JP5973845B2 - Pipe cooling system and pipe cooling method - Google Patents

Description

  The present invention mainly relates to suppression of temperature cracks in concrete, and more specifically, a pipe that suppresses temperature rise of concrete by cooling concrete after placement using a refrigerant such as water or air. The present invention relates to a cooling system and a pipe cooling method.

  Concrete is the most important construction material together with steel, and is used in various structures including civil engineering structures such as dams, tunnels, and bridges, and architectural structures such as housing complexes and office buildings. This concrete structure may be manufactured in advance at a factory, etc., and transported to a specified location. However, in the case of a civil engineering structure or a building structure, it is constructed by placing concrete directly in a specified location. There are many. In any case, concrete (fresh concrete) in which cement, water, aggregates, etc. are mixed is placed in the formwork, and the concrete structure is constructed by removing the formwork after the concrete has hardened. It is common.

  As described above, concrete is a material that hardens over time. Specifically, as shown in FIG. 6, as the internal temperature of the concrete increases with time (FIG. 6 (a)), its strength also increases. It is a material that rises (Fig. 6 (b)) and also improves its elastic modulus (Fig. 6 (c)). By the way, it is a structure in the process of becoming a "hardened concrete" from fresh concrete or after hardening. Concrete cracks may occur while in service, and some of the concrete cracks are harmless that does not affect the use of the structure, but are harmful. There are also cracks, so the cause and mechanism of the occurrence of cracks have been fully elucidated so far, and various methods have been adopted for countermeasures. There.

  The types of cracks are classified according to the cause of the cracks, and are further roughly divided into causes before and after hardening the concrete. Causes before hardening include “initial cracks” caused by mold movement and abnormal setting of cement, “plastic shrinkage cracks” caused by rapid drying of the surface during curing, and the like. On the other hand, the causes after hardening are “dry shrinkage cracks” caused by shrinkage of cement gel due to water loss, “temperature cracks” caused by heat of hydration of cement, corrosion of reinforcing bars and alkali aggregate reaction. Examples include “physical / chemical cracks” that occur, and “structural cracks” that occur due to the action of excessive loads and the settlement of structures.

  It has been clarified by past studies and achievements that these cracks can be generally suppressed by appropriate design (mixing), construction, and curing. For example, in the case of a temperature crack, since it occurs due to a temperature difference between the inside and outside of the housing as described later, the following measures are adopted at the time of design and construction respectively. In other words, as a countermeasure at the time of designing, in order to suppress the rise in heat of hydration, the formulation design is devised, such as the use of low exothermic cement, the reduction of cement amount, the use of an admixture that reduces the heat of hydration. . Alternatively, the installation of a crack-inducing joint may be planned for the purpose of inducing a crack in a place where there is no influence even if a crack is relatively generated. Typical measures at the time of construction include pre-cooling, post-cooling, and long-term insulation curing. Pre-cooling is to cool the fresh concrete temperature at the time of pouring, using flaky ice for mixing water, spraying liquid nitrogen during mixing in mixers and track agitators, various cooling methods Is adopted.

  Post-cooling has a method of promoting natural cooling by providing a temperature diffusion surface inside the housing, such as a cooling slot, but pipe cooling, which cools concrete by passing cooling water through the pipe laid in the housing, is the mainstream. It is. In this pipe cooling, a cooling pipe such as a thin-walled steel pipe (hereinafter referred to as “cooling pipe”) is laid in the housing in advance, and after placing concrete, water or air at a low temperature (for example, concrete temperature −20 ° C. or less) ( Hereinafter, it is a rational and economical method that can be realized with relatively simple equipment and work by simply taking the “refrigerant” into the cooling pipe. Moreover, if there are rivers, ponds, etc. near the concrete placement site, it is easy to procure refrigerants, and cracking countermeasures can be implemented at a lower cost.

  Also, when it is necessary to develop concrete strength early, such as when it is necessary to complete a structure in a dry season in a river, etc. It may be difficult to cope with concrete blending such as use of cement and reduction of cement amount. If early-strength cement is used, as shown in FIG. 6 (a), the concrete temperature rises quickly, that is, tensile stress is generated in a state where the tensile strength is low, and this causes the occurrence of temperature cracking. . On the other hand, the pre-cooling measures are relatively expensive and require considerable equipment, and may not be adopted due to cost and yard problems. Pipe cooling can be used without any particular problem in such a case, so it can be said that this is an effective countermeasure against temperature cracks.

  However, pipe cooling has not been used so often until now. This is due to the fact that “horizontal pipe cooling” in which the cooling pipes are arranged horizontally is the mainstream. Usually, countermeasures against temperature cracks are often performed on mass concrete, which is large massive concrete. In the concrete standard method, when the plate thickness is 80-100 cm or more with a wide slab and the wall thickness is 50 cm or more with a wall having a constraint at the lower end, measures against temperature cracking are taken as mass concrete. If the mass concrete has a large spread in a plane, the arrangement of the cooling pipes is easy, and horizontal pipe cooling is also easy to adopt. However, mass concrete that needs countermeasures against temperature cracking includes columnar objects such as bridge piers and wall-shaped objects such as large-scale retaining walls. These columnar and wall-shaped mass concretes generally have a relatively small horizontal cross section and are long in the vertical direction. In such a case, horizontal pipe cooling is difficult to employ. Because the horizontal cooling pipes are laid in a narrow area, the work is extremely complicated due to the presence of rebars, and the number of lifts (vertical placement blocks) is divided, so complicated piping work is repeated. Because it must be done.

  By the way, in addition to horizontal pipe cooling, there is a technique called “vertical pipe cooling” in which cooling pipes are arranged in the vertical direction. The vertical pipe cooling is basically the same as the horizontal pipe cooling, but since there is various know-how in the details, it is actually being implemented by some people with many achievements. If the cooling pipe is laid in the vertical direction in advance, this vertical pipe cooling can be suitably used for the above-mentioned column-shaped and wall-shaped mass concrete without the need for piping the cooling pipe for each driving lift. In addition, since the water (refrigerant) that has flowed through the cooling pipe can be used as it is for surface submersion curing, it is an extremely rational countermeasure technique. That is, if this vertical pipe cooling and horizontal pipe cooling are appropriately adopted according to the situation, it is considered that pipe cooling is a more general countermeasure against temperature cracking.

  As described above, pipe cooling is an effective countermeasure against temperature cracking, and of course, various proposals related to pipe cooling have been made. For example, Patent Document 1 discloses an invention in which a spiral tube using a strip steel plate is used as a cooling tube (in this document, “tubular body”), and after cooling, the cooling tube is pulled up while returning to a strip shape.

JP 2007-303159 A

  When pipe cooling is performed, temperature analysis is performed in advance as specified in the concrete standard method. The temperature distribution after placing the concrete is obtained over time by analyzing the temperature and conditions of the shape and size of the frame, the constraint conditions of the frame, the concrete composition, the unexpected temperature, etc. Based on the volume change due to this temperature distribution, etc. Conduct a stress analysis of concrete and check for the occurrence of harmful cracks. If it is predicted that harmful cracks will occur, the pipe cooling conditions will be further planned by analysis. That is, the arrangement and quantity of pipes, the temperature of the refrigerant, and the like are set so that the temperature history does not cause temperature cracks.

  However, even if pipe cooling is performed under the planned conditions described above, there are many differences between the analytical temperature change and the actual temperature change. Normally, when temperature analysis is performed, the calculation is performed based on a completed frame, but in actual construction, concrete is placed in a predetermined lift height. FIG. 7 is a schematic diagram for explaining concrete placement for each lift. As shown in the example of this figure, the first lift is driven from 9 o'clock, but the fifth lift is not driven until 11:00. That is, a difference in material age of 2 hours has already occurred between the first lift and the fifth lift. In this way, in the analysis, the entire body is assumed to be the same age, but the actual concrete temperature tends to be higher than the analytical temperature because the age is actually different for each lift. . For the same reason, the time when the actual concrete reaches the maximum temperature (peak time) may be delayed from the peak time determined by the analysis. As the age advances, the elastic modulus of concrete increases, and as the elastic modulus is larger, tensile stress is more likely to occur as will be described later, and therefore, temperature cracking is more likely to occur as the peak time is delayed.

  However, it is rare to compare the concrete temperature from the analysis with the actual concrete temperature during construction. In addition, in order to measure temperature during or after placing concrete, a thermometer is installed in the housing in advance, but if the temperature cannot be measured due to unforeseen circumstances, or if the thermometer is broken There was no means to deal with this even when an erroneous measurement occurred due to the above. In addition, the actual concrete temperature has been monitored, and no appropriate measures have been taken when it rises above the analytical temperature. For this reason, even though pipe cooling was carried out as planned by analysis, it was not uncommon for thermal cracks to occur in the concrete frame.

  The object of the present invention is to monitor the concrete temperature during or after placing concrete, and if it is different from the concrete temperature in the analysis, change the conditions and perform pipe cooling to prevent the occurrence of temperature cracks. To provide a pipe cooling system and a pipe cooling method for suppressing the above. In addition, even if the thermometer installed in the enclosure stops functioning due to unforeseen circumstances, or even if the thermometer cannot be installed inside the enclosure, a means of grasping the concrete temperature during and after placement It is also an object of the present invention to provide this.

  In the present invention, while monitoring the concrete temperature during placement or after placement, while performing appropriate pipe cooling, the concrete temperature is estimated by focusing on the temperature change of the refrigerant used. It was based on an idea that did not exist.

The pipe cooling system of the present invention suppresses the temperature rise in the concrete by allowing cooling water to flow through the cooling pipe laid from the top to the bottom in the concrete. The cooling pipe, the refrigerant pressure feeding means, the temperature grasping Means, monitoring means, and adjustment determination means. The refrigerant pressure sending means is for sending cooling water into the cooling pipe, and the temperature grasping means is for obtaining the internal temperature of the concrete. The monitoring means obtains a temperature difference between the concrete internal temperature and the predicted temperature of the concrete obtained by analyzing under the condition that the cooling water is allowed to flow. The adjustment judging means cools based on the temperature difference. This is to determine whether or not the water temperature and flow rate need to be adjusted.

The pipe cooling system according to the present invention can also include an adjustment determination unit and a refrigerant pressure feeding unit having the following functions. That is, the adjustment determination means has a function surplus to calculate the proper temperature and proper flow rate of the cooling water flowing past on the basis of the temperature difference, coolant pumping means, on the basis of the proper temperature and proper flow rate is calculated by adjusting judging means And has a control function for adjusting the temperature and flow rate of the cooling water .
Moreover, the pipe cooling system of this invention can also be provided with the branch pipe. This branch pipe branches the cooling water sent from the refrigerant pressure feeding means into a plurality of cooling pipes, and the amount of cooling water pumped can be adjusted by selectively opening and closing the branch port of the branch pipe.

The pipe cooling system according to the present invention may include a refrigerant temperature measuring unit and a temperature estimating unit. The refrigerant temperature measuring means measures the temperature change of the cooling water while flowing, and the temperature estimating means estimates the concrete internal temperature based on the temperature change of the cooling water obtained by the refrigerant temperature measuring means. To do. In this case, the monitoring means obtains a temperature difference based on the concrete internal temperature obtained by the temperature estimation means and the predicted concrete temperature obtained by analyzing under the condition that the cooling water flows.

The pipe cooling system of this invention can also be equipped with the temperature measurement means which measures the internal temperature of concrete. The monitoring means in this case obtains a temperature difference based on the concrete internal temperature obtained by the temperature measuring means and the predicted concrete temperature obtained by analyzing under the condition that the cooling water flows.

The pipe cooling method of the present invention is a method for suppressing the temperature rise in the concrete by allowing cooling water to flow through the cooling pipes laid from the top to the bottom in the concrete. Prediction process, placing process, cooling process The method includes a monitoring step. In the prediction step, the temperature of the concrete is predicted by performing an analysis under the condition that the cooling water is allowed to flow. In the placing step, the concrete is placed with the cooling pipe laid. In the cooling process, cooling water is passed through the cooling pipe, and in the monitoring process, the concrete internal temperature is compared with the predicted concrete temperature. When the temperature difference obtained by the analysis of the monitoring process exceeds a predetermined threshold value, the cooling process is performed again after adjusting the temperature and flow rate of the cooling water .

The pipe cooling method of the present invention can be a method further comprising a refrigerant temperature measuring step and a temperature estimating step. In the refrigerant temperature measurement step, the temperature change of the cooling water while flowing is measured, and in the temperature estimation step, the concrete internal temperature is estimated based on the temperature change of the cooling water . The monitoring process in this case compares the concrete internal temperature obtained in the temperature estimation process with the predicted concrete temperature.

The pipe cooling method of this invention can also be set as the method provided with the temperature measurement process which measures the internal temperature of concrete. In this monitoring step, the concrete internal temperature measured in the temperature measurement step is compared with the predicted concrete temperature.
Further, the pipe cooling method of the present invention provides a branch pipe (one that branches the cooling water sent from the refrigerant pressure feeding means into a plurality of cooling pipes) when the temperature difference obtained by the comparison in the monitoring step exceeds a predetermined threshold. A method of adjusting the pumping amount of the cooling water by selectively opening and closing the branch port may be employed.

The pipe cooling system and the pipe cooling method of the present invention have the following effects.
(1) Since appropriate cooling according to the situation can be performed while grasping the actual concrete temperature during or after placing, temperature cracks can be reliably suppressed as compared with the conventional case.
(2) By estimating the concrete temperature based on the temperature change of the refrigerant that has passed through, it is possible to easily cope with unforeseen circumstances such as failure of a thermometer installed in the housing. Further, depending on the situation, a thermometer installed in the housing can be omitted, and in this case, the cost can be reduced.
(3) If the adjustment determination means calculates the proper temperature and flow rate of the refrigerant, the refrigerant can be adjusted immediately, so that more effective cooling can be performed.

1 is an overall perspective view showing a pipe cooling system and a pipe cooling method of the present invention. The schematic diagram which shows the condition which installed the thermometer in the housing and the cooling pipe. The perspective view which shows the condition where the cooling pipe was inserted in the casing pipe embed | buried in concrete. (A) is a detailed view showing a parallel type branch pipe, (b) is a detailed view showing a series type branch pipe. The relationship figure which shows the relationship between an actual concrete temperature change and the temperature change on analysis. (A) is a relationship figure which shows the time-dependent change of the internal temperature of concrete, (b) is a relation figure which shows the time-dependent change of the tensile strength of concrete, (c) is a relation figure which shows the time-dependent change of the static elastic modulus of concrete. The schematic diagram explaining the concrete placement for every lift.

  An example of an embodiment of a pipe cooling system and a pipe cooling method of the present invention will be described with reference to the drawings.

(Overview)
Since the present invention is a technology related to pipe cooling that suppresses temperature cracks, first, temperature cracks will be briefly described. It is known that cracks occur when a significant temperature difference occurs between the inside and near the surface of the concrete during the curing period. This is a so-called “temperature crack” phenomenon. This temperature crack is roughly divided into those caused by internal restraint and those caused by external restraint.

  As concrete hardens, the reaction between water and cement occurs. At that time, heat of hydration is generated, so the internal temperature of the concrete rises with time. However, if the outside air temperature is low, the portion close to the concrete surface (outer peripheral portion) does not increase so much by heat transfer. In addition, when a new concrete is handed over the existing concrete, the temperature of the concrete outer peripheral portion does not increase so much by conducting heat to the low temperature existing concrete. As a result, a remarkable temperature difference occurs between the inside and the outer periphery of the concrete, and a temperature crack occurs due to the tensile force acting on the outer periphery due to the difference in volume expansion. This is a temperature crack due to internal restraint.

  When the concrete reaches a predetermined temperature, it starts to drop in temperature. As the temperature drops, concrete tends to shrink as a whole, but it cannot be shrunk freely because it is in a restrained state where it is in contact with existing concrete. As a result, a difference in volume change occurs in the concrete, and a temperature crack occurs due to the tensile force acting inside. This is a temperature crack due to external constraints. Note that temperature cracks due to external constraints often result in cracks penetrating the housing.

In order to suppress the temperature cracks generated by such a mechanism, it is necessary to suppress the temperature rise inside the concrete. Here, the suppression of the temperature rise has the meaning of lowering the maximum temperature of the concrete and the meaning of lowering the concrete temperature at an early stage. As described above, the temperature crack is caused by the tensile stress due to the volume change of the concrete. The stress is determined by the product of strain and elastic modulus. Naturally, the smaller the elastic modulus, the smaller the stress applied. As shown in FIG. 6C, the elastic modulus of concrete is small while the age is young. In other words, if the concrete is young, even if the internal temperature rises, so much tensile stress does not occur. On the other hand, concrete that has been aged has a large elastic modulus, and it reacts sensitively to temperature rise and generates considerable tensile stress. As also described above, the peak time of the real concrete tends to lag behind that obtained by the analysis, which is a factor of one to generate a temperature cracks. Thus, how early the concrete temperature is lowered (during young age) is an important factor in cooling.

  Next, an outline of the present invention will be described. Note that the present invention is an invention related to pipe cooling and can be implemented by horizontal pipe cooling or vertical pipe cooling, but here, for convenience, the case of vertical pipe cooling will be described. FIG. 1 is an overall perspective view showing a pipe cooling system and a pipe cooling method of the present invention. The frame 1 in this figure is a pier constructed in a river, and is constructed in a state where it is dried by a closing sheet pile 2. A plurality (ten in the figure) of casing pipes 31 are installed in the housing 1 in advance, and cooling pipes 32 are inserted into the casing pipe 31. In this figure, a flexible hose is used as the cooling pipe 32.

  In this case, the refrigerant flowing through the cooling pipe 32 is river water and is pumped up by a water intake pump. Cooling water (refrigerant) pumped up by the water intake pump is stored in the water tank by the water intake hose, further pumped up by the water supply pump 33, and sent to the first branch pipe 35 through the first water supply hose 34. The second water supply hose 36 branched from the first branch pipe 35 is connected to the second branch pipe 37 and further branches into a plurality of cooling pipes 32 from here. Thus, one end of the cooling pipe 32 is connected to the second branch pipe 37 and the other end extends to the vicinity of the bottom of the casing pipe 31, whereby the cooling water can flow from the top of the housing 1 to the bottom. it can. The cooling water that has flowed to the bottom of the housing 1 may be accumulated on the upper surface of the housing 1 for water curing, or may be drained to a river or the like through a drain pipe 38 as shown in FIG.

  Before placing the concrete of the frame 1, a temperature analysis is performed under the same conditions as in the construction, and the concrete temperature history (change over time) is predicted. Then, during and after the concrete placement of the frame 1, the concrete temperature is measured by the frame thermometer 4 shown in FIG. 2. FIG. 2 is a schematic diagram showing a situation in which thermometers are installed in the housing 1 and the cooling pipe 32. As shown in this figure, the frame thermometer 4 is disposed in the center where the temperature of the concrete increases significantly, and is attached to, for example, a reinforcing bar. The predicted temperature by analysis and the temperature actually measured by the housing thermometer 4 are compared, and when the temperature difference is larger than a predetermined threshold value, the temperature and amount of cooling water are adjusted.

  The temperature of the concrete can also be estimated from the temperature change of the cooling water flowing through the cooling pipe 32. Since the cooling water lowers the concrete temperature by exchanging heat with the concrete, the temperature of the cooling water after flowing sufficiently through the housing 1 is higher than that immediately after entering the housing 1. Should have been. For example, when cooling water is allowed to flow from the upper part to the lower part using the cooling pipe 32 and is discharged as it is from the lower end, the upper refrigerant thermometer 5U shown in FIG. 2 has the lowest temperature. The temperature should be higher in the order of 5C and the lower refrigerant thermometer 5L. Or it is a case where the cooling pipe 32 is inserted in the casing pipe | tube 31, Comprising: A cooling water is made to flow through from the upper part to a lower end in the cooling pipe 32, and between the casing pipe | tube 31 and the cooling pipe | tube 32 flows upwards. When the temperature is lowered with cooling water, the lower refrigerant thermometer 5L shown in FIG. 2 has the lowest temperature, and hereinafter, the central refrigerant thermometer 5C and the upper refrigerant thermometer 5U should show higher temperatures in this order. If the temperature change of the cooling water in a state where the concrete temperature is normally lowered is grasped in advance, whether or not the concrete temperature has fallen as planned based on the measurement results of the refrigerant thermometers 5U, 5C, and 5L. As a result, the temperature and amount of cooling water can be adjusted.

  Hereinafter, the present invention is divided into a “pipe cooling system” and a “pipe cooling method”, and will be described in detail for each constituent element. The contents common to the pipe cooling system and the pipe cooling method will be described in the example of the pipe cooling system, and the contents specific to the pipe cooling method will be described.

1. Pipe cooling system (refrigerant)
The refrigerant is a low-temperature medium that flows through the refrigerant pipe 32, and water is a typical example. In addition to water, air or the like can be used, or a liquid other than water or a gas other than air can be used. The refrigerant needs to be at a low temperature, and the temperature can be designed as appropriate. In general, the refrigerant is set to a temperature 20 ° C. or more lower than the concrete temperature to be placed. Here, the case where the refrigerant is “water” will be described, and this water is referred to as “cooling water”.

(Cooling pipe)
The cooling pipe 32 is a hollow pipe because the cooling water is allowed to flow through it. In FIG. 1, a flexible hose is used, but various other pipes such as a thin steel pipe and a vinyl chloride pipe are used. be able to. The cooling pipe 32 is installed in the range in which the concrete temperature is to be lowered in the casing 1. For example, when the entire casing 1 is to be cooled, the cooling pipe 32 is densely planar as shown in FIG. 1 and from the top to the bottom. 32 is arranged.

  In order to cool the concrete of the casing 1, the cooling pipe 32 is embedded in the casing 1, but the concrete may be cast with the cooling pipe 32 installed at a predetermined position in the formwork. However, as shown in FIG. 3, the casing pipe 31 can be embedded in the concrete, and the cooling pipe 32 can be inserted therein. The casing tube 31 needs to be self-supporting within the formwork, and can be attached to a reinforcing bar in the formwork or a frame made of shape steel (for example, angle steel). In the case of vertical pipe cooling, concrete can be cast for each lift with the casing pipe 31 (or cooling pipe 32) installed, but in the case of horizontal pipe cooling, after placing for each lift, each time A cooling pipe 32 (or casing pipe 31) is installed on the concrete surface.

(Refrigerant pressure feeding means)
The refrigerant pressure feeding means supplies cooling water into the cooling pipe 32, and the water supply pump 33 shown in FIG. 1 is preferably used. As shown in FIG. 1, cooling water can be stored in a water tank as a water source, pumped from here by a water supply pump 33, and sent to the water source, or depending on the situation of the site, the water supply pump 33 can be directly installed in a water source such as a river. It can also be pumped up. As will be described later, when adjusting the temperature of the cooling water, it is desirable to store the cooling water in a water tank or the like and adjust the temperature using this water tank.

  Usually, since a large number of cooling pipes 32 are installed in the housing 1, a branching unit is placed between the water supply pump 33 and the cooling pipe 32. This branching means is not limited to one place, and may be installed at a plurality of places. In FIG. 1, there are one parent branch pipe (first branch pipe 35) and two child branch pipes (second branch pipe 37). Placed in place. FIG. 4 is a detailed view showing a branch pipe, where (a) shows a parallel-type branch pipe and (b) shows a series-type branch pipe. This branch pipe is provided with a main pipe 35a and a plurality of (six locations in the figure) branch openings 35b. Cooling water supplied from the water supply pump 33 enters the main pipe 35a and is connected to the cooling pipe 32 connected to the branch opening 35. Sent. Of course, the branch pipe is preferably made of a material or a structure that takes water pressure into consideration.

(Concrete temperature prediction)
Before placing the concrete of the frame 1, a temperature analysis is performed in advance to predict how the temperature distribution in the frame 1 will change over time. Since the concrete temperature predicted here is compared with the actual temperature measurement result, this temperature analysis is performed in accordance with various conditions in actual placement. In addition, the temperature analysis performed here can employ | adopt various analysis methods, such as a finite element method, a finite difference method, a Schmidt method, and a Carlson method. The result (predicted temperature) obtained by the temperature analysis is recorded in a storage medium (computer hard disk, CD-ROM, etc.) in a format that can be processed by a computer, for example.

(Temperature grasping means)
When the concrete of the frame 1 is placed, the actual concrete temperature is grasped by the temperature grasping means. This temperature grasping means is roughly divided into a method for directly measuring concrete temperature and a method for indirectly estimating the concrete temperature from the temperature change of the cooling water. When measuring concrete directly, it measures with the frame thermometer 4 (temperature measurement means) installed in the frame 1 as shown in FIG. The housing thermometer 4 can be measured in a state of being embedded in concrete, and can be exemplified by a thermocouple, for example. The housing thermometer 4 is installed at a location where the temperature is to be grasped in the housing 1. For example, in the central portion of the housing 1 where the temperature rise is expected to be the highest or in the vicinity of the surface of the housing 1, in any number of locations. Installed. In addition, in order to embed the frame thermometer 4 in the concrete, the frame thermometer 4 is attached using a reinforcing bar or the like before placing.

  When estimating the concrete temperature indirectly from the temperature change of the cooling water, grasp the temperature change of the cooling water. As described above, the temperature drop of the concrete is performed by heat exchange with the cooling water. By grasping the temperature difference of the cooling water before entering the housing 1 and when leaving the housing 1, the temperature of the concrete is reduced. The amount of descent can be estimated. Therefore, it is necessary to measure the temperature of the cooling water at two or more locations. Desirably, the cooling water temperature immediately before entering the housing 1 or immediately after entering the housing 1 is measured, the cooling water temperature immediately after exiting the housing 1 or immediately before exiting, and the temperature difference is grasped. As shown in FIG. 2, the coolant temperature near the center may be measured. When measuring the temperature of the cooling water, a refrigerant thermometer (refrigerant temperature measuring means) such as a thermocouple is attached to the surface (outside) of the refrigerant pipe 32, or a refrigerant thermometer is attached inside the refrigerant pipe 32 and measured. Similarly to the housing thermometer 4, the refrigerant thermometer can use a thermocouple or the like.

  By analyzing based on the temperature change of the cooling water, the amount of decrease in the concrete temperature can be estimated. For example, if the amount of heat is calculated using various conditions such as concrete volume, shape, placement temperature, arrangement and number of cooling pipes 32, flow rate (flow velocity) of cooling water, etc., the amount of decrease in concrete temperature can be obtained. it can. This calculation is executed by temperature estimation means such as a computer, and can be processed by a computer as a program, for example, and can be simulated in advance or processed immediately during or after placing concrete.

(Monitoring means)
The monitoring means compares the concrete predicted temperature obtained by the temperature analysis performed in advance with the concrete measured temperature obtained by the temperature grasping means. As described above, the concrete measured temperature tends to be higher than the concrete predicted temperature. FIG. 5 is a relationship diagram showing the relationship between the actual concrete temperature change and the analytical temperature change. Usually, pipe cooling is planned so as not to cause temperature cracks, and this is confirmed by temperature analysis. Therefore, as shown in this figure, if the actual measured temperature of the concrete continues to be higher than the predicted concrete temperature, there is a risk that temperature cracks will eventually occur. In order to prevent this, the concrete measurement temperature and the concrete prediction temperature are compared by the monitoring means.

  The comparison by the monitoring means is performed in a state where the measurement point and the measurement time are combined. Specifically, the predicted temperature analyzed under the same conditions as the position within the housing 1 where the temperature was actually measured, the time when the temperature was actually measured (for example, the elapsed time from the start of placing), is used for comparison by the monitoring means. The comparison between the two can be displayed as a graph as shown in FIG. 5, for example. Further, if the concrete measured temperature and the concrete predicted temperature are stored in a format that can be processed by a computer, a graph or a list can be displayed on a display or the like.

  Further, the monitoring means calculates a temperature difference that is a difference between the actually measured concrete temperature and the predicted concrete temperature. This calculation can be processed by a computer by a program. This program can have a function of inputting the actual measured concrete temperature and the predicted concrete temperature, and can also have a function of reading the actual measured concrete temperature and the predicted concrete temperature stored in the storage medium in advance. The temperature difference calculated here is stored in a storage means (computer hard disk, CD-ROM, etc.) in a computer processable format.

(Adjustment judgment means)
The adjustment determination unit determines whether or not the cooling water needs to be adjusted based on the temperature difference obtained by the monitoring unit. The cooling water is adjusted by changing the temperature of the cooling water, changing the amount of water, or a combination of both. Specifically, a threshold value is provided in advance, the temperature difference is compared with this threshold value, and if it is larger than the threshold value, it is determined that adjustment of the cooling water is necessary, and a message to that effect is displayed. When the temperature difference is smaller than the threshold value, this may be displayed, but it may not be displayed. This adjustment determination means can also be processed by a computer by a program.

  For example, when the concrete measured temperature is higher than the concrete predicted temperature and the temperature difference is larger than the threshold value, the cooling water temperature is lowered or displayed instead of (or in addition to) the cooling water amount. . Alternatively, if the measured concrete temperature is lower than the predicted concrete temperature and the temperature difference is greater than the threshold, the cooling water temperature decrease is stopped, or instead (or in addition), the cooling water amount is reduced. You can also

  The temperature adjustment of the cooling water can be realized by providing cooling means in the water tank shown in FIG. In addition, the amount of cooling water can be adjusted by adjusting the pressure of the refrigerant pumping means (water supply pump 33), or the branch of the main branch pipe (first branch pipe 35) or the sub branch pipe (second branch pipe 37). This can also be realized by selectively opening and closing 35b.

  An appropriate temperature (appropriate temperature) and an appropriate flow rate (appropriate flow rate) of the cooling water can be calculated based on the temperature difference between the concrete measured temperature and the concrete predicted temperature. As explained in the temperature estimation means, for example, if the calorific value is calculated using various conditions such as the volume and shape of the concrete and the water temperature and flow rate (flow velocity) of the current cooling water, Appropriate flow rate can be obtained. This calculation can be processed by a computer as a program, and can be simulated in advance or processed immediately during or after concrete placement.

  Furthermore, it is possible to provide a control means for automatically adjusting the cooling water based on the appropriate temperature and the appropriate flow rate of the cooling water obtained by the adjustment determining means. This control means receives the information on the appropriate temperature and the appropriate flow rate sent from the adjustment determination means, adjusts the cooling means such as the water tank or adjusts the pressure of the refrigerant pressure sending means according to the information, and branches the branch pipe branch 35b Select to open and close.

2. Pipe cooling method (prediction process)
The prediction step is a step of performing a temperature analysis in advance before placing the concrete of the frame 1, and the content thereof is the same as the description of “concrete temperature prediction” of the pipe cooling system.

(Placement process)
The placing process is a process of placing concrete in a state where the formwork and the bar arrangement are performed and the casing pipe 31 (or the cooling pipe 32) is installed. If necessary, before placing concrete, a frame thermometer (temperature measuring means) is installed on the reinforcing bar and the like, and a refrigerant thermometer (refrigerant temperature measuring means) is installed on the cooling pipe 32.

(Cooling process)
The cooling step is a step of reducing the temperature of the concrete by passing cooling water through the cooling pipe 32. When the cooling process is carried out, the concrete internal temperature is grasped. In order to grasp the concrete internal temperature, the concrete internal temperature is directly measured by a frame thermometer installed in the concrete (temperature measurement process), or the temperature change of the refrigerant is measured by a refrigerant thermometer installed in the cooling pipe 32. However, it is possible to appropriately select such as estimating the concrete internal temperature based on the temperature change (temperature estimation step) or grasping the combination of both.

(Monitoring process)
In the monitoring process, the concrete internal temperature is compared with the predicted concrete temperature predicted in the prediction process, and a temperature difference that is the difference between the two is obtained. Furthermore, this temperature difference is compared with a predetermined threshold value to determine whether or not adjustment of the cooling water (adjustment of temperature and flow rate) is required. It should be noted that the calculation of the temperature difference and the necessity of adjustment of the cooling water can be made by human judgment, or as explained in “Concrete temperature prediction” of the pipe cooling system, it can be processed by a computer as a program. Good. When adjustment of the cooling water (adjustment of temperature and flow rate) is required, the temperature of the cooling water is adjusted by adjusting the cooling means provided in the water tank or the like, and the pressure of the refrigerant pumping means (water supply pump 33) is adjusted. Alternatively, the flow rate of the cooling water is adjusted by selectively opening and closing the branch ports 35b of the parent branch pipe (first branch pipe 35) and the child branch pipe (second branch pipe 37).

  The pipe cooling system and the pipe cooling method of the present invention can be used for civil engineering structures such as bridge substructures and dams, building structures such as office buildings, and other various concrete structures. Considering that the present invention provides a high-quality concrete structure with few temperature cracks, it can be said that the invention can be used not only industrially but can also make a great social contribution.

DESCRIPTION OF SYMBOLS 1 Housing 2 Closing sheet pile 31 Casing pipe 32 Cooling pipe 33 Water supply pump 34 1st water supply hose 35 1st branch pipe 35a (Branch pipe) main pipe 35b (Branch pipe) branch port 36 2nd water supply hose 37 2nd branch pipe 38 Drain pipe 33 Water supply pump 4 Body thermometer 5U Upper refrigerant thermometer 5C Central refrigerant thermometer 5L Lower refrigerant thermometer

Claims (7)

In the pipe cooling system that suppresses the temperature rise inside the concrete by flowing the cooling water through the cooling pipe laid in the concrete,
A cooling pipe laid from the top to the bottom in the concrete,
A refrigerant pressure sending means for sending the cooling water into the cooling pipe;
Concrete temperature grasping means for acquiring the internal temperature of the concrete;
Monitoring means for obtaining a temperature difference between the concrete internal temperature obtained by the concrete temperature grasping means and the predicted temperature of the concrete obtained by analyzing under the condition of flowing the cooling water ;
An adjustment determination means for determining whether or not the temperature and / or flow rate of the cooling water needs to be adjusted based on the temperature difference obtained by the monitoring means;
A pipe cooling system characterized by comprising: The adjustment determination means calculates an appropriate temperature and / or an appropriate flow rate of the cooling water that flows based on the temperature difference,
The refrigerant pressure feeding means includes a control function for adjusting the temperature and / or flow rate of the cooling water to be pressure-fed based on the appropriate temperature and / or the appropriate flow rate calculated by the adjustment determination means.
The pipe cooling system according to claim 1. A branch pipe for branching the cooling water sent from the refrigerant pressure feeding means into a plurality of the cooling pipes;
By selectively opening and closing the branch port of the branch pipe, the pumping amount of the cooling water can be adjusted.
The pipe cooling system according to claim 1 or 2, characterized by the above. Refrigerant temperature measuring means for measuring a temperature change of the cooling water while flowing,
Temperature estimating means for estimating the concrete internal temperature based on the temperature change of the cooling water obtained by the refrigerant temperature measuring means,
The monitoring means obtains a temperature difference between the concrete internal temperature obtained by the temperature estimation means and the predicted temperature of the concrete obtained by analyzing under conditions for allowing the cooling water to flow.
The pipe cooling system according to any one of claims 1 to 3, wherein the pipe cooling system is provided. In the pipe cooling method that suppresses the temperature rise inside the concrete by flowing the cooling water through the cooling pipe laid in the concrete,
Analyzing under the condition of flowing the cooling water , predicting the temperature of the concrete,
A placing step of placing concrete in a state where the cooling pipe is laid,
A cooling step of allowing the cooling water to flow through the cooling pipe laid from the top to the bottom ;
A monitoring step of comparing the concrete internal temperature and the predicted concrete temperature predicted in the prediction step,
When the temperature difference obtained by the comparison in the monitoring step exceeds a predetermined threshold, the temperature and / or flow rate of the cooling water is adjusted.
A pipe cooling method characterized by that. A refrigerant temperature measuring step of measuring a temperature change of the cooling water while flowing,
A temperature estimation step of estimating the concrete internal temperature based on the temperature change of the cooling water obtained in the refrigerant temperature measurement step,
The monitoring step compares the concrete internal temperature obtained in the temperature estimation step with the predicted concrete temperature.
6. A pipe cooling method according to claim 5, wherein: When the temperature difference obtained by the comparison in the monitoring step exceeds a predetermined threshold value, the cooling water is selectively opened and closed to open and close the branch pipe branch that branches the cooling water into the plurality of cooling pipes. Adjust the pumping amount,
The pipe cooling method according to claim 5 or 6, characterized by the above.

Images