CN109444387A - Mass concrete engineering constraint degree implementation method - Google Patents
Mass concrete engineering constraint degree implementation method Download PDFInfo
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- CN109444387A CN109444387A CN201811283566.4A CN201811283566A CN109444387A CN 109444387 A CN109444387 A CN 109444387A CN 201811283566 A CN201811283566 A CN 201811283566A CN 109444387 A CN109444387 A CN 109444387A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000012360 testing method Methods 0.000 claims abstract description 32
- 239000011435 rock Substances 0.000 claims description 9
- 238000005336 cracking Methods 0.000 claims description 8
- 238000004088 simulation Methods 0.000 claims description 8
- 238000010998 test method Methods 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 10
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 230000007246 mechanism Effects 0.000 abstract description 2
- 230000023753 dehiscence Effects 0.000 abstract 1
- 238000004364 calculation method Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000009662 stress testing Methods 0.000 description 4
- 238000006073 displacement reaction Methods 0.000 description 3
- 238000013480 data collection Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 238000005266 casting Methods 0.000 description 1
- 230000001112 coagulating effect Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/38—Concrete; Lime; Mortar; Gypsum; Bricks; Ceramics; Glass
- G01N33/383—Concrete or cement
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Abstract
The invention discloses a kind of mass concrete engineering constraint degree implementation methods, this method mainly comprises the steps that (1) normal constraint degree, according to Practical Project concret block size, in conjunction with the bullet mould of young concrete and old concrete, the constraint degree of mass concrete corresponding position is calculated；(2) Engineering constraint degree calculates the constraint degree of mass concrete corresponding position according to the relaxation modulus of field measurement and Free Transform；(3) combine site operation, survey mass concrete time-temperature curve and when m- deformation curve；(4) by the time-temperature curve of actual measurement and when m- deformation curve be input to computer system and test；(5) according to identical temperature history and deformation mechanisms, realize the conversion of mass concrete engineering constraint degree machine constraint degree, according to the parameters such as the stress of actual measurement, strain and dehiscence process, the anti-crack ability of concrete is evaluated, formulates more accurate normal constraint degree.
Description
Technical field
The present invention relates to a kind of concrete Bit andits control whole process simulation experimental rig and methods, belong to hydraulic and hydroelectric engineering
Technical field, more particularly to the temperature stress emulated test under mass concrete difference constraint degree.
Background technique
After concreting, due to the effect of the heat of hydration, concrete heating conduction is poor in addition, the heat overwhelming majority of generation
It cannot dissipate, so as to cause concrete temperature raising, volume expansion.In general, the concrete in hydraulic engineering, adiabatic temperature rise
Up to 10~40 DEG C, even if considering surface radiating, inside concrete maximum temperature still than pouring when it is 7~35 DEG C high, when block ruler
When very little very big, internal temperature rise can be higher.Temperature declines in contraction, and block will be made to generate tensile stress under constraint condition, when
Tensile stress is more than the tensile strength of concrete, will lead to concrete cracking.Crack stress and stress under Complete Bind at this time
Ratio is defined as Engineering constraint degree.
Less about the implementation method of constraint degree at present, current method is concentrated mainly on analogue simulation analysis and theoretical meter
It calculates, mainly from the elasticity of concrete or Linear Viscoelastic Constitutive Relation, the temperature history of simulation concrete passes through calculating for emulation
Maximum temperature stress obtains constraint degree；Mainly pass through mechanics means establishes equation to theoretical calculation, is obtained in the way of solution
To constraint degree.With the appearance of temperature stress testing machine, the regulatable field test of constraint degree is realized.But to large volume
Concrete works constraint degree is converted into that temperature stress testing machine constraint degree method is less, and especially temperature stress testing machine is constraining
It spends in controlled process, Engineering constraint degree and simulation test apparatus realize the relationship between constraint degree.Therefore, a kind of realization large volume
The simulation test apparatus and method of concrete works constraint degree become the needs of concrete temperature stress.
Summary of the invention
Present invention aims at the temperature stresses for improving constraint degree method calculating concrete, from test angle, to mixed
It coagulates the development overall processes of the factors under different constraint degrees such as stress, the strain of soil to be tested, for evaluation mass concrete
Cracking ability provides foundation.
The technical solution of the invention is as follows: concrete cracking overall process experimental rig and method under different constraint degrees,
Including the following contents:
(1) specification regulation mass concrete engineering constraint degree
At present standardize as defined in mass concrete engineering constraint degree calculation method mainly include the following types:
U.S. ACI specification:
L and H is the length and height of pour respectively in formula, and h is And of Varying Depth (0≤h≤H).
The restraint stress of concrete proportionally reduces, the γ found out with the reduction of basic material rigidityRIt will be multiplied by one
A coefficient.
A in formulaCAnd ECIt is to pour fast contact area and play mould, AFAnd EFIt is the contact area and bullet mould on basis.On basement rock
Massive Concrete Blocks, it is considered that AFIt is AC2.5 times, i.e. AF=2.5AC。
Country's specification:
1 Engineering constraint degree value of table (when modulus of elasticity of concrete and equal basement rock)
Note: l is pour long side length, m；Y is the height calculated point from base surface, m.
2 Engineering constraint degree value of table (whens modulus of elasticity of concrete and not equal basement rock)
(2) temperature stress testing machine constraint degree
Experimental rig controls at the both ends of concrete sample with collet, and one end is fixed, and the other end can be controlled by collet
Test specimen compression and stretching, the Free Transform of concrete sample are ε0(t), according to the practical distortion ε generated under different constraint degrees
(t), by computer control system, Loading Control System, data collection system, the free margins of concrete sample is made to form ratio
Reduction, corresponding constraint then can be generated to concrete sample, be machine constraint degree.
T is time, ε in formula0(t) and ε (t) be respectively concrete block Free Transform and practical distortion.
(3) mass concrete engineering constraint degree
Under different temperature histories, newly-laid concrete block is answered by the temperature that basement rock or old concrete are constrained and generated
The ratio of theoretical temperatures stress obtains Engineering constraint degree in the case of power, with Complete Bind.Wherein R (t, t0) it is relaxation modulus.
σ (t) is the temperature stress that concret block is generated under basement rock old concrete restrained condition living, σ in formulafix(t) it is
The temperature stress generated under concret block Complete Bind state, R (t, t0) it is relaxation modulus of the concret block in t moment.
Detailed description of the invention
Fig. 1 is mass concrete engineering constraint degree experiment process schematic diagram of the present invention；
Fig. 2 is functional schematic of the present invention；
Fig. 3 is that mass concrete engineering constraint degree implementation method overall process of the present invention tests schematic diagram；
Fig. 4 is mass concrete engineering constraint degree implementation method schematic diagram of the present invention；
Fig. 5 is that mass concrete engineering constraint degree of the present invention surveys schematic diagram；
Fig. 6 is each measuring point temperature history curve of concret block；
Fig. 7 is each wet environment curve of concret block；
Fig. 8 is temperature stress curve under each measuring point difference constraint degree.
Specific embodiment
As shown in Figure 1, Figure 2, Figure 3 and Figure 4, mass concrete engineering constraint degree can by standardizing, surveying to obtain,
It can be realized by following tests mode:
Mass concrete under actual condition, in block centre, there are maximum tension stresses, that is, most dangerous
Position carries out actual measurement and analogue simulation to concret block centre when carrying out mass concrete temperature stress calculating
It calculates, the anti-crack ability of concrete is evaluated.Constraint degree calculating is being carried out for same concret block, constraint degree is not only
It is influenced by own dimensions and basement rock (or old concrete) plays mould, casting concrete bullet mould also has much relations, according to existing public affairs
Formula can calculate the constraint degree of concrete: can be with defined method is standardized, according to size, the contact surface for pouring block
Long-pending and basement rock bullet mould calculates each position constraint degree of concret block；With measurement method, block centre difference is surveyed
Its temperature, deformation mechanisms are measured, meanwhile, the test of each mechanical property parameters of concrete is carried out, including concrete each age
It plays mould and parameter of creeping, prepares to calculate the relaxation modulus of concrete, measure the temperature deformation of concrete under the same conditions
And Free Transform, calculate concrete works constraint degree；With laboratory test mode, temperature history deformation is measured according to scene and is gone through
Journey, when drafting m- temperature curve and time-displacement curve be input to computer, pass through computer control system, Bit andits control
System, temperature control system, Loading Control System and data collection system control test specimen free end, become it freely
Shape follows time-displacement curve variation, realizes mass concrete engineering constraint degree.According to the normal constraint degree being calculated,
Engineering constraint degree and test measure machine constraint degree, temperature stress course, by data processing system, when stress curve is dashed forward
Change shows concrete cracking, and it is mixed that temperature at this time, stress, which can serve as cracking index of the concrete under corresponding constraint degree,
The cracking resistance evaluation for coagulating soil refers to.
Embodiment
The test method tests on-site concrete test block, has verified that mass concrete engineering constraint degree is realized
The validity and reasonability of method.Fig. 5 is the size of concret block, and point 1,2,3,4 is the test point of block, is poured from concrete
It builds and starts to test its temperature history and deformation, the temperatur-timel curve of drafting and time-displacement curve are input to computer, directly
To off-test.
The temperature history curve and deformation curve of test point 1,2,3,4 are shown in Fig. 6 and 7, in addition to temperature history and deformation curve
The constraint degree of difference, each measuring point becomes smaller with the increase of height, and each measuring point can regard identical concrete material as while pour.
The constraint degree that test point 1,2,3,4 is calculated according to different constraint degree calculation methods, is shown in Table 3, is standardized and is led according to ACI
If considering concret block size and playing mould, the constraint degree that the constraint degree and Actual measurement being calculated obtain is not much different；
The constraint degree for obtaining test point 1 according to domestic proper calculation is almost the same with other two kinds of algorithms, illustrates the constraint degree of test point 1
Calculated result is more reliable, and the result of test point 2,3,4 and other two kinds of algorithms have larger gap, mainly since specification is directed to
Length to height ratio is the concret block in the case of 1, and 1 block is greater than for length to height ratio, underestimates basis to the pact of concret block
Shu Chengdu is reduced rapidly its constraint factor, and calculated temperature stress also can be less than normal, therefore, is obtained using Actual measurement
Constraint degree is input to computer and is tested.
From the test data that obtains of test can be seen that the time-temperature curve for obtaining actual measurement and when m- deformation curve
It is input to computer, it is identical that obtained temperature stress, which removes curve and the data of actual measurement,.Test point 1 was split at the 4th day
Seam, corresponding crack stress are 3.3MPa, and the concrete sample of identical temperature history and deformation was broken at the 4th day, fracture
When stress be 3.5MPa；Test point 2 occurred crack at the 4th day, and corresponding crack stress is 3.0MPa, identical temperature history
It was broken with the concrete sample of deformation at the 4th day, stress when fracture is 3.4MPa；There is not crack in test point 3,
Stress is 1.7MPa, and the restraint stress that the concrete sample of identical temperature history and deformation is subject to is 1.73MPa；Test point 4 does not have
Crack is occurred, the temperature stress being calculated is -0.5MPa, the pact that the concrete sample of identical temperature history and deformation is subject to
Shu Yingli is -0.75MPa.The 1 temperature stress 3.3MPa of measuring point to 2 temperature stress 3MPa of test point obtained from field measurement is surveyed
Point 3 temperature stress 1.7MPa and 4 temperature stress -0.5MPa of measuring point, increase with height, constraint energy of the basis to concret block
Power reduces, and the anti-crack ability of block increases.The corresponding crack stress 3.5MPa of measuring point 1, the corresponding crack stress of measuring point 2
3.4MPa, the corresponding restraint stress 1.73MPa of measuring point 3, the corresponding restraint stress -0.5MPa of measuring point 4, obtained temperature are answered
Power and field actual measurement results are almost the same, realize conversion of the mass concrete engineering constraint degree to machine constraint degree.Simultaneously
It observes, the anti-crack ability of concrete is closely related with temperature history, constraint degree, in the lesser situation of the temperature difference, constrains journey
Degree increases also will appear crack to a certain extent, and measuring point 1 is compared with measuring point 2 and can be concluded that.
The constraint degree of each test point of table 3
Claims (5)
1. mass concrete engineering constraint degree implementation method, including 1, normal constraint degree；2, Engineering constraint degree；3, machine constrains
Degree.It is to calculate and simulate mass concrete engineering constraint degree that it, which is acted on,.It is characterized in that mass concrete block can be simulated
Degree of restraint, same time-temperature curve and when m- deformation curve under the conditions of carry out concrete sample analogue simulation examination
It tests, realizes Engineering constraint degree with the mode of machine constraint degree, and then obtain concrete cracking overall process parameter under different constraint degrees,
Formulate more accurate normal constraint degree.
2. according to mass concrete engineering constraint degree implementation method described in right 1, it is characterised in that the method according to
The size and bullet mould of Practical Project concret block, obtain each position of mass concrete by the constraint journey of old concrete or basement rock
Degree.
3. according to mass concrete engineering constraint degree implementation method described in right 1, it is characterised in that the method according to
The time-temperature curve of Practical Project concret block, when the relevant parameters such as m- deformation curve and relaxation modulus, obtain substantially
Product each position of concrete is by old concrete or the degree of restraint of basement rock.
4. according to mass concrete engineering constraint degree implementation method described in right 1, it is characterised in that the method carries out
Same time-temperature and time-deformation curve machine constraint degree test.
5. according to mass concrete engineering constraint degree implementation method described in right 1, it is characterised in that the method according to
Machine constraint degree test method obtains the anti-crack abilities relevant parameter such as mass concrete crack stress, strain, to concrete by
The overall process of constraint carries out analogue simulation, provides reference to improve the cracking resistance of concrete.
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| CN201811283566.4A CN109444387B (en) | 2018-10-24 | 2018-10-24 | Method for realizing engineering restraint degree of mass concrete |
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| CN201811283566.4A CN109444387B (en) | 2018-10-24 | 2018-10-24 | Method for realizing engineering restraint degree of mass concrete |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110376049A (en) * | 2019-07-19 | 2019-10-25 | 东南大学 | A kind of temperature stress testing machine improving strain acquisition system |
| CN110702886A (en) * | 2019-10-23 | 2020-01-17 | 中国水利水电科学研究院 | Method for inverting parameters of mass concrete material |
| CN110907632A (en) * | 2019-12-27 | 2020-03-24 | 上海建工集团股份有限公司 | Large-volume concrete cracking early warning system and method |
| CN112729082A (en) * | 2020-12-22 | 2021-04-30 | 中交四航工程研究院有限公司 | Entity member external constraint degree evaluation method based on integral deformation monitoring |
| CN112816677A (en) * | 2021-03-04 | 2021-05-18 | 中国水利水电科学研究院 | Method and equipment for testing concrete aging coefficient under variable restraint action |
| CN116644599A (en) * | 2023-06-05 | 2023-08-25 | 重庆大学 | Crack prediction method based on elastic modulus of concrete under capillary pore stress effect |
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| JP2013002904A (en) * | 2011-06-15 | 2013-01-07 | Japan Concrete Institute | Method of preventing cracks in concrete |
| CN103513018A (en) * | 2012-12-31 | 2014-01-15 | 中交四航工程研究院有限公司 | Systematic detection method for anti-cracking performance of concrete |
| CN105352876A (en) * | 2015-09-09 | 2016-02-24 | 中国水利水电科学研究院 | Real environment-based concrete cracking whole process test apparatus and method |
| CN106021755A (en) * | 2016-05-26 | 2016-10-12 | 中国核工业第二二建设有限公司 | Simulation analysis method for temperature stress of mass concrete in raft foundations of nuclear island of nuclear power station |
| CN108593770A (en) * | 2018-03-29 | 2018-09-28 | 中国水利水电科学研究院 | Concrete imitation true experiment machine is combined the apparatus and method of monitoring concrete overall process cracking with microseism |
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Patent Citations (5)
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| JP2013002904A (en) * | 2011-06-15 | 2013-01-07 | Japan Concrete Institute | Method of preventing cracks in concrete |
| CN103513018A (en) * | 2012-12-31 | 2014-01-15 | 中交四航工程研究院有限公司 | Systematic detection method for anti-cracking performance of concrete |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110376049A (en) * | 2019-07-19 | 2019-10-25 | 东南大学 | A kind of temperature stress testing machine improving strain acquisition system |
| CN110702886A (en) * | 2019-10-23 | 2020-01-17 | 中国水利水电科学研究院 | Method for inverting parameters of mass concrete material |
| CN110907632A (en) * | 2019-12-27 | 2020-03-24 | 上海建工集团股份有限公司 | Large-volume concrete cracking early warning system and method |
| CN112729082A (en) * | 2020-12-22 | 2021-04-30 | 中交四航工程研究院有限公司 | Entity member external constraint degree evaluation method based on integral deformation monitoring |
| CN112729082B (en) * | 2020-12-22 | 2022-05-17 | 中交四航工程研究院有限公司 | Entity member external constraint degree evaluation method based on integral deformation monitoring |
| CN112816677A (en) * | 2021-03-04 | 2021-05-18 | 中国水利水电科学研究院 | Method and equipment for testing concrete aging coefficient under variable restraint action |
| CN112816677B (en) * | 2021-03-04 | 2021-11-30 | 中国水利水电科学研究院 | Method and equipment for testing concrete aging coefficient under variable restraint action |
| CN116644599A (en) * | 2023-06-05 | 2023-08-25 | 重庆大学 | Crack prediction method based on elastic modulus of concrete under capillary pore stress effect |
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