CN109992833B - Temperature control anti-cracking tensile stress safety coefficient control design method for circular section lining concrete - Google Patents
Temperature control anti-cracking tensile stress safety coefficient control design method for circular section lining concrete Download PDFInfo
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Abstract
A temperature control anti-cracking tensile stress safety coefficient control design method for circular section lining concrete is characterized in that a temperature control anti-cracking target, an anti-cracking safety coefficient allowable value and a variable quantity of the circular section lining concrete are determined, the tensile stress and the age corresponding to the minimum anti-cracking safety coefficient in the construction period of the circular section lining concrete are calculated according to a formula, then the minimum anti-cracking safety coefficient is calculated, the method is applied to actual lining concrete construction, and can optimize and improve construction temperature control measures in real time aiming at the change of found problems, construction technologies and conditions in the pouring construction process to realize the temperature control anti-cracking target.
Description
Technical Field
The invention belongs to the technical field of temperature control and crack prevention of concrete, and relates to a temperature control and crack prevention tensile stress safety coefficient control design method for circular section lining concrete.
Background
In recent years, the construction of water conservancy and hydropower engineering is developed at a high speed, the scale and the section size of underground hydraulic engineering are increased more and more, and the environmental conditions such as geology and the like are more and more complicated. As the height of the dam is increased, the flow rate of the drained water is higher and higher, and the strength grade of the concrete is higher. The large-section high-strength underground hydraulic lining concrete generates a large number of cracks without any effective measures, and most of the cracks generate penetrating temperature cracks in the construction period.
Underground structural engineering works in a wet environment and a dry environment and a wet environment alternately for a long time, the safety of the engineering structure, the construction progress period, leakage and even infiltration damage caused by existence of harmful cracks, durability, service life, engineering cost and attractiveness are seriously influenced, and other diseases can be induced to occur and develop.
The existing design specifications generally lack clear and specific regulations on the control of the underground engineering lining concrete temperature cracks and the calculation method thereof, and have no clear temperature control standard. For example, the structural member required to be subjected to crack control in use is required to be subjected to crack resistance or crack width checking calculation according to the 'Hydraulic concrete Structure design Specification' at 4.1.2 (3), and the temperature stress calculation is required to be performed and the construction measures are preferably adopted to eliminate or reduce the temperature stress when the temperature change has a large influence on the building during the construction and operation of the building is specified to be 4.1.8. In the case of a reinforced concrete structural member which is allowed to develop cracks in use, the influence of crack development, which causes a reduction in the rigidity of the member, should be considered in calculating the temperature stress. But does not specify the calculation method of temperature stress and temperature control crack prevention. And as the design Specification of Hydraulic engineering Tunnel (DL/T5195-2004) only requires 11.2.6 items, the influence of temperature change, stress generated by concrete drying and expansion and grouting pressure on the lining is preferably solved by construction measures and constructional measures. Special studies should be made for the temperature stress generated in high-temperature areas.
The temperature control and crack prevention design calculation of part of underground engineering lining concrete (such as high-flow-rate flood discharging tunnels, power generation tunnel water diversion sections and the like) which requires crack control in use during construction is mainly carried out by adopting a finite element method at present. After the structural design is finished, a construction temperature control anti-cracking scheme and a field construction highest temperature control standard are provided through simulation calculation analysis of temperature and temperature stress of a large number of schemes. By doing so, the precision is higher, can optimize the construction temperature control scheme moreover. But the concrete mixing proportion and a large number of performance parameter tests need to be carried out firstly, and the test and the simulation calculation need to take more time; but also needs to spend more funds; the method can not be carried out when the construction mixing proportion is not determined and the performance parameters of the concrete are not obtained through tests; and the method is not suitable for the rapid adjustment of the scheme in the preliminary design stage and construction. Especially, the prior relevant specifications have no requirement value of anti-cracking safety coefficient of the temperature control anti-cracking design in the construction period, and the design specifications of dams are all referred when the temperature control anti-cracking design of hydraulic tunnel lining concrete is adopted.
Some design units also propose a maximum temperature control value (hereinafter referred to as a strong constraint method) by referring to the temperature control standard of concrete in a strong constraint area of the dam, and a temperature control construction scheme is established by the construction units. The construction unit generally calculates the highest temperature of the concrete of the lining structure according to the concrete mixing ratio, the transportation distance and mode, the air temperature and the like to the planned concrete mixing (whether to refrigerate or not and measures thereof) and the pouring construction temperature control (such as water cooling), and provides a construction scheme meeting the design standard. Firstly, the temperature control standard of dam concrete cannot be suitable for a thin-wall lining structure, and the influence of differences of concrete strength, surrounding rock performance, lining thickness, structure size and the like is not reflected; secondly, the error of the construction unit for calculating the highest temperature inside the lining concrete is large, and the value of a large number of coefficients is strong in man-made property; the temperature difference between the two aspects may cause the formulated construction schemes to be far apart, and the temperature crack control target is difficult to achieve effectively. In particular, the temperature stress was not calculated and analyzed.
The combination of the above conditions shows that the temperature control and crack prevention during the construction period of the lining concrete of the current underground engineering have no clear requirements and technical standards; a simple high-precision design method is not available, the finite element method takes more time and cost, and the method cannot be suitable for the quick adjustment of the preliminary design stage without concrete test results and the scheme in construction; the strong constraint method has larger error and can not calculate the temperature stress; it is difficult to effectively achieve the temperature crack control goal.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a control design method for the temperature control anti-cracking tensile stress safety coefficient of the lining concrete with the circular section, which can optimize and improve construction temperature control measures in real time aiming at the problems found and the changes of construction technology and conditions in the pouring construction process and realize the temperature control anti-cracking target.
In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a control design method for temperature control anti-cracking tensile stress safety coefficient of lining concrete with a circular section is used for calculating the temperature control anti-cracking tensile stress safety coefficient of the lining concrete in actual engineering and comprises the following steps:
s1, determining a temperature control anti-cracking target of lining concrete with a circular section;
s2, determining an allowable value of the crack-resistant safety coefficient of the lining concrete with the circular section;
s3, determining the variable quantity of lining concrete of the circular section;
s4, calculating the tensile stress when the minimum crack resistance safety coefficient of the circular section lining concrete occurs;
s5, calculating the age of the circular section lining concrete when the minimum crack resistance safety coefficient occurs;
and S6, calculating the minimum crack resistance safety coefficient of the circular section lining concrete in the construction period according to the parameters determined in the S1-S5.
The temperature control anti-cracking target and the anti-cracking safety coefficient allowable value of the circular section lining concrete are determined according to the design specification, the grade of the lining structure, the damage of the crack in the operation period, the safety and the anti-seepage performance.
The calculation formula of the tensile stress when the minimum crack resistance safety coefficient of the circular section lining concrete occurs is sigma =0.274H +0.12R +0.044C +0.056E-0.0017E 2 +0.219T 0 +0.069T g -0.157T a +0.539△T-0.0007CT g +0.0318HE-0.0039T 0 T g -0.0145T a △T-1.9131 (1)
In the formula: sigma is the lining concrete construction period K min Tensile stress (MPa) at the time of occurrence;
h is the thickness (m) of the lining concrete structure;
r is the inner radius (m) of the lining concrete structure;
e-surrounding rock deformation modulus (GPa);
c, strength grade (MPa) of lining concrete designed according to the age of 90 days;
T 0 -lining concrete pouring temperature (° c);
T a -air temperature in the tunnel (c) during lining concrete casting construction;
T min the winter lowest temperature (DEG C) in the hole;
T g ＝35-T w temperature effect value (DEG C) representing the cooling with and without water, and T is taken when cooling without water w =35 ℃ calculation of T g =0; when cooling with water, T w The water temperature (DEG C);
△T＝T a -T min representing the temperature T in the hole during pouring a With the lowest temperature T in the hole in winter min A difference of (d);
replacing the thickness and the inner radius of the circular section lining structure, the concrete strength grade, the surrounding rock deformation modulus, the pouring temperature, the air temperature in the tunnel during pouring construction, the annual variation of the air temperature in the tunnel, whether water cooling is conducted or not and the water temperature into the tunnel (1), thereby obtaining the tensile stress (MPa) corresponding to the minimum crack resistance safety coefficient of the lining concrete during the construction period of pouring the circular section lining concrete at the period.
The calculation formula of the age when the circular section lining concrete minimum anti-cracking safety coefficient is
d＝365-(t 1 -t 0 )+12.77H+0.089R-0.0148C+0.0045E-1.33T 0 +0.53Tg-0.88Ta
-0.045(t 1 -t 0 )-0.0007(t 1 -t 0 ) 2 -0.5987△T+0.024Ta△T-0.58HT 0 -0.07H Tg
+0.078H(t 1 -t 0 )-0.039T 0 Tg-24.38
In the formula: t is t 0 Representing the days of the lowest temperature appearance time in the tunnel from 1 month to 1 day;
t 1 representing the number of days from the casting date of 1 month and 1 day.
The calculation formula of the minimum crack resistance safety coefficient of the circular section lining concrete is K min ＝(E×ε)/σ(3)
In the formula: k is min The minimum crack resistance safety factor is set in the construction period of the lining concrete;
e is the deformation modulus (GPa) of the lining concrete age d;
epsilon is the ultimate tensile value of lining concrete age d.
When the strength grade designed for the 28-day age is adopted in the lining concrete with the circular section, the strength grade designed for the 90-day age needs to be converted according to the specification.
The circular section lining concrete adopts a curtain to preserve heat, the air temperature of the underground cavern is increased, and then Ta, tmin and Delta T adopt the increased air temperature in the cavern.
When the thickness of the lining concrete with the circular cross section is smaller, the water-passing and cooling water pipes are arranged in a single row.
A temperature control anti-cracking tensile stress safety coefficient control design method for circular section lining concrete is characterized in that a temperature control anti-cracking target, an anti-cracking safety coefficient allowable value and a variable quantity of the circular section lining concrete are determined, the tensile stress and the age corresponding to the minimum anti-cracking safety coefficient in the construction period of the circular section lining concrete are calculated according to a formula, then the minimum anti-cracking safety coefficient is calculated, the method is applied to actual lining concrete construction, and can optimize and improve construction temperature control measures in real time aiming at the change of found problems, construction technologies and conditions in the pouring construction process to realize the temperature control anti-cracking target.
Drawings
The invention is further illustrated with reference to the following figures and examples:
FIG. 1 is a schematic representation of the present invention lining a concrete crack.
Fig. 2 is a schematic structural view of the round cross-section lining concrete of the present invention.
FIG. 3 is a schematic diagram of the three-dimensional finite element structure of FIG. 2.
FIG. 4 is a graph showing the annual temperature change of the cavern of the spillway tunnel in the practical application of the invention.
Detailed Description
As shown in fig. 1 to 4, a method for controlling and designing a temperature-controlled anti-cracking tensile stress safety coefficient of a lining concrete with a circular cross section is used for calculating the temperature-controlled anti-cracking tensile stress safety coefficient of the lining concrete in actual engineering, and comprises the following steps:
s1, determining a temperature control anti-cracking target of lining concrete with a circular section;
preferably, the thickness and the inner radius of the round section lining, the concrete strength grade, the deformation modulus of the geological condition surrounding rock, the annual change rule of the air temperature in the tunnel, the annual change rule of the water temperature, the concrete, the pouring temperature, the air temperature in the tunnel during pouring construction and the water cooling working condition are recorded according to engineering actual data.
S2, determining an allowable value of the crack-resistant safety coefficient of the lining concrete with the circular section;
preferentially, the underground hydraulic circular section lining concrete temperature control anti-cracking grading target and the anti-cracking safety coefficient allowable value
【K】 Selected according to the following table.
Table 1, the temperature control anti-cracking grading target and the allowable value of anti-cracking safety coefficient of the circular section lining concrete (K).
S3, determining the variable quantity of lining concrete of the circular section;
preferably, in different temperature control anti-cracking design stages, the design parameters which are related to temperature control anti-cracking and can be changed in the stage under the condition of meeting the standard requirements are analyzed; in the structural design stage, the lining thickness and the concrete strength are main variable; in the construction stage, the pouring temperature, the water cooling and the water temperature thereof, and the heat preservation of the closed hole in winter are mainly variable; the winter closed hole heat preservation is an economic and effective measure which must be taken, and the proposed construction measure scheme mainly comprises the combination of pouring temperature, water cooling and water temperature;
preferably, the winter minimum temperature is increased.
S4, calculating the tensile stress of the circular section lining concrete when the minimum crack resistance safety coefficient occurs;
s5, calculating the age of the circular section lining concrete when the minimum crack resistance safety coefficient is reached;
and S6, calculating the minimum crack resistance safety coefficient of the circular section lining concrete in the construction period according to the parameters determined in the S1-S5.
In the preferred scheme, the temperature control anti-cracking target and the anti-cracking safety coefficient allowable value of the circular section lining concrete are determined according to the design specification, the grade of the lining structure, the damage of the crack in the operation period, the safety and the anti-seepage performance.
In the preferred scheme, the calculation formula of the tensile stress when the minimum crack resistance safety coefficient of the circular section lining concrete occurs is sigma =0.274H +0.12R +0.044C +0.056E-0.0017E 2 +0.219T 0 +0.069T g -0.157T a +0.539△T-0.0007CT g +0.0318HE-0.0039T 0 T g -0.0145T a △T-1.9131 (1)
In the formula: sigma is the lining concrete construction period K min Tensile stress (MPa) at the time of occurrence;
h is the thickness (m) of the lining concrete structure;
r is the inner radius (m) of the lining concrete structure;
e-surrounding rock deformation modulus (GPa);
c, lining concrete according to the strength grade (MPa) designed by the age of 90 days;
T 0 -lining concrete pouring temperature (° c);
T a -air temperature in the tunnel (c) during lining concrete casting construction;
T min the winter lowest temperature (DEG C) in the hole;
T g ＝35-T w temperature effect value (DEG C) representing the cooling with and without water, and T is taken when cooling without water w =35 ℃ calculation of T g =0; when cooling with water, T w The water temperature (DEG C);
△T＝T a -T min representing the temperature T in the hole during casting a And the lowest temperature T in the winter tunnel min A difference of (d);
substituting the thickness and the inner radius of a circular section lining structure, the strength grade of concrete, the deformation modulus of surrounding rocks, the pouring temperature, the air temperature in a hole during pouring construction, the annual amplitude of the air temperature in the hole, whether water cooling is provided or not and the water temperature into the formula (1), thereby obtaining the tensile stress (MPa) corresponding to the minimum crack resistance safety factor of the lining concrete during the construction period of pouring the circular section lining concrete in the period.
In the preferable scheme, the calculation formula of the age when the circular section lining concrete has the minimum anti-cracking safety coefficient is as follows
d＝365-(t 1 -t 0 )+12.77H+0.089R-0.0148C+0.0045E-1.33T 0 +0.53Tg-0.88Ta-0.045(t 1 -t 0 )-0.0007(t 1 -t 0 ) 2 -0.5987△T+0.024Ta△T-0.58HT 0 -0.07H Tg+0.078H(t 1 -t 0 )-0.039T 0 Tg-24.38 (2)
In the formula: t is t 0 Representing the days of the lowest temperature appearance time in the tunnel from 1 month to 1 day;
t 1 representing the number of days from the casting date of 1 month and 1 day.
In the preferred scheme, the calculation formula of the minimum crack resistance safety coefficient of the circular section lining concrete is K min ＝(E×ε)/σ (3)
In the formula: k min The minimum crack resistance safety factor is set in the construction period of the lining concrete;
e is the deformation modulus (GPa) of the lining concrete at age d;
ε is the ultimate tensile value of lining concrete age d.
In a preferred embodiment, when the strength grade designed for 28-day-old lining concrete is adopted, the strength grade designed for 90-day-old lining concrete needs to be converted according to specifications.
In the preferred scheme, the circular section lining concrete adopts a curtain to preserve heat, the air temperature of the underground cavern is increased, and then T is obtained a 、T min And delta T is the increased temperature of the air in the hole.
In a preferable scheme, when the thickness of the lining concrete with the circular cross section is smaller, the water-passing cooling water pipes are arranged in a single row.
In the following practical application, various possible situations are calculated on the basis of the structure of the pressure section circular section of the flood discharge tunnel and related parameters thereof and by combining similar projects. The basic parameters and calculation schemes are shown in Table 2, and each scheme is most suitable for lining concrete in the construction periodSmall crack resistance safety factor K min The results of the tensile stress σ and age d calculations are shown in Table 2.
TABLE 2 calculation scheme of temperature stress of lining concrete with circular cross section and safety coefficient Kmin of minimum crack resistance
For the round section lining concrete construction period K of Table 2 min The tensile stress sigma and the age d at the time of occurrence are subjected to statistical analysis, and the formulas (1) and (2) are obtained. Since sigma, E and epsilon are K min Tensile stress at age, modulus of deformation, ultimate tensile value, K calculated by equation (3) min Namely the minimum anti-cracking safety coefficient of the lining concrete.
The following are examples according to practical engineering applications:
(1) Determining basic parameters
The spillway tunnel is the main building (level I), the pressure section is a circular section, and the lining and surrounding rock categories are listed in Table 3. The inner diameter of the lining section is 7.5m, and the designed strength grade C of lining concrete 90 And 40, the length of the structural section seam is 9m. According to the measured data in the initial excavation and the data provided by the design institute, the average temperature of the design unit for many years is 23.5 ℃, and the annual variation of the temperature is 3.0 DEG CAnd calculating by using a cosine formula (2) according to the specification. The construction conditions and the bidding documents can provide the refrigerated commercial concrete with the temperature of 14 ℃ at the machine outlet, and the pouring temperature is 18 ℃. Two kinds of water can be provided for water cooling, namely, cooling water at 12 ℃; secondly, normal temperature tap water, 22 ℃ in summer and 12 ℃ in winter.
In the formula: t is a unit of a The temperature of the air at the time tau in the hole;
τ is the time (day) 1 day from 1 month;
τ 0 taking tau as the time (day) from the highest temperature in the tunnel to 1 month and 1 day 0 =210 days.
TABLE 3 flood discharge Lining and surrounding rock Classification
The mechanical parameters of the lining concrete are listed in table 4.
TABLE 4 mechanical parameters of lining concrete
The function expression of the elastic modulus fitting formula is
In the formula: τ -age, day;
a. b, c-formula coefficients, listed in Table 5.
TABLE 5 modulus of elasticity fitting formula coefficients
The function expression of the ultimate stretching value fitting formula is
t t0 ε(τ)＝ετ/(s+τ) (6)
In the formula, tau is age, day;
t0 epsilon, S-formula coefficient, using the data in Table 6.
TABLE 6 coefficient of ultimate stretch fit
The design institute determines that the pressurized-section lining concrete of the flood discharge tunnel adopts C according to related design specifications, concrete mix proportion optimization and performance test thereof and finite element method calculation results (the temperature in the tunnel is calculated by adopting a cosine function formula 2) 90 And 40, the length of the pouring section is 9m, the pouring temperature of the bottom arch with the pressing section is not more than 18 ℃, the highest temperature is not more than 37 ℃, the pouring temperature of the top arch with the pressing section is not more than 18 ℃, and the highest temperature is not more than 38 ℃. In winter construction, natural warehousing concrete can be adopted for pouring under the condition that the concrete pouring temperature can be lower than 18 ℃. The following scheme is recommended during summer construction: the pressure section is pressed, the concrete pouring temperature is 18 ℃, the distance between water pipes is 1.0m, the length of the water pipes is 100m, and the cooling water flow is 2.0m 3 And h, cooling the water at 20 ℃ (normal temperature water), and introducing water for cooling for 15 days when the concrete is poured.
(3) Temperature control and crack control construction scheme for lining concrete
According to the design requirements, the construction scheme plans that the whole flood discharge tunnel is basically poured according to 9m bins, and the temperature control anti-cracking scheme for the lining concrete construction is as follows:
(1) the pre-cooled concrete is adopted, and the temperature of the outlet of the machine reaches 12-14 ℃.
(2) The temperature rise in the concrete transportation and pouring process is reduced. The transportation capacity is increased, and the pouring blank on the concrete bin surface can be effectively covered in time; establish movable canvas sunshade at concrete transport vehicle carriage top, install foaming heat preservation device etc. on concrete transport vehicle box.
(3) And (4) strengthening management and accelerating construction speed. Through strengthening management, waiting time for unloading or unloading and warehousing time is reduced, repeated material transfer and warehousing and the like are avoided, and concrete pouring and covering time is not more than 1h.
(4) Rationally arrange concrete construction progress. The concrete pouring time is arranged to be carried out in low-temperature seasons and at low morning and evening temperatures as much as possible. Preparation before pouring is carried out in high-temperature time periods in the daytime, and pouring is carried out as much as possible from 16 pm to 10 am of the next day.
(5) And (4) air conditioning in the bin. The steel mould trolley is provided with an air conditioner for summer construction in the bin, so that the pouring environment temperature in the bin is reduced, the temperature control is facilitated, and the heatstroke prevention and cooling effects can be achieved.
(6) And (5) surface maintenance. After the concrete is demoulded, the running water maintenance is started, a plastic pipe with the diameter of 35mm is adopted, small holes with the diameter of about 1mm are drilled every 20-30 cm, the small holes are hung on the template or the exposed reinforcing steel bar heads, and the water flow is about 15L/min. Uninterrupted flowing water curing is carried out in daytime, interrupted flowing water curing is carried out at night (20: 00-6: 00), namely flowing water is maintained for 1h, the water is kept moist for 1h, uninterrupted curing is carried out when the temperature exceeds 25 ℃, and the curing time of the pressure section, the side arch and the non-pressure section is not less than 28d.
(7) And (5) introducing water for cooling. The flow rate of the cooling water is 35L/min, and the difference between the concrete temperature and the water temperature is not more than 22 ℃. The cooling water pipe adopts the PE pipe, is on a parallel with the water flow direction and snakelike arranges in the middle part of every pouring block, and single water pipe length is not more than 100m, and perpendicular interval is 1.0m. The tail of the dragon falling from the right bank is firstly introduced with cooling water for 48 hours (about 14 to 20 ℃) in high-temperature seasons, and then is generally heated in 7 days; the cold season is usually warm water.
(8) Concrete is specially heat-insulating in winter. In winter, the exposed surface of the concrete is covered by the heat-insulating material with good heat-insulating effect, so that cracks are prevented from being generated on the surface of the concrete. The tunnel portal can adopt a door curtain hanging mode, and cold air is prevented from being poured into the tunnel to cause concrete surface cracks.
(9) Shortening the shift time. The field shift system is implemented, so that equipment operators have to shift shifts on the field, and the shift time cannot exceed 30min; the pouring can not be stopped when eating, the eating must be staggered in batches, and the continuity of the concrete pouring in the bin needs to be ensured.
Reinforced concrete temperature measurement. In order to verify whether the temperature of the concrete in the construction period meets the temperature control requirement, a resistance thermometer or a thermocouple pre-embedded in the concrete is adopted to measure the temperature of the concrete, and the result is analyzed; in the concrete pouring process, measuring the outlet temperature of the concrete, the pouring temperature of the concrete and the air temperature every 4h, and recording; and in the temperature measuring process, the condition exceeding the temperature control standard is found and reported in time.
(4) Temperature observation result of lining concrete
Statistical analysis is carried out on the temperature control results of the pressure section lining concrete of the flood discharge tunnels on the left bank and the right bank and the overtemperature condition of the pressure section lining concrete, and the results are listed in tables 7-10.
TABLE 7 statistics table for internal highest temperature of lining concrete of flood discharge tunnel in 2010
Table 8 statistical table of concrete placement temperature for lining of flood discharging tunnel on left and right banks in 2010
TABLE 9 2011 statistical table for internal highest temperature of lining concrete of flood discharging tunnel at left bank and right bank
Table 10 2011 statistical table for concrete pouring temperature of lining of flood discharging tunnel on left bank and right bank
The observation result of the internal temperature of the concrete shows that: compared with the design standard, the casting temperature overtemperature phenomenon of the left bank and the right bank in 2010 and 2011 is respectively 56.6% and 13.33%; in addition, the water temperature for water cooling also generally exceeds the design standard; therefore, the maximum temperature also has a certain overtemperature phenomenon, which is 45.28% and 16.67%, respectively.
(5) Lining concrete crack conditions
The concrete cracks are lined on the pressure section round section of the flood discharge tunnel, the bottom arch concrete has no cracks, and the statistics of the cracks of the side top arch concrete are listed in table 11.
TABLE 11 Overall situation of pressure-section circular cross-section lining concrete cracks of left and right bank flood discharge tunnels
| Location of a body part | Total number of bins | Number of cracked bins | Ratio of | Total number of cracks | Remarks for note |
| 1# pressure section side top arch | 66 | 57 | 0.86 | 146 | Left bank |
| 2# pressure section side top arch | 55 | 45 | 0.82 | 134 | Left bank |
| 3# pressing segment side top arch | 67 | 49 | 0.73 | 90 | Right bank |
| 4# pressing segment side top arch | 83 | 54 | 0.65 | 93 | Right bank |
According to the characteristics of the pressure section structure of the flood discharge tunnel, the construction process of lining concrete and the statistical condition of cracks of the surface 11, the following knowledge can be obtained through comprehensive analysis:
(a) The pressure section side top arch lining concrete has more cracks, and the bottom plate has no cracks. The estimation is related to the fact that the dimension of the side wall (side arch) is larger than that of the bottom plate, and the maintenance condition of the bottom plate is better. The result is consistent with the finite element method simulation calculation conclusion. Therefore, the temperature control and crack prevention of similar large tunnel lining concrete should be put on the side arch in the future. This is also the reason why the above design calculation formula is performed only on the dome arch.
(b) Compared with flood discharging tunnels on the two banks, the left bank 1# and the right bank 2# have more cracks than the right bank 3# and the right bank 4# in lining concrete, and are related to the fact that the maximum temperature and the overtemperature proportion of the lining concrete on the left bank are large (including the influence of high water temperature of water-through cooling water).
(c) According to the details of the general investigation of the cracks, the harder the surrounding rock, the more complete the temperature cracks. The pressure sections of the flood discharge tunnel are E1 type linings of II type surrounding rock areas with hard and complete surrounding rocks, and the pressure sections are main generation areas of temperature cracks although the thickness of the linings is small; the lining concrete with large thickness in the IV-type surrounding rock area generally has few temperature cracks.
(6) Finite element method simulation calculation result
The design technical requirements are provided according to the simulation calculation result of the finite element method in the design phase. In addition, table 1 also lists a number of finite element method simulation calculations. Such as: class II surrounding rock area 1.0m thick lining is poured 8 months and 1 day in summer, and K of calculation scheme 49 is designed in the stage of pouring at 16 ℃ and water cooling at 16 DEG C min ＝1.88，K min Tensile stress at occurrence σ =2.06mpa min Age at occurrence d =31 days; k of 18 ℃ pouring +16 ℃ water cooling calculation scheme 45 in construction stage (actual construction state) min ＝1.16，K min In-time tensile stress sigma max ＝4.64MPa，K min Age of onset d =189 days; k of calculation scheme 5 of pouring at 16 ℃ and water cooling at 16 DEG C min ＝1.22，K min Tensile stress at occurrence σ max ＝4.4MPa，K min Age d =189 days of occurrence. III 2 type surrounding rock area E3 type 1.0m thickness lining is poured 8 months and 1 day in summer, and in the construction stage, pouring is carried out at 16 ℃ and water cooling is carried out at 16 ℃ in the K of the calculation scheme 21 min ＝1.41，K min When occurred σ =3.8mpa min Age d =189 days of occurrence.
Example 1 flood discharge Tunnel with pressure section type II surrounding rock zone E1 type 1.0m thick lining
The lining with the thickness of 1.0m in the II-type surrounding rock area is a structural section with the largest difficulty in temperature control and crack prevention in the circular section of the whole flood discharge tunnel pressure section.
(1) Collecting and calculating temperature control anti-cracking data of lining structure
Lining structure design data, lining thickness, inner radius and concrete strength grade; environmental data, deformation modulus of surrounding rock under geological conditions, annual change rule of air temperature in the tunnel and annual change rule of water temperature; etc. as described above.
(2) Analyzing and determining temperature control anti-cracking target and anti-cracking safety coefficient allowable value (K)
The stream luodie flood discharging tunnel is a first-level building, the flow rate is high, the damage of cracks in the operation period is large, similar engineering experience is referred, and according to the table 1, the temperature control anti-cracking target of the lining concrete is subjected to level 1 anti-cracking, and the allowable value (K) of the anti-cracking safety coefficient is 1.6.
(3) Design stage temperature control anti-cracking measure scheme design
(3.1) variable quantity analysis and establishment of temperature control and anti-cracking construction measure scheme for lining concrete
Because the lining thickness and the concrete strength grade are determined, the variable quantity is only the pouring temperature and the water temperature of the water cooling. For 8 months of pouring in summer, the bidding document can provide 14 ℃ of refrigerated commercial concrete at the machine outlet, and the pouring temperature is 18 ℃. According to construction conditions, 3 temperature control schemes of pouring temperature of 18 ℃, non-water cooling, 16 ℃ refrigeration water cooling and 22 ℃ normal temperature water cooling are planned.
(3.2) calculating the construction period K of each scheme lining concrete min A tensile stress σ occurs. The values of σ calculated by substituting the above parameters into equation (1) are shown in Table 12.
(3.3) calculating the construction period K of concrete lining in each scheme min Age d of onset. The d values calculated by substituting each proposed temperature control measure scheme for formula (2) are shown in Table 12.
(3.4) calculating the minimum anti-cracking safety coefficient K of each scheme in the construction period of lining concrete min . Substituting each planned temperature control measure scheme and concrete performance parameters into formula (3) to calculate K min The values are given in Table 12.
Design calculation of temperature control anti-cracking measure scheme in table 12 E1 type 1.0m thickness lining design stage
| Scheme(s) | σ ( MPa ) | d | K min |
| Pouring at 18 ℃ without water cooling | 2.67 | 200.48 | 1.44 |
| Pouring at 18 deg.C, cooling with 16 deg.C water | 2.12 | 195.89 | 1.76 |
| Pouring at 18 deg.C, and cooling with 22 deg.C water | 2.29 | 197.34 | 1.64 |
(3.5) in calculating K min On the premise of being more than or equal to K, the measure scheme is optimized according to the principle of simplicity, practicability and economy. According to the calculation results of 3 schemes, a 22 ℃ water cooling scheme K is adopted min And the product can meet the requirement, and is most economical, simple and practical. Therefore, construction is recommended.
(4) Scheme design for real-time temperature control and crack prevention measures in construction process
In construction, because the tunnel excavation is communicated with the outside, the air temperature in the tunnel rapidly drops to approach the change of the outside air temperature. In 2009 from 10 to 2012 from 11, the temperature measurement was performed 300 times in total for the spillway tunnel (left and right banks), and the results are collectively shown in fig. 4. With day 1 of 2010 as the date axis for day one. Wherein the abscissa is time (days); the ordinate is temperature (. Degree. C.). Fitting cosine function by least square method
In the formula: t is a Temperature in hole (. Degree. C.);
τ is the time (day) of 1 day from 1 month.
Due to the temperature change in the tunnel, a temperature control measure scheme must be redesigned in real time in the construction process.
And (3) according to the design method, pouring construction is carried out in 8 months and 1 day in summer, and the temperature T in the hole is calculated according to a formula (7) a At 25.99 ℃, the 16 ℃ water cooling under the 16 ℃ pouring condition, the 8 ℃ water cooling and the 16 ℃ water cooling under the 18 ℃ pouring condition are calculated, and the reinforced heat preservation enables the lowest temperature in winter in the tunnel to be increased to 14 ℃ (the highest temperature in summer is 26 ℃) + the 18 ℃ pouring + the 8 ℃ water cooling, and the total of 4 schemes are carried out. The results of substituting the above calculations are shown in Table 13.
Real-time temperature control anti-cracking measure scheme design in table 13 E1 type 1.0m thickness lining construction process
According to the results of Table 13, K of 18 ℃ pouring, 8 ℃ water cooling, 14 ℃ heat preservation (namely strictly sealing the opening in winter and increasing the lowest temperature in winter in the hole to 14 ℃) is poured min And (4) the steel is set to be 1.59 to be 1.6, and construction is recommended.
In actual construction, a scheme of pouring at 18 ℃ and water cooling at 14-20 ℃ is adopted. The patent method calculates K of a scheme of pouring at 18 ℃ and introducing water cooling at 16 DEG C min =1.39, less than 1.6 still having a risk of cracking.
Example 2 flood discharge Tunnel with pressure section round section III 2 type surrounding rock zone E3 type lining
(1) The basic data are the same as above. In order to reduce space, summer temperature control calculation results in a design stage and a construction real-time control stage are only briefly introduced.
(2) Analyzing and determining temperature control anti-cracking target and anti-cracking safety coefficient allowable value (K)
The stream luo-ferry flood discharging tunnel is a first-level building, has high flow speed and large damage of cracks in the operation period, and is lined with concrete according to a table 1 by referring to similar engineering experiences, wherein the target level 1 is crack prevention, and the allowable value (K) of the crack prevention safety coefficient is 1.6.
(3) Design stage temperature control anti-cracking scheme
And according to the construction conditions, 3 temperature control schemes of cooling without water at the casting temperature of 18 ℃, cooling with water at the temperature of 16 ℃ and cooling with water at the temperature of 16 ℃ for casting and cooling with water at the temperature of 16 ℃ are also planned.
In the design stage, the air temperature in the tunnel is calculated to be 25 ℃ in the casting period of 8 months and 1 day according to the formula (8). The results of the calculations using the 3 proposed temperature control schemes and the above parameters are entered into the above equations are shown in Table 14.
Design calculation of temperature control anti-cracking measure scheme in table 14 E3 type 1.0m thickness lining design stage
K according to Table 14,3 protocols min The pouring temperature is more than or equal to K, and a scheme of pouring water-blocking cooling at 18 ℃ is recommended according to the simple, practical and economic principle.
(4) Construction real-time control stage
Pouring construction is carried out 8 months and 1 day in summer, and the temperature T in the tunnel is calculated by the formula (7) a The temperature was 25.99 ℃. And similarly, calculating 4 schemes of no water cooling, 16 ℃ refrigerating water cooling, 16 ℃ pouring, 16 ℃ refrigerating water cooling, and reinforced heat preservation, wherein the lowest temperature in winter in the tunnel is increased to 14 ℃ (26 ℃ highest temperature in summer), 16 ℃ pouring, 16 ℃ water cooling. The results obtained by substituting the above calculations are shown in Table 15.
Real-time temperature control anti-cracking measure scheme design in table 15 E3 type 1.0m thickness lining construction process
K according to Table 15,3 Water-Cooling protocols min Not less than K, the scheme of pouring at 18 ℃ and cooling by introducing cooling water at 16 ℃ is recommended according to the simple, practical and economic principle, and K is min ＝1.59≈1.6。
In actual construction, a scheme of pouring at 18 ℃ and water cooling at 14-20 ℃ is adopted. The patent method calculates K of a scheme of pouring at 18 ℃ and introducing water cooling at 16 DEG C min And the product has the following formula of 1.59 ≈ 1.6, and meets the requirement. In actual construction, both the pouring temperature and the water cooling temperature are overtemperature (tables 7-10), and the crack resistance safety coefficient is less than 1.6, so that the lining concrete has possibility of cracks in actual engineering.
4. Comparative analysis
And comparing with the finite element method calculation result, and performing calculation precision analysis. K of calculation scheme 45 of lining with thickness of 1.0m in class II surrounding rock area being poured 8 months and 1 day in summer, and pouring at 18 ℃ and water cooling at 16 ℃ in construction stage (actual construction state) min ＝1.16，K min The occurring tensile stress sigma =4.64MPa min Age of onset d =189 days; formula (1) calculates σ =3.6MPa, error-22.4%, formula (2) calculates d =195.35 days, error 3%, formula (3) calculates K min =1.39, error 19.8%. K of calculation scheme 5 of 16 ℃ pouring +16 ℃ water cooling min ＝1.22，K min Tensile stress at onset σ =4.4mpa min Age d =189 days of occurrence; formula (1) calculates σ =3.31MPa with an error of-24.8%, formula (2) calculates d =200.65 days with an error of 6%, and formula (3) calculates K min =1.52, error 24.5%. III 2 type surrounding rock area E3 type 1.0m thickness lining is poured 8 months and 1 day in summer, and in the construction stage, pouring is carried out at 16 ℃ and water cooling is carried out at 16 ℃ in the K of the calculation scheme 21 min ＝1.41，K min When occurred σ =3.8mpa min Age d =189 days of occurrence; the formula (1) calculates σ =2.86MPa with an error of-24.7%, the formula (2) calculates d =200.55 days with an error of 6%, and the formula (3) calculates K min =1.59, error 12.7%. And comparing with the temperature crack inspection result. The calculation result of the method of the invention shows that the actual construction of the lining concrete with the thickness of 1.0m in the II-type surrounding rock areaScheme K min =1.39, there is a certain risk of cracking; k of actual construction scheme of lining concrete with thickness of 1.0m in III 2 type surrounding rock area min However, the actual temperature control result has an overtemperature phenomenon, and therefore, there is a certain risk of cracking. But obviously, the cracking resistance safety coefficient of the lining of the class II surrounding rock area is much smaller than that of the class III 2 surrounding rock area, so that the concrete cracks are more. And (c) the conclusion that the harder the surrounding rock, the more complete the temperature cracks is consistent with the temperature crack inspection result shown in the table 6.
To sum up, the calculation and analysis of the examples show that the method has a simple calculation formula, and can comprehensively and reasonably reflect the influences of main factors such as the thickness and the inner radius of the lining structure, the strength grade of concrete, the performance (deformation modulus) of surrounding rock, the pouring temperature, the annual change of the air temperature in the tunnel, the air temperature in the tunnel during the pouring period, whether water cooling is conducted or not, the water temperature and the like. The maximum temperature tensile stress and the crack resistance safety coefficient of the concrete lining of the circular section structure poured at any time period can be rapidly calculated, the calculation error is small, and the designed temperature control measure scheme is consistent with the actual temperature control and crack resistance effects on site. The method can be completely used for the design of temperature control anti-cracking measures in actual engineering, especially for preliminary design and real-time rapid design in field construction period.
The above-described embodiments are merely preferred technical solutions of the present invention, and should not be construed as limiting the present invention, and the embodiments and features in the embodiments in the present application may be arbitrarily combined with each other without conflict. The scope of the present invention is defined by the claims, and is intended to include equivalents of the features of the claims. I.e., equivalent alterations and modifications within the scope hereof, are also intended to be within the scope of the invention.
Claims (5)
1. A control design method for the temperature control anti-cracking tensile stress safety coefficient of lining concrete with a circular section is used for calculating the temperature control anti-cracking tensile stress safety coefficient of the lining concrete in actual engineering and is characterized by comprising the following steps:
s1, determining a temperature control anti-cracking target of lining concrete with a circular section;
s2, determining an allowable value of the crack resistance safety coefficient of the lining concrete with the circular section;
s3, determining the variable quantity of lining concrete of the circular section;
s4, calculating the tensile stress of the circular section lining concrete when the minimum crack resistance safety coefficient occurs;
s5, calculating the age of the circular section lining concrete when the minimum crack resistance safety coefficient occurs;
s6, calculating the minimum crack resistance safety coefficient of the circular section lining concrete in the construction period according to the parameters determined in the S1-S5;
the calculation formula of the tensile stress when the minimum crack resistance safety coefficient of the circular section lining concrete occurs is sigma =0.274H +0.12R +0.044C +0.056E-0.0017E 2 +0.219T 0 +0.069T g -0.157T a +0.539△T-0.0007CT g +0.0318HE-0.0039T 0 T g -0.0145T a Δ T-1.9131 (1) wherein: sigma is the lining concrete construction period K min Tensile stress in the event;
h is the thickness of the lining concrete structure;
r is the inner radius of the lining concrete structure;
e, surrounding rock deformation modulus;
c, lining concrete according to the strength grade designed by the age of 90 days;
T 0 -lining concrete casting temperature;
T a -air temperature in the tunnel during the concreting construction of the lining;
T min the lowest winter temperature in the hole;
T g ＝35-T w temperature effect values representing the case of cooling with and without water, taking T when there is no water cooling w =35 ℃ calculation of T g =0; when cooling with water, T w The water temperature is the water passing temperature;
△T＝T a -T min representing the temperature T in the hole during casting a And the lowest temperature T in the winter tunnel min A difference of (d);
substituting (1) the thickness and the inner radius of a circular section lining structure, the strength grade of concrete, the deformation modulus of surrounding rocks, the pouring temperature, the air temperature in a hole during pouring construction, the annual amplitude of the air temperature in the hole, whether water cooling is carried out or not and the water temperature of the water cooling, so as to obtain the tensile stress when the minimum crack resistance safety coefficient of the lining concrete occurs in the construction period corresponding to the pouring of the circular section lining concrete in the construction period;
the calculation formula of the age when the circular section lining concrete minimum anti-cracking safety coefficient is
d＝365-(t 1 -t 0 )+12.77H+0.089R-0.0148C+0.0045E-1.33T 0 +0.53Tg-0.88Ta-0.045(t 1 -t 0 )-0.0007(t 1 -t 0 ) 2 -0.5987△T+0.024Ta△T-0.58HT 0 -0.07H Tg+0.078H(t 1 -t 0 )-0.039T 0 Tg-24.38
In the formula: t is t 0 Representing the days of the lowest temperature appearance time in the tunnel from 1 month to 1 day;
t 1 representing the number of days from the casting date to 1 month and 1 day;
the calculation formula of the minimum crack resistance safety coefficient of the circular section lining concrete is K min ＝(E×ε)/σ(3)
In the formula: k min The minimum crack resistance safety factor is set in the construction period of the lining concrete;
e is the deformation modulus of the lining concrete in age d;
ε is the ultimate tensile value of lining concrete age d.
2. The temperature-control anti-cracking tensile stress safety factor control design method for the concrete with the circular cross section lining as claimed in claim 1, which is characterized in that: the temperature control anti-cracking target and the anti-cracking safety coefficient allowable value of the circular section lining concrete are determined according to the design specification, the grade of the lining structure, the damage of the crack in the operation period, the safety and the anti-seepage performance.
3. The temperature-control anti-cracking tensile stress safety factor control design method for the concrete with the circular cross section lining as claimed in claim 1, which is characterized in that: when the strength grade designed for 28-day age is adopted in the lining concrete with the circular section, the strength grade designed for 90-day age needs to be converted according to the specification.
4. The temperature-control anti-cracking tensile stress safety factor control design method for the concrete with the circular cross section lining as claimed in claim 1, which is characterized in that: the circular section lining concrete adopts the curtain to keep warm, the air temperature of the underground cavern is increased, then T a 、T min And delta T is the increased temperature of the air in the hole.
5. The temperature-control anti-cracking tensile stress safety factor control design method for the concrete with the circular cross section lining as claimed in claim 1, which is characterized in that: when the thickness of the lining concrete with the circular cross section is smaller, the water-cooling water pipes are arranged in a single row.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102808395A (en) * | 2012-08-22 | 2012-12-05 | 清华大学 | Personalized control method for cantilever height of ultra-high arch dam |
| CN103556597A (en) * | 2013-10-24 | 2014-02-05 | 中国水利水电科学研究院 | Mass concrete surface cracking risk early warning, intervening and decision-making system |
| CN103676997A (en) * | 2013-10-16 | 2014-03-26 | 中国水利水电科学研究院 | Large-volume concrete temperature monitoring method based on real-time monitoring data |
| CN104018673A (en) * | 2013-09-12 | 2014-09-03 | 江苏绘天建筑安装工程有限公司 | Extra-huge-volume concrete one-time continuous pouring multi-cycle real-time temperature control construction technology |
| CN108981966A (en) * | 2018-07-02 | 2018-12-11 | 雷元新 | A kind of mass concrete temperature gradient Analysis of Limit Value method and device |
-
2019
- 2019-03-01 CN CN201910157434.5A patent/CN109992833B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102808395A (en) * | 2012-08-22 | 2012-12-05 | 清华大学 | Personalized control method for cantilever height of ultra-high arch dam |
| CN104018673A (en) * | 2013-09-12 | 2014-09-03 | 江苏绘天建筑安装工程有限公司 | Extra-huge-volume concrete one-time continuous pouring multi-cycle real-time temperature control construction technology |
| CN103676997A (en) * | 2013-10-16 | 2014-03-26 | 中国水利水电科学研究院 | Large-volume concrete temperature monitoring method based on real-time monitoring data |
| CN103556597A (en) * | 2013-10-24 | 2014-02-05 | 中国水利水电科学研究院 | Mass concrete surface cracking risk early warning, intervening and decision-making system |
| CN108981966A (en) * | 2018-07-02 | 2018-12-11 | 雷元新 | A kind of mass concrete temperature gradient Analysis of Limit Value method and device |
Non-Patent Citations (1)
| Title |
|---|
| 《白鹤滩输水系统进水塔底板混凝土温控特性分析》;肖照阳等;《水利发电学报》;20170825;第99-101页 * |
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