CN105372171B - Concrete cracking overall process experimental rig based on true environment - Google Patents

Abstract

The present invention provides a kind of concrete cracking overall process experimental rig based on true environment, including pedestal, and be equipped on pedestal: an environmental cabinet is separated with ambient enviroment；One concrete sample accommodating device is located in the environmental cabinet, including fixed bolster plate in the middle part of fixed chuck, active chuck, test specimen, and split constitutes a concrete sample accommodating space, and fixed chuck is installed in environmental cabinet, and active chuck is movably disposed；Environmental cabinet and concrete sample accommodating space set temperature sensor；One true environment simulation system includes at least a temperature-adjusting device and is located in environmental cabinet and concrete sample accommodating device to propose fixed true environment in temperature upper mold；One loading system, so that active chuck position is fixed or, on active chuck setting displacement/deformation-sensor perception concrete sample deformation mobile in axis direction；If strain gauge perceives the load that test specimen is born.The present apparatus can be tested from test angle, development overall process of the factors such as temperature and stress to concrete under the conditions of changeable environment.

Description

Concrete cracking overall process experimental rig based on true environment

Technical field

The invention belongs to hydraulic and hydroelectric engineering technical fields, are related to a kind of concrete cracking overall process based on true environment Test method and the experimental rig for using this method are tried more particularly, to the cracking whole process simulation of mass concrete The device tested.

Background technique

For a long time, " not splitting on no dam " is always unsolved world-famous puzzle, and the appearance in crack affects dam structure Appearance, performance and safety, eventually affect the people's lives and property.How to reduce or even prevents the generation in crack from just becoming work The problem of journey builder must be taken into consideration.As related fields is theoretical and the progress of technical research, the research in dam concrete crack Work achieves obvious progress, especially Temperature Controlling of Mass Concrete anticracking and works, and has formd comparatively perfect at present Basic theory and method system.But in view of the complexity of hydraulic and hydroelectric engineering, the especially abominable of location environment, dam Distress in concrete problem does not still solve thoroughly.

There are many factor for causing concrete to generate crack, and structure, material and construction factor are likely to become crack appearance Inducement, but for dam, the dam especially built in big temperature difference high altitude localities, surrounding weather environment gradually at For the emphasis factors of temperature controlled anticracking control.Atmospheric environment not only in real time surrounds entire concrete works, and atmospheric environment The varied temperature that important influence, especially ambient enviroment are also generated to engineering, humidity, rainfall, wind speed and sun spoke It the factors such as penetrates, drastically influences the generation of distress in concrete, atmosphere environment impact factor advises the influence that distress in concrete generates How is rule, and influence degree has much again, and there is presently no final conclusions.Therefore, it is complete to develop the concrete cracking based on true environment Process testing device and method just become needed for concrete dam project construction.

Summary of the invention

It is an object of the invention to improve limitation and deficiency in the simulation of existing concrete temperature stress and crack research, mention For one kind from test angle, development overall process of the factors such as temperature and stress to concrete under the conditions of changeable environment into The device of row test.

The technical solution of the invention is as follows:

Concrete cracking overall process experimental rig provided by the invention based on true environment, including a pedestal, at the bottom It is provided on seat

One environmental cabinet at least has four walls and upper cover, forms a closed space, separates with ambient enviroment；

One concrete sample accommodating device is arranged in the environmental cabinet comprising fixed chuck, active chuck, test specimen Middle part fixed bolster plate, three's split constitute the concrete sample accommodating space that a upper end is open or upper and lower side is open, The fixed chuck is fixed in the environmental cabinet, and the active chuck can be along the length of the concrete sample accommodating space The axis in direction is movably arranged；

In the environmental cabinet or the environmental cabinet and concrete sample accommodating space, temperature sensor is set；

One true environment simulation system includes at least a temperature-adjusting device, to heat and/or cool device, It is arranged on the environmental cabinet and concrete sample accommodating device to provide and at least propose fixed true environment in temperature upper mold；

One loading system, including a frame, a transmission device and a power device, the frame are arranged in the pedestal On, the transmission device include a straight-line motion mechanism, driven member therein by the side wall of the environmental cabinet enter environmental cabinet and The active chuck is fixed and the active chuck position is made to fix or move in the axis direction, in the straight-line motion mechanism Driving link it is fixed on the frame；The power device setting on said frame, connects in the straight-line motion mechanism The driving link；

Displacement/deformation-sensor perception concrete examination is set on the active chuck or the component connecting with active chuck The deformation of part；Strain gauge is set on the straight-line motion mechanism and perceives the load that test specimen is born.

It suitably with the experimental rig, further include a computer, which is connected by data line and a control system It connects, which includes: to control the control unit of each executing agency's movement of master trip machine true environment simulation system；With main examination It tests in machine and controls the control unit of power device movement in concrete sample loading system；

The computer also passes through the signal output end that the temperature sensor of environmental parameter is monitored described in data line；

Displacement/deformation displacement/deformation-sensor signal output end of the monitoring concrete sample；

The signal output end of the strain gauge of the monitoring test specimen stress is connected；

The control signal output of the control system is connected with the control terminal of each executing agency.

Temperature control unit receives the instruction of computer, control executing agency, that is, heating/cooling device work, so that coagulation Native test specimen accommodating space also may include that the temperature of environmental cabinet meets the parameter of setting.

Displacement/deformation control unit and load control unit control the dress of the power in executing agency i.e. loading system together It sets.

Data processing system in computer calculate concrete sample in the true environment of the simulation include about Shu Yingli, free variable, elasticity modulus, deformation separation, result of at least one of creeping simultaneously export.

The cross-sectional shape of the accommodating space are as follows: both ends are the shorter heads of width greater depth, centre be width compared with The small longer interlude of length, the head and interlude connect transition by boring section；The fixed chuck and active chuck with Splicing seams in the middle part of test specimen between fixed bolster plate are located in the intermediate segment limit of the accommodating space.

Further, it can also include a cope plate that the test specimen, which accommodates fixed device, close the concrete examination The upper end of part accommodating space is open.

For seam between the side template and the active chuck and/or fixed chuck there are gap, which includes side Gap between the end of template and the active chuck, to guarantee test specimen side template and active chuck non-contravention in compression, It further include the gap between the side of side template and fixed chuck and active chuck.

The side template can be arranged in transverse shifting in the environmental cabinet.

In use, concrete can be directly poured into the concrete sample accommodating space and forms test specimen, it can also To be placed in manufactured in the concrete sample accommodating space with the matched test specimen of test specimen accommodating space shape.

Be arranged in the climate control system in the environmental cabinet heat and/or cool device can be setting exist In the tank wall of the environmental cabinet or in closed space, the tank wall has hollow chamber, and/or, setting test specimen, which accommodates, to be fixed The fixed chuck, active chuck and side template at least one in device has hollow chamber；

Each hollow chamber's setting inlet and outlet is connected to the medium channel of the heating or cooling device, described to hold Jie that row mechanism can be the electric heating coil being arranged on the medium channel of the heating-cooling device or driving is heated or cooled The dynamic delivery pump of mass flow, for providing in test thermal energy or cold energy as needed.

In the present invention, main climate control system in true environment system is simulated, there can be two parts, a part is It is arranged on environment cabinet, another part is accommodated in test specimen to be arranged on fixed device.It is arranged on environmental cabinet, is more simulation Temperature in true environment, and accommodate in test specimen and be arranged on fixed device, it can simulate in a short time in true environment for example The temperature of concrete dam.All without such comprehensive climate control system in experimental rig in the prior art.

In the present invention, concrete directly can be cast directly over into the concrete sample accommodating that test specimen accommodates fixed device In space, in this manner it is possible to test concrete in the true environment of simulation from lean state to solidification again to hardening complete procedure The variation of dilatancy and stress, in this way, for such as dam from pour, be solidified to hardening process stress, strain in difference It can be carried out testing under environmental condition, obtain comprehensive data, provide valuable information for design, the construction of dam.It is existing Experimental rig in technology does not all expect the test for yet not accomplishing this complete procedure.Certainly, test dress provided by the invention Test specimen in setting accommodates fixed device and can also test manufactured concrete sample.

Computer control system provided by the invention is substantially the prior art, is implemented function such as wherein: when due to When test specimen deforms in the true environment of simulation and pushes against the active chuck, strain gauge collects stress, passes through data The signal output end of processing system and data output system connect with power device and starts power device driving active chuck and move It moves until the stress sensed on strain gauge is reduced to zero, the power device stops.

Such structure can make this experimental rig realize the test such as free variable.

There are also be exactly that starting power device driving active chuck is mobile and reduces deflection, by institute after free variable Displacement sensors obtain displacement, obtain corresponding stress value by the strain gauge.

The true environment simulation system can also include that the environment is arranged other than the weather adjustment device At least one of case regulating device: humidity control apparatus, solar radiation regulating device, rainfall regulating device, wind speed adjust dress Set, further include such as at least one of lower sensor correspondingly: humidity sensor, solar radiation sensor, rainfall sensor and Air velocity transducer is connect with the computer, the executing agency of the control system connection.

Specifically, apertured, connecting line, the piping connection it can supply gas on the tank wall of the environmental cabinet, send vapour, air-supply At least one of with water injector, humidity control apparatus, rainfall regulating device and wind-speed adjusting device are correspondingly constituted；With/ Or, apertured on the tank wall of the environmental cabinet, the lamps and lanterns that simulated solar irradiates are arranged in hole and constitute solar radiation regulating device.

Each executing agency is associated with so that simulating the true environment of setting with the control system.

Each regulating device, which can also be, establishes one's own system, such as temperature-adjusting device, including heating controller, temperature control Instrument connects heating element and temperature sensor and realizes heating function.In this way, can simplify the structure of control system.

Further, the frame is the frame for including the rectangle that two crossbeams and two columns are constituted, and one fixed horizontal Beam is fixed on the pedestal of the fixed chuck side, and two columns fixed cross beam that is connected in parallel is located at institute Environmental cabinet two sides are stated, a fine motion crossbeam is arranged on the pedestal of the active chuck side, connect with the column, institute It states power device to be arranged on the fine motion crossbeam, reaction frame is consequently formed, the straight-line motion mechanism passes through the fine motion crossbeam It is connect with active chuck, the support section of the displacement/deformation-sensor and the strain gauge is directly or indirectly fixed On the base.

Frame provided by the invention, two crossbeams, one fixation form fixed cross beam on the base, another is Setting does not have fixed structure to form fine motion crossbeam with the pedestal on the base, and loading system is arranged on fine motion crossbeam.

In this way, frame can bear very big stress and might have the deformation of very little when loading system exerts a force to test specimen, But this power and deformation will not be transmitted to pedestal.Therefore, the measurement accuracy of displacement sensor and force snesor is not by frame deformation It influences, guarantees good measurement accuracy.

The material and sectional dimension of the column are as follows: guarantee that its rigidity is to bear the 5-20 of the maximum strength stress of concrete Times power and indeformable or stiffness K be more than or equal to 2MN/mm；And/or guarantee that its temperature stability is the temperature model in test Enclose (such as -20-80 DEG C) it is interior when its temperature deformation less than 10 microns.

The frame provided by the invention, using upright post cross-beam type, stable structure, column therein has enough in addition Rigidity and temperature deformation stability, can guarantee test well precision.

Further, form is set on the case lid of the environmental cabinet, so that test process visualization.

The preferred servo motor of power device connects worm reduction gear transmission mechanism.Such power device makes to control The big raising of precision, feedback speed, efficiency.

The transmission mechanism of the linear motion uses screw-drive mechanism.

A hoisting mechanism is also set up in the pedestal, fixed dress is accommodated in the test specimen and centers a bottom plate for putting It sets test specimen or is poured test specimen on it, which connects the hoisting mechanism, can be by test specimen from mixed by running the hoisting mechanism In solidifying soil test specimen accommodating space into and out.

It can also include an ancillary test machine in experimental rig provided by the invention, which includes a test specimen The temperature is arranged in the test specimen accommodating cavity for placing test specimen identical with the test specimen tested in the master trip machine in accommodating cavity Regulating device, or setting at least one of the temperature-adjusting device and following regulating device: humidity control apparatus, too Sun radiation regulating device, rainfall regulating device and wind-speed adjusting device；Temperature sensor is set in the test specimen accommodating cavity, is also set up Such as at least one of lower sensor: humidity sensor, solar radiation sensor, rainfall sensor and air velocity transducer, it is each The sensor is connect with the computer, which connects the regulating device and adjust the test specimen accommodating cavity inner ring Border parameter is identical as the master trip environmental cabinet；Displacement/deformation-sensor is also set up in the test specimen accommodating cavity to perceive test specimen Deformation.

The control system further includes controlling the various execution machines of true environment simulation system in the ancillary test machine The control unit of structure movement.

It is put into test specimen accommodating cavity with the test specimen in master trip device, so that test specimen can Free Transform.Ancillary test Test specimen in machine in same environment, for being compared with the test specimen in master trip device.Ancillary test machine is in test specimen and machine Under the conditions of device bottom plate coefficient of friction is sufficiently small, the Free Transform of measurement and master trip machine auxiliary test specimen under the conditions of synthermal.It is synthermal Condition parallel test machine, makes test data have integrality.

Experimental rig provided by the invention is mainly used for distress in concrete mechanism and temperature stress test.It can carry out more Under the conditions of kind temperature control measures, concrete, should from the test for being poured into the development process of its own temperature stress in hardening overall process Process may include the process that adiabatic temperature rise, thermal expansion coefficient, elasticity modulus and the parameters such as creep develop at any time；It can also simulate Simulating realistic weather environment, under the influence of natural cause temperature stress and Cracking Mechanism emulate.The experimental rig can root According to needing to be arranged different temperature and constraint degree condition, including insulation, constant temperature, the process for setting temperature rise temperature drop etc..Pass through coagulation Soil cracking whole process simulation test, evaluates the cracking resistance of concrete.

Using above-mentioned experimental rig, the concrete cracking overall process test method based on true environment, comprising the following steps:

(1), concrete is cast in the concrete sample accommodating space, or concrete sample is arranged and is mixed at this It is fixed on device in solidifying soil test specimen accommodating space；The both ends of the test specimen are connected with the fixed chuck and active chuck respectively；

(2) a true environment simulation system is constructed, the environmental cabinet and/or concrete are made by the executing agency At least temperature parameter in test specimen accommodating device reaches setting true environment to be simulated requirement, and the environment in the environmental cabinet can be with It is a constant environment, or the environment of Parameters variation within the set range；

(3) at least one following test procedure is then carried out under the true environment of setting:

A. it freely constrains:

Experimental rig fixes concrete sample one end, other end retractable, provides in true environment simulation system Under the true environment of setting, free variable test is carried out to the test specimen, in the time zone (t) of setting, the acquisition of setting period Deflection ε (t),

When expansion or shrinkage occurs in test specimen, the strain gauge of setting shows stress value, i.e. starting power device, So that straight-line motion mechanism in the movement of deformation direction identical direction until strain gauge shows that stress value is zero, from displacement/ Deformation-sensor obtains the numerical value of free variable at this time.

The concrete operations freely constrained are as follows: experimental rig clamps the both ends of concrete sample, and one end is fixed, and one end is controllable System moves, and under true environment simulated conditions, load, setting time interval (t), according to position is not added in the controllable end of the test specimen The data of shifting/deformation-sensor and strain gauge detection, act power device by control system, thus, make the examination The free displacement of part is μ (t), as the free variable ε (t) of t moment concrete.

The purpose of measuring the free variable of concrete is separated for concrete various modifications.

B. restraint stress:

Experimental rig clamps the both ends of concrete sample, and one end is fixed, the controllable movement in one end, i.e., first allow test specimen with One end free extension of active chuck connection, after test specimen has an elongation or shrinkage in the true environment, if It fixes time and is spaced (t), according to the data that displacement/deformation-sensor and strain gauge detect, fill power by control system Movement is set, thus, reduce the displacement of test specimen movable terminal, test the concrete stress in the case of different degree of restraint, Restraint stress test is carried out to the test specimen.

Concrete operations are: experimental rig clamps the both ends of concrete sample, and one end is fixed, the controllable movement in one end.Very Under real environment simulated conditions, the free displacement of the concrete sample movable terminal is that μ (t) passes through calculating according to actual needs Machine control system, displacement/Deformation control system and loading system, reduce the displacement of test specimen movable terminal, at this moment described It is the concrete temperature stress σ (t) in the case of constraint factor f (t) that strain gauge, which measures each moment difference degree of restraint,.

The displacement that movable terminal reduces are as follows:

f(t)×μ(t) (6)

In formula, t is the time, and concrete constraint factor when f (t) is t, μ (t) is the freedom of concrete sample movable terminal Displacement.

C. elasticity modulus:

The elasticity modulus of concrete cracking overall process experimental rig measurement concrete based on true environment, in computer Set interval Δ t in computer, i.e., the elasticity modulus of a concrete is measured every the Δ t time.

Specifically, set interval Δ t in a computer, every Δ t time interval, according to displacement/deformation-sensor With the data of strain gauge detection, act power device by control system, thus, so that test specimen movable terminal is done primary position Variation, i.e. the change in displacement value (such as 2 microns) for setting are moved, reaches setting position when piece lengths extend or shorten length When moving changing value (such as 2 microns), a change in displacement is done to test specimen movable terminal, this setting change in displacement value is pushed back Or pull back, stress variation caused by measuring this change in displacement according to strain gauge, elasticity modulus is carried out to the test specimen Test.

Concrete operations are as follows: passed through every the Δ t time according to the data that displacement/deformation-sensor and strain gauge detect Control system acts power device, thus, so that test specimen movable terminal is a change in displacement Δ μ (t), refers to one on test specimen The difference of the length at a moment and this moment obtains deformation Δ ε (t), refers to a moment and this moment on test specimen Length difference divided by test specimen total length, be Δ σ (t) according to the stress variation that strain gauge is measured, then the coagulation of t moment Native elasticity modulus are as follows:

According to the time interval of design, computer control system can automatically measure the concrete elastic mould of different moments Amount, can be obtained concrete in the elasticity modulus of entire development process.

D. the separation deformed

According to the temperature change that thermal expansion coefficient of concrete and temperature sensor measure, the temperature deformation of concrete is obtained, In conjunction with the Free Transform measured, the isolated test which is deformed.

The separation of deformation refers to be separated total deformation is measured.Because measuring total deformation is that various deformation is blended in one It rises, has and deform (such as expanding with heat and contract with cold) caused by temperature, have deformation caused by drying shrinkage, have autogenous volumetric deformation, caused by having stress Deformation etc..Here separation, for example separated that a part is deformed caused by only temperature from deformation the inside is measured, with Understand deformation etc. of the concrete only under temperature action.

Concrete operations are as follows: do free constraint first: experimental rig fixes concrete sample one end, and the other end can freely be stretched Contracting, by true environment simulation system provide setting true environment, to the test specimen carry out free variable test, setting when Between in region (t), setting period acquisition deflection ε (t).

After 1 day age of concrete, thermal expansion coefficient would not change again substantially, it is considered that and it is a constant, The parameter can also be measured by dedicated thermal expansion coefficient tester, here it is considered that being constant α.According to thermal expansion coefficient of concrete The change in temperature Δ T (t) that α and temperature control system measure, it can be deduced that the temperature of concrete becomes under true environment simulated conditions Shape:

Δε_T(t)=α Δ T (t) (8)

It in conjunction with the Free Transform ε (t) measured, is separated, you can get it, and other deform Δ ε_aIt (t), mainly include spontaneous Cubic deformation and dry-shrinkage deformed:

Δε_a(t)=ε (t)-Δ ε_T(t) (9)

E. concrete creep

According to the Free Transform that the abovementioned steps C modulus of elasticity of concrete measured and abovementioned steps A are measured, can calculate not By concrete stress when Creep Effect；According to the data that displacement/deformation-sensor and strain gauge detect, pass through control system Power device is acted, thus, make the deformation zero of test specimen, at this moment measure another stress, according to the two stress variations, to this The test of test specimen progress concrete creep.

Concrete operations are as follows: according to the modulus of elasticity of concrete E (t) and Free Transform ε (t) obtained, true ring can be calculated Not by concrete stress σ (t) when Creep Effect under the simulated conditions of border:

σ (t)=ε (t) E (t) (10)

According to the data that displacement/deformation-sensor and strain gauge detect, act power device by control system, To control concrete deformation, be morphed into zero, at this moment measuring stress is σ₀(t), then true environment simulated conditions Under creep caused by stress reduce are as follows:

σ_c(t)=σ (t)-σ₀(t) (11)

Pass through σ_c(t) size it can be concluded that concrete creep influence degree, wherein t is the time.

F. concrete cracking overall process

Concrete sample is allowed to bear tensile stress in the temperature change of setting or apply in the simulation true environment of setting Add pulling force until cracking, obtain the temperature variations of concrete cracking or in the true environment of setting concrete sample it is anti- Tensile strength or limit stretch value.

The concrete operations of concrete cracking overall process may is that concrete temperature changes to set temperature from initial temperature, Test specimen two ends fix, one end applies pulling force, when tensile stress data reduce suddenly, be displaced increase suddenly, correspondence when m- stress, when When being mutated on the curve of m- deformation/displacement, concrete cracking obtains the relevant parameter of at this moment concrete, including temperature, Tensile strength, limit stretch value.

G. concrete cracking overall process evaluation is carried out to the test specimen

In conjunction with test data, that is, experimental condition of step A, B, C, D, E, F and as a result, to true in the simulation for testing setting Concrete sample carries out assessment of performance in environment.

Further, in conjunction with the test data of at least one front A, B, C, D, E, F and as a result, i.e. in conjunction with the phase of concrete Close environmental parameter such as temperature, stress, displacement and deformation, to the test specimen carry out from concrete sample it is intact or since pouring up to Cracking overall process makes evaluation.

In this step, being directed to engineering, weather environment changes this complicated feature in practice, and a variety of environmental factors are arranged Variation model, the environmental factor parameter includes environment temperature, is also comprised in humidity, rainfall, wind speed and solar radiation At least one.

Relevant parameter temperature, stress, displacement and the deformation of concrete can be used as the cracking under the conditions of real-world temperature Index provides important test reference for engineering design, construction and construction.

It can be seen from the above, the experimental rig and method can Free Transform to concrete under real environmental conditions into Row test；The temperature stress of concrete difference restrained condition under real environmental conditions can be tested；It can be to true ring The elasticity modulus development process of border Under Concrete is tested；It can be to the various deformation of concrete under real environmental conditions Carry out separation test；Creeping for concrete under real environmental conditions can be tested；It can be according under real environmental conditions Development process and the dehiscence process for testing the parameters such as concrete temperature, stress, the strain obtained, to the cracking overall process of concrete It is analyzed and evaluated, provides reference for the Crack Control Design of concrete.

The simulation of the true environment refers to the hydrometeorological condition according to Practical Project location, input environment temperature The relevant informations such as degree, humidity, rainfall, wind speed and solar radiation simulate true engineering weather environment.It in this step, can needle To engineering, weather environment changes this complicated feature in practice, and a variety of environmental factor variation models are arranged.

Method provided by the invention, can also be since concrete be poured test specimen up to each of such overall process that crack Stage or various aspects are tested and are evaluated.

It in the above-mentioned methods, can be with the following method for the simulation of true environment:

1. environment temperature

Depending on local situation, that is, the locality of true environment is simulated, the above monthly mean temperature data is fitted to one Cosine curve, following formula (1) are the calculation formula after fitting:

Consider climate simulation, calculated using following formula:

In formula, T_aFor temperature, T_amFor average temperature of the whole year, A_aFor temperature year luffing, τ is time (moon), τ₀For maximum temperature Time (moon).

Consider temperature diurnal variation, calculated using following formula:

In formula,For daily temperature, T_aFor monthly mean temperature, A is temperature diurnal variation amplitude, at the time of t is in 1 day (when) root Depending on the Various Seasonal of different regions.

2. solar radiant heat

Concrete structure is often an exposure under solar radiation, is had a major impact to concrete temperature.Unit The heat that solar radiation comes on unit area in time is S, wherein set the part absorbed by concrete as R, remainder quilt It reflects away, then:

R=α_s·S (3)

In formula, α_sFor absorption coefficient, also referred to as coefficient of blackness, concrete surface generally takes 0.65.

S=S₀(1-kn) (4)

In formula, S₀For fine day solar radiant heat, n is cloud amount, and k is coefficient, these three numerical value can be provided by local weather station.

The temperature that the influence of sunshine is equivalent to surrounding air increases Δ T_a,

ΔT_a=R/ β (5)

In formula, β is concrete surface exothermic coefficient, can be calculated according to surface roughness and wind speed.

3. rainfall

The rainfall for inquiring engineering location meteorological department, by rainfall equipment and rainfall amount controller come simulated rainfall.

4. wind speed

The wind speed of the meteorological department in engineering location, threshold wind velocity simulator are inquired, and coagulation can be obtained according to wind speed Native surface coefficient of heat transfer.

Concrete cracking overall process experimental rig provided by the invention based on true environment can carry out a variety of temperature controls and arrange Under the conditions of applying, concrete is swollen from the development process for being poured into its own temperature stress in hardening overall process, including adiabatic temperature rise, heat The process that swollen coefficient, elasticity modulus and the parameters such as creep develop at any time, can be with the true weather environment of analog simulation, to nature Temperature stress and Cracking Mechanism under the influence of factor are emulated.Different temperature and constraint degree can be set as needed in the device Condition, including insulation, constant temperature, setting temperature rise temperature drop process etc..It is tested by concrete cracking whole process simulation, evaluates concrete Cracking resistance.

The present apparatus and method have the advantages that

1) this experimental rig uses environmental cabinet and concrete sample accommodating space dual structure, can be since pouring test specimen It is tested, various true environments can be simulated in addition, can fully understand the case where concrete is poured into hardening complete procedure, Comprehensive test data is provided for various industries concrete structure.

2) the reaction frame structure for using high rigidity, is suitable for the permanent creep test of concrete.

3) using floating frame structure, i.e. two end floor beams, one is fixed on the base, and one is only placed on pedestal, Measurement accuracy is higher, and systematic error is smaller.

4) test specimen automatic lifting device is increased, so that test specimen treatment process after specimen molding and test is saved physical strength, just In operation；

5) test specimen is increased in the function of test process adjusting constraint, can make to try in test process adjusting micro-adjusting mechanism Part constraint is gradually reduced to zero；

6) real-time tracking records data, and sampling time interval can be freely arranged；

Therefore, the present apparatus be widely used in mine, mining industry, underground engineering, metallurgical construction, national defence people's air defense, universities and colleges, The testing equipment of the ideal high performance-price ratio of the industries such as communications and transportation.

Below by drawings and examples, the invention will be described in further detail.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of experimental rig provided by the invention.

Fig. 2 is the structural schematic diagram of the external structure of the master trip machine in experimental rig provided by the invention.

Fig. 3 is the structural schematic diagram of the internal structure of master trip machine provided by the invention.

Fig. 4 is the portion the A partial enlargement structural representation of Fig. 3.

Fig. 5 is the case lid 22 of the removal environmental cabinet of master trip machine shown in Fig. 3 and the plan structure signal after cope plate 314 Figure.

Fig. 6 is the portion the A partial enlargement structural representation of Fig. 5.

Fig. 7 is displacement sensor setting structure schematic diagram.

Fig. 8 is medium recycle circuit structural schematic diagram in side template.

Fig. 9 is medium heating procedure schematic diagram.

Figure 10 is the structural schematic diagram of one embodiment of heating device.

Figure 11 is that the present invention is based on the control principle drawings that the concrete cracking overall process of true environment is tested.

Figure 12 is another control principle drawing.

Figure 13 is functional schematic of the invention.

Figure 14 is temperature and concrete stress graph based on true environment.

Specific embodiment

Concrete cracking overall process experimental rig provided by the invention based on true environment is as shown in Figure 1, include one A master trip machine A and ancillary test machine B.It is additionally provided with computer D, computer D is connected by a data line L and control system D1 It connects, control system D1 includes:

1. controlling the control unit of the various executing agencies of true environment simulation system in master trip machine A and ancillary test machine B；

2. controlling the power in control unit, that is, loading system of the executing agency of concrete sample load in master trip machine A The control unit of device.

The data line L of computer D is also connected with:

1. monitoring the signal output end of the temperature sensor of environmental parameter in master trip machine A and ancillary test machine B；

2. monitoring displacement/deformation displacement/deformation-sensor of concrete sample in master trip machine A and ancillary test machine B Signal output end；

3. monitoring the signal output end of the strain gauge of test specimen stress in master trip machine A.

The major function of computer D is:

1. the parameters of true environment to be simulated and the changing rule of parameters are set by computer D, according to The movement of each execution unit of this control simulation true environment, will also receive the ring for monitoring each sensor feedback of environmental parameter Border parameter and the operation that executing agency is controlled accordingly by control unit；

2. by the various test parameters in computer D setting test, such as: displacement/deformation-sensor and stress sensing The monitoring time interval of device；

3. control unit, which is arranged, instructs the power device movement and the displacement/deformation-sensor and the stress sensing The incidence relation of device；

4. passing through various tests knots in the data processing system and each test of data output system output in computer D Fruit.

One computer control system including the acquisition at least temperature, the displacement/deformation that are made of aforementioned each sensor and is answered Data collection system and data including power handle and export system；The signal output end of each sensor and computer control The data processing system of system processed is connected with the corresponding signal input terminal of data output system, the data processing system and data The signal output end of output system is connect with the signal input part of an executing agency, which includes dynamic in loading system Device is heated and/or cooled in power device and weather adjustment device, to adjust environmental cabinet and/or concrete sample accommodating space Environment it is consistent with the true environment of setting and/or start or stop the power device；The data processing system and data Output system connect and calculate concrete sample in the true environment of the simulation include restraint stress, free variable, Elasticity modulus, deformation separation, result of at least one of creeping simultaneously export.

The true ring of simulation being arranged by computer D and control system D1 and in master trip machine A and ancillary test machine B The executing agency in border simulates the true environment of a setting on test specimen and locating for test specimen in environment, in this context, lead to It crosses computer D and control system D1 and deformation of the test specimen in the environment such as different temperatures is obtained by displacement/deformation-sensor, then lead to It crosses the loading system that computer D and control system D1 are set and controlled and pulling force or pressure is applied to test specimen in master trip machine A, complete It such as freely constrains, restraint stress, elasticity modulus, the separation of deformation, the test of concrete creep and concrete cracking overall process, Obtain the various performance parameters of the concrete in various simulated environments, the identical test block in ancillary test machine B is in freely without about The deformation etc. of the state of beam, the test block can be used as comparison.

Experimental rig provided by the invention and test method are described in detail below.

Fig. 2 shows a kind of master trip machines comprising environmental cabinet 2 is arranged on pedestal 1, is additionally provided on pedestal 1 for pedestal 1 One frame 4 is additionally provided with test specimen in environmental cabinet 2 and accommodates fixed device 3 (see Fig. 5).

Environmental cabinet 2 includes the cabinet 21 of a upper end opening and the case lid 22 (see Fig. 3) for closing the upper end opening, with this An enclosure space separated with ambient enviroment is constituted, wherein to build up setting for test needs by true environment simulation system Fixed true environment.

Environmental cabinet 2 completely cuts off internal heat and transmits to reaction frame i.e. frame 4 and pedestal 1, while also completely cutting off external heat It internally transmits, ensure that temperature controlled easily-controllable property, while avoiding shadow of the rising-heat contracting-cold to measurement result of plant bottom case 1 It rings.

As shown in Figure 3 and Figure 5, the test specimen accommodates fixed device 3, is arranged in the environmental cabinet 2, including fixed chuck 311, active chuck 312, test specimen middle part fixed bolster plate 313, three's split constitutes a upper end opening or upper and lower side is spacious The concrete sample accommodating space 31 of mouth, the cross-sectional shape of the accommodating space 31 are as follows: both ends are that width greater depth is shorter Head, centre, which is the longer interlude of width smaller length, the head and interlude, connects transition by boring section；The fixation Splicing seams in the middle part of collet 311 and active chuck 312 and test specimen between fixed bolster plate 313 are located at the centre of the accommodating space 31 In segment limit, there are sideshake a1, the end face of side template 31 and active chucks with active chuck 312 for the side of side template 313 There are end clearance a2 (as shown in Figure 6) between 312.It is test specimen C that the shape of concrete sample accommodating space 31, which is substantially equal to, Shape.

A kind of test specimen accommodates the structure of fixed device 3 are as follows: fixed chuck 311 is fixed on pedestal 1, active chuck 312 can be movably disposed at pedestal 1 relative to pedestal 1 along the axis of the length direction of the concrete sample accommodating space On；It further includes a cope plate 314 that test specimen, which accommodates fixed device 3, closes the described of the concrete sample accommodating space 31 Upper end is open.The example that fixed device is accommodated for the open test specimen of upper and lower side, sets on bottom surface in the accommodating space 31 One bottom plate, that is, lower template (not shown).Bolster and two side templates are 304 Stainless Molding Boards totally 4 with a thickness of 70mm Block.

In use, it is formed on the bottom plate that concrete can be directly poured into the concrete sample accommodating space 31 Test specimen C can also be placed in manufactured on the bottom plate in accommodating space 31 with the matched test specimen C of the test specimen accommodating space shape. In bottom plate following settings support base 31-1 (see Fig. 5).

As shown in Figure 5 and Figure 6, in order to guarantee the repetitive positioning accuracy of side template 313, installation fixed form uses T-type Slot guidance mode, in the fixed side form sliding block 313-1 of 313 lateral surface of side template, the fixed T-slot in corresponding position is solid in environmental cabinet 2 Determine block 313-2, side form sliding block 313-1 is slidably fixed in the T-slot on T-slot fixed block 313-2, so that side template 313 can install a screw rod 313-3, spiral shell in the lateral movement of the longitudinal axis perpendicular to accommodating space 31, environmental cabinet side wall Bar 313-3 is screwed on side form sliding block 313-1, fixed adjusting handle 313-4 on screw rod 313-3.Rotate adjusting handle 313- 4, drive side template 313 to horizontally slip in environmental cabinet 2 along T-slot by side form sliding block.

As shown in fig. 6, maximal regulated distance a1 between 313 side of side template and active chuck 312 is 10mm, when demoulding, can It is maximum that side template 313 is transferred to distance outward.Gap a2 between 313 end of side template and active chuck is 5mm, guarantees test specimen Side template 313 and 312 non-contravention of active chuck in compression.Cope plate 314 and lower template i.e. bottom plate and side template 313 it Between gapless, guarantee that test specimen C cement in production does not squeeze out, the gap a2 of 313 end of side template and active chuck is tried in production It is lived when part C with one section very thin of copper sheet pad.

As shown in figure 3, further including a stripper apparatus, a lifting device is connected on the bottom surface of the bottom plate, the lifting device One ejection decelerating motor 32 of connection, can go out accommodating space 31 for bottom plate item by the ejection decelerating motor 32 and be easily removed Concrete sample C.

Specifically, demoulding uses screw rod ejecting structure, is mounted on the both ends of test specimen bottom, by ejecting decelerating motor 32 drive sprocket wheel chains are transferred to feed screw nut, and the lifting of nut rotary screw drives mandril lifting, for ejecting test specimen C, most Big ejection distance 150mm.Dust seal is installed at mandril and end template, that is, bottom plate, prevents dust and sundries from falling to gap It is interior.Mandril via hole at bottom plate or lower template guarantees that liquid will not leak using stainless steel tube and bed die welding form.Test specimen top Before need rotation side template adjusting handle 313-4 that side template 313 is removed some gaps out.

The shape of test specimen accommodating space 31 make test specimen collet segment shape be bone-shaped, have Rouno Cormer Pregrinding Wheel transition, protect Card test specimen is broken in effective length.

Frame 4 on the pedestal 1 is set, as shown in Fig. 2, Fig. 3, Fig. 4 and Fig. 5, frame 4 include two root posts 41, One fixed cross beam 42 and a fine motion crossbeam 43 form a rectangle frame, the longitudinal direction of column 41 and accommodating space, that is, concrete examination The axis direction of part is parallel, and two crossbeams are separately fixed at the both ends of two columns.Fixed cross beam 42 is fixed on pedestal 1, and fine motion is horizontal Beam is set on the base, but does not have fixed structure between pedestal.

The material and sectional dimension of column 41 are as follows: guarantee that its rigidity is 5-20 times for bearing the maximum strength stress of concrete Power and indeformable or stiffness K be more than or equal to 2MN/mm；Further more, the material and sectional dimension of column also guarantee that its temperature is steady It is qualitative for when temperature is -20-80 DEG C its temperature deformation less than 10 microns.

One straight-line motion mechanism is arranged on the fine motion crossbeam 43, specifically, as shown in Figure 4 and Figure 5, straight-line motion mechanism For the screw mechanism 44 that a ball screw nut component is constituted, the nut 441 in screw mechanism passes through floating by nut set 442 Crossbeam 43 is fixed on constraint axis 443, and the side wall that constraint axis 443 passes through environmental cabinet 2 is connected on the end face of active chuck 312, So that 312 position of active chuck is fixed or in axis direction movement；The screw rod 444 being spirally connected with nut 441 is rotationally It is fixed on fine motion crossbeam 43.

Displacement/deformation-sensor 443-3 is set between constraint axis 443 and environmental cabinet 2, specifically, on constraint axis 443 Setting measurement top plate 443-1, on 2 lateral wall of environmental cabinet be arranged support base 443-2, on the support base 443-2 setting displacement/ Deformation-sensor 443-3, the displacement/deformation-sensor 443-3 sensing part are against on measurement top plate 443-1.In nut 441 Upper connection strain gauge 441-1, sensing part thereon are against on support base or constraint axis 443 and sense stress.

Displacement/deformation-sensor 443-3 this setup can be so as not to load test specimen by power device Influence and reduce detection accuracy.This is because the fine motion crossbeam 43 in frame 4 is not connected with pedestal 1, power device tension and compression The counter-force of test specimen will not pass on pedestal 1, and displacement/deformation-sensor 443-3, which is fixed on environmental cabinet to be equal to, is fixed on pedestal 1 On, so being unaffected.

As shown in figs. 4 and 7, displacement/deformation-sensor 443-3 is mounted on the both ends of test specimen, is arranged symmetrically, respectively in 2 Road precision ± 1 μm, in same ancillary test B machine.Master trip seat in the plane shifting/deformation-sensor range: ± 100 μm, auxiliary examination Test seat in the plane shifting/deformation-sensor range: ± 2000 μm.

Support base 443-2 is mounted on pedestal 1, when laboratory ambient temperature is constant, displacement/deformation-sensor measurement end with The relative position of test specimen fixing end will not change, theoretically error free.

Specific to a specific embodiment, the constraint axis 443, active chuck 312 and fixed chuck 311 are all made of Gao Gang The invar steel of degree, the minimum material linear expansion coefficient is only (- 20-100 DEG C) 1.4x10^-6/ DEG C, the influence to whole device is only It is 0.000924mm/ DEG C, this error can be deducted in experimental result, it is as a result more accurate；Active chuck 312 below and pedestal 1 it Between use high-precision railroad, ensured measuring accuracy.

One loading system, including a power device, which is arranged on the frame 4, specifically, power device Be it is as shown in Figure 4, Figure 5, be arranged on fine motion crossbeam 43.Power device includes that helical gear-worm and gear, reduction ratio reach 650 Speed reducer 445 and the servo motor 446 that is connected of speed reducer, which is controlled by the load of computer computer connection Control unit starts and stops it and limits its steering.And loading control unit is according to set displacement/deformation sensing The signal that device and strain gauge issue, according to the parameters such as start and stop for the requirement control servo motor 446 specifically tested 's.

The screw pitch for the screw rod 444 being spirally connected with nut 441 is 12mm.Straight-line motion mechanism so, single pulse displacement Only 0.007 μm, servo motor band closed loop feedback substantially increases plus unloads precision, can be light threshold value is arranged at 1 μm Reply.

The preferred servo motor of power device connects worm reduction gear transmission mechanism.Such power device makes to control The big raising of precision, feedback speed, efficiency.

Because long term creep strain test (loading force is constant) is done with this experimental rig, using full servo motor Hardened gear face worm gear Speed reducer driving method, the accuracy than the control of stepper motor loading stress greatly improve.During the experiment, concrete deformation Very little, servo motor 446 and speed reducer 445, which match, to be used, and 446 speed of servo motor is stepless adjustable, and load step-length can be any Selection, therefore Bit andits control accuracy is higher than stepper motor；Kind of drive ball-screw, transmission effect higher than common lead screw precision Rate is also much higher (95%), and transmission uses rolling friction, long service life.

The frame 4 uses 45 steel makings, is designed to the connection structure for the fine motion crossbeam that one end fixed cross beam one end is floated, In stress, its deformation will not generate interference to displacement measurement, will not introduce measurement error.

Because of reaction frame, that is, frame floating end, that is, fine motion cross beam movement when load, and fixing end, that is, fixed cross beam and test specimen Fixed reference end is motionless, and displacement/deformation-sensor measurement top plate and test specimen fixing end relative position are motionless, so survey will not be introduced Measure error.

Frame structure uses upright post cross-beam type, about 4 tons of weight, is adapted to long term creep strain test requirements document testing machine itself Rigidity requirement, (stiffness K >=2MN/mm).

Specifically, when loading frame bears 200KN load, maximum stress point is about 60MPa, far smaller than material yield Intensity and tensile strength.When loading frame bears 200KN load, fixed cross beam and the outside lateral bend of fine motion crossbeam in frame, Two heel posts elongate and since the effect of moment of flexure curve inwardly, and axial total deformation is 0.04655+0.04670= 0.09325mm, rigidity 200000/0.09325=2144772N/mm=2.14MN/mm.It is carried when loading frame bears 200KN When lotus, frame minimum safety factor is 6.49.

The frame provided by the invention, using upright post cross-beam type, stable structure, column therein has enough in addition Rigidity and temperature deformation stability, can guarantee test well precision.

The constraint axis 443 of fixed chuck 311, active chuck 312 and both ends is all made of invar steel 4J36 manufacture, constrains axis 443 diameter 150mm, the elasticity modulus of invar steel is big, linear expansion coefficient very little, the average linear within the scope of 20-100 DEG C The coefficient of expansion only has 1.4x10^-6/ DEG C, is 660mm on the influential part length of measurement, therefore is on the influence of the result of experiment 0.000924mm/ DEG C, and be basically unchanged at -80-100 DEG C, experimental result influence can be calculated or be measured, measurement result is more Precisely.

Form is set on the case lid of the environmental cabinet, so that test process visualization.

Figure 11 gives the concrete based on true environment in one embodiment in experimental rig provided by the invention The control principle drawing of the overall process that cracks test.

As shown in figure 11, experimental rig provided by the invention further includes a computer D and control system D1, control system D1 It include: the control unit that the various executing agency's movements of true environment simulation system are controlled in master trip machine A and ancillary test machine B； And the power in master trip machine A in control unit, that is, loading system of executing agency's movement of control concrete sample load The control unit of device.

The computer D is connected by data line L with control system D1, meanwhile, computer D also passes through data line L and prison Survey signal output end, the monitoring concrete sample displacement/deformation displacement/deformation-sensor of the temperature sensor of environmental parameter Signal output end, the signal output end for the strain gauge for monitoring test specimen stress are connected；

The control signal output of the control system D1 is connected with the control terminal of each executing agency.

The control unit of each executing agency includes: temperature control unit, displacement/deformation control unit and load control Unit, computer D provide instruction, and control system D1 controls each executing agency's movement i.e.: be heated or cooled, loading mechanism movement with Direction initialization load or unload allows test specimen C Free Transform or controllably deforming, and starting, the direction of action of executing agency's movement It is controlled by the instruction that computer D receives displacement/deformation-sensor signal and issues to Loading Control System with stopping.Computer Data processing system in D carries out data processing according to specific test for the information obtained from each sensor, calculates examination It tests structure and/or draws out parameter curve output.

In the environmental cabinet 2 for having temperature control unit to control and test specimen accommodates the heating or cooling device in fixed device 3 It can be, cavity is set inside the fixed chuck 311, active chuck 312 and side template 313 that composition accommodates fixed device, is led to It crosses the cavity and extraneous connecting line is passed through heat medium or cooling medium into cavity.By taking a side template 313 as an example, such as scheme Shown in 8, water conservancy diversion grid is set in the internal cavities of side template 313, forms tortuous flow path, internal diversion grid plays simultaneously Reinforcing rib effect guarantees indeformable after long-time adds unloading test.For another example cope plate 314 is also such structure, such as Fig. 3 institute Show, which is arranged medium inlet 313-5 at one end, and media outlet 313-6 is arranged in the other end.Medium inlet and outlet connection Medium heating or cooling device, as shown in Figure 9 and Figure 10.Adapter tube 313-5 connection one on the medium inlet of side template 313 pumps The outlet of 313-7, the inlet connection for pumping 313-7 connect the outlet of an insulating box 313-8, are provided with refrigerator pipes 313-9, connect Refrigerating plant, the compressor refrigerant in refrigerating plant is nontoxic using R502, no pollution to the environment.In insulating box 313-8 In set heated cooling medium using 40% glycol water, -25 DEG C of freezing point temperature.The entrance of insulating box 313-8 connects side form The medium outlet of plate 313.Heating coil 313-10 is set on the inlet tube of pump 313-7.

Heating/cooling device as shown in Figure 9 is needed according to test to side template, cope plate so that fixed chuck, work Heat medium or cooling medium are conveyed in the cavity of tank wall in dynamic collet or even environmental cabinet 2 etc..The heating or cooling device In pump 313-7, connect refrigerator pipes 313-9 refrigerating plant and heating coil 313-10 be executing agency, be controlled by meter The temperature parameter set in calculation machine D.It, can also be by temperature control unit all or part in order to simplify the structure of computer Ground is separated from computer D, and flow chart can become Figure 12 from Figure 11.

The heating system of heating coil 313-10 is as shown in Figure 10, and heating tube namely pumps the inlet tube 313- on 313-7 The signal input output end of the signal output end connection temperature controller b of jointing temp sensor a on 12, temperature sensor a, the temperature control Instrument b temperature data transmission end connection heating controller c the end corresponding signal IO, according to temperature controller b transmit temperature data, Voltage, the electric current that heating controller c is suitble to heating coil 313-10 output, so that heating coil 313-10 generates heat, to ectosome Existing set temperature, provides the simulation of the true environment of setting.

If providing low temperature, heater stop work, cooling device starts, circularly cooling agent in refrigerator pipes 313-9, Medium d glycol water in cooling insulating box, pump 313-7 work, to the cavity of fixed chuck, active chuck and side template Interior conveying cooling medium can also convey in the heat exchanger that be arranged into environmental cabinet simultaneously.313-7 is pumped as executing agency, It starts and stops and revolving speed is temperature controlled the control of unit, required temperature is provided.

In order to measure the temperature of test specimen, temperature sensor can be plugged in test specimen, the general temperature that will monitor test specimen Degree sensor is plugged in the axis line location of test specimen.For this purpose, in each template such as side template 313 and fixed chuck and active chuck On can have template thermometer hole 1, in embodiment as shown in Figure 1, a thermometer hole 313-11 is set on side template.Cope plate 314-1 is separately arranged there are three test specimen thermometer hole 314-2, for by temperature sensor inserting to the inside test specimen C or surface, temperature to be passed Sensor is distributed at piece lengths 1/4,1/2 and 3/4.

Cope plate handle 314-2 is provided on cope plate.

Cope plate placing flat can be freely disassembled and install above test specimen, circulation fluid junction medium inlet 313-5 and Media outlet 313-6 is connected using hose, and disassembly hose is not had to when removing and installing, guarantees sealed reliable no leakage.

To guarantee temperature transmitting uniformly, lattice structure inside template, limitation liquid in internal nowed forming, test specimen Up and down for journey circulation fluid inside four pieces of hollow templates；PID accurately calculates control heating and refrigerating plant, guarantees fine Cold and hot compensation controls the flow of input template circulation fluid, and the temperature of circulation fluid is made to meet the various requirement of test.

The temperature of environmental cabinet is set to meet the various requirement of test.Environment tank shell uses stainless steel material, and inside filling is protected Adiabator seals tightly without deformation, with a thickness of 150mm.

Test specimen, template, collet and partially restrained axis are wrapped in inside by thermal environment case.

Other than containing refrigeration unit, heating device, can also be including air humidifying device, that is, humidifier, rainer Spray equipment, air flow system, that is, fan assembly, schematic diagram are as shown in figure 12.

True environment simulation system further includes solar radiation device i.e. bulb.

Simulated atmosphere natural environment, above-mentioned each device is arranged in environmental cabinet, for example, apertured on the tank wall of environmental cabinet 2, even Road is taken over, which at least one of supplies gas, send vapour, air-supply and water injector.Apertured on the tank wall of the environmental cabinet, The lamps and lanterns that simulated solar irradiates are set in hole and constitute solar radiation regulating system.Humidity sensor, wind are set in environmental cabinet Fast sensor and solar radiation sensor.

Correspondingly, in order to simulate true environment, other than temperature control unit, it is also provided with humidity controlling unit control The opening and closing or humidification intensity of humidifier processed；Opening and closing and the flow of rainfall control unit control spray equipment are set；Wind speed control is set The opening and closing of unit control fan processed and revolving speed, setting solar radiation device control units control the opening and closing and brightness of bulb.This A little control devices can also be arranged in simultaneously in ancillary test machine B.

The control unit of above-mentioned executing agency can be included in control system D1, flow chart such as Figure 11 and Figure 12 It is shown.

If increasing the simulation of solar radiation, can the aperture on environmental cabinet, be arranged bulb.

Each control unit and the incidence relation of computer D are described as follows by taking solar radiation as an example: the switch of bulb is i.e. For executing agency, correspondingly, solar radiation sensor is set in environmental cabinet, in control system D1 or is separately provided sun spoke Control unit association switch is penetrated, which is controlled by the true environment parameter set in computer D again and holds The operation such as row open and close and strong and weak adjusting.

The comparing that computer D is acquired according to the parameters and related sensor of the true environment simulation system of setting As a result, being instructed to each control unit, or starts or stops each executing agency or adjust its degree.It as a result, can be in environment Various true environments are simulated in case, and the various tests of test specimen is allowed to carry out in specific environment.

Computer D includes the information of temperature sensor, displacement/deformation-sensor and strain gauge by acquisition, can be with Test function as shown in fig. 13 that: restraint stress, free variable, elasticity modulus, deformation separation and concrete creep is carried out, if Test block is that directly concrete is cast in testing machine, so that it may which concrete is carried out from the test for being solidified to cracking overall process And evaluation.

In the present invention, main climate control system in true environment system is simulated, there can be two parts, a part is It is arranged on environment cabinet, another part is accommodated in test specimen to be arranged on fixed device.It is arranged on environmental cabinet, is more simulation Temperature in true environment, and accommodate in test specimen and be arranged on fixed device, it can simulate in a short time in true environment for example The temperature of concrete dam.All without such comprehensive climate control system in experimental rig in the prior art.

In the present invention, concrete directly can be cast in the concrete sample accommodating space that test specimen accommodates fixed device In, become again to the expansion of hardening overall process in this manner it is possible to test concrete in the true environment of simulation from lean state to solidification The variation of shape and stress, it is such test for such as dam from pour, be solidified to hardening overall process stress, strain in difference It can be carried out testing under environmental condition, obtain comprehensive data, provide valuable information for design, the construction of dam.It is existing Experimental rig in technology does not all expect the test for yet not accomplishing this overall process.Certainly, experimental rig provided by the invention In test specimen accommodate fixed device and concrete sample made of can also be tested.

As shown in Figure 1, the ancillary test machine F in experimental rig provided by the invention, including an environmental cabinet, that is, it include one A test specimen accommodating cavity is for placing test specimen identical with the test specimen tested in the master trip machine, as one embodiment, the examination The temperature-adjusting device is set in part accommodating cavity, is also provided with humidity control apparatus, solar radiation regulating device, rainfall adjusting dress It sets and wind-speed adjusting device；Temperature sensor is set in the test specimen accommodating cavity, also sets up humidity sensor, solar radiation sensing Device, rainfall sensor and air velocity transducer, each sensor are connect with the computer, described in control system D1 connection Regulating device and to adjust test specimen accommodating the cavity environment parameter identical as the master trip environmental cabinet；In the test specimen accommodating cavity also Displacement/deformation-sensor is set to perceive the deformation of test specimen.

Environmental parameter in ancillary test case is identical as master trip case, is provided with the bottom surface of a placement test specimen, so that Test specimen can Free Transform, be provided with true environment simulation system, the simulation system include at least a temperature regulating system, be Heating or cooling device in the environmental cabinet and/or on test specimen is set；It further include temperature sensor and displacement/deformation sensing Device, the temperature sensor setting is on the test specimen and/or in environmental cabinet；The displacement/deformation-sensor is arranged in test specimen On, it is identical as master trip case；The signal output end of each sensor is associated with computer.

Ancillary test machine and test specimen and machine bed plate coefficient of friction it is sufficiently small under the conditions of, measure it is synthermal with master trip machine Under the conditions of auxiliary test specimen Free Transform, synthermal condition parallel test machine makes test data have integrality.

Experimental rig provided by the invention, concrete cracking overall process experimental rig and method based on true environment are logical Cross what following manner was realized:

(1) under the conditions of concrete test test specimen completes and is ready to complete with relevant device, starting computer control system System is computer, carries out relative parameters setting；Open true environment simulation system, fill in engineering location monthly mean temperature, The parameters such as water temperature, cloud amount, fine day solar radiant heat, cloud amount, latitude and concrete surface exothermic coefficient, need to start according to test The simulation of Related Environmental Factors, environment temperature/humidity/rainfall/wind speed/solar radiation；

(2) computer measures temperature, displacement and the deformation of concrete according to each sensor, obtains true environment simulated conditions Under concrete free variable, the concrete operations for measuring Free Transform may is that test specimen is fixed on fixed chuck and active chuck Between, since temperature etc. changes, when expansion or shrinkage occurs in test specimen, the strain gauge of setting shows stress value, controls System processed starts power device, so that straight-line motion mechanism is in the identical direction movement of deformation direction until strain gauge is aobvious Show that stress value is zero, obtains Free Transform amount at this time from displacement/deformation-sensor, survey free variable is concrete various deformation (temperature deformation, autogenous volumetric deformation and creep) carries out separation and makes preparation；

(3) by computer, control system such as temperature control unit, displacement/deformation control unit, load control unit and Respective sensor controls the Free Transform of test specimen movable terminal, according to Free Transform and controls reduced deformation, can survey The concrete temperature stress under true environment simulated conditions in the case of each moment difference degree of restraint is obtained, including is reduced to displacement Stress when zero, i.e. temperature stress under the conditions of staff cultivation；

(4) by computer, control system such as temperature control unit, displacement/deformation control unit, load control unit and Respective sensor carries out a secondary control to the Free Transform of test specimen movable terminal, every certain time interval, to displacement/change Shape makes primary change, while acquiring corresponding stress variation, obtains the elasticity modulus at the moment, repeatedly, can be obtained true Elasticity modulus of the environmental simulation Under Concrete in entire development process；

(5) the change in temperature Δ T (t) obtained according to thermal expansion coefficient of concrete α and data collection system, it can be deduced that true The pure temperature deformation of concrete under real environment simulated conditions, in conjunction with the Free Transform measured, other deformations that you can get it are main to wrap Include autogenous volumetric deformation and dry-shrinkage deformed；

(6) according to the modulus of elasticity of concrete and Free Transform that measure, can calculate under true environment simulated conditions not by Concrete stress when Creep Effect, starting computer control system, displacement/deformation control unit, load control unit and corresponding Sensor, concrete deformation is controlled, is morphed into zero, at this moment measures stress and stress when not by Creep Effect Difference be then caused stress of creeping under true environment simulated conditions；

(7) log-on data processing system, in conjunction with all test datas and data and curves, when occurring on stress and displacement curve When being mutated, indicate that concrete cracking, associated temperature, stress, displacement and the deformation parameter of the concrete at this moment can be made For the cracking index under the conditions of real-world temperature, test reference is provided for crack-resistant performance of concrete evaluation.

The concrete operations freely constrained are as follows: experimental rig clamps the both ends of concrete sample, and one end is fixed, one end It is controllable to move, under true environment simulated conditions, load is not added in the controllable end of concrete, passes through setting time interval (t) Computer control system, displacement/Deformation control system and loading system, make its free displacement μ (t), as t moment concrete Free variable ε (t).

The concrete operations of the restraint stress are: experimental rig clamps the both ends of concrete sample, and one end is fixed, one end Controllable to move, under true environment simulated conditions, the free displacement of concrete sample movable terminal is μ (t), according to practical need It wants, by computer control system, displacement/deformation control unit and loading system, the displacement of test specimen movable terminal is subtracted Small, it is the concrete temperature in the case of constraint factor f (t) that at this moment the strain gauge, which measures each moment difference degree of restraint, Stress σ (t)；

The displacement that movable terminal reduces are as follows:

f(t)×μ(t) (6)

In formula, t is the time, and concrete constraint factor when f (t) is t, μ (t) is the freedom of concrete sample movable terminal Displacement.

The elasticity modulus concrete operations are as follows: specifically, set interval in computer control system, every the time Interval, does a change in displacement to test specimen movable terminal by displacement control system, measures this displacement according to strain gauge Stress variation caused by changing carries out elasticity modulus test to the test specimen.

Every the Δ t time, primary displacement is done to movable terminal to test specimen and loading system by displacement/Deformation control system Changes delta mu (t) obtains deformation Δ ε (t), is Δ σ (t) according to the stress variation that strain gauge is measured, then t moment is mixed Solidifying soil elasticity modulus are as follows:

According to the time interval of design, computer control system automatically measures the modulus of elasticity of concrete of different moments, Concrete can be obtained in the elasticity modulus of entire development process.

The separation concrete operations of the deformation are as follows: do free constraint first: experimental rig fixes concrete sample one end, Other end retractable, provides the true environment of setting by true environment simulation system, carries out free variable to the test specimen Test, in the time zone (t) of setting, setting period acquisition deflection ε (t).

After 1 day age of concrete, thermal expansion coefficient would not change again substantially, it is considered that and it is a constant, The parameter can also be measured by dedicated thermal expansion coefficient tester, here it is considered that being constant α.According to thermal expansion coefficient of concrete The change in temperature Δ T (t) that α and temperature control system measure, it can be deduced that the temperature of concrete becomes under true environment simulated conditions Shape:

Δε_T(t)=α Δ T (t) (8)

It in conjunction with the Free Transform ε (t) measured, is separated, you can get it, and other deform Δ ε_aIt (t), mainly include spontaneous Cubic deformation and dry-shrinkage deformed:

Δε_a(t)=ε (t)-Δ ε_T(t) (9)

The concrete creep concrete operations are as follows: according to the modulus of elasticity of concrete E (t) that measures and Free Transform ε (t), It can calculate under true environment simulated conditions not by concrete stress σ (t) when Creep Effect:

σ (t)=ε (t) E (t) (10)

Start concrete displacement control system, concrete deformation is controlled, zero is morphed into, at this moment measures stress For σ₀(t), then stress caused by creeping under true environment simulated conditions reduces are as follows:

σ_c(t)=σ (t)-σ₀(t) (11)

Pass through σ_c(t) size it can be concluded that concrete creep influence degree, wherein t is the time.

The concrete operations of the concrete cracking overall process are: concrete temperature changes to set temperature from initial temperature, Pulling force is fixed or applied to test specimen two ends, when tensile stress data reduce suddenly, be displaced increase suddenly, be corresponding when m- stress, when it is m- When being mutated on deformation/displacement curve, concrete cracking obtains the relevant parameter of at this moment concrete, including temperature, tension Intensity, limit stretch value.

The concrete operations of evaluation are: in conjunction with front A, B, C, D, E test data and as a result, concrete temperature changes to sets Determine degree, when tensile stress data reduce suddenly, are displaced increase suddenly, be mutated on homologous thread when, concrete cracking, at this moment Relevant parameter temperature, stress, displacement and the deformation of concrete, which can be used as, carries out concrete cracking overall process evaluation to the test specimen.

True environment can be set with the following method:

1. environment temperature

Depending on local situation, i.e. simulation true environment is local, and the above monthly mean temperature data is fitted to one Cosine curve, following formula (1) are the calculation formula after fitting:

In formula, T_aFor temperature, T_amFor average temperature of the whole year, A_aFor temperature year luffing, τ is time (moon), τ₀For maximum temperature Time (moon).

Consider temperature diurnal variation, calculated using following formula:

In formula,For daily temperature, T_aFor monthly mean temperature, A is temperature diurnal variation amplitude, at the time of t is in 1 day (when) root Depending on the Various Seasonal of different regions.

2. solar radiant heat

Concrete structure is often an exposure under solar radiation, is had a major impact to concrete temperature.Unit The heat that solar radiation comes on unit area in time is S, wherein set the part absorbed by concrete as R, remainder quilt It reflects away, then:

R=α_s·S (3)

In formula, α_sFor absorption coefficient, also referred to as coefficient of blackness, concrete surface generally takes 0.65.

S=S₀(1-kn) (4)

In formula, S₀For fine day solar radiant heat, n is cloud amount, and k is coefficient, these three numerical value are provided by local weather station；

The temperature that the influence of sunshine is equivalent to surrounding air increases Δ T_a,

ΔT_a=R/ β (5)

In formula, β is concrete surface exothermic coefficient, is calculated according to surface roughness and wind speed.

3. rainfall

The rainfall for inquiring engineering location meteorological department, by rainfall equipment and rainfall amount controller come simulated rainfall.

4. wind speed

Inquire the wind speed of the meteorological department in engineering location, threshold wind velocity simulator, to obtain concrete according to wind speed Surface coefficient of heat transfer.

One specific test example is as follows:

Concrete test block is tested using above-mentioned test method and experimental rig, verifying is mixed based on true environment The validity and reasonability of solidifying soil cracking overall process experimental rig and method.Test ambient temperature value is the close of certain Practical Project 1 year temperature measured value inputs computer, enables experimental rig, so that experimental enviroment becomes fully according to this actual measurement temperature Change, test under the conditions of this ambient air temperature, the stress variation situation of concrete test block, studies the concrete based on true environment Crack overall process.

The test data obtained from test can be seen that ambient air temperature and meet the actual sinusoidal variations rule of engineering, can be true Real reaction Practical Project environment；It can reflect true stress variation rule based on the test temperature stress under the conditions of this ambient air temperature Rule, with Temperature cycling fluctuation, based on the effect expanded with heat and contract with cold, environment temperature is increased, coagulation soil compressive stress increases；Environment temperature It reduces, the reduction tensile stress increase of coagulation soil compressive stress, sees Figure 14.

Claims (9)

1. a kind of concrete cracking overall process experimental rig based on true environment, it is characterised in that: including a pedestal, at the bottom It is provided on seat

One environmental cabinet at least has four walls and upper cover, forms a closed space, separates with ambient enviroment；

One concrete sample accommodates fixed device, is arranged in the environmental cabinet, including in fixed chuck, active chuck, test specimen Portion's fixed bolster plate, three's split constitute the concrete sample accommodating space that a upper end is open or upper and lower side is open, institute It states fixed chuck to be fixed in the environmental cabinet, the active chuck can be along the length side of the concrete sample accommodating space To axis be movably arranged；

In the environmental cabinet or the environmental cabinet and concrete sample accommodating space, temperature sensor is set；

One true environment simulation system includes at least a temperature-adjusting device, and to heat and/or cool device, setting exists To propose fixed true environment in temperature upper mold in the environmental cabinet and concrete sample accommodating device；

One loading system, including a frame, a transmission device and a power device, the frame setting on the base, should Transmission device includes a straight-line motion mechanism, and driven member therein enters environmental cabinet and the work by the side wall of the environmental cabinet Dynamic collet is fixed and the active chuck position is made to fix or move in the axis direction, the active in the straight-line motion mechanism Part is fixed on the frame；The power device setting on said frame, connects the active in the straight-line motion mechanism Part；

Displacement/deformation-sensor perception concrete sample is set on the active chuck or the component connecting with active chuck Deformation；Strain gauge is set on the straight-line motion mechanism and perceives the load that test specimen is born；

The frame is the frame for including the rectangle that two crossbeams and two columns are constituted, and a fixed cross beam is fixed on described solid On the pedestal of the first side of clamp, two columns fixed cross beam that is connected in parallel is located at the environmental cabinet two sides, One fine motion crossbeam is arranged on the pedestal of the active chuck side, connect with the column, and the power device is set It sets on the fine motion crossbeam, reaction frame is consequently formed, the straight-line motion mechanism passes through the fine motion crossbeam and active chuck connects It connects, the support section of the displacement/deformation-sensor and the strain gauge is directly or indirectly fixed on the base.

2. experimental rig according to claim 1, it is characterised in that: the cross-sectional shape of the accommodating space are as follows: both ends It is the shorter head of width greater depth, centre is the longer interlude of width smaller length, and the head and interlude pass through It bores section and connects transition；Splicing seams in the middle part of the fixed chuck and active chuck and test specimen between fixed bolster plate are located at the accommodating In the intermediate segment limit in space；And/or it further includes a cope plate that the test specimen, which accommodates fixed device, closes the coagulation The upper end of native test specimen accommodating space is open；And/or

For seam between the side template and the active chuck and/or fixed chuck there are gap, which includes side template End and the active chuck between gap, to guarantee test specimen side template and active chuck non-contravention in compression, and/or Gap between side and fixed chuck and active chuck including side template；And/or

The side template can be arranged in transverse shifting in the environmental cabinet.

3. experimental rig according to claim 1 or 2, it is characterised in that: the true environment simulation system further includes setting Set at least one of environmental cabinet regulating device: humidity control apparatus, solar radiation regulating device, rainfall regulating device, Wind-speed adjusting device further includes correspondingly such as at least one of lower sensor: humidity sensor, solar radiation sensor, drop Rain sensor and air velocity transducer.

4. according to claim 1 to experimental rig described in one of 2, it is characterised in that: described in being arranged in the environmental cabinet The device that heats and/or cools in temperature-adjusting device is: being arranged in the tank wall of the environmental cabinet or in closed space, institute Tank wall is stated with hollow chamber, and/or, setting test specimen accommodates the fixed chuck, active chuck and the side form in fixed device Plate at least one has hollow chamber；

Each hollow chamber's setting inlet and outlet is connected to the medium channel of the heating or cooling device, and executing agency is The media flow that the electric heating coil or driving being arranged on the medium channel for heating and/or cooling device are heated or cooled Delivery pump, for providing in test thermal energy or cold energy as needed.

5. experimental rig according to claim 3, it is characterised in that: the temperature being arranged in the environmental cabinet is adjusted The device that heats and/or cools in device is: being arranged in the tank wall of the environmental cabinet or in closed space, the tank wall tool Have hollow chamber, and/or, setting test specimen accommodate the fixed chuck, active chuck and side template in fixed device at least its One has hollow chamber；

Each hollow chamber's setting inlet and outlet is connected to the medium channel of the heating or cooling device, and executing agency is The media flow that the electric heating coil or driving being arranged on the medium channel for heating and/or cooling device are heated or cooled Delivery pump, for providing in test thermal energy or cold energy as needed.

6. experimental rig according to claim 3, it is characterised in that: apertured on the tank wall of the environmental cabinet, connecting line, The piping connection at least one of supplies gas, send vapour, air-supply and water injector, correspondingly constitutes humidity control apparatus, rainfall tune Regulating device and wind-speed adjusting device；And/or apertured on the tank wall of the environmental cabinet, the lamp that simulated solar irradiates is set in hole Tool constitutes solar radiation regulating device.

7. experimental rig described in one of according to claim 1 to 2 and 6, it is characterised in that:

In the frame that two crossbeams and two columns are constituted, the material and sectional dimension of the column are as follows: protect Demonstrate,prove its rigidity be bear the maximum strength stress of concrete 5-20 times of power and indeformable or stiffness K more than or equal to 2MN/ mm；And/or guarantee that its temperature deformation is less than 10 microns when its temperature stability is in -20-80 DEG C of temperature range of test； And/or

Form is set on the upper lid of the environmental cabinet, so that test process visualization；And/or

The power device is servo motor, connects worm reduction gear；And/or

The straight-line motion mechanism uses screw-drive mechanism；And/or

Also set up a hoisting mechanism in the pedestal, the test specimen accommodate fixed dress center a bottom plate for place examination Part is poured test specimen on it, which connects the hoisting mechanism, by running the hoisting mechanism, can test specimen be moved into or be moved Concrete sample accommodating space out.

8. experimental rig according to claim 3, it is characterised in that:

In the frame that two crossbeams and two columns are constituted, the material and sectional dimension of the column are as follows: protect Demonstrate,prove its rigidity be bear the maximum strength stress of concrete 5-20 times of power and indeformable or stiffness K more than or equal to 2MN/ mm；And/or guarantee that its temperature deformation is less than 10 microns when its temperature stability is in -20-80 DEG C of temperature range of test； And/or

Form is set on the upper lid of the environmental cabinet, so that test process visualization；And/or

The power device is servo motor, connects worm reduction gear；And/or

The straight-line motion mechanism uses screw-drive mechanism；And/or

Also set up a hoisting mechanism in the pedestal, the test specimen accommodate fixed dress center a bottom plate for place examination Part is poured test specimen on it, which connects the hoisting mechanism, by running the hoisting mechanism, can test specimen be moved into or be moved Concrete sample accommodating space out.

9. experimental rig according to claim 4, it is characterised in that:

In the frame that two crossbeams and two columns are constituted, the material and sectional dimension of the column are as follows: protect Demonstrate,prove its rigidity be bear the maximum strength stress of concrete 5-20 times of power and indeformable or stiffness K more than or equal to 2MN/ mm；And/or guarantee that its temperature deformation is less than 10 microns when its temperature stability is in -20-80 DEG C of temperature range of test； And/or

Form is set on the upper lid of the environmental cabinet, so that test process visualization；And/or

The power device is servo motor, connects worm reduction gear；And/or

The straight-line motion mechanism uses screw-drive mechanism；And/or

Also set up a hoisting mechanism in the pedestal, the test specimen accommodate fixed dress center a bottom plate for place examination Part is poured test specimen on it, which connects the hoisting mechanism, by running the hoisting mechanism, can test specimen be moved into or be moved Concrete sample accommodating space out.