CN109977484A - Circular cross section lining concrete temperature controlled anticracking temperature stress controls Fast design method - Google Patents
Circular cross section lining concrete temperature controlled anticracking temperature stress controls Fast design method Download PDFInfo
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Abstract
A kind of circular cross section lining concrete temperature controlled anticracking temperature stress control Fast design method, pass through the determination to circular cross section lining concrete temperature controlled anticracking target, permission temperature stress value and variable, it is calculated from the formula circular cross section lining concrete construction time maximum temperature controlled anticracking temperature stress value, applied in the construction of practical lining concrete, it can be during pouring construction for the change found the problem with construction technology, condition, quickly calculate temperature controlled anticracking temperature stress, in real time for Optimal improvements construction temperature control measures, temperature controlled anticracking target is realized.
Description
Technical field
The invention belongs to Concrete Temperature Control crack prevention technique fields, are related to a kind of circular cross section lining concrete temperature controlled anticracking temperature
Spend Stress Control Fast design method.
Background technique
Crack is one of Major Diseases of concrete.According to the leading reason that crack generates, external load effect can be divided into and drawn
Non-structural crack two major classes caused by the structural crack served and deformation variation.Metamorphosis includes that temperature, drying shrinkage are wet
Swollen and surrouding rock deformation etc., wherein 80% is all thermal cracking.In recent years, hydraulic and hydroelectric engineering built high speed development, underground water conservancy project
Scale and cross dimensions it is increasing, the environmental conditions such as geology become increasingly complex.With the increase of height of dam, the flow velocity of sluicing is got over
Come higher, strength grade of concrete is also higher.Big cross section high intensity underground water conservancy project lining concrete, effectively arranges as long as not taking
It applies, all produces a large amount of cracks bar none, and be the thermal cracking for the construction time generating penetrability mostly.
Construction of underground structure, which is in for a long time in moist, alternation of wetting and drying environment, to work, harmfulness crack there are serious shadows
It rings the safety of engineering structure, the construction speed duration, lead to leakage even seepage failure, durability and service life, project cost
And beauty, it is also possible to induce the occurrence and development of other diseases.
It is existing general for the control of used in Underground Engineering Lining concrete thermal cracking and its calculation method in relation to design specification
All lack clear and specific regulation, also without specific Winkler's foundation.If " design of hydraulic concrete structures specification " is in 4.1.2
(3) it requires " to the structural elements for using upper requirement to carry out Crack Control, Ying Jinhang cracking resistance or crack width calculation ", in 4.1.8
Regulation " building between construction and run phrase, when having larger impact to building such as the variation of temperature, Ying Jinhang temperature stress meter
It calculates, and uses construction measure and working measure preferably to eliminate or reduce temperature stress.Allow the reinforcing bar for crack occur mixed in use
Xtah Crude Clay structure component is considered as crack developing and makes the influence of stiffness of structural member reduction in calculation of temperature stresses ".But do not refer to
The calculation method of bright temperature stress and temperature controlled anticracking.For another example " hydraulic tunnel design specification " (DL/T5195-2004) only exists
11.2.6 " influence of stress and grouting pressure to lining cutting caused by temperature change, concrete shrinkage and expansion, preferably leads to for item requirement
It crosses working measure and construction measure solves.For the temperature stress that high temperature area generates, Ying Jinhang particular study ".
To the part underground engineering lining concrete for requiring control critical eigenvalue on using, (such as high flow rate flood discharging tunnel, power tunnel draw
Water section etc.) in the temperature controlled anticracking design calculating of construction time, FInite Element is mainly used at present.After completing structure design, pass through
The temperature of a large amount of schemes and the Simulation Analysis of temperature stress propose construction temperature controlled anticracking scheme and its site operation highest temperature
Spend control standard.It does so, precision is higher, and can be with Optimizing Construction Scheme.But need first to carry out concrete mix and big
Performance parameter test is measured, test and simulation calculation need to spend the more time；And it needs to spend more fund；For not having
There is determining coordination in works and without concrete performance test when can not carry out；It is not applied in concept phase and construction
Scheme quickly adjusts.Especially so far the factor of safety against cracking required value of the no construction time temperature controlled anticracking design of related specification,
It is all with reference to design standard of large dams when such as the design of hydraulic tunnel lining concrete temperature controlled anticracking.
Some designing units are to propose that maximum temperature controlling value is (following with reference to the Winkler's foundation of dam strong constraint area concrete
Referred to as strong constraint method), temperature-control construction scheme is formulated by unit in charge of construction.Unit in charge of construction is usually according to concrete mix, transport
Distance and mode, temperature etc. are to drafting concrete mixing (whether freeze and its measure) and pouring construction temperature control (such as water flowing is cooling)
Scheme carries out liner structure concrete maximum temperature and calculates, and proposes the arrangement and method for construction for meeting design standard.It does so, is big first
The Winkler's foundation of dam concrete cannot be applicable in thin-walled liner structure, do not reflect concrete strength, country rock performance, lining thickness and
The other influence of structure dimension equal difference；Followed by the error of maximum temperature is big inside unit in charge of construction's calculating lining concrete, a large amount of to be
The number artificial property of value is strong；The arrangement and method for construction that the both sides temperature difference may cause formulation is far apart, it is difficult to effectively realize that temperature is split
Seam control target.In particular, not calculating analysis temperature stress.
In summary situation illustrates, the phase temperature controlled anticracking of used in Underground Engineering Lining concrete construction at present does not clearly require
And technical standard；Existing design calculation method, FInite Element spend time, expense more, are not applied for no concrete test
Scheme quickly adjusts in the concept phase of achievement and construction；Strong constraint method error is larger, is unable to calculation of temperature stresses；It is all difficult
Effectively to realize temperature crack control target.
Summary of the invention
Technical problem to be solved by the invention is to provide a kind of circular cross section lining concrete temperature controlled anticracking temperature stresses
Fast design method is controlled, can quickly be calculated during pouring construction for the change found the problem with construction technology, condition
Temperature controlled anticracking temperature stress out realizes temperature controlled anticracking target in real time for Optimal improvements construction temperature control measures.
In order to solve the above technical problems, the technical scheme adopted by the invention is that: a kind of circular cross section lining concrete temperature
It controls anticracking temperature stress and controls Fast design method, for being safely to lining concrete temperature controlled anticracking tensile stress in Practical Project
Number calculates, it includes the following steps:
S1 determines circular cross section lining concrete temperature controlled anticracking target；
S2 determines that circular cross section lining concrete allows temperature stress value；
S3 determines circular cross section lining concrete variable；
S4 calculates circular cross section lining concrete construction time maximum temperature tensile stress according to the parameter determined in S1~S3.
The circular cross section lining concrete temperature controlled anticracking target and permission temperature stress value are according to design specification, lining
The rank of works, the harm in runtime crack, safety and barrier properties are built to require to determine.
The calculation formula of the circular cross section lining concrete construction time temperature controlled anticracking maximum stress are as follows: σmax=0.45H+
0.145R+0.028C+0.069E-0.0017E2+0.325T0+0.14Tg-0.194Ta+0.24△T-0.0147(H×Tg)+
0.021(H×E)-0.009(T0×Tg)-2.655 (1)
In formula: σmaxFor circular cross section lining concrete construction time maximum temperature tensile stress (MPa)；
H is the thickness (m) of lining concrete structure；
R is the inside radius (m) of lining concrete structure；
E-surrounding rock deformation monitor (GPa)；
C-lining concrete presses the strength grade (MPa) of 90 day age design；
T0- lining concrete placing temperature (DEG C)；
TaAir themperature (DEG C) in hole when-lining concrete pouring construction；
△ T is temperature year luffing, i.e. summer maximum temperature-winter minimum temperature in hole；
Tg=35-TwThe temperature effect value (DEG C) of water flowing and the cooling situation of obstructed water is represented, no water flowing takes T when coolingw=
35 DEG C of calculating Tg=0；When water flowing is cooling, TwFor water flowing temperature (DEG C)；
By circular cross section liner structure thickness and inside radius, strength grade of concrete, surrounding rock deformation monitor, placing temperature,
Air themperature in hole when pouring construction, in hole temperature year luffing, whether water flowing is cooling and its water temperature substitutes into formula (1), to obtain
The corresponding period pours the construction time maximum temperature tensile stress (MPa) of circular cross section lining concrete.
When the strength grade that the circular cross section lining concrete was designed using 28 day age, need to be scaled according to specification
The strength grade of 90 day age design.
The circular cross section lining concrete is kept the temperature using curtain, and underground chamber air themperature improves, then Ta is using raising
Air themperature in hole afterwards.
When the thickness of the circular cross section lining concrete is smaller, all single-row arrangement of water flowing cooling water pipe.
A kind of circular cross section lining concrete temperature controlled anticracking temperature stress control Fast design method, by circular cross section
Lining concrete temperature controlled anticracking target, the determination for allowing temperature stress value and variable are calculated from the formula circular cross section lining
Building concrete construction time maximum temperature controlled anticracking temperature stress value is applied in the construction of practical lining concrete, can be in pouring construction
In the process for the change found the problem with construction technology, condition, temperature controlled anticracking temperature stress is quickly calculated, in real time for excellent
Change and improve construction temperature control measures, realizes temperature controlled anticracking target.
Detailed description of the invention
Present invention will be further explained below with reference to the attached drawings and examples:
Fig. 1 is the schematic diagram of lining concrete of the present invention.
Fig. 2 is the structural schematic diagram of circular cross section lining concrete of the present invention.
Fig. 3 is the three-dimensional finite element structural schematic diagram of Fig. 2.
Fig. 4 is flood discharging tunnel cavern climate simulation curve graph in practical application of the present invention.
Specific embodiment
In FIG. 1 to FIG. 4, a kind of circular cross section lining concrete temperature controlled anticracking temperature stress control Fast design method,
For calculating in Practical Project lining concrete temperature controlled anticracking tensile stress safety coefficient, it includes the following steps:
S1 determines circular cross section lining concrete temperature controlled anticracking target；
Preferably, according to engineering real data record circular cross section lining thickness and inside radius, strength grade of concrete,
Climate simulation rule, water temperature annual variation law, concrete, placing temperature, pouring construction in matter condition surrounding rock deformation monitor, hole
When hole in the cooling operating condition of air themperature and water flowing.
S2 determines that circular cross section lining concrete allows temperature stress value；
S3 determines circular cross section lining concrete variable；
S4 calculates circular cross section lining concrete construction time maximum temperature tensile stress according to the parameter determined in S1~S3.
In preferred scheme, the circular cross section lining concrete temperature controlled anticracking target and permission temperature stress value are roots
It requires to determine according to design specification, the rank of liner structure object, the harm in runtime crack, safety and barrier properties.
In preferred scheme, the calculation formula of the circular cross section lining concrete construction time temperature controlled anticracking maximum tension stress
Are as follows: σmax=0.45H+0.145R+0.028C+0.069E-0.0017E2+0.325T0+0.14Tg-0.194Ta+0.24△T-
0.0147(H×Tg)+0.021(H×E)-0.009(T0×Tg)-2.655 (1)
In formula: σmaxFor circular cross section lining concrete construction time maximum temperature tensile stress (MPa)；
H is the thickness (m) of lining concrete structure；
R is the inside radius (m) of lining concrete structure；
E-surrounding rock deformation monitor (GPa)；
C-lining concrete presses the strength grade (MPa) of 90 day age design；
T0- lining concrete placing temperature (DEG C)；
TaAir themperature (DEG C) in hole when-lining concrete pouring construction；
△ T is temperature year luffing, i.e. summer maximum temperature-winter minimum temperature in hole；
Tg=35-TwThe temperature effect value (DEG C) of water flowing and the cooling situation of obstructed water is represented, no water flowing takes T when coolingw=
35 DEG C of calculating Tg=0；When water flowing is cooling, TwFor water flowing temperature (DEG C)；
In preferred scheme, by circular cross section liner structure thickness and inside radius, strength grade of concrete, surrouding rock deformation mould
Air themperature in hole when amount, placing temperature, pouring construction, in hole temperature year luffing, whether water flowing is cooling and its water temperature substitutes into formula
(1), to obtain the construction time maximum temperature tensile stress (MPa) that the corresponding period pours circular cross section lining concrete.
In preferred scheme, when the circular cross section lining concrete uses the strength grade of 28 day age design, need
The strength grade of 90 day age design is scaled according to specification.
In preferred scheme, the circular cross section lining concrete is kept the temperature using curtain, and underground chamber air themperature improves,
Then Ta is using air themperature in the hole after improving.
In preferred scheme, when the thickness of the circular cross section lining concrete is smaller, all single-row cloth of water flowing cooling water pipe
It sets.
In following practical application, have based on pressing section circular cross section structure and its related parameter by flood discharging tunnel, and combine class
Like engineering, various possible situations are calculated.Basic parameter and numerical procedure are shown in Table 1, each scheme lining concrete construction time
Maximum temperature tensile stress sigmamaxCalculated result is listed in table 1.
1 circular cross section lining concrete temperature stress calculation scheme of table and maximum tension stress
For the lining concrete construction time maximum temperature tensile stress sigma of table 1maxCalculated value is for statistical analysis, i.e. acquisition formula
(1)。
Embodiment -1,
Flood discharging tunnel is key construction (I grade), and having pressure section is circular cross section, and lining cutting and surrounding rock category are listed in table 2.Lining cutting is disconnected
The internal diameter in face is 7.5m, lining concrete design strength grade C9040, structural sections parting length is 9m.According in excavation initial stage hole
The data that field data and designing institute provide, it is 23.5 DEG C that designing unit, which takes many years temperature on average, and temperature year luffing is 3.0 DEG C,
It is calculated according to specification using cosine formula (2).Execution conditions, bidding document can provide machine outlet 14 DEG C of refrigerated merchandise coagulations
Soil realizes 18 DEG C of placing temperature.It is cooling for water flowing that two kinds of water can be provided, first is that 12 DEG C of chilled waters；Second is that tap water at normal temperature,
22 DEG C of summer, 12 DEG C of winter.
In formula: TaFor the air themperature at τ moment in hole；
The time (day) that τ is 1 day away from January；
τ0For the highest temperature in hole 1 day away from January time (day), τ is taken0=210 days.
2 flood discharging tunnel lining cutting of table and rocvk classification
(2) temperature controlled anticracking design and its technical requirements
Designing institute is according to related design specification, concrete mix optimization and its performance test, Finite element arithmetic achievement
(temperature is calculated using formula (2) in hole), it is determined that flood discharging tunnel has pressure section lining concrete using C9040, segment length 9m is poured, is had
Section bottom arch placing temperature is pressed to be no more than 18 DEG C, maximum temperature is not more than 37 DEG C, has pressure section side and roof arch to build temperature no more than 18 DEG C, most
High-temperature is not more than 38 DEG C.Winter construction can be using entering in the case where temperature of concrete during construction can be lower than 18 DEG C naturally
The concreting in storehouse.Recommend following scheme when hot weather construction: having a pressure section, 18 DEG C of temperature of concrete during construction, water pipe spacing 1.0m,
Length of pipe 100m, cooling water flow 2.0m3/ h, 20 DEG C of coolant water temperature (normal-temperature water), when concreting, starts water flowing, water flowing
It is 15 days cooling.
(3) lining concrete temperature controlled anticracking arrangement and method for construction
According to the above design requirement, arrangement and method for construction plans entire flood discharging tunnel substantially by 9m sequence placing, and lining concrete is applied
Work temperature controlled anticracking scheme is as follows:
1. using Outputting Pre-cooling Concrete, outlet temperature reaches 12 DEG C~14 DEG C.
2. reducing temperature recovery in concrete transportation casting process.Increase transport capacity is effectively ensured concrete storehouse surface and pours
Base covers in time；Packaged type canvas sunshade is set at the top of concrete transportation automobile bodies, in concrete mixer cabinet
Upper installation foamed heat insulating device etc..
3. strengthening management, accelerate speed of application.By strengthening management, reduces to wait and unload the time or when discharging is put in storage
Between, it avoids repeatedly turning to expect to put in storage, the concreting cover time is no more than 1h.
4. reasonable arrangement concrete construction progress.The concreting period be arranged in as far as possible low temperature season, morning and evening temperature compared with
It is carried out when low.The high temperature period on daytime pours preceding preparation, arranges 16 to be poured when the next day morning 10 or so in the afternoon as far as possible
It builds.
5. air-conditioning in storehouse.It is equipped with air-conditioning on telescoping steel form, for hot weather construction in storehouse, pours environment temperature in storehouse to reduce
Degree, not only improves temperature control, and can play the role of reducing temperature of heatstroke prevention.
6. surface maintenance.Start flowing water maintenance after concrete demoulding, using φ 35mm plastic tube, is bored every 20~30cm
The aperture of φ 1mm or so, hang in template or exposed steel bar head on, water flowing flow is 15L/min or so.Daytime carries out uninterrupted
Flowing water maintenance, night (20: 00~6: 00) carry out interruption flowing water maintenance, i.e. flowing water 1h keeps wet 1h, when temperature is more than 25 DEG C
When uninterruptedly conserve, have pressure section side and roof arch without pressure section curing time be no less than 28d.
7. water flowing is cooling.The difference of cooling water flow 35L/min, concrete temperature and water temperature is no more than 22 DEG C.Cooling water pipe
It is managed using PE, is parallel to the snakelike middle part for being arranged in each pour of water (flow) direction, single water pipe length is not more than 100m, vertically
Spacing is 1.0m.Right bank dragon falls tail and first leads to 48 hours chilled waters (about 14~20 DEG C) in high temperature season, later 7 days usual warm water；
The usual warm water of low temperature season.
8. the special heat preservation of cold weather concrete.Into winter, the thermal insulation material oversite concrete exposure that heat insulation effect is good is selected
Face prevents concrete surface from generating crack.Door hanging curtain mode can be used at tunnel portal, avoid cold wind from flowing backward in hole, cause
Concrete surface crack.
9. shortening the changeover time.Live shift system is carried out, so equipment operations staff, it is necessary to join at the scene
Class, the changeover time is no more than 30min；It cannot stop pouring when having a meal, it is necessary to be staggered have a meal in batches, it is ensured that mix in storehouse
The continuity that solidifying soil pours.
10. reinforcing concrete temperature measuring.In order to verify whether construction time concrete temperature meets temperature requirements, using pre-
The resistance thermometer or thermocouple measurement concrete temperature being embedded in concrete, and achievement is analyzed；In concrete
In casting process, every 4h measures the outlet temperature of a concrete, the placing temperature of concrete, temperature, and makes a record；Temperature
During measurement is surveyed, the case where discovery beyond Winkler's foundation, notify at once.
(4) lining concrete temperature observation achievement
There are pressure section lining concrete temperature control achievement and its overtemperature situation for statistical analysis left and right bank flood discharging tunnel, is listed in
Table 3~6.
Maximum temperature statistical form inside 3 2010 years flood discharging tunnel lining concretes of table
Table 4 2010 years left and right bank flood discharging tunnel lining concrete placing temperature statistical forms
Maximum temperature statistical form inside table 5 2011 years left and right bank flood discharging tunnel lining concretes
Table 6 2011 years left and right bank flood discharging tunnel lining concrete placing temperature statistical forms
Concrete internal temperature observing buoy shows: compared with design standard, 2010 and left bank in 2011 and right bank
Placing temperature overheating problem, respectively 56.6%, 13.33%；In addition the cooling water temperature of water flowing is also generally more than design standard；Cause
This, maximum temperature also has certain overheating problem, respectively 45.28%, 16.67%.
(5) lining concrete situation
Flood discharging tunnel has pressure section circular cross section lining concrete situation, and bottom arch concrete does not have crack, side and roof arch coagulation
Native crack count is listed in table 7.
The left and right bank flood discharging tunnel of table 7 has pressure section circular cross section lining concrete overall condition
There are pressure segment structure feature, the crack count situation of lining concrete construction technology and table 7 according to flood discharging tunnel, it is comprehensive to divide
Analysis can obtain following understanding:
(a) there is pressure section side and roof arch lining concrete more, bottom plate free from flaw.Estimation is greater than with abutment wall (side and roof arch) scale
Bottom plate, and bottom plate curing condition is quite a lot of related.This result is consistent with FInite Element simulation calculation conclusion.Therefore, right from now on
Similar large size tunnel lining Concrete Temperature Control anticracking emphasis should be placed on side and roof arch.This is also above-mentioned design calculation formula only opposite side
The reason of crown carries out.
(b) two sides flood discharging tunnel is compared, and left bank 1#, 2# are more than right bank 3#, the hole 4# lining concrete, mixed with left bank lining cutting
Solidifying soil maximum temperature overtemperature ratio is big related (including the higher influence of water flowing coolant water temperature).
(c) details generally investigated according to crack, the more hard complete thermal cracking of country rock are more.Flood discharging tunnel has pressure section all
It is the E1 type lining cutting in the hard complete II class surrounding rock area of country rock, is the main generating region of thermal cracking although lining thickness is small
Domain；The big generally seldom thermal cracking of lining concrete of IV class surrounding rock area thickness.
(6) FInite Element simulation calculation achievement
Technical requirement on design is proposed according to design phase FInite Element simulation calculation achievement.In addition, table 1 is also listed
A large amount of FInite Element simulation calculation achievements.Such as: II class surrounding rock area 1.0m thickness lining cutting pours for summer August 1st, design phase meter
The σ of calculation scheme 49max=2.06MPa, minimum factor of safety against cracking 1.88；The σ of construction stage numerical procedure 5max=4.4MPa, most
Small factor of safety against cracking 1.22.III 2 class surrounding rock area E3 type 1.0m are poured for thickness lining cutting summer August 1st, construction stage numerical procedure
21 σmax=3.8MPa, minimum factor of safety against cracking 1.41.
Embodiment -2,
Flood discharging tunnel has pressure II class surrounding rock area E1 type 1.0m thickness lining cutting of section circular cross section
II class surrounding rock area 1.0m thickness lining cutting is that entire flood discharging tunnel has temperature controlled anticracking difficulty in pressure section circular cross section maximum
Structural sections.
(1) it collects and calculates circular cross section liner structure temperature controlled anticracking data
Liner structure design data, lining thickness and inside radius, strength grade of concrete；Environmental data, geological conditions enclose
Climate simulation rule, water temperature annual variation law in rock deformation modulus, hole；Etc. as described above.
(2) it analyzes and determines temperature controlled anticracking target, determine that circular cross section lining concrete allows temperature stress [σmax] value.
Flood discharging tunnel is crossed in small stream Lip river, is level-one building according to " hydraulic tunnel design specification ", flow velocity is high, the danger in runtime crack
Evil is big, with reference to similar engineering experience, it should carry out Crack Control Design.According to " design of hydraulic concrete structures specification ", " water conservancy project reinforcing bar
Code for design of concrete structures ", circular cross section lining cutting C90The axial tensile strength standard value of 40 pump concretes is 2.39MPa.
(3) design phase temperature controlled anticracking measure scheme designs
(3.1) variable is analyzed, circular cross section lining concrete temperature controlled anticracking working measure scheme is drafted
Since liner structure size, strength grade of concrete determine, and winter must all close hole heat preservation, therefore can
Variable only has placing temperature and water flowing coolant water temperature.It was poured with summer August 1st and carries out temperature controlled anticracking design for representative.Bid text
Part can provide machine outlet 14 DEG C of refrigerated merchandise concrete, realize 18 DEG C of placing temperature.According to execution conditions, placing temperature is drafted
It is all 18 DEG C, it is cold that obstructed water cooling, logical 12 DEG C of chilled water coolings, logical 22 DEG C of normal-temperature waters cooling and 16 DEG C pour+16 DEG C of water flowings
But 4 temperature control measures schemes.
(3.2) circular cross section lining concrete construction time maximum temperature tensile stress sigma is calculatedmax
Since lining thickness 1.05m includes sandblasting pulp layer 0.05m, and Finite element arithmetic is to take thickness in table
1.0m, in order to compared with Finite element arithmetic value, take lining thickness 1.0m to calculate.Summer August 1 day is poured, is calculated by formula (2)
Ta≈25℃.σ is calculated to obtain by II class surrounding rock area E1 type lining cutting of circular cross section related parameter substitution formula (1) to each draft schememax=
2.67MPa、2.05MPa、2.29MPa、1.89MPa。
(3.3) σ is being calculatedmax≤【σmax] under the premise of, according to the principle advantageous measure scheme of simple and practical economy, for applying
Work application.In above-mentioned 4 draft schemes, 18 DEG C pour+12 DEG C of chilled water coolings, 18 DEG C pour+22 DEG C of normal-temperature water coolings, 16 DEG C
It pours the cooling 3 temperature control measures schemes of+16 DEG C of water flowings and meets calculating σmax≤【σmax]=2.39MPa, according to safety, economy, conjunction
Reason, simple possible principle select 18 DEG C to pour+22 DEG C of normal-temperature water cooling schemes and arrange for construction temperature control in conjunction with technical requirement on design
Apply scheme.
(4) tensile stress calculated value comparative analysis.The cooling scheme of+16 DEG C of water flowings is poured for 16 DEG C, the design phase is limited
First method scheme 49 calculates σmax=2.06MPa, formula (1) calculated value 1.89MPa, error -8.25%, precision is higher, meets engineering
Design requirement.
18 DEG C taken in practice of construction pour+12 DEG C of water flowings coolings, σmax=2.05MPa is less than axial tensile strength mark
Quasi- value is 2.39MPa, therefore design mistake is met the requirements.
(4) work progress real-time temperature control anticracking scheme optimization designs
In construction, due to tunnel excavation and extraneous perforation, in hole, air themperature declines rapidly changes close to outside air temperature.
It is in October, 2009 in November, 2012, total to flood discharging tunnel (left and right bank) to have carried out more than 300 temperature actual measurements, summarize and is shown in figure
4.Wherein on January 1st, 2010 for date reference axis first day.Wherein abscissa is time (day)；Ordinate is temperature (DEG C).
Cosine function is carried out using least square method to be fitted
In formula: TaFor temperature (DEG C) in hole；
τ is the time (day) apart from January 1.
Due to temperature change in hole, temperature controlled anticracking scheme must be redesigned in construction in real time.
Also according to above-mentioned design method, summer August pouring construction on the 1st, formula (3) calculates temperature T in holeaIt is 25.99
DEG C, winter minimum temperature Tmin=12.59 DEG C.It drafts and each parameter is substituted into formula (1), calculate 18 DEG C and pour+12 DEG C of water flowings coolings
Scheme σmin=4.35MPa；16 DEG C pour+16 DEG C of water flowing cooling scheme σmin=4.19MPa；18 DEG C pour+8 DEG C of water flowings it is cooling+
14 DEG C of heat preservations (i.e. stringent closing hole, by the lowest temperature in winter hole from Tmin=12.59 DEG C are increased to Tmin=14 DEG C) scheme
σmin=3.14MPa.Each scheme σminCalculated value is both greater than axial tensile strength standard value 2.39MPa, it is necessary to take tightened up
Temperature control measures.
(5) stress achievement calculates error and analysis of design scheme
+ 16 DEG C of water flowings coolings, the σ of FInite Element simulation calculation scheme 5 are poured according to 16 DEG C of the construction stagemin=4.4MPa,
Formula (1) calculated value 4.35MPa, error are -1.1%, and Stress calculation value precision is high.
18 DEG C are taken to pour the cooling scheme of+12 DEG C of water flowings in practice of construction, stress is more than axial tensile strength standard value
2.39MPa has crack risk, needs to further strengthen temperature control, reduces placing temperature, reinforces water flowing coolant water temperature, reinforces winter
Hole heat preservation improves temperature etc. in hole.
Embodiment -3,
Flood discharging tunnel has pressure III 2 class surrounding rock area E3 type lining cutting of section circular cross section, lining concrete temperature controlled anticracking target and permission
Temperature stress value is same as above.
Design phase, summer August pouring construction on the 1st, formula (2) calculate temperature T in holeaIt is 25 DEG C, is counted using formula (1)
It calculates 18 DEG C and pours obstructed water cooling scheme σmax=2.22MPa；18 DEG C pour+12 DEG C of water flowing cooling scheme σmax=1.55MPa；16
DEG C pour+16 DEG C of water flowing cooling scheme σmax=1.39MPa.Both less than axial tensile strength standard value is 2.39MPa, recommends to adopt
Obstructed water cooling scheme is poured with 18 DEG C.
It constructs the real-time control stage, summer August pouring construction on the 1st, formula (3) calculates temperature T in holeaIt is 25.99 DEG C, adopts
18 DEG C, which are calculated, with formula (1) pours+12 DEG C of water flowing cooling scheme σmax=3.85MPa.16 DEG C pour+16 DEG C of water flowing cooling schemes
σmax=3.69MPa, both greater than axial tensile strength standard value are 2.39MPa.The temperature controlled anticracking measure scheme that practice of construction uses
18 DEG C pour+14~20 DEG C of water flowings coolings, and it is 2.39MPa that temperature stress, which is greater than axial tensile strength standard value, is easy to happen temperature
Spend crack.It needs to reinforce temperature control measures, it is proposed that take 16 DEG C to pour cooling+14 DEG C of heat preservations of+16 DEG C of water flowings and (strictly close hole
Mouthful, by the lowest temperature in winter hole from Tmin=12.59 DEG C are increased to Tmin=14 DEG C) scheme, calculation of temperature stresses σmax=
2.63MPa, less times greater than axial tensile strength standard value 2.39MPa.
Stress achievement calculates error and analysis of design scheme.+ 16 DEG C of water flowing cooling schemes are poured for 16 DEG C of the construction stage,
21 calculated value σ of FInite Element schememax=3.8MPa, formula (1) calculated value 3.69MPa, error are -2.9%, and error is smaller, full
Sufficient engineering calculation required precision.But 18 DEG C of practice of construction scheme pour+14~20 DEG C of water flowings coolings, and temperature stress is greater than axis
Heart tensile strength standard value is 2.39MPa, is easy to happen thermal cracking.
4, formula (1) computational accuracy and design temperature controlled anticracking scheme analysis on its rationality
With Finite element arithmetic comparison of results.II class surrounding rock area E1 type 1.0m thickness lining cutting, 16 DEG C to pour+16 DEG C of water flowings cold
But, the σ of design phase Finite element arithmetic scheme 49max=2.06MPa, formula (1) calculated value 1.89MPa, error are -8%；
Construction stage, the σ of FInite Element simulation calculation scheme 5max=4.4MPa, formula (1) calculated value 4.19MPa, error be-
4.8%.III 2 class surrounding rock area E3 type lining cutting, 16 DEG C of the construction stage pour+16 DEG C of water flowing Cooling calculation schemes 21, and FInite Element is imitative
The σ really calculatedmax=3.8MPa, formula (1) calculated value 3.69MPa, error are -2.9%.Error is all smaller, meets engineering design
Computational accuracy requirement.
Compared with thermal cracking checks achievement.In practice of construction, the lining concrete in II, III 2 class surrounding rock areas is all adopted
18 DEG C are taken to pour+14~20 DEG C of water flowing cooling provisions.Formula (1) calculates stress achievement explanation, and it is anti-that temperature stress is both greater than axle center
Tensile strength standard value is 2.39MPa, is easy to happen thermal cracking.And lining cutting of the II class surrounding rock area than III 2 class surrounding rock areas is answered
Power is much bigger, and distress in concrete is more.6 thermal cracking of table inspection achievement, circular cross section lining concrete side and roof arch 65%~
86% occurs thermal cracking.And (c) conclusion " the more hard complete thermal cracking of country rock is more ".Stress achievement is calculated to split with temperature
Seam checks that achievement is completely the same.
To sum up example calculation analytic explanation, the present invention, calculation formula is simple, can comprehensively, rationally reflect liner structure thickness
Change and pour with air themperature year in inside radius, strength grade of concrete, country rock performance (deformation modulus), placing temperature, hole
Temperature in phase hole, whether water flowing is cooling and its influence of the principal elements such as water temperature.Arbitrary period can be calculated rapidly and pour circle
The maximum temperature tensile stress of shape section structure lining concrete construction time, calculate error it is small, can be completely used for Practical Project into
Trip temperature Crack Control Design, especially Preliminary design and site operation phase are designed real-time, quickly.
The above embodiments are only the preferred technical solution of the present invention, and are not construed as limitation of the invention, this Shen
Please in embodiment and embodiment in feature in the absence of conflict, can mutual any combination.Protection model of the invention
The technical solution that should be recorded with claim is enclosed, the equivalent replacement side of technical characteristic in the technical solution recorded including claim
Case is protection scope.Equivalent replacement i.e. within this range is improved, also within protection scope of the present invention.
Claims (6)
1. a kind of circular cross section lining concrete temperature controlled anticracking temperature stress controls Fast design method, for right in Practical Project
Lining concrete temperature controlled anticracking tensile stress safety coefficient calculates, characterized in that it includes the following steps:
S1 determines circular cross section lining concrete temperature controlled anticracking target；
S2 determines that circular cross section lining concrete allows temperature stress value；
S3 determines circular cross section lining concrete variable；
S4 calculates circular cross section lining concrete construction time maximum temperature tensile stress according to the parameter determined in S1~S3.
2. circular cross section lining concrete temperature controlled anticracking temperature stress according to claim 1 controls Fast design method,
It is characterized in that: the circular cross section lining concrete temperature controlled anticracking target and allow temperature stress value be according to design specification,
The rank of liner structure object, the harm in runtime crack, safety and barrier properties require to determine.
3. described in any item circular cross section lining concrete temperature controlled anticracking temperature stress controls are quick according to claim 1~2
Design method, it is characterized in that: the calculation formula of the tensile stress when circular cross section lining concrete minimum factor of safety against cracking
Are as follows: σmax=0.45H+0.145R+0.028C+0.069E-0.0017E2+0.325T0+0.14Tg-0.194Ta+0.24△T-
0.0147(H×Tg)+0.021(H×E)-0.009(T0×Tg)-2.655 (1)
In formula: σmaxFor circular cross section lining concrete construction time maximum temperature tensile stress (MPa)；
H is the thickness (m) of lining concrete structure；
R is the inside radius (m) of lining concrete structure；
E-surrounding rock deformation monitor (GPa)；
C-lining concrete presses the strength grade (MPa) of 90 day age design；
T0- lining concrete placing temperature (DEG C)；
TaAir themperature (DEG C) in hole when-lining concrete pouring construction；
△ T is temperature year luffing, i.e. summer maximum temperature-winter minimum temperature in hole；
Tg=35-TwThe temperature effect value (DEG C) of water flowing and the cooling situation of obstructed water is represented, no water flowing takes T when coolingw=35 DEG C
Calculate Tg=0；When water flowing is cooling, TwFor water flowing temperature (DEG C)；
By circular cross section liner structure thickness and inside radius, strength grade of concrete, surrounding rock deformation monitor, placing temperature, pour
Air themperature in hole when construction, in hole temperature year luffing, whether water flowing is cooling and its water temperature substitutes into formula (1), to obtain correspondence
The period pours the construction time maximum temperature tensile stress (MPa) of circular cross section lining concrete.
4. circular cross section lining concrete temperature controlled anticracking temperature stress according to claim 3 controls Fast design method,
It is characterized in that: being needed by weight of specification when the circular cross section lining concrete uses the strength grade of 28 day age design
For the strength grade of 90 day age design.
5. circular cross section lining concrete temperature controlled anticracking temperature stress according to claim 3 controls Fast design method,
It is characterized in that: the circular cross section lining concrete is kept the temperature using curtain, underground chamber air themperature is improved, then Ta is using raising
Air themperature in hole afterwards.
6. circular cross section lining concrete temperature controlled anticracking temperature stress according to claim 3 controls Fast design method,
It is characterized in that: when the thickness of the circular cross section lining concrete is smaller, all single-row arrangement of water flowing cooling water pipe.
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