CN106289844B - The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load - Google Patents
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load Download PDFInfo
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- CN106289844B CN106289844B CN201610813763.7A CN201610813763A CN106289844B CN 106289844 B CN106289844 B CN 106289844B CN 201610813763 A CN201610813763 A CN 201610813763A CN 106289844 B CN106289844 B CN 106289844B
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Abstract
The invention discloses a kind of experimental rigs of tunnel bottom structure accumulated damage under cyclic load.Digital display type jack is all around used to provide restraining force to simulate actual forced status locating for tunnel bottom structure in test specimen, it uses the mode for the spring that gathers to simulate tunnel bottom country rock to the effect of contraction of bottom structure in test specimen bottom, is loaded on the top of test specimen by MTS loading system to simulate the effect of train cyclic loading；The accumulated damage characteristic of test specimen under cyclic load is tested using dynamic strain measuring system and piezoelectric ceramics test macro.This method and device can simulate the influence of different stage country rock by changing the rigidity of test specimen bottom spring, the actual conditions that tunnel bottom country rock locally comes to nothing or softens can be simulated come quantification by different-stiffness and the spring assembly of number simultaneously, the application problem of bottom restraint when the uneven situations such as softening, cavity occurs in test specimen bottom can not be considered by solving existing test method and device.
Description
Technical field
The present invention relates to a kind of experimental rigs of tunnel bottom structure accumulated damage under cyclic load.
Background technique
After operation after a period of time, there is bottom structure breakage in part tunnel in China existing railway tunnel, turns over
Phenomena such as slurry emits mud, has seriously affected the operation security in tunnel.The durability and stability of tunnel bottom structure are to railway tunnel
The long-term operation security of (especially high-speed railway and heavy haul railway tunnel) is significant.It is therefore desirable to train cyclic loading
The accumulated damage and long-term dynamic characteristics for acting on lower tunnel bottom structure carry out deep experimental study.
Mainly there are uniaxial tensile test, single shaft pressure to the test method of test specimen accumulated damage under cyclic load both at home and abroad at present
Contracting is tested, the test etc. under the conditions of simple bending, using stress locating for these test method test specimens and boundary condition and tunnel
Bottom structure actual forced status difference is obvious, can not reflect the long-term dynamic characteristics of tunnel bottom structure under train load.
In recent years, true triaxial test machine starts to be applied in the test of structure accumulated damage and power performance, the testing machine
With an axial stress σ1Application system, the stress σ of two horizontal directions2And σ3Lateral stress application system, respectively by only
Vertical hydraulic system is controlled, and the function of three-dimensional anisobaric load may be implemented.However the pilot system is in some single side
Uniform load can only be realized upwards, for tunnel bottom structure, when country rock local softening occurs in bottom or cavity occurs
When, the bottom surface of tunnel bottom structure is obviously in a kind of non-homogeneous stress, and existing true triaxial test system can not be simulated
This actual stress of tunnel bottom structure.And the pilot system applies certain enclose to test specimen by loading system
Pressure, but one-to-one relationship can not be established between the actual wall rock condition of the size of added confining pressure and test specimen periphery.
On the whole, at present both at home and abroad under existing cyclic load the test method of test specimen accumulated damage with dynamic triaxial
Based on test, this method can provide the uneven confining pressure of three-dimensional, but can not establish tunnel surrounding grade and added confining pressure size
One-to-one relationship, also can not be to uneven confining pressure be applied on the single direction of test specimen bottom, the considerations of it is even more impossible to quantification
The non-uniform influence in this part of tunnel bottom, obtained experimental result are difficult to really reflect tunnel bottom structure under train load
Accumulated damage characteristic.
Therefore, it develops and accumulates damage under a kind of cyclic load of the unidirectional uneven confining pressure of application of novel energy quantification
The test method and device of wound have been urgent need.
Summary of the invention
It can not be obtained in test really to solve the accumulated damage characteristic of tunnel bottom structure under current train load
The technical issues of reflection, the present invention provide it is a kind of can in a single direction also can quantification application uneven confining pressure
The experimental rig of accumulated damage under cyclic load.
In order to achieve the above technical purposes, the technical scheme is that, tunnel bottom structure is tired under a kind of cyclic load
The experimental rig of product damage, including experiment casing, lateral charging assembly, top-loaded system, bottom restraint component and test
System, the experiment casing upper end opening and interior be equipped with test test specimen, and the lateral charging assembly is around test test specimen
Side wall setting simultaneously applies pressure to test test specimen, and the top-loaded system is set to the top of test test specimen and tries test
Part applies downward pressure, and the bottom restraint component is set to the bottom of test period and provides support for test test specimen,
The test macro is set in experiment casing with monitoring test test specimen.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the lateral charging assembly
Including multiple identical lateral sub-components, a lateral sub-component is at least arranged in every face on the four sides side wall of test specimen of testing, described
Lateral sub-component include a jack, the jack both ends be pushed against respectively experiment casing inner wall and test test specimen
Side wall on.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the lateral sub-component is also
Including one piece for dispersing the lateral backing plate of pressure, the lateral backing plate be set to jack and test test specimen side wall it
Between, the jack is digital display type hydraulic jack.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the top-loaded system
Including counter-force component, loading head and supporting element, the counter-force component is fixed on above experiment casing, and loading head is set to counter-force
Between component and the top for testing test specimen, supporting element is fixed on the bottom of experiment casing and supports entire experiment casing.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the counter-force component include
Counter-force bar and reaction plate, the reaction plate are fixed on the top of experiment casing simultaneously by the counter-force bar being set to outside experiment casing
Connect loading head.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the bottom restraint component
Including multiple springs disposed in parallel, the spring is set between test test specimen and the bottom surface of experiment casing.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the bottom restraint component
It further include upper constraint backing plate and lower constraint backing plate, the upper constraint backing plate is set between spring top and test test specimen, institute
The lower constraint backing plate stated is set between spring bottom and experiment casing.
The experimental rig of tunnel bottom structure accumulated damage, the spring rate under a kind of cyclic load
With the conversion relation of wall rock assortment are as follows:
C=KS
Wherein C is the stiffness coefficient of spring, and K is the resistance coefficient of country rock, and S is the active area of single spring.
The experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, the rigidity system of the spring
Number is identical or different, distribution that spring is distributed as being uniformly distributed or gap is left a blank.
The experimental rig of tunnel bottom structure accumulated damage, the test macro include under a kind of cyclic load
Sensing chip and piezoelectric ceramics piece are strained, the strain sensing chip and piezoelectric ceramics piece are respectively arranged on test test specimen outer wall.
The technical effects of the invention are that the present invention can not only can also apply uneven constraint in test specimen bottom direction
Pressure, moreover it is possible to this uneven confining pressure of the determination of quantification, so as to more accurate simulation tunnel bottom in difference
Accumulated damage characteristic under contact condition, damaged item cannot be had to Tunnel Base by especially solving existing test method and device
The problem of accumulated damage under part is tested.The present invention is different to Tunnel Base using the spring of different-stiffness coefficient simultaneously
Wall rock condition is simulated, and by the conversion of spring rate and wall rock assortment, is realized test specimen bottom spring and is enclosed
The quantification corresponding relationship of rock condition, solving existing test method, in test confining pressure size and wall rock condition do not correspond to
Problem.In conclusion under a kind of cyclic load provided by the invention tunnel bottom structure accumulated damage test method and dress
Set, can the more accurate accumulated damage characteristic to tunnel bottom structure carry out test simulation, thus for tunnel bottom structure
Design, which calculates, provides foundation.
The present invention will be further explained below with reference to the attached drawings.
Detailed description of the invention
Fig. 1 is the overall design drawing of apparatus of the present invention；
Fig. 2 is apparatus of the present invention bottom spring setting figure；
Fig. 3 is the detail structure figure of apparatus of the present invention；
Fig. 4 is the sectional view of apparatus of the present invention；
Fig. 5 is the top view of test method of the present invention and device；
Wherein, 1 is experiment casing, and 2 is test test specimen, and 3 be top-loaded system, and 4 be loading head, and 5 be jack, and 6 are
Lateral backing plate, 7 be spring；8 be constraint backing plate, and 9 be strain gauge, and 10 be piezoelectric ceramics piece.
Specific embodiment
The present invention is determined using bottom spring by analysing in depth to stress locating for tunnel bottom structure come mould
Quasi- tunnel bottom country rock simulates tunnel bottom by the spring of one group of densely covered same stiffness to the effect of contraction of bottom structure
Even round pressure state；For practical feelings such as tunnel bottom in practice of construction there may be parts to come to nothing, soften, constructional deficiencies
Condition can be enclosed by the number that reduces test specimen bottom spring or the position for adjusting spring come the simulation bottom of quantification in test
The state of coming to nothing of rock simulates the local damage and ruckbildung of tunnel bottom country rock by reducing the rigidity of partial spring；It is logical
The spring assembly for crossing different-stiffness and number can be realized the quantification of the uneven confining pressure in test specimen bottom and apply problem, reach
To the accurate simulation of tunnel bottom structure actual forced status.
In tunnel load-tactic pattern analytical calculation, embodied using elasticity resisting coefficient in tunnel load bearing process
Country rock is to the effect of contraction of tunnel structure, and there are conversion relations between elasticity resisting coefficient and the stiffness coefficient of spring.Therefore
Test method provided by the invention simulates the influence of different stage country rock by changing the stiffness coefficient of bottom spring itself,
It according to the resistance coefficient for the different stage country rock that existing tunnel design specification determines, that is, can determine the stiffness coefficient of spring, realize
Experimental condition is corresponding with the quantification of practical wall rock condition.The conversion relation of spring rate and wall rock assortment is as follows:
C=KS
Wherein C is the stiffness coefficient of spring, and K is the resistance coefficient of country rock, and S is the active area of single spring.
The confining pressure of test specimen all around is accurately controlled by digital display type hydraulic jack, to simulate tunnel bottom
Structure all around locating actual forced status.The application of top cyclic load then passes through MTS system and is accurately controlled, with
Train operation load is simulated to the long term of tunnel bottom structure.By MTS loading system, hydraulic jack and spring are real
The application that existing test specimen three-dimensional unevenly constrains, thus accumulation of the accurate simulation tunnel bottom structure under long-term High-speed Train Loads
Damage feature.
By two sets of test macros of dynamic strain measuring system and piezoelectric ceramics test macro during test, to circulation
The accumulated damage characteristic of test specimen is tested under load, and the test result of two sets of test macros can be compared verifying, thus more
The reliability of good guarantee test result.
Referring to Fig. 1, the chamber of a cuboid is made of steel plate first, length can be according to the size of test specimen
It is adjusted, chamber steel plate thickness is 10mm or more, has enough rigidity with guarantee test case.Gather bullet for chamber bottom
Spring is to simulate the wall rock condition of tunnel bottom, and spring top is the steel plate corresponding to the spring active area, and test test specimen is placed in
On the steel plate of spring top, Even round pressure state, the bullet of different-stiffness coefficient are simulated using the spring of one group of same stiffness coefficient
Spring simulates non-homogeneous confining pressure state, simulates the state of coming to nothing of tunnel bottom structure using partial spring is reduced.Before chamber
Left and right arranges digital display type hydraulic jack afterwards, passes through jack and the enough about beam pressures of application all around that can give test specimen
Power, to simulate tunnel bottom structure locating actual forced status all around.Testing upper box part is opening, by entire chamber
It is placed on MTS hydraulic loading system, by the load actuation head of MTS, cyclic load can be applied to test specimen, to simulate train fortune
Load is sought to the long term of tunnel bottom structure, the influence for runing axis weight, speed etc. of train can load by adjusting MTS is
The amount of force and frequency of system is realized.Test position before test in test specimen arranges corresponding foil gauge and piezoelectric ceramics
Piece can be to the accumulated damage spy of test specimen under cyclic load by dynamic strain measuring system and piezoelectric ceramics test macro
Property is tested.
When it is implemented, the following steps are included:
(1) referring to Fig. 1-5, the cuboid chamber 1 of a upper opening, length root are made of steel plate first
It is determined according to the size of test specimen, chamber steel plate thickness is 10mm or more, has enough rigidity with guarantee test case.
(2) spring 7 is gathered to simulate the wall rock condition of tunnel bottom in chamber bottom, and spring top, bottom are corresponding to this
The steel plate 8 of spring active area, test test specimen 2 is placed on the steel plate of spring top, using the spring of one group of same stiffness coefficient
Uniform restraint state is simulated, the spring of different-stiffness coefficient is simulated non-uniform constraints state, simulated using partial spring is reduced
The state of coming to nothing of tunnel bottom structure.
(3) chamber all around arranges digital display type hydraulic jack 5, and jack is uniform by confining pressure by steel plate 6
The front and back side for being applied to test specimen, the size of steel plate is consistent with the cross dimensions of the test specimen direction, can by jack and spring
To give the front and back of test specimen to apply enough confining pressures according to the actual situation.
(4) entire chamber is placed on MTS hydraulic loading system 3, by the loading head 4 of MTS, test specimen can be applied
Cyclic load, to simulate train operation load to the long term of tunnel bottom structure, the shadow for runing axis weight, speed etc. of train
Sound can be realized by adjusting the amount of force and frequency of MTS loading system.
(5) test position before test in test specimen arranges corresponding strain gauge 9 and piezoelectric ceramics piece 10, by dynamically answering
Become test macro and piezoelectric ceramics test macro, the accumulated damage characteristic of test specimen under cyclic load can be tested.
Claims (7)
1. the experimental rig of tunnel bottom structure accumulated damage under a kind of cyclic load, which is characterized in that including experiment casing, side
To charging assembly, top-loaded system, bottom restraint component and test macro and interior are set the experiment casing upper end opening
There is test test specimen, the lateral charging assembly is arranged around the side wall of test test specimen and applies pressure to test test specimen, described
Top-loaded system be set to test test specimen top and to test test specimen apply downward pressure, the bottom restraint group
Part is set to the bottom of test period and provides support for test test specimen, and the test macro is set in experiment casing to supervise
Test specimen is tested in test；
The bottom restraint component includes multiple springs disposed in parallel, and the spring is set to test test specimen and chamber
Between the bottom surface of body；
The bottom restraint component further includes upper constraint backing plate and lower constraint backing plate, and the upper constraint backing plate is set to spring
Between top and test test specimen, the lower constraint backing plate is set between spring bottom and experiment casing；
The conversion relation of the spring rate and wall rock assortment are as follows:
C=KS
Wherein C is the stiffness coefficient of spring, and K is the resistance coefficient of country rock, and S is the active area of single spring.
2. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 1
It is, the lateral charging assembly includes multiple identical lateral sub-components, tests on the four sides side wall of test specimen every face at least
One lateral sub-component is set, and the lateral sub-component includes a jack, and the jack both ends are pushed against respectively
On the inner wall of experiment casing and the side wall of test test specimen.
3. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 2
It is, the lateral sub-component further includes one piece for dispersing the lateral backing plate of pressure, and the lateral backing plate is set to thousand
Between jin top and the side wall of test test specimen, the jack is digital display type hydraulic jack.
4. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 1
It is, the top-loaded system includes counter-force component, loading head and supporting element, and the counter-force component is fixed on chamber
Above body, loading head is set between counter-force component and the top for testing test specimen, and supporting element is fixed on the bottom of experiment casing simultaneously
Support entire experiment casing.
5. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 4
It is, the counter-force component includes counter-force bar and reaction plate, and the reaction plate passes through the counter-force that is set to outside experiment casing
Bar is fixed on the top of experiment casing and connects loading head.
6. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 1
It is, the stiffness coefficient of the spring is identical or different, distribution that spring is distributed as being uniformly distributed or gap is left a blank.
7. the experimental rig of tunnel bottom structure accumulated damage, feature under a kind of cyclic load according to claim 1
It is, the test macro includes strain sensing chip and piezoelectric ceramics piece, and the strain sensing chip and piezoelectric ceramics piece divide
It is not set on test test specimen outer wall.
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| CN106683562B (en) * | 2017-02-23 | 2023-06-23 | 中国科学院武汉岩土力学研究所 | Simulation device and method for simulating near-field surrounding rock elastic energy accumulation and release |
| CN106959338A (en) * | 2017-03-10 | 2017-07-18 | 西南交通大学 | A kind of dynamic response analogue means of multi-level underground space structure and country rock |
| CN107228803B (en) * | 2017-05-09 | 2020-02-07 | 昆明理工大学 | Pseudo-static test device and method for lining component |
| CN110646282A (en) * | 2019-09-16 | 2020-01-03 | 中国国家铁路集团有限公司 | Surrounding rock elastic reaction coefficient k determination method based on surrounding rock quality index BQ |
| CN110686980B (en) * | 2019-10-30 | 2022-01-07 | 长安大学 | Tunnel excavation analogue means under inhomogeneous side direction load |
| CN112577827B (en) * | 2020-12-02 | 2022-03-29 | 天津大学 | Test method for simulating uniform load of pipeline in deepwater environment |
| CN112577826B (en) * | 2020-12-02 | 2022-12-23 | 天津大学 | Test platform for simulating uniform load of pipeline in deepwater environment |
| CN114383932B (en) * | 2021-12-29 | 2023-11-17 | 大连理工大学 | Circumferential strain detection test method for shield tunnel model |
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