东科技大学 | Under-well meter for pile foundation drilling aperture measuring meter |
| CN201300227Y (en) * | 2008-10-23 | 2009-09-02 | 成都飞机工业（集团）有限责任公司 | Drilling tool for drilling axially and evenly distributed holes |
| CN102979506B (en) * | 2012-11-30 | 2015-07-22 | 山东大学 | Measuring device and measuring method of underground engineering construction drilling attitude combination |
| CN104089561B (en) * | 2014-07-30 | 2016-08-31 | 中国计量科学研究院 | Deep hole internal diameter measures system |
| CN205825866U (en) * | 2016-06-23 | 2016-12-21 | 庆铃汽车（集团）有限公司 | Deep hole conical surface diameter measuring device |
| CN107725026B (en) * | 2017-09-18 | 2023-04-18 | 山东科技大学 | Rock-soil geologic body drilling deformation testing device and testing method thereof |
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