CN114263466B - Winter prefabrication construction temperature crack control method for well wall of well drilling in alpine region - Google Patents
Winter prefabrication construction temperature crack control method for well wall of well drilling in alpine region Download PDFInfo
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Abstract
The invention provides a method for controlling a prefabricated construction temperature crack of a well wall of a well drilling in a alpine region in winter, which comprises the following steps: s1, measuring a concrete thermophysical parameter; s2, concrete strength measurement and construction step numerical simulation; s3, binding reinforcement cages and arranging temperature measuring elements; s4, preparing concrete pouring; s5, pouring concrete; s6, steam curing; s7, natural maintenance. The method has the advantages of reasonable design, simple steps of the winter construction method, obvious characteristics of convenient operation, informatization and automation, strong operability, good quality of the concrete well wall formed in winter in the western severe cold region, no frost damage to the poured concrete, and no temperature crack caused by overlarge temperature stress on the surface of the well wall.
Description
Technical Field
The invention relates to the technical field of control of temperature cracks of mass concrete in winter construction in alpine regions, in particular to a method for controlling temperature cracks of well drilling well walls in winter prefabrication in alpine regions.
Background
The research project is a return air vertical shaft project of a certain mine in a western alpine region, the net diameter phi of a return air vertical shaft is designed to be 6.0m, and the depth is 521.5m, and the construction is carried out by adopting a drilling method. The total length of the well wall design is 542.5m, 91 sections in total, and the well wall design comprises 1 section at the bottom of the well wall, 39 sections of an inner layer steel plate-reinforced concrete composite well wall, 51 sections of the reinforced concrete well wall, 1000mm in wall thickness and 6m in height of each section. The winter concrete construction period of the project is arranged from the middle and late 11 months to the middle and late 3 months, and according to the monitoring statistics of the weather bureau, the winter temperature of the region where the project is located is about minus 5 ℃ throughout the year, so that when the concrete is constructed, how to effectively ensure that the concrete is not subjected to low-temperature freeze injury and the well wall structure is not cracked is a key for ensuring the construction quality of the well wall of the large-volume concrete precast well. Because the external temperature of the large-volume concrete in winter construction in the alpine region is too low, before the initial setting of the concrete, the water in the concrete is condensed into ice due to the too low temperature, and the concrete cannot normally undergo hydration reaction; and the internal temperature is high when the concrete is hydrated, the external temperature is overlarge in internal-external temperature difference due to low ambient temperature, so that temperature cracks are easily caused, and the safety of a mine well wall structure is greatly influenced.
Disclosure of Invention
The invention aims to provide a method for controlling the temperature cracks of winter prefabrication construction of a well wall of a well drilling in a alpine region, wherein a poured concrete well wall cannot be frozen in the alpine region, and temperature cracks cannot appear on the surface and the inside of the well wall of the well drilling.
In order to achieve the above object, the present invention provides the following technical solutions:
a winter prefabrication construction temperature crack control method for a well wall of a well drilling in a alpine region comprises the following steps:
s1, measuring a concrete thermophysical parameter;
s2, concrete strength measurement and construction step numerical simulation;
s3, binding reinforcement cages and arranging temperature measuring elements;
s4, preparing concrete pouring;
s5, pouring concrete;
s6, steam curing;
s7, natural maintenance.
In the method for controlling the winter prefabrication construction temperature cracks of the well wall of the well in the alpine region, in the step S1, concrete is formed by mixing ordinary Portland cement, fine aggregate, coarse aggregate, an additive and water, and the concrete mass proportion is as follows: ordinary Portland cement, fine aggregate, coarse aggregate, admixture, water=1:1-2:2-3.5:0.2-0.4:0.26-0.32.
Further, in the method for controlling the winter prefabrication construction temperature crack of the well wall of the well in the alpine region, in the step S2, concrete strength measurement comprises form removal strength measurement and freezing critical strength measurement; measuring the strength of the concrete with the mass mixing ratio in the step S1 under the standard curing condition, and respectively measuring the early strength of 1 day, 2 days, 3 days, 4 days, 5 days, 6 days and 7 days to obtain the form removal strength, the freezing critical strength and the hoisting strength of the well wall of the well under the standard curing condition; and (2) establishing a finite difference method numerical model by adopting engineering calculation software FLAC 3D according to the thermophysical and mechanical properties of the concrete in the step (S1), and simulating and analyzing the generation and development processes of hydration heat generation and cooling and temperature stress of the well wall of the concrete well.
Further, in the method for controlling the winter prefabrication construction temperature crack of the well wall of the well in the alpine region, in the step S3, the specific steps are as follows:
binding a reinforcement cage;
and arranging an optical fiber temperature measuring element;
then setting up a template;
preferably, the specific layout steps of the optical fiber temperature measuring element are as follows: four directions are determined along the east, south, west and north of the well wall of the well, four horizontal positions A, B, C and D are arranged along the height of the well wall of the well in each direction, five measuring points are uniformly arranged along the radial direction of the well wall of the well in each horizontal position, and the five measuring points are radial six equally divided points of the well wall of the well.
In the method for controlling the winter prefabrication construction temperature cracks of the well wall of the well in the alpine region, in the step S4, common Portland cement, fine aggregate, coarse aggregate, additive and water used for mixing are heated, and the heating temperature of each material is not lower than 10 ℃ at the lowest; setting up a steam maintenance cover, and arranging a concrete transportation pipeline and a steam pipeline at a position where a well wall of a well is required to be placed in the steam maintenance cover.
Further, in the method for controlling the winter prefabrication construction temperature crack of the well wall of the well in the alpine region, in the step S5, the specific steps are as follows:
S51, stirring, namely, when the concrete is stirred, stirring water is not higher than 80 ℃, the lower limit of water temperature is not lower than 5 ℃, and when the concrete is stirred, heated coarse aggregate, fine aggregate, additive and water are sequentially added, and cement is added when the temperature is not higher than 40 ℃ and the stirring is uniform;
preferably, the coarse aggregate is bright basalt with the maximum particle size not exceeding 19.0mm, and the fine aggregate is river sand with the fineness modulus of 2.73; preferably, the additive is mining composite additive NF-F, which is obtained by mixing the following components in proportion, specifically: NF high-efficiency water reducer, slag powder and fly ash=1:2.78:13.84;
s52, transporting, wherein mortar is adopted to preheat a transportation pipeline of the concrete before the concrete is pumped and poured;
s53, pouring, namely pouring concrete in a curing cover, pumping the mixed concrete to a template through a transportation pipeline by adopting a concrete pump, symmetrically and simultaneously sending the concrete into the built molding template from four directions to obtain a molding blank of the well wall of the well drilling, and leaving no construction joint after pouring is completed;
preferably, layering is compacted by vibrating bars during pouring, so that the mold entering temperature of concrete is not lower than 10 ℃;
S54, setting a same-condition construction test block: setting four groups of construction test blocks with the same maintenance conditions as the well wall of the well, wherein one group is used for determining the mold removal strength of the well wall of the well to be inspected, the second group is used for determining the freezing critical strength, the third group is used for determining the hoisting strength of the well wall of the well to be inspected, and the fourth group is used for inspecting the strength value of concrete under the same maintenance conditions for 28 days.
Further, in the method for controlling the winter prefabrication construction temperature crack of the well wall of the well in the alpine region, in the step S6, the specific steps are as follows: performing strength test on the on-site set test block under the same condition, and performing die stripping after the die stripping strength is reached; and after the template is removed, steam maintenance is started, the real-time temperature inside the well wall of the well is enhanced to be detected, the computer is used for automatic inspection, the control system is used for adjusting the temperature inside the steam maintenance cover, the temperature difference between the inside and the outside of the well wall is ensured to be not more than 20 ℃, and preferably, the temperature difference between the inside and the outside of the well wall is controlled to be not more than 5 ℃.
Further, in the method for controlling the winter prefabrication construction temperature cracks of the well wall of the well in the alpine region, the steam-cured steam pipeline comprises an inner steam pipe and an outer steam pipe, the inner steam pipe is positioned at the inner side of the well wall of the well, the outer steam pipe is positioned at the outer side of the well wall of the well, the inner steam pipe comprises a circumferential pipeline and a straight pipeline, the circumferential pipeline is horizontally arranged, and the straight pipeline is vertically arranged; eight straight pipelines are arranged, and steam is fed from the upper ports of the eight straight pipelines; steam outlet holes are uniformly formed in the annular pipeline and are arranged at the periphery of the annular pipeline, the steam outlet holes face the well wall, and the section of each steam outlet hole is plum blossom-shaped; the annular pipeline is provided with three layers, preferably, the axle center of the lowest annular pipeline is 1m away from the ground, and the axle center distance between two adjacent annular pipelines is 2m; the radial section of the steam pipeline has an outer diameter of 8cm and an inner diameter of 7.2cm; the diameter of a circle formed by the axis of the annular pipeline is 4m, and the distance between the axis of the annular pipeline and the inner surface of the concrete well wall is 1m.
Further, in the method for controlling the winter prefabrication construction temperature cracks of the well wall of the well drilling in the alpine region, steam outlets on the annular pipeline are sequentially increased from top to bottom according to the number of layers; the steam outlet on the annular pipeline is smaller in diameter from the opening which is closer to the junction of the straight pipeline and the annular pipeline; the size of the steam outlet is changed according to linear change, and the change coefficient range is as follows: 1.0 to 1.4 portions of the straight pipeline are arranged in the same pipeline; 1.0 to 1.2 parts of the same annular pipeline; the distance between two adjacent steam outlets is 15cm, and the distance calculating method is the distance between the centers of plum blossom-shaped center circles; the quincuncial shape comprises a center circle and a plurality of outer ring circles surrounding the center circle, wherein the center points of the outer ring circles are positioned on concentric circles with the center circle, and the radius of the concentric circles is 3 times of that of the center circle; the radius of the center circle and the radius of the outer ring circle of the quincuncial steam outlet are the same.
Further, in the method for controlling the winter prefabrication construction temperature crack of the well wall of the well in the alpine region, in the step S7, the specific steps are as follows: s71, covering a layer of plastic waterproof material on the surface of the well wall before the concrete well wall is subjected to steam curing, and performing heat preservation and moisture preservation treatment, wherein the heat preservation material at the corners of the well wall is thickened, namely the thickness of the heat preservation material at the corners of the well wall is 2 times or more than that of the heat preservation material on the surface of the well wall; s72, paving a concrete cushion layer in a preset well wall placing area before the concrete well wall is out of the steam curing shield, wherein the thickness range of the concrete cushion layer is 5 cm-15 cm; s73, hoisting the concrete drilling well wall onto a concrete cushion layer, and carrying out natural maintenance until the design strength is reached, so as to prepare for suspension and sinking construction to form a shaft.
Analysis shows that the invention discloses a winter prefabrication construction temperature crack control method for a well wall of a well drilling in a alpine region, and the technical scheme aims to solve the technical problems of the prior art, and provides a winter construction method for a large-volume prefabrication well wall of a well drilling in the alpine region, which has the advantages of reasonable design, simple construction method steps, convenience in operation, short construction period, strong operability, good quality of a large-volume concrete well wall formed by winter construction in the alpine region, no freezing of the poured concrete well wall in the alpine region, and no temperature crack on the surface and inside of the well wall of the well drilling.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. Wherein:
FIG. 1 is a schematic cross-sectional front view of an optical fiber temperature sensing element arrangement according to an embodiment of the present invention.
Fig. 2 is a schematic top view of fig. 1.
FIG. 3 is a schematic view of the steam curing hood and steam pipeline structure.
Fig. 4 is a schematic top view of a steam pipe structure.
Fig. 5 is a schematic front view of a steam pipe structure.
Fig. 6 is a schematic perspective view of a steam pipe structure.
Fig. 7 is a schematic view of a steam outlet structure.
Fig. 8 is a schematic view of a detachable buckle structure.
Reference numerals illustrate: 1. an optical fiber temperature measuring element 1; 2. an optical fiber temperature measuring element 2; 3. an optical fiber temperature measuring element 3; 4. an optical fiber temperature measuring element 4; 5. an optical fiber temperature measuring element 5; 6. a well wall; 7. a straight pipe; 8. a circumferential pipe; 9. a steam outlet; 10. an inner steam pipe; 11. an outer steam pipe; 12. a steam raising shield; 13. the fastener can be detached.
Detailed Description
The invention will be described in detail below with reference to the drawings in connection with embodiments. The examples are provided by way of explanation of the invention and not limitation of the invention. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield still a further embodiment. Accordingly, it is intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and their equivalents.
In the description of the present invention, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", etc. refer to the orientation or positional relationship based on that shown in the drawings, merely for convenience of description of the present invention and do not require that the present invention must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. The terms "coupled," "connected," and "configured" as used herein are to be construed broadly and may be, for example, fixedly connected or detachably connected; can be directly connected or indirectly connected through an intermediate component; either a wired electrical connection, a radio connection or a wireless communication signal connection, the specific meaning of which terms will be understood by those of ordinary skill in the art as the case may be.
One or more examples of the invention are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms "first," "second," and "third," etc. are used interchangeably to distinguish one component from another and are not intended to represent the location or importance of the individual components.
As shown in fig. 1 to 8, according to an embodiment of the present invention, there is provided a method for controlling a prefabricated construction temperature crack of a well wall in winter in a well drilling well in a alpine region in northwest, the method comprising the steps of:
s1, measuring thermal physical parameters of concrete
The well wall concrete is formed by mixing common silicate cement, fine aggregate, coarse aggregate, additive and water, and the proportion of the concrete is designed and optimized before the well wall 6 of the well in the northwest alpine region is prefabricated in winter; calculating hydration heat according to the optimized mixing ratio through a hydration heat theory, and obtaining main thermal physical parameters of the prepared concrete through a test; and obtaining the relevant temperature of the raw materials during the well wall concrete stirring in winter in the northwest alpine region according to the concrete thermal calculation.
Specifically, concrete is prepared in a laboratory, and optimization design is carried out to obtain the mixing ratio of the drilling well wall pumping construction concrete, namely, the proportion of cement, aggregate, additive and water is determined. In the example, taking the proportion of concrete of a well wall of a well drilling in a special stratum section in a northwest alpine region as an example, concrete is selected as a wall building material of a prefabricated well wall 6, ordinary Portland cement is selected as cement, aggregate comprises coarse aggregate and fine aggregate, and an additive is a water reducing agent. The specific mass mixing ratio is as follows: the proportion of the common silicate cement, the fine aggregate, the coarse aggregate, the additive and the water=1:1-2:2-3.5:0.2-0.4:0.26-0.32 can be adjusted in the range. After the mixing proportion is obtained, the heating temperature of each raw material of the concrete is determined according to the concrete thermal engineering calculation, and the heating temperature of each material is not lower than 10 ℃ at the lowest. The heating temperature of each material is not lower than 10 ℃, so that the requirement that the molding temperature does not reach 5 ℃ required by the specification can be avoided.
The optimization principle of laboratory prepared concrete is as follows:
low heat of hydration; the concrete has good workability and large slump, and is convenient for concrete transportation and pouring; the concrete preparation process is simple; the main material sources are localized, and the cost is low; high durability; low shrinkage and high barrier properties.
By optimizing the concrete mix ratio, the amount of materials which can participate in hydration reaction is reduced on the premise of ensuring the strength, and the hydration reaction material in the example is ordinary Portland cement. The proportion design reduces the consumption of the ordinary Portland cement by the proportion design of the ordinary Portland cement, the fine aggregate, the coarse aggregate, the additive and the water=1:1-2:2-3.5:0.2-0.4:0.26-0.32.
S2 concrete strength measurement and construction step numerical simulation
Concrete strength measurements include demold strength measurements and freeze critical strength measurements. The strength of the concrete with the mass mixing ratio in the step S1 under the standard curing condition is measured in a laboratory through experiments, and the early strengths of 1 day, 2 days, 3 days, 4 days, 5 days, 6 days and 7 days are respectively measured, so that the demolding strength, the freezing critical strength and the hoisting strength of the drilling well wall 6 under the standard curing condition under the mass mixing ratio are obtained; and (3) establishing a finite difference method numerical model by adopting large engineering calculation software FLAC 3D according to the thermophysical and mechanical properties of the concrete obtained in the test in the step (S1), and simulating and analyzing the hydration heat generation and cooling and the generation and development processes of temperature stress of the wall 6 of the concrete well. In the process of establishing the numerical model, various mechanical and thermophysical parameters of hydration reaction of the concrete material are brought into the numerical model, and meanwhile, the temperature boundary condition, initial condition and other related parameters of the numerical model are determined in combination with engineering actual conditions. And the maximum inner and outer temperature difference of the concrete well wall 6 in the engineering is determined through numerical analysis, so that the corresponding control scheme is convenient to determine. In one embodiment, the indoor maintenance environment temperature after the well wall 6 is poured is set to be 10 ℃ (283K), the maximum temperature of the core of the well wall 6 obtained through numerical simulation is 30.87 ℃, and the maximum temperature difference between the core and the surface of the well wall 6 is 18.21 ℃.
S3 reinforcement cage binding and temperature measuring element layout
Binding a reinforcement cage according to a construction drawing before concrete pouring construction, and arranging an optical fiber temperature measuring element; the template is then set up.
The specific layout steps of the optical fiber temperature measuring element are as follows: as shown in fig. 1 and 2, four directions are determined along the east, south, west and north of the well wall 6, four horizontal positions A, B, C and D are arranged along the height of the well wall 6 in each direction, five measuring points are uniformly arranged along the radial direction of the well wall 6 in each horizontal position, and the five measuring points are radial six equally divided points of the well wall 6; the temperature measuring elements arranged at five measuring points arranged at each horizontal position in each direction are sequentially from outside to inside: the optical fiber temperature measuring element 1, the optical fiber temperature measuring element 2, the optical fiber temperature measuring element 3, the optical fiber temperature measuring element 4, the optical fiber temperature measuring element 5 and a section of well wall 6 are provided with 80 measuring points in total, so that the internal temperature distribution condition of the concrete well wall 6 during pouring construction maintenance can be accurately monitored. The optical fiber temperature measuring element 3 is arranged at the central position of the concrete of the well wall 6, and the optical fiber temperature measuring element 1 and the optical fiber temperature measuring element 5 are respectively arranged on the outer surface and the inner surface of the well wall 6.
The optical fiber temperature measuring element arranged in the step S3 synchronously uploads the temperature data monitored in real time to a computer for analysis processing and synchronous record display, and automatically adjusts the set temperature of the steam curing shield 12 according to the data analysis processing result, so that the temperature difference between the outer surface temperature of the concrete well wall 6 and the central temperature of the concrete is not more than 20 ℃, and the temperature difference refers to the temperature difference between the optical fiber temperature measuring element 1 and the optical fiber temperature measuring element 3 and the temperature difference between the optical fiber temperature measuring element 5 and the optical fiber temperature measuring element 3; in the steam curing process, the temperature rising speed of the concrete well wall 6 structure is controlled to be not more than 15 ℃/h, and the temperature reducing speed of the concrete well wall 6 structure is controlled to be not more than 10 ℃/h. The concrete diameter ratio is larger in thickness, if the temperature difference between the inner side and the outer side is larger, the concrete diameter ratio is cracked, so that the temperature difference between the inner side and the outer side is controlled to be smaller than 20 ℃; concrete is a material with low thermal conductivity, and the temperature rise or fall rate is too fast, so that a temperature difference exists between the surface and the interior of the concrete, which causes damage to the interior of the concrete, and therefore, the temperature rise and fall rate of the concrete is limited according to the test result.
S4 concrete placement preparation
Before concrete is stirred, common Portland cement, fine aggregate, coarse aggregate, additive and water used for mixing are heated, the heating temperatures of the fine aggregate, the coarse aggregate, the additive and the water are required to be calculated by thermal engineering according to the ambient temperature, but the heating temperature of each material is not lower than 10 ℃; a large steam maintenance cover 12 is erected, and concrete transportation pipelines and steam pipelines are arranged at positions where the well wall 6 of the well needs to be placed in the steam maintenance cover 12.
The method specifically comprises the following steps: hoisting a large steam raising shield 12 manufactured in advance to a prefabricated well wall 6, covering a pouring platform, and installing; and a steam pipeline and a concrete transportation pipeline are arranged in the steam curing shield 12 of the pouring platform, and a heat preservation layer is additionally arranged on the transportation pipeline before concrete pouring construction, so that the temperature of the transported concrete in a mould is not lower than 10 ℃, and the rapid occurrence of a concrete hydration reaction is not facilitated due to the excessively low temperature, so that the lower limit value is set. The temperature of the concrete in the mould is not higher than 40 ℃, and the hydration of the cement can be affected when the temperature is higher than 40 ℃. The heat preservation layer adopted by the transportation pipeline is made of rubber and plastic sponge heat preservation materials.
In this example, the heating temperature of each material used for blending was calculated by thermal engineering, and the original temperature of each material was assumed as shown in table 1 below:
TABLE 1 raw temperatures of the materials
| Material | Original temperature |
| Cement and its preparation method | 0℃ |
| Additive agent | 0℃ |
| Sand | 0℃ |
| Stone | 0℃ |
| Water and its preparation method | 2℃ |
The temperature of the cement mixture can be calculated according to the following formula given by concrete thermal engineering calculation in JGJ104-2011 "construction procedure in winter of construction engineering":
T 0 -concrete mix temperature (°c)
T s Temperature of the admixture (. Degree. C.)
T ce -temperature of cement (DEG C)
T sa Temperature (. Degree. C.) of sand (fine aggregate)
T g -temperature of stone (coarse aggregate) (. Degree.C.)
T w Temperature of Water (. Degree. C.)
m w Mixing water dosage (kg)
m sa -amount of sand (fine aggregate) (kg)
m g -stone (coarse aggregate) dosage (kg)
m ce Cement amount (kg)
m s -additive amount (kg)
c w Specific heat capacity of water [ kJ/(kg. K)]
c i Ice dissolution heat (kJ/kg), when the temperature of the aggregates (fine aggregates and fine aggregates) is greater than 0 ℃): c w ＝4.2，c i ＝0；
When the temperature of the aggregate (fine aggregate and fine aggregate) is 0 ℃ or less: c w ＝2.1，c i ＝335
ω sa Moisture content of Sand (Fine aggregate) (%)
ω g Water content of stone (coarse aggregate) (%)
The concrete mix outlet temperature is calculated as follows:
T 1 ＝T 0 -0.16(T 0 -T P )
T 1 -temperature of the concrete mixture at the outlet (DEG C)
T P -temperature in the blender shelter (DEG C)
The temperature of the concrete for on-site mixing can be calculated according to the following formula when pumping construction is adopted (the temperature of the concrete is the mold-in temperature when default pumping construction is adopted here):
T 2 ＝T 1 -ΔT b
T 2 -temperature (c) of the concrete mix during transport and delivery to the casting site
ΔT b When the pump pipe is used for conveying concreteTemperature decrease (. Degree. C.)
ΔT b The calculation can be performed according to the following formula:
wherein:
ΔT 1 -temperature difference (c) between the temperature of the concrete in the pump pipe and ambient air, when the in-situ concrete is transported by pumping process: delta T 1 ＝T 1 -T a
T a Ambient air temperature (DEG C)
Omega-ventilation coefficient, the surrounding layer is made of materials which are not easy to ventilate, and when the wind speed is lower than 3 m/s: ω=1.3
d b Thickness (m) of heat insulation layer outside pump pipe
λ b Heat conductivity coefficient of heat insulation material outside pump pipe [ W/(m.K)]
t-time (h) for transporting concrete in pump tube
D w Concrete pump pipe outer diameter (including peripheral insulation material) (m)
c c Specific heat capacity of concrete [ kJ/(kg. K)]
ρ c Mass density (kg/m) of concrete 3 )
D l Inner diameter (m) of concrete pump pipe
If the materials are mixed according to the original temperature, the requirement that the molding temperature is higher than 10 ℃ is obviously not met, so that the materials are heated and then subjected to thermal calculation.
The actual working conditions are shown in table 2:
TABLE 2 values of parameters for actual conditions
| ω sa ＝ω g ＝0％ | T ce ＝10℃ | T s ＝10℃ | T sa ＝10℃ | T g ＝10℃ | T w ＝25℃ |
| m w ＝118kg | m sa ＝710kg | m g ＝1110kg | m ce ＝394kg | m s ＝118kg | c w ＝4.2[kJ/(kg·K)] |
| c i ＝0[kJ/(kg·K)] | T P ＝0℃ | ΔT 1 ＝10.76℃ | T a ＝0℃ | ω＝1.3 | d b ＝0.05 |
| λ b ＝0.033W/(m·k) | t＝0.1h | d w ＝0.259m | c c ＝0.97kJ/(kg·K) | ρ c ＝2450kg/m 3 | D l ＝0.15m |
To sum up, calculate the modulus-entering temperature T 2 =10.70 ℃, conforming to the in-mold temperature above 10 ℃.
Therefore, the requirement that the molding temperature is higher than 10 ℃ can be met by heating water to 25 ℃, and heating the fine aggregate, the coarse aggregate, the additive and the cement to 10 ℃.
S5 concrete pouring
Concrete pouring work is carried out in a large-scale curing hood, the temperature curing is carried out in a boiler steam heating chamber, the indoor temperature and humidity are automatically detected, and the indoor temperature and humidity are automatically controlled by a computer.
The method comprises the following specific steps:
s51, when the concrete is stirred, the water-cement ratio of the concrete with each strength grade is strictly controlled, the stirring water is not higher than 80 ℃, the highest water temperature limit of the concrete with different grades is set in the concrete winter construction specification, the lower water temperature limit is not lower than 5 ℃, the heated coarse aggregate, the heated fine aggregate, the heated admixture and the heated water are sequentially added during mixing, and cement is added when the temperature is uniformly stirred and is not higher than 40 ℃. The coarse aggregate mainly comprises broken stone and the like, and the fine aggregate is sand and the like. The coarse aggregate used in the embodiment is the bright basalt with the maximum particle size not exceeding 19.0mm, the fine aggregate is river sand with the fineness modulus of 2.73, and the bright basalt has excellent compression resistance and fracture resistance mechanical property, good wear resistance and low water absorption and is often used as the coarse aggregate of high-strength concrete; the river sand has good grading and less impurity, and is a good material for preparing high-strength concrete.
The additive is mining composite additive NF-F. The mining composite additive NF-F is prepared by mixing the following components in proportion: NF high-efficiency water reducer, slag powder and fly ash=1:2.78:13.84; NF type high-efficiency water reducer is a commercial product. The mining composite additive NF-F can reduce the cement consumption, reduce the hydration heat and increase the concrete fluidity.
S52, transporting, wherein mortar is adopted to preheat a transportation pipeline of the concrete before the concrete is pumped and poured;
s53, pouring, namely pouring concrete in a large-scale curing cover, pumping the mixed concrete to a forming well wall 6 template through a conveying pipeline by adopting a large-scale concrete pump, symmetrically and simultaneously sending the mixed concrete into the built forming template from four directions to obtain a forming blank of the large-scale concrete drilling well wall 6, and leaving no construction joint after pouring is completed; the vibrating rod is used for vibrating compaction in layering during concrete pouring, so that defects after forming are prevented. When the concrete is poured, the mold entering temperature of the concrete is ensured to be not lower than 10 ℃;
s54, setting a same-condition construction test block: setting four groups of construction test blocks with the same curing conditions as those of the well wall 6, wherein one group is used for determining the demolding strength of the well wall 6, the second group is used for determining the freezing critical strength, the third group is used for determining the hoisting strength of the well wall 6, and the fourth group is used for curing the strength value of the concrete under the same conditions for 28 days.
S6 steam curing
The concrete well wall 6 performs strength test on the on-site set same-condition test block according to the form removal strength measured in a laboratory, and performs form removal after reaching the form removal strength; and after the template is removed, steam curing is started, the real-time temperature inside the concrete well wall 6 is enhanced and detected, the computer is used for automatic inspection, the control system is used for adjusting the temperature inside the steam curing shield 12, the temperature difference between the inside and the outside of the well wall 6 is ensured to be not more than 20 ℃, concrete cracking caused by overlarge temperature stress is prevented, and the temperature difference is preferably controlled to be not more than 5 ℃. The temperature difference is reduced as much as possible because the cracks in the well wall 6 during the forming strength are not only caused by temperature stress, but also caused by excessive stress due to the constraint of the formwork and the internal reinforcing steel bars, thereby causing the cracking of the concrete. The steam curing hood 12 is shown in fig. 3.
The method comprises the following specific steps: steam is introduced during the concrete pouring period, the temperature during the pouring period is ensured not to be lower than 10 ℃, and the high-temperature steam temperature of the steam curing shield 12 is regulated after the pouring is finished to start curing; the temperature in the steam maintenance shield 12 is controlled and regulated by a computer through monitoring temperature data inside the well wall 6.
The steam-cured steam pipeline comprises an inner steam pipe 10 and an outer steam pipe 11, wherein the inner steam pipe 10 is positioned on the inner side of the well wall 6 of the well, and the outer steam pipe 11 is positioned on the outer side of the well wall 6 of the well. The inner steam pipe 10 on the inner side of the well wall 6 is distributed as shown in fig. 3-6, the inner steam pipe 10 comprises a circular pipeline 8 and a straight pipeline 7, the circular pipeline 8 is horizontally arranged, and the straight pipeline 7 is vertically arranged.
Eight straight pipelines 7 are arranged, and steam is fed from the upper ports of the eight straight pipelines 7; the annular pipeline 8 is uniformly provided with steam outlet holes, the steam outlet holes are arranged at the periphery of the annular pipeline 8, the steam outlet holes face the well wall 6, and the section of the steam outlet holes is plum blossom-shaped.
The annular pipeline 8 is provided with three layers, and is arranged according to the following positions: the axle center of the lowest annular pipeline 8 is 1m away from the ground, and the axle center distance between two adjacent annular pipelines 8 is 2m.
The radial section of the steam pipeline has an outer diameter of 8cm and an inner diameter of 7.2cm.
The diameter of the circle formed by the axis of the annular pipeline 8 is 4m, and the distance between the axis of the annular pipeline 8 and the inner surface of the concrete well wall 6 is 1m.
The straight pipeline 7 is provided with an interface for arranging a circular pipeline 8. Interfaces can be reserved on the straight pipelines 7 between two adjacent layers of circumferential pipelines 8, for example, the interfaces are arranged at equal positions of the straight pipelines 7, which are away from the adjacent circumferential pipelines 8, so that the circumferential pipelines 8 can be conveniently added.
The lower end of the straight pipeline 7, namely the part contacting the ground, is subjected to sealing treatment, so that the lower end of the straight pipeline 7 is ensured not to escape steam, and the straight pipeline can be used as a support of the whole internal steam pipeline;
the steam in the steam pipeline is conveyed from top to bottom, the steam pressure of the upper part is naturally higher than that of the lower part, and in order to make the steam evenly sprayed out, steam outlet holes on the steam pipeline are arranged as follows:
1. the size of the steam outlet 9 on the annular pipeline 8 is increased from top to bottom according to the layer number.
2. The closer the steam outlet 9 on the annular pipe 8 is to the junction of the straight pipe 7 and the annular pipe 8, the smaller the opening diameter thereof is.
3. The size of the steam outlet 9 varies linearly with the range of coefficients: 1.0 to 1.4 of the same straight pipeline 7; 1.0 to 1.2 of the same annular pipeline 8.
Assuming that the diameter of the steam outlet 9 of the uppermost annular duct 8 near the junction of the annular duct 8 and the straight duct 7 is 0.8cm, the diameter of the steam outlet 9 of the layer furthest from the junction (i.e., the intermediate position) is 0.8x1.2=0.96 cm; the diameter of the steam outlet 9 of the lowest layer of annular pipeline 8 near the junction of the annular pipeline 8 and the straight pipeline 7 is 0.8x1.4=1.12 cm, and the diameter of the steam outlet 9 of the layer furthest from the junction (namely the middle position) in the annular direction is 1.12x1.2=1.344 cm; the diameter of the steam outlet 9 on the annular steam pipe 8 in the middle layer is calculated by interpolation, and the diameter of the steam outlet 9 on the annular steam pipe between the straight pipe 7 and the straight pipe 7 is also calculated by interpolation.
4. The number of steam outlets 9 is arranged: the distance between two adjacent steam outlets 9 is 15cm, and the distance calculation method is the distance between the centers of quincuncial center circles.
5. The design method of the quincuncial steam outlet 9 comprises the following steps: comprising a central circle and a plurality of outer ring circles surrounding the central circle. The center points of the outer ring circles are positioned on concentric circles with the center circle and are uniformly distributed, and the radius length of the concentric circles is 3 times of that of the center circle; the radius of the center circle and the outer circle of the quincuncial steam outlet 9 are the same, as shown in fig. 7.
The steam pipeline is of a detachable structure and consists of a pipeline, a multi-way joint (3-way joint and 4-way joint) and a closed joint cover. The end of pipeline is for dismantling buckle 13 structure, is provided with the lug on the lateral wall of one end of pipeline promptly, is provided with the hole on the lateral wall of the other end of pipeline, and lug and hole form and can dismantle buckle 13 structure, and the lug inserts two pipelines in the hole and connects, installs, dismantles conveniently.
The steam raising shields 12 are uniformly provided with steam outlets 9 at intervals of 2 meters in the height direction, and 4 steam outlet areas are arranged on each layer, so that the concrete well wall 6 is heated uniformly. Meanwhile, a condenser is additionally arranged on the steam raising shield 12, so that condensed water is prevented from flowing in a large range; when the concrete is cured, high-temperature steam is introduced into the steam curing shield 12 to carry out curing, the curing temperature is changed along with the change of the monitoring temperature, the temperature difference inside and outside the concrete of the well wall of the well is controlled to be always kept within 20 ℃, and the concrete is prevented from cracking due to overlarge temperature stress.
S7, natural maintenance
When the strength of the concrete reaches the hoisting strength (design strength is 70%), slowly cooling the structure of the prefabricated well wall 6, and fully exerting the stress relaxation effect of the concrete; and dismantling and hanging away the large-scale maintenance cover and the steam pipeline, and then hanging and hanging the well wall 6 of the well which is well cured by the steam to a preset maintenance area for continuous maintenance so as to prepare for suspension and sinking construction into a shaft.
The method comprises the following specific steps:
and S71, before the concrete well wall 6 is covered with the steam curing cover 12, covering a layer of waterproof material such as plastic cloth on the surface of the well wall 6, performing heat preservation and moisture preservation treatment, thickening the heat preservation material at the corners of the well wall 6, wherein the thickness of the heat preservation material at the corners of the well wall 6 is 2 times or more than that of the heat preservation material on the surface of the well wall 6. The contact surface between the edge and corner of the well wall 6 and the air is larger, so that the well wall is more susceptible to freeze injury, and double treatment is needed.
S72, before the concrete well wall 6 is discharged out of the steam curing shield 12, a layer of concrete cushion layer is paved on the area where the well wall 6 is scheduled to be placed, and the thickness of the concrete cushion layer ranges from 5cm to 15cm. The foundation soil can expand when being frozen, and a layer of concrete cushion layer is paved on the area where the well wall 6 is placed, so that uneven site or sinking of the foundation caused by freeze thawing effect can be prevented when the structure of the concrete well wall 6 is placed, and damage to the well wall 6 is avoided; the concrete cushion should be laid before winter comes and reaches the design strength.
S73, hoisting the concrete well drilling wall 6 to a concrete cushion layer, and carrying out natural maintenance until the design strength is reached, so as to prepare for suspension and sinking construction to form a shaft.
Before the natural curing in the step S7, a judgment needs to be made on whether the structure of the well wall 6 reaches the critical freezing strength and the hoisting strength, the judgment basis is a concrete early strength curve measured in the experiment in the step S2, the judgment is performed according to the concrete age, the real-time strength is measured by a concrete test block subjected to steam curing under the same condition in an auxiliary manner, and the strength error of the construction site and the ideal environment in a laboratory is adjusted.
Compared with the prior art, the invention has the following advantages:
1. the design is reasonable, the concrete proportion is optimized in the early construction stage according to the optimization principle, a large number of material strength and thermodynamic tests are carried out on the concrete obtained by optimizing the proportion, and the material performance is fully explored; the construction method has the advantages of simple steps, convenient operation and strong operability, and can provide a reference method for future automatic construction and unmanned construction.
2. The environmental temperature condition of the construction site is fully considered, the heating temperature required by the concrete mixture in construction is controlled, the mold entering temperature of the concrete mixture is ensured to be higher than 5 ℃, and the phenomenon of freezing injury of the concrete is prevented.
3. The well wall 6 of the well formed by construction is good in quality, the poured concrete cannot be frozen in severe cold weather, and temperature cracks cannot occur on the surface and inside of the well wall 6.
4. The construction simulation calculation adopts large engineering calculation software FLAC 3D to establish a finite difference method model, and the generation and development processes of hydration heat generation and cooling and temperature stress of the concrete well wall 6 are simulated and analyzed. The key point of the hydration heat analysis by adopting software is to establish analysis conditions and analysis models similar to the measures adopted in the actual situation of the construction scheme, determine the thermodynamic parameters of materials such as specific heat parameters, activation energy, maximum hydration heat and the like of the concrete according to material tests, and determine all boundary constraint conditions according to engineering practice. A finite difference well wall 6 model with a length of 6 meters, an inner diameter of 6 meters and an outer diameter of 7.2 meters is established under the measure of ensuring the concrete mold-in temperature and steam curing, and quite reliable theoretical data is provided for the actual engineering construction process by establishing the well wall 6 model.
5. The method for carrying out winter temperature control on the structure of the well wall 6 by adopting the detachable steam curing cover 12 can effectively promote the generation of initial strength of concrete, prevent the concrete from being frozen due to too low temperature, further prevent the surface of the concrete well wall 6 from being cracked, realize real-time temperature adjustment and control by data real-time transmission detected by the optical fiber temperature measuring element arranged in the well wall 6, not only realize good temperature difference control effect, but also realize low investment cost and less required personnel, and provide a good reference method for automatic construction of the prefabricated well wall 6 in the future;
6. Advanced temperature measurement and control technology: the optical fiber temperature measuring element is adopted to measure the temperature of the hydration heat generated at each position inside the concrete well wall 6, the data is transmitted to the data analysis processing computer to be processed, analyzed and synchronously displayed, and the age-strength curve and the age-temperature curve measured according to the early-stage material strength test are compared with the real-time monitoring data of the concrete well wall 6 to judge whether the concrete well wall 6 reaches the stripping strength and the freezing critical strength. Removing the mould of the 6 sections of the well wall of the well, which reach the mould removing strength, and cooling the 6 sections of the well wall of the well, which reach the freezing critical strength, so as to prepare for the next natural maintenance;
7. the maintenance step is reasonable in design: the steam curing shield 12 mainly plays a role in controlling temperature and moisturizing, and the main purpose of controlling the temperature of the surface of the concrete well wall 6 is to control the temperature difference between the inside and outside of each position of the whole well wall 6 structure to be less than 20 ℃, reduce the temperature difference and prevent the occurrence of temperature cracks of the structure caused by overlarge temperature stress; the main function of moisture preservation is to prevent shrinkage cracks on the concrete surface caused by shrinkage of the concrete mass due to hydration and water loss. The steam curing shield 12 is adopted to cover the well wall 6 of the well, so that the temperature difference between the inside and the outside of the concrete structure can be effectively reduced, and particularly, the temperature in the steam curing shield 12 is regulated according to the data of real-time detection of the temperature in the concrete by the optical fiber temperature measuring element, so that informatization and automatic construction are realized, and the construction of the well wall 6 of the well in the alpine region in winter is a powerful guarantee.
In conclusion, the prefabricated well wall 6 formed by construction in winter in the western alpine region has good quality, the poured concrete cannot be frozen, and temperature cracks caused by overlarge temperature stress cannot occur on the inner side surface and the outer side surface of the well wall 6 and the invisible inner side. Specifically: before the concrete drilling well wall 6 is poured, the concrete mixing proportion is optimized, and the thermophysical property and the early mechanical property of the concrete drilling well wall 6 are detected through experiments; by referring to meteorological data and monitoring the local environment temperature in real time, performing concrete thermal calculation, and controlling the temperature of each mixing material when concrete is mixed; the external heat preservation measure of the transportation pipeline effectively slows down the heat loss of the concrete when the concrete is poured, so that the temperature of the concrete entering the mould is kept above 10 ℃; in the aspect of maintenance temperature control, the steam maintenance shield 12 is adopted to accurately monitor the temperature inside and outside the concrete well wall 6 structure in real time through the temperature detection control system, and the temperature inside the steam maintenance shield 12 is controlled, so that the temperature difference inside and outside the well wall 6 structure is reduced, the generation of temperature cracks is effectively prevented, and the construction quality of the prefabricated well wall 6 in the western alpine region in winter is ensured.
The method has the advantages of reasonable design, simple steps of the winter construction method, convenient operation, obvious informatization and automation characteristics, strong operability, good quality of the concrete drilling well wall 6 formed in winter in the western severe cold region, no frost damage to the poured concrete, and no temperature crack caused by overlarge temperature stress on the surface of the drilling well wall 6.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A winter prefabrication construction temperature crack control method for a well wall of a well drilling in a alpine region is characterized by comprising the following steps:
s1, measuring a concrete thermophysical parameter;
s2, concrete strength measurement and construction step numerical simulation;
s3, binding reinforcement cages and arranging temperature measuring elements;
in the step S3, the specific steps are as follows:
binding a reinforcement cage;
and arranging an optical fiber temperature measuring element;
then setting up a template;
the specific layout steps of the optical fiber temperature measuring element are as follows: four directions are determined along the east, south, west and north of the well wall of the well, four horizontal positions A, B, C and D are arranged along the height of the well wall of the well in each direction, five measuring points are uniformly arranged along the radial direction of the well wall of the well in each horizontal position, the five measuring points are radial six equally divided points of the well wall of the well,
S4, preparing concrete pouring;
setting up a steam maintenance cover, arranging a concrete transportation pipeline and a steam pipeline at a position where a well wall of a well is required to be placed in the steam maintenance cover,
the method specifically comprises the following steps: hoisting a large steam curing shield manufactured in advance to a prefabricated well wall of a well, covering a pouring platform, and installing; arranging a steam pipeline and a concrete transportation pipeline in a steam curing shield of a pouring platform, adding an insulation layer to the transportation pipeline before concrete pouring construction, ensuring that the temperature of the transported concrete in a mold is not lower than 10 ℃, the temperature of the concrete in the mold is not higher than 40 ℃,
s5, pouring concrete;
s6, steam curing;
the optical fiber temperature measuring element arranged in the step S3 synchronously uploads the temperature data monitored in real time to a computer for analysis processing and synchronous record display, and automatically adjusts the set temperature of the steam curing shield according to the data analysis processing result, so that the temperature difference between the outer surface temperature of the concrete well wall and the temperature of the concrete center is not more than 20 ℃;
in the steam curing process, the temperature rising speed of the concrete well wall structure is controlled to be not more than 15 ℃/h, the temperature reducing speed of the concrete well wall structure is controlled to be not more than 10 ℃/h,
S7, naturally curing the mixture,
the steam pipe for steam maintenance comprises an inner steam pipe and an outer steam pipe, the inner steam pipe is positioned at the inner side of the well wall of the well, the outer steam pipe is positioned at the outer side of the well wall of the well, the inner steam pipe comprises a circumferential pipeline and a straight pipeline, the circumferential pipeline is horizontally arranged, and the straight pipeline is vertically arranged;
eight straight pipelines are arranged, and steam is fed from the upper ports of the eight straight pipelines;
steam outlet holes are uniformly formed in the annular pipeline and are arranged at the periphery of the annular pipeline, the steam outlet holes face the well wall, and the section of each steam outlet hole is plum blossom-shaped;
the annular pipeline is provided with three layers,
the axle center of the lowest layer of annular pipeline is 1m away from the ground, and the axle center distance between two adjacent annular pipelines is 2m;
the radial section of the steam pipeline has an outer diameter of 8cm and an inner diameter of 7.2cm;
the diameter of a circle formed by the axis of the annular pipeline is 4m, the distance between the axis of the annular pipeline and the inner surface of the concrete well wall is 1m,
the size of the steam outlet on the annular pipeline is sequentially increased from top to bottom according to the layer number;
the steam outlet on the annular pipeline is smaller in diameter from the opening which is closer to the junction of the straight pipeline and the annular pipeline;
the size of the steam outlet is changed according to linear change, and the change coefficient range is as follows: 1.0 to 1.4 portions of the straight pipeline are arranged in the same pipeline; 1.0 to 1.2 parts of the same annular pipeline;
The distance between two adjacent steam outlets is 15cm, and the distance calculating method is the distance between the centers of plum blossom-shaped center circles;
the quincuncial shape comprises a center circle and a plurality of outer ring circles surrounding the center circle, wherein the center points of the outer ring circles are positioned on concentric circles with the center circle, and the radius of the concentric circles is 3 times of that of the center circle; the radius of the center circle and the radius of the outer ring circle of the quincuncial steam outlet are the same.
2. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in the step S1, concrete is formed by mixing ordinary Portland cement, fine aggregate, coarse aggregate, additive and water,
the specific mass mixing ratio is as follows: ordinary Portland cement, fine aggregate, coarse aggregate, admixture, water=1:1-2:2-3.5:0.2-0.4:0.26-0.32.
3. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in said step S2, concrete strength measurements include a form removal strength measurement and a freeze critical strength measurement; measuring the strength of the concrete with the mass mixing ratio in the step S1 under the standard curing condition, and respectively measuring the early strength of 1 day, 2 days, 3 days, 4 days, 5 days, 6 days and 7 days to obtain the form removal strength, the freezing critical strength and the hoisting strength of the well wall of the well under the standard curing condition;
And (2) establishing a finite difference method numerical model by adopting engineering calculation software FLAC 3D according to the thermophysical and mechanical properties of the concrete in the step (S1), and simulating and analyzing the generation and development processes of hydration heat generation and cooling and temperature stress of the well wall of the concrete well.
4. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in the step S4, the common silicate cement, the fine aggregate, the coarse aggregate, the additive and the water used for mixing are heated, and the heating temperature of each material is not lower than 10 ℃ at the lowest.
5. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in the step S5, the specific steps are as follows:
s51, stirring, namely, when the concrete is stirred, stirring water is not higher than 80 ℃, the lower limit of water temperature is not lower than 5 ℃, and when the concrete is stirred, heated coarse aggregate, fine aggregate, additive and water are sequentially added, and cement is added when the temperature is not higher than 40 ℃ and the stirring is uniform;
the coarse aggregate is photoperiod basalt with the maximum particle size not exceeding 19.0mm, and the fine aggregate is river sand with the fineness modulus of 2.73;
the additive is mining composite additive NF-F, which is obtained by mixing the following components in proportion, specifically: NF high-efficiency water reducer, slag powder and fly ash=1:2.78:13.84;
S52, transporting, wherein mortar is adopted to preheat a transportation pipeline of the concrete before the concrete is pumped and poured;
s53, pouring, namely pouring concrete in a curing cover, pumping the mixed concrete to a template through a transportation pipeline by adopting a concrete pump, symmetrically and simultaneously sending the concrete into the built molding template from four directions to obtain a molding blank of the well wall of the well drilling, and leaving no construction joint after pouring is completed;
the layering is compacted by vibrating bars during pouring, so that the mold entering temperature of the concrete is not lower than 10 ℃;
s54, setting a same-condition construction test block: setting four groups of construction test blocks with the same maintenance conditions as the well wall of the well, wherein one group is used for determining the mold removal strength of the well wall of the well to be inspected, the second group is used for determining the freezing critical strength, the third group is used for determining the hoisting strength of the well wall of the well to be inspected, and the fourth group is used for inspecting the strength value of concrete under the same maintenance conditions for 28 days.
6. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in the step S6, the specific steps are as follows: performing strength test on the on-site set test block under the same condition, and performing die stripping after the die stripping strength is reached; and after the template is removed, steam maintenance is started, the real-time temperature inside the well wall of the well is detected in an enhanced mode, a computer automatically carries out inspection, and the temperature inside the steam maintenance cover is regulated by a control system.
7. The winter prefabrication construction temperature crack control method for the well wall of the well in the alpine region according to claim 1, wherein,
in the step S7, the specific steps are as follows:
s71, covering a layer of plastic waterproof material on the surface of the well wall before the concrete well wall is subjected to steam curing, and performing heat preservation and moisture preservation treatment, wherein the heat preservation material at the corners of the well wall is thickened, namely the thickness of the heat preservation material at the corners of the well wall is 2 times or more than that of the heat preservation material on the surface of the well wall;
s72, paving a concrete cushion layer in a preset well wall placing area before the concrete well wall is out of the steam curing shield, wherein the thickness range of the concrete cushion layer is 5 cm-15 cm;
s73, hoisting the concrete drilling well wall onto a concrete cushion layer, and carrying out natural maintenance until the design strength is reached, so as to prepare for suspension and sinking construction to form a shaft.
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