CN113191042A - Method and system for calculating temperature control anti-cracking parameters of lining concrete with circular section - Google Patents
Method and system for calculating temperature control anti-cracking parameters of lining concrete with circular section Download PDFInfo
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- 239000000395 magnesium oxide Substances 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention provides a method and a system for calculating temperature control anti-cracking parameters of circular section lining concrete, which can objectively and accurately obtain the temperature control anti-cracking parameters suitable for the circular section lining concrete and scientifically and reasonably realize temperature control anti-cracking. The invention provides a method for calculating temperature control anti-cracking parameters of lining concrete with a circular cross section, which is characterized by comprising the following steps of: step 1, obtaining data for temperature control of lining concrete with a circular section; step 2, calculating the allowable foundation temperature difference delta T of the concrete lining of the side wall with the circular cross section poured in each month, namely 4.47H-0.103R-0.1995L +0.0986C-0.053E +0.302Ta+11.945, wherein: h is lining structure thickness, R is lining structure inner radius, L is lining structure section length, C is lining concrete 90d design age strength grade, E is surrounding rock elastic modulus, T is lining concrete lengthaThe temperature in the concrete pouring period is shown as the temperature in the hole.
Description
Technical Field
The invention belongs to the technical field of concrete temperature control and crack prevention, and particularly relates to a method and a system for calculating temperature control and crack prevention parameters of circular section lining concrete.
Background
Cracks are one of the main diseases of concrete, and 80% of concrete in structural engineering is temperature cracks. Along with the development of hydraulic and hydroelectric engineering construction, the scale and the section size of a hydraulic tunnel are larger and larger, and the drainage flow rate and the concrete strength grade are higher and higher. The large-section high-strength hydraulic lining concrete generates a large number of cracks without any exception as long as effective measures are not taken, and most of the cracks generate penetrating temperature cracks during construction (see fig. 1 and 2).
The temperature crack is generated when the stretching deformation of the restrained concrete under the action of temperature difference exceeds the limit stretching value (or the stretching stress exceeds the stretching strength). To this end, one approach to avoid temperature cracking is to eliminate or reduce the constraints (internal, external); the second is to eliminate or reduce the temperature difference. Therefore, after the design is completed, the key point of the temperature crack control in the engineering construction is to control the temperature difference. Regarding design and construction specification of mass concrete, taking "design specification for concrete dam temperature control (NB/T35092-: the 8.1.1 temperature differential standard should include the base allowable temperature differential, the new and old concrete allowable temperature differential, and the internal and external allowable temperature differentials. 8.1.2 the base allowable temperature difference of the concrete in the base restriction area is selected according to the following regulations: the ultimate tensile value of the normal concrete 28d age is not less than 0.85 multiplied by 10-4Linear expansion coefficient of aggregate for concrete and 1.0X 10-5The temperature difference is not large, the construction quality is good, the modulus of elasticity of the bedrock is similar to that of the concrete, and the allowable temperature difference of the normal concrete foundation can be taken according to the specification of the table 1 when the pouring blocks are uniformly raised in a short interval. Similar provisions are made for roller compacted concrete dams.
TABLE 1 Normal concrete base allowable temperature Difference (. degree. C.)
The allowable temperature difference of the concrete foundation should be demonstrated for the following cases:
1) linear expansion system of aggregate for concreteNumber and 1.0X 10-5The difference is large/° c;
2) the limit tensile value of the normal concrete 28d age is lower than 0.85 multiplied by 10-4；
3) The elastic modulus of the bedrock is greatly different from that of the concrete;
4) the cement containing more magnesium oxide is adopted, and experimental or actual measurement data show that the concrete has obvious autogenous volume deformation;
5) the pouring block is stopped for a long time in the basic constraint range;
6) the length-width ratio of the structural dimension of the dam body is larger than 2.0;
7) the height-length ratio of the structure size is less than 0.5;
8) the dam height is more than 200 m.
The hydraulic tunnel lining concrete temperature control design and construction, because the design and construction specifications of hydraulic tunnels and the like do not have the regulations of temperature control standards and the like, the giant engineering tunnels of three gorges, Wudongde, oriented dams and the like refer to the design specifications of dams, and strong constraint areas are selected to allow the basic temperature difference (table 1) to be controlled by temperature. But the thickness of the lining structure is small, namely the height-length ratio of the 7 th strip structure is more between 0.05 and 0.1 and is far less than 0.5; the concrete strength is C25-C60 in a large range, and the ultimate tensile value is lower than 0.85 multiplied by 10-4And some are much larger than 0.85 × 10-4(ii) a And because the strength range of the concrete is large, the concrete often passes through different rock regions with large elastic modulus difference, and the elastic modulus of the bedrock is greatly different from that of the concrete. Therefore, the allowable basic temperature difference of the lining concrete is seriously insufficient by adopting a dam specification value, and particularly, the influences of the size of the lining structure, the strength of the concrete, the elastic modulus of a rock mass, the environmental temperature in a pouring period and the like are not comprehensively reflected.
In addition, the temperature cracks are generated when the stretching deformation of the restrained concrete under the action of the temperature difference exceeds the ultimate stretching value (or the stretching stress exceeds the stretching strength), the structural shapes and the sizes are different, the external restraint and the internal restraint are different, and the allowable basic temperature difference of the lining concrete in different structural forms is naturally different, so that the more refined allowable basic temperature difference calculation method of the lining concrete in different structural forms is suitable to be researched and provided. For example, as shown in fig. 1, temperature cracks of an urban door opening type section mostly occur in a side wall, and a circular section mostly occurs in the horizontal development of a waist line axis of a side arch (fig. 2), see fan kindness and section sublight 'temperature control and crack prevention innovation of hydraulic tunnel lining concrete in practice'.
Disclosure of Invention
The invention provides a method and a system for calculating temperature control anti-cracking parameters of lining concrete with a circular section, aiming at the circular section commonly used by a pressure tunnel in engineering and aiming at solving the problem that the allowable basic temperature difference of the lining concrete adopts a dam specification value.
In order to achieve the purpose, the invention adopts the following scheme:
< method >
As shown in fig. 3, the invention provides a temperature control anti-cracking parameter calculation method for lining concrete with a circular cross section, which is characterized by comprising the following steps:
step 2, calculating the allowable foundation temperature difference delta T (DEG C) of concrete lining of the side wall with the circular cross section poured in each month:
△T＝4.47H-0.103R-0.1995L+0.0986C-0.053E+0.302Ta+11.945 (equation 1)
In the formula: h is lining structure thickness (m), R is lining structure inner radius (m), L is lining structure section length (m), C is lining concrete 90d design age strength grade (MPa), E is surrounding rock elastic modulus (GPa), T is lining concrete lengthaThe air temperature (DEG C) in the hole during the concrete pouring period. When the lining concrete adopts the strength grade designed in the 28-day age, the strength grade designed in the 90-day age needs to be converted according to the specification.
Preferably, the method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section provided by the invention can further comprise the following steps: step 3, calculating the allowable highest temperature [ T ] of lining concrete of the circular section poured in each month according to the allowable foundation temperature difference Delta Tmax】(℃)。
Preferably, the method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section provided by the invention can also have the following characteristics: in step 3, the allowable maximum temperature [ T ] is calculated using the following formulamax】
【Tmax】＝Tmin+. DELTA T (formula 2)
In the formula, TminThe lowest temperature (DEG C) in winter in the tunnel. Because: 1) pouring lining concrete after the tunnel is excavated for several months, wherein the temperature of surrounding rock of the tunnel wall is basically the temperature in the tunnel; 2) the lining structure is small in thickness, and the temperature after pouring for several months is basically the temperature in the tunnel; 3) the temperature in winter in the hole is lowest. Therefore, the winter minimum temperature T in the hole can be takenminThe temperature of the concrete serving as a lining structure is quasi-stable.
Preferably, the method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section provided by the invention can also have the following characteristics: in step 2, if the heat preservation of the closed opening is adopted in the construction period, the air temperature of the underground cavern is increased, and T is obtainedaAn elevated temperature of the air in the hole should be used.
Preferably, the method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section provided by the invention can also have the following characteristics: and (3) executing the steps 1 and 2 by adopting a control processing device, so that an operator inputs temperature control data according to prompts and calculates the allowable basic temperature difference delta T.
Preferably, the method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section provided by the invention can also have the following characteristics: executing the step 3 by adopting a control processing device, and calculating the allowable highest temperature [ T ] T of the lining concrete for pouring the circular section according to the allowable foundation temperature difference Delta Tmax】。
< System >
Further, the invention also provides a temperature control and crack control system for the lining concrete with the circular section, which is characterized by comprising the following components:
an input display part for the operator to input the collected data for controlling the temperature of the circular cross section lining concrete according to the prompt;
a storage unit for storing the input temperature control data;
a calculating part, based on the data for temperature control, calculating the allowable foundation temperature difference Delta T (DEG C) of the concrete for lining the side wall with the circular cross section by adopting the following formula:
△T＝4.47H-0.103R-0.1995L+0.0986C-0.053E+0.302Ta+11.945 (equation 1)
In the formula: h is lining structure thickness (m), R is lining structure inner radius (m), L is lining structure section length (m), C is lining concrete 90d design age strength grade (MPa), E is surrounding rock elastic modulus (GPa), T is lining concrete lengthaThe air temperature (DEG C) in the hole in the concrete pouring period is shown; substituting the thickness, the inner radius and the length of the circular cross-section lining structure, the concrete strength grade, the elastic modulus of surrounding rocks and the air temperature in the tunnel in the pouring construction period into a formula 1 to obtain the allowable foundation temperature difference of the concrete poured with the circular cross-section lining structure in the month;
a maintenance part for executing corresponding maintenance measures according to the allowable basic temperature difference Delta T; and
and the control part is in communication connection with the input display part, the storage part, the calculation part and the maintenance part and controls the operation of the input display part, the storage part, the calculation part and the maintenance part.
Preferably, the temperature-control anti-cracking control system for the lining concrete with the circular cross section provided by the invention can also have the following characteristics: the calculation part also calculates the allowable maximum temperature (T) of the lining concrete for pouring the circular section by adopting the following formula based on the data for temperature controlmax】(℃)：
【Tmax】＝Tmin+. DELTA T (formula 2)
In the formula, TminThe lowest temperature (DEG C) in winter in the tunnel;
the maintenance part is based on the allowable basic temperature difference Delta T and the allowable maximum temperature [ TmaxCorresponding maintenance measures are performed.
Preferably, the temperature-control anti-cracking control system for the lining concrete with the circular cross section provided by the invention can also have the following characteristics: the input display part also calculates the allowable basic temperature difference Delta T and the allowable maximum temperature [ T ] of the calculation part according to the operation instructionmaxAnd (6) displaying.
Preferably, the temperature-control anti-cracking control system for the lining concrete with the circular cross section provided by the invention can also have the following characteristics: the input display part also displays maintenance measures executed by the maintenance part according to the operation instruction.
In addition, step 2 aboveThe proposed formula 1 is obtained based on the deep research and analysis of the hydraulic tunnel circular section lining structure and related parameters thereof. Here, a typical circular cross-section lining shown in fig. 4 is taken as an example to establish a model, and simulation calculation is performed on a crown arch with a large pouring range and large temperature stress. Combining actual parameters of a brook luo-crossing flood discharge hole, a diversion hole of an underground power station on the left bank of the three gorges and a power generation hole of a river power station on the river plateau, wherein the thickness of a lining structure is 0.8m, 1.0m and 1.5 m; the inner radius is 4.25m, 6.7m and 7.5 m; the length of the seam is 9m and 12 m; concrete strength C9040、C9050、C9060, adding a solvent to the mixture; the elastic modulus of the surrounding rock is 5GPa, 9GPa, 20GPa and 30 GPa; the air temperature in the tunnel in the casting period is 13.28 ℃, 16.21 ℃, 22.62 ℃ and 25.33 ℃ (namely casting in different seasons); the concrete performance parameters of each strength grade are all obtained from the actual engineering. And carrying out simulation calculation on 62 schemes of various combinations, and carrying out sorting analysis on temperature, temperature stress and crack resistance safety coefficients. Because the minimum anti-cracking safety factor of the whole process from the lining concrete construction to the operation is more than 1.0, temperature cracks basically cannot be generated in principle. In addition, if the anti-cracking safety coefficient is too large, the margin is large, and the engineering investment is increased due to excessive temperature control. Therefore, each scheme with the minimum crack resistance safety factor of 1.0-1.2 in the whole process and the temperature difference (delta T ═ T) of the 62 schemes are arrangedmax-TminAnd allowable base temperature difference in the table) is shown in table 2, and the base temperature difference is analyzed and studied to obtain a formula 1 as the allowable base temperature difference of the circular cross-section lining concrete.
TABLE 2 simulation calculation results and statistical analysis of various schemes of 1.0-1.2 of circular section lining concrete crack resistance safety coefficient
Action and Effect of the invention
The temperature control anti-cracking parameter calculation method for the lining concrete with the circular cross section, provided by the invention, has a simple calculation formula, and can comprehensively and reasonably reflect the influences of the structure size, the concrete strength, the elastic modulus of a rock mass, the environmental temperature in a pouring period and the like of the circular cross section; the allowable basic temperature difference of the lining concrete for pouring the circular section in any month can be rapidly calculated, the allowable highest temperature control standard is provided, the allowable highest temperature control standard is used for construction temperature control, and the structural safety of the lining concrete for the tunnel portal-shaped section of the tunnel is practically guaranteed.
Further, the temperature control and crack prevention control system for the lining concrete with the circular cross section, provided by the invention, can automatically calculate the allowable basic temperature difference delta T of the lining concrete with the side wall with the circular cross section according to the temperature control data of the lining concrete with the circular cross section, and execute corresponding maintenance measures, has no human factor interference in the whole process, is high in automation degree, and can quickly and effectively perform temperature control and crack prevention.
Drawings
FIG. 1 is a diagram of a concrete crack lining a flood discharging tunnel of a three-plate creek power station in the background art;
FIG. 2 shows a three gorges right bank underground power station 6 of the background art#Diversion tunnel 3#A unit waist line axial crack condition diagram;
FIG. 3 is a flow chart of a temperature control and crack prevention parameter calculation method for circular cross section lining concrete according to the invention;
FIG. 4 is a schematic view of a tunnel circular cross-section lining concrete structure according to an embodiment of the present invention;
FIG. 5 is a sectional view of a pressure section A of the Wudongde flood discharge tunnel according to the embodiment of the present invention (dimension unit: cm in the figure);
FIG. 6 is a sectional view of a pressed section B of an Udoude spillway tunnel according to an embodiment of the present invention (dimension unit: cm in the drawing).
Detailed Description
The concrete embodiments of the temperature control and crack prevention parameter calculation method and system for the circular cross-section lining concrete according to the present invention will be described in detail below with reference to the accompanying drawings, taking the pressure-section circular cross-section lining concrete of the flood discharge tunnel of the wudongde hydropower station as an example.
< Wudongde hydropower station flood discharge tunnel engineering lining concrete temperature control data >
The Wudongde hydropower station mainly generates electricity and has the functions of flood control, shipping, sand blocking and the like. Installed capacity 10200MW of power station. The dam is a concrete hyperbolic arch dam, and the flood discharge is mainly performed by adopting the dam body to discharge the floodAnd the shoreside flood discharge tunnel is an auxiliary mode. The three flood discharging holes are all of tunnel type tunnels with pressure holes and then door-connected holes, and each tunnel type tunnel comprises a water inlet, a pressure hole section, a working gate chamber, a non-pressure hole section, an outlet section and an energy dissipation plunge pool, and the outlets adopt trajectory jet energy dissipation. The pressure tunnel of the flood discharge tunnel has a circular cross section, the inner diameter is 14m, the lining thickness is 0.8m and 1m, see fig. 5 and 6, the length of the parting joint is 9m, the rock types around the tunnel are II and III types of surrounding rocks respectively, the elastic modulus of the surrounding rocks is 32GPa and 20GPa, and the lining structure uses C9030 pumping the concrete. The temperature in the tunnel is 16-26 ℃, and is calculated by a cosine function formula 3.
In the formula: t isaAir temperature (. degree. C.) at time τ inside the hole; τ is the time (day) 1 day from 1 month; tau is0Taking tau as the time (day) between the highest temperature in the tunnel and 1 month and 1 day0Day 210.
Carry out temperature control to the concrete at the overall process of concrete placement and maintenance, avoid the concrete fracture, the design requirement temperature control measure includes:
(1) quality control and mix proportion optimization of concrete raw material
The water content of the concrete fine aggregate is controlled to be below 6%, and the fluctuation range of the water content is less than 2%. The mixing proportion of the concrete is optimized, and the using amount of concrete cementing materials is reduced; the construction management is enhanced, the construction process is improved, the concrete performance is improved, and the concrete anti-cracking performance is improved. On the premise of meeting the concrete strength, durability, workability and concrete pouring quality required by design, the concrete aggregate gradation is improved by adopting larger aggregate particle size as much as possible after the approval of a manager. And the Wudongde hydropower station flood discharge tunnel is cast by low-heat cement concrete.
(2) Reasonably arranging concrete construction procedure and construction progress
The reasonable arrangement of concrete construction procedures and construction progress is one of the main measures for preventing foundation from penetrating cracks and reducing surface cracks. The concrete construction procedure and the construction progress should be reasonably arranged, and the construction management level should be improved in an effort.
(3) Controlling concrete internal maximum temperature
Necessary temperature control measures should be taken so that the maximum temperature does not exceed the design allowable maximum temperature (table 3). The effective measures comprise concrete pouring temperature reduction, cementing material hydration heat temperature rise reduction, initial water cooling and the like. The concrete production system provides mixed concrete meeting the outlet temperature requirement. The contractor is responsible for controlling the temperature of concrete during the concrete transportation, warehousing and casting and curing after leaving the machine outlet. According to the analysis of computational results, the concrete pouring temperature of the gentle slope section of the flood discharging tunnel of the Wudongde hydropower station is suggested to be controlled according to the table 3. And if the measured temperature can not meet the maximum temperature allowed by the design, the buried cooling water pipe needs to be filled with water for cooling.
(4) Reasonably controlling the thickness of the pouring layer and the interval period between layers
When concrete at each part is poured, if the poured concrete temperature can not meet the relevant requirements, a supervisor is immediately informed, the concrete is processed according to the instruction of the supervisor, and effective measures are immediately taken to control the concrete pouring temperature.
Table 3 units of maximum temperature and casting temperature allowed during construction of flood tunnel lining concrete: c
| Month of the |
12. 1 month | 2. 11 month | 3. 10 |
4. 9 month | 5 to 8 months |
| Allowable maximum temperature | 40 | 41 | 42 | 43 | 44 |
| Allowable casting temperature | Naturally put into storage | Naturally put into storage | 18 | 20 | 22 |
< example I > flood discharge tunnel pressure section 1.0m thickness A type lining concrete
A-shaped lining structure with the pressure section of 1.0m and the thickness of A-shaped lining structure of the flood discharge tunnel is shown in figure 5, the circular cross section is provided with annular construction parting joints every 9m along the axial direction of the flood discharge tunnel, III-class surrounding rocks have the elastic modulus of 20 GPa. Pouring concrete by stages 2: the top arch is arranged at the front side and the bottom arch is arranged at the back side. Concrete strength C of side arch9030, the 1.0m thick round section lining concrete is described here to allow for foundation temperature difference calculations.
As shown in fig. 3, the method for calculating the temperature-controlled anti-cracking parameter of the lining concrete with the circular cross section provided by the embodiment includes the following steps:
Collecting structural lining concrete temperature control basic data, including: the lining structure design data, in particular the temperature crack control design calculation requirement and the related temperature control calculation data, the concrete pouring construction data, and the temperature control analysis.
And 2, calculating the allowable foundation temperature difference of the lining concrete for pouring the circular section in each month by adopting a formula 1. According to the above data, H is 1.0m, R is 7.0m, L is 9.0m, C is 30MPa, E is 20GPa, and Ta is calculated according to equation 3, and the result is shown in table 4. The allowable foundation temperature difference results of concrete pouring lining for 1-12 months are shown in table 4.
TABLE 4 flood discharge tunnel 1.0m thick round section lining concrete allowable base temperature difference and allowable maximum temperature
And 3, analyzing and calculating the quasi-stable temperature of the concrete of the lining structure, and taking the lowest winter temperature in the tunnel as the quasi-stable temperature of the concrete of the lining structure. The minimum value is 16 c, i.e. the metastable temperature is 16 c, calculated from equation 3.
And 4, analyzing and calculating the allowable maximum temperature of lining concrete for pouring the circular section in each month, and calculating according to a formula 2. The results are shown in Table 3.
The circular section lining concrete is maintained according to the temperature control anti-cracking parameters obtained by calculation, no temperature crack exists through field inspection, and the temperature control anti-cracking obtains a good effect.
< example II > flood discharge tunnel pressure section 0.8m thick B-type lining concrete
A B-shaped lining structure with the pressure section of 0.8m and the thickness of the flood discharge tunnel is shown in figure 6, the circular cross section is provided with annular construction joints every 9m along the axial direction of the flood discharge tunnel, II-class surrounding rocks have the elastic modulus of 32 GPa. Pouring concrete by stages 2: the top arch is arranged at the front side and the bottom arch is arranged at the back side. Strength of concrete C9030, the 0.8m thick circular cross-section lining concrete is described here to allow for foundation temperature difference calculations.
As shown in fig. 3, the method for calculating the temperature-controlled anti-cracking parameter of the lining concrete with the circular cross section provided by the embodiment includes the following steps:
And 2, calculating the allowable foundation temperature difference of the lining concrete for pouring the circular section in each month by adopting a formula 1. According to the above data, H is 0.8m, R is 7.0m, L is 9.0m, C is 30MPa, E is 32GPa, TaCalculating pouring period (date calculated in month) value according to formula 3The results are shown in Table 5. The allowable foundation temperature difference results of concrete pouring lining for 1-12 months are shown in Table 5.
TABLE 5 flood discharge tunnel 0.8m thick circular section lining concrete allowable base temperature difference and allowable maximum temperature
And 3, analyzing and calculating the quasi-stable temperature of the concrete of the lining structure, and taking the lowest winter temperature in the tunnel as the quasi-stable temperature of the concrete of the lining structure. The minimum value is 16 c, i.e. the metastable temperature is 16 c, calculated from equation 3.
And 4, analyzing and calculating the allowable maximum temperature of lining concrete for pouring the circular section in each month, and calculating according to a formula 2. The results are shown in Table 4.
The circular section lining concrete is maintained according to the temperature control anti-cracking parameters obtained by calculation, no temperature crack exists through field inspection, and the temperature control anti-cracking obtains a good effect.
< comparative analysis > and design technical requirement table 3, comparison of finite element method simulation calculation result
In order to facilitate comprehensive comparison, the lining thickness is changed to be 1.5m, the elastic modulus of IV-type surrounding rock is changed to be 5GPa, the concrete strength is changed to be 40GPa, and the rest conditions are unchanged, and the temperature difference and the allowable maximum temperature of the circular section lining concrete foundation poured in each month are calculated according to the steps, and the results are shown in Table 6. In order to compare with the design technical requirements and the finite element method simulation calculation results, the month is consistent with the design technical requirements in the table 3 and the month is rounded, and the method calculation values, the design technical requirements and the finite element method simulation calculation results are summarized in the table 7.
TABLE 6 flood discharge tunnel 1.5m thick circular section lining concrete allowable foundation temperature difference and allowable maximum temperature
TABLE 7 methods for calculating allowable base temperature difference and allowable maximum temperature of concrete lining with circular cross section of different thickness
Table 7 the results show that:
(1) the allowable maximum temperature calculated by the three methods is consistent in the case of IV-type surrounding rocks with the thickness of 1.5m, and the design requirements (standard temperature difference) are higher than those of the simulation calculation value of the method and the finite element method in other cases;
(2) the method calculates the allowable highest temperature, and the allowable highest temperature is consistent with the finite element simulation calculation result under the conditions of different lining structure sizes, concrete strength, surrounding rock elastic modulus, pouring period and in-hole environment temperature change, because the method allows a basic temperature difference calculation formula to scientifically and comprehensively reflect the influence of the lining structure size, the concrete strength, the surrounding rock elastic modulus, the pouring period and in-hole environment temperature change on temperature control and crack prevention of the lining concrete;
(3) design requirements (strong constraint method) and design requirements (standard temperature difference) of reference dam recommended values do not comprehensively reflect influences of lining structure size, concrete strength and surrounding rock performance in actual engineering.
In summary, the example calculation and analysis shows that the method is simple in calculation formula, can comprehensively and reasonably reflect the influence of the size of the lining structure, the strength of concrete, the elastic modulus of surrounding rock, the pouring period and the change of the environmental temperature in the tunnel on temperature control and crack prevention of the lining concrete, can quickly calculate the allowable basic temperature difference and the allowable highest temperature of the concrete for pouring the circular section lining structure at any time period, is basically consistent with the simulation calculation recommended value of a finite element method, and can be completely used for temperature control design calculation of actual engineering, particularly for real-time quick design calculation of preliminary design and on-site construction period.
< third embodiment > temperature control and crack control system for lining concrete with circular cross section
The embodiment provides a system capable of automatically realizing the temperature control and anti-cracking parameter calculation method for the lining concrete with the circular cross section, and the system comprises the following steps: an input display unit, a storage unit, a calculation unit, a maintenance unit, and a control unit.
The input display part allows an operator to input collected data for temperature control of the circular cross-section lining concrete according to prompts, and can calculate the allowable basic temperature difference Delta T and the allowable maximum temperature [ T ] of the calculation part according to operation instructionsmaxAnd (6) displaying. For example, the input display unit can provide the allowable base temperature difference Δ T and the allowable maximum temperature [ T ] calculated by the calculation unit according to the operation commandmaxAnd displaying, and displaying maintenance measures executed by the maintenance department according to the operation instruction.
The storage part stores the input round section lining concrete temperature control data.
The calculation part calculates the allowable basic temperature difference delta T of the lining concrete of the side wall of the circular section by adopting the following formula based on the data for controlling the temperature of the lining concrete of the circular section:
△T＝4.47H-0.103R-0.1995L+0.0986C-0.053E+0.302Ta+11.945 (equation 1)
In the formula: h is the thickness of the lining structure, H0For lining structure side wall height, L is lining structure section length, C is lining concrete 90d design age strength grade, E is surrounding rock elastic modulus, TaThe temperature in the concrete pouring period is the temperature in the hole;
the calculation part also calculates the allowable maximum temperature (T) of the lining concrete of the circular section by adopting the following formula based on the data for temperature controlmax】：
【Tmax】＝Tmin+. DELTA T (formula 2)
In the formula, TminThe lowest temperature in winter in the tunnel;
the maintenance part is based on the allowable basic temperature difference Delta T and the allowable maximum temperature TmaxCorresponding maintenance measures are carried out, such as regulating and controlling the temperature and time of water cooling.
The control part is connected with the input display part, the storage part, the calculation part and the maintenance part in a communication way and controls the operation of the input display part, the storage part, the calculation part and the maintenance part.
The above embodiments are merely illustrative of the technical solutions of the present invention. The method and system for calculating the temperature-controlled anti-cracking parameters of the lining concrete with the circular cross section are not limited to the contents described in the above embodiments, but are subject to the scope defined by the claims. Any modification or supplement or equivalent replacement made by a person skilled in the art on the basis of this embodiment is within the scope of the invention as claimed in the claims.
Claims (10)
1. The method for calculating the temperature control anti-cracking parameters of the lining concrete with the circular section is characterized by comprising the following steps of:
step 1, obtaining data for temperature control of lining concrete with a circular section;
step 2, calculating the allowable foundation temperature difference Delta T of the lining concrete of the circular section:
△T＝4.47H-0.103R-0.1995L+0.0986C-0.053E+0.302Ta+11.945 (equation 1)
In the formula: h is lining structure thickness, R is lining structure inner radius, L is lining structure section length, C is lining concrete 90d design age strength grade, E is surrounding rock elastic modulus, T is lining concrete lengthaThe temperature in the concrete pouring period is shown as the temperature in the hole.
2. The temperature-control anti-cracking parameter calculation method for the lining concrete with the circular cross section according to claim 1, characterized by further comprising the following steps of:
step 3, calculating the allowable highest temperature [ T ] of lining concrete of the circular section according to the allowable basic temperature difference Delta Tmax】。
3. The temperature-control anti-cracking parameter calculation method for the lining concrete with the circular cross section as claimed in claim 2, characterized in that:
wherein, in the step 3,the allowable maximum temperature [ T ] is calculated using the following formulamax】
【Tmax】＝Tmin+. DELTA T (formula 2)
In the formula, TminThe lowest temperature in winter in the tunnel.
4. The temperature-control anti-cracking parameter calculation method for the lining concrete with the circular cross section according to claim 1, which is characterized by comprising the following steps of:
wherein, in the step 2, if the heat preservation of the closed opening is adopted in the construction period to ensure that the air temperature of the underground cavern is increased, T is carried outaAn elevated temperature of the air in the hole should be used.
5. The temperature-control anti-cracking parameter calculation method for the lining concrete with the circular cross section according to claim 1, which is characterized by comprising the following steps of:
wherein, the control processing device is adopted to execute the steps 1 and 2, so that an operator inputs temperature control data according to the prompt and calculates the allowable basic temperature difference Delta T.
6. The method for calculating the temperature-control anti-cracking parameter of the lining concrete with the circular cross section according to claim 2 or 3, which is characterized by comprising the following steps of:
wherein, a control processing device is adopted to execute the step 3, and the allowable highest temperature [ T ] of the lining concrete of the circular section is calculated according to the allowable basic temperature difference Delta Tmax】。
7. Circular section lining concrete control by temperature change crack control system, its characterized in that includes:
an input display part for the operator to input the collected data for controlling the temperature of the circular cross section lining concrete according to the prompt;
a storage unit for storing the input temperature control data;
a calculating part, based on the data for temperature control, calculating the allowable foundation temperature difference Delta T of the concrete lining of the side wall with the circular section by adopting the following formula:
△T＝4.47H-0.103R-0.1995L+0.0986C-0.053E+0.302Ta+11.945 (equation 1)
In the formula: h is lining structure thickness, R is lining structure inner radius, L is lining structure section length, C is lining concrete 90d design age strength grade, E is surrounding rock elastic modulus, T is lining concrete lengthaThe temperature in the concrete pouring period is the temperature in the hole;
a maintenance part for executing corresponding maintenance measures according to the allowable basic temperature difference Delta T; and
and the control part is in communication connection with the input display part, the storage part, the calculation part and the maintenance part and controls the operation of the input display part, the storage part, the calculation part and the maintenance part.
8. The temperature-control anti-cracking control system for the lining concrete with the circular cross section as claimed in claim 7, characterized in that:
wherein the calculation part further calculates the allowable maximum temperature [ T ] of the lining concrete with the circular cross section based on the data for temperature control by using the following formulamax】：
【Tmax】＝Tmin+. DELTA T (formula 2)
In the formula, TminThe lowest temperature in winter in the tunnel;
the maintenance part is based on the allowable basic temperature difference Delta T and the allowable maximum temperature [ TmaxCorresponding maintenance measures are performed.
9. The temperature-control anti-cracking control system for the lining concrete with the circular cross section as claimed in claim 8, characterized in that:
wherein the input display part also calculates the allowable basic temperature difference Delta T and the allowable maximum temperature [ T ] of the calculation part according to the operation instructionmaxAnd (6) displaying.
10. The temperature-control anti-cracking control system for the lining concrete with the circular cross section as claimed in claim 8, characterized in that:
and the input display part is also used for displaying the maintenance measures executed by the maintenance part according to the operation instructions.
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