JP2012082667A - Management method of concrete compaction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method of more objectively and quantitatively evaluating concrete compaction based on stable fundamental data having less noise, without using a complicated device.SOLUTION: An oil pressure gauge 3 and/or an oil pressure sensor are installed in a hydraulic hose 10 between a hydraulic pump and a vibrator 1. During insertion of an oscillating vibrator 1 into placed concrete C for compacting the concrete C, the oil pressure of the vibrator 1 compacting the concrete C is measured with the oil pressure gauge 3 and/or an oil pressure sensor, so that the degree of compaction of the concrete C is evaluated by the variation with time in oil pressure of the vibrator 1.

Description

  The present invention relates to a concrete compaction management method used for evaluating the degree of compaction when mass concrete such as dam concrete is compacted.

In concrete dam construction, compacting of dam concrete is very important to ensure the watertightness, durability and strength of the dam body. According to the Japan Society of Civil Engineers Standard Specification (Dam), when compacting with an internal vibrator, “determining the insertion interval of the vibrator and the vibration time per location so that a uniform vibration is applied to the concrete that has been laid. It is necessary to make these known to the workers in advance. " In addition, as evidence that the compaction is sufficient, it is no longer possible to see a line of cement paste appearing on the contact surface between the concrete and the board, or the concrete volume is reduced, and the surface appears shiny. Judging from the fact that the entire concrete appears to have melted uniformly. And in the case of general concrete, the standard of compaction time is supposed to be 5 to 15 seconds.
By the way, in the construction of such a dam, since a hydraulic heavy machine equipped with a vibrator called a vibrate is used as an internal vibrator in the main part of the dam concrete, the insertion interval of the vibrator is an interval between vibrators already installed, for example, It becomes about 60 cm. Moreover, in the case of dam concrete, the compaction time by buy-back is longer than that of general concrete, and is about 40 seconds when judged from the accumulated standard of dam concrete. In this case, the compaction time of the concrete is determined by the operator's visual inspection. The management situation for obtaining is not always sufficient.
Therefore, conventionally, it has been proposed to evaluate the completion of compaction of concrete by quantitatively observing the load on the vibrator and changes in the physical properties of the concrete. This kind of compaction evaluation method is described in Patent Documents 1 and 2 and the like.

  Patent Document 1 relates to an effective operation management device for a concrete vibrator. In this management device, operation status data having a correlation with a load at the time of concrete vibrator operation of any one of power factor, frequency, and volume is detected, and the detection is performed. By comparing the measured value with a threshold value, it is determined whether or not the concrete vibrator is in an operating state that contributes to compaction. By managing the effective operation time in this manner, the operator can perform a compacting operation that meets the standard without depending on experience, and the administrator can manage the effective operation time as numerical data. As a result, the concrete compaction work conforming to the standard is performed, and the concrete compaction work and, consequently, the reliability of the concrete strength is improved.

  Patent Document 2 relates to a concrete compaction judgment method. In this judgment method, the sound pressure due to vibration of a vibrator rises over time from the start of compaction to the end of compaction, and peaks. Appropriate sound pressure due to vibration of the vibrator from the start of compaction to the end of compaction Approximate the time-varying data with an envelope and set the joint load coefficient as the teacher data with the maximum matching rate, and then start compaction of the concrete in the process of completing the neural network and the actual compaction work While detecting the sound pressure change over time due to the vibration of the vibrator, A step of sequentially comparing the change in sound pressure due to sound with the teacher data using the neural network to obtain a match rate between the two, and a step of determining completion of compaction when the match rate is equal to or greater than a predetermined threshold value. Is included. In this way, it is possible to know the appropriate timing to stop the vibrator regardless of human judgment, so it is not possible to obtain sufficient strength because the vibrator is applied for too short time, or the time for applying the vibrator is too long for breathing It becomes possible to solve the problem of water generation, reduce the burden of monitoring the timing of compaction judgment by the worker, and can cope with the current situation where skilled workers are insufficient. To do.

Japanese Patent No. 3605576 Japanese Patent No. 4404494

  However, the concrete compaction evaluation method according to Patent Documents 1 and 2 has the following problems. Buyback is a compacting machine used in the construction site of concrete dams, and a vibrator is mounted on a hydraulic heavy machine. For this reason, the power factor for managing the power efficiency cannot be used. Also, when detecting the volume, other heavy equipment and construction machines (cable cranes and transporting machines) are in operation during concrete placement, and these sounds are also detected. Many. The frequency at which vibration is directly measured has changes such as amplitude, and is not necessarily proportional to the load. That is, even if the frequency increases, the total load may be the same if the amplitude increases.

  The present invention solves such a conventional problem, and this kind of concrete compaction management method is based on stable basic data with less noise by a simple method without using a complicated device. The objective is to evaluate the compaction of concrete more objectively and quantitatively.

In order to achieve the above object, the present invention applies vibration to the placed concrete by using a hydraulic vibrator that vibrates the vibrator by pressure oil supplied from the hydraulic pump through a hydraulic pipe by driving the hydraulic pump. In a concrete compaction management method for evaluating the degree of concrete compaction by measuring various data correlated with the load during operation of the vibrator during compaction of concrete to be compacted, A hydraulic meter and / or a hydraulic sensor for measuring the hydraulic pressure of the vibrator is installed, and while the vibrator is inserted into the placed concrete and the concrete is compacted, the vibrator concrete is removed by the hydraulic meter and / or the hydraulic sensor. Measure the hydraulic pressure when compacting, and the vibrator The hydraulic pressure of aging, to evaluate the tightening degree hardened concrete, is summarized in that.
In this case, the hydraulic pressure of the vibrator starts to increase with the insertion of the vibrator in the hydraulic pressure gauge and / or the hydraulic pressure sensor, rises with time, reaches a peak, and gradually decreases as the concrete compaction progresses. The time change of the oil pressure approaching a substantially constant value is displayed, and when the oil pressure or the slope of the oil pressure change falls below a predetermined threshold, or when the rate of decrease in the oil pressure decreases Is preferably determined as completion of compaction of the concrete.
In this case, it is preferable to perform a warming-up operation of the vibrator and to keep the temperature of the pressure oil constant before measuring the hydraulic pressure of the vibrator.

  According to the concrete compaction management method of the present invention, a hydraulic meter and / or a hydraulic sensor is installed in the hydraulic pipe between the hydraulic pump and the vibrator, and the vibrator is inserted into the concrete in which the vibrator is placed. During compaction, the hydraulic pressure at the time of compacting the vibrator concrete is measured with a hydraulic meter and / or a hydraulic sensor, and the degree of compaction of the concrete is evaluated by the change in the vibrator hydraulic pressure over time. When the pressure drops below a predetermined threshold value, or when the rate of decrease in hydraulic pressure decreases, it is determined that the compaction of the concrete has been completed, so there is less noise using a simple method without using complicated equipment. More objective and quantitative evaluation of concrete compaction based on stable foundation data It can Rukoto exhibits exceptional effect that.

The figure which shows the compaction management method of the concrete by this invention The figure which shows the time-dependent change of the oil pressure of a hydraulic vibrator and the 1st floor, 2nd floor, 3rd floor differential curve

Next, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 shows a concrete compaction management method. As shown in FIG. 1, this concrete compaction management method uses a hydraulic vibrator 1 that vibrates a vibrator 11 with pressure oil supplied from the hydraulic pump through a hydraulic hose (hydraulic pipe) 10 by driving the hydraulic pump. Then, when concrete is compacted by applying vibration to the placed concrete C, the hydraulic pressure of the vibrator 1 having a correlation with the load during operation of the vibrator 1 is measured to evaluate the degree of compaction of the concrete C. To do. In contrast to the conventional power factor, frequency, volume, and sound pressure caused by vibration of the vibrator, which are correlated with the load during vibrator operation, hydraulic pressure is considered to be the most comprehensive expression of dynamic load. The characteristic of the measured load fluctuation is close to the theoretical prediction.
In this concrete compaction work, a construction machine vibrator 2, in which a hydraulic vibrator 1 is mounted on a dedicated base machine, is employed in order to compact mass concrete such as dam concrete. Here, the buyback 2 includes a crawler 21, an operator cab 22 and a machine cab 23 that are rotatably disposed on the crawler 21, and an actuator 24 and a hydraulic vibrator 1 provided on the front side of the cab 22. The actuator 24 has a boom 242 supported by a cylinder 241 so as to be tiltable by a front portion of the cab 22, and an arm 244 supported rotatably by a cylinder 243 at a tip portion of the boom 242. The hydraulic vibrator 1 is attached to the front end portion of the cylinder by a cylinder 245 so as to be rotatable. In this case, the hydraulic vibrator 1 includes four rod-shaped vibrators 11, and a hydraulic motor (not shown) is driven by pressure oil supplied from the hydraulic pump through the hydraulic hose 10 by driving a hydraulic pump (not shown). Each rod-shaped vibrator 11 is vibrated.

  In this concrete compaction management method, the hydraulic pressure of the vibrator 1 is measured between a hydraulic hose 10 connected between the hydraulic pump of the vibrator 2 and the vibrator 1 and supplying pressure oil from the hydraulic pump to the vibrator 1. While the hydraulic meter 3 and / or the hydraulic sensor are installed and the vibrating vibrator 1 is inserted into the placed concrete C and the concrete C is compacted, the concrete C of the vibrator 1 is compacted by the hydraulic meter 3 and / or the hydraulic sensor. The hydraulic pressure at the time is measured, and the degree of compaction of the concrete C is evaluated by the change with time of the hydraulic pressure of the vibrator 1. Then, the time point when the compaction of the concrete C is completed is determined by a predetermined method using the change in hydraulic pressure over time.

  When installing the hydraulic gauge 3 and / or the hydraulic sensor in the hydraulic hose 10, the hydraulic circuit of the Viback 2 is complicated, but the hydraulic system connected from the hydraulic pump to the vibrator hydraulic circuit is independent, Whether the boom 242 or the arm 244 is used by installing the oil pressure gauge 3 and / or the oil pressure sensor in the independent part so that the oil pressure gauge 3 and / or the oil pressure sensor is not affected by other hydraulic systems. Regardless, it is possible to measure the hydraulic pressure acting only on the vibrator 1. By arranging the vibrator's hydraulic meter 3 at a position that can be seen from the cab 22 or the driver's seat, the operator of the buyback 2 can always check the hydraulic pressure of the vibrator 1 with the hydraulic meter 3. Also, by connecting the hydraulic sensor to a personal computer, the hydraulic pressure can be converted into a voltage by the hydraulic sensor and recorded on a personal computer or the like.

  By installing the hydraulic pressure gauge 3 and / or the hydraulic sensor in the hydraulic hose 10 of the vibrator 1 of the vibe 2 as described above, the operator of the vibe 2 can easily measure the oil pressure of the vibrator 1. While the operator inserts the vibrating vibrator 1 into the placed concrete C and compacts the concrete C, the operator displays the change in the hydraulic pressure of the vibrator 1 on the hydraulic gauge 3 and / or the hydraulic sensor, and monitors the hydraulic pressure. Check the progress of compaction of concrete C. In this case, before measuring the hydraulic pressure of the vibrator 1, it is preferable to perform a warm-up operation of the vibrator 1 so that the temperature of the pressure oil is constant. While the concrete C is compacted, when the change over time of the hydraulic pressure of the vibrator 1 is displayed by the hydraulic gauge 3 and / or the hydraulic sensor, the hydraulic pressure of the vibrator 1 starts increasing with the insertion of the vibrator 1 and increases with the passage of time. As a result, the hydraulic pressure gradually decreases with the progress of compaction of the concrete C, and approaches a substantially constant value. The operator evaluates the degree of compaction of the concrete C from this change in hydraulic pressure over time.

  Measure the oil pressure when compacting the vibrator concrete with an oil pressure gauge and / or oil pressure sensor, and see the result of this oil pressure measurement as a time-dependent curve of the oil pressure. is doing. The tendency of this curve is similar to the monitoring results of vibrator load torque in previous studies. When the concrete compaction behavior is examined, concrete compaction is performed in two stages according to the load torque literature. Done. In the first stage, the cement paste is liquefied, the aggregate particles are arranged and moved, and the horizontally placed aggregate particles try to change into a vertical state, and a maximum load torque is generated. Here, the concrete and the vibrator are in close contact with each other, and the load on the vibrator is maximized. This is the initial settlement stage. In the second stage, bubbles in the concrete (mainly entrapped air) move upward and defoaming occurs. A liquefied cement paste layer is formed in the vicinity of the vibrator, causing material separation. Here, the degree of adhesion between the concrete and the vibrator decreases. As a result, the transmission of the vibration wave is lowered, and it is considered that the load torque is reduced. Here, the subsidence of the surface settles and becomes stable, and approaches the torque during idling. If this stage is continued for a long time, material separation occurs. An oil pressure gauge and an oil pressure sensor are effective in grasping such load torque easily and reliably.

This concrete compaction evaluation method uses the change in the hydraulic pressure of the vibrator over time (the shape of the hydraulic pressure change curve), but the degree of concrete compaction varies depending on the physical properties of the concrete and construction conditions. Based on the above, a test is performed at each construction site, and the concrete compaction point is determined from the change over time of the vibrator hydraulic pressure. There are several determination methods, but typical ones are as follows.
(1) It is determined that concrete compaction is complete when the hydraulic pressure falls below a certain threshold. In the case shown in FIG. 2, it is determined that the compaction is completed at 65 seconds.
(2) It is determined that the compaction of the concrete has been completed when the slope of the change in hydraulic pressure becomes smaller than a certain threshold value. In the case shown in FIG. 2, it is determined that the compaction is completed at the time point of 70 seconds.
(3) It is determined that the concrete has been compacted when the degree of adhesion between the concrete and the vibrator decreases and the rate of decrease in hydraulic load decreases. If the shape of the second-order differential of the oil pressure change curve is a positive number, the oil pressure change over time is concave, and the change point at which this maximum value is reached, that is, the point at which the change rate of the recess is maximized is determined by compaction. It can be considered a standard. This point is the point at which the curve of the third order derivative changes from positive to negative. In the case shown in FIG. 2, it is determined that the compaction is completed at the time point of 46 seconds.

  As described above, according to the concrete compaction management method, while the vibrator 1 to be vibrated is inserted into the placed concrete C and the concrete C is compacted, the vibrator 1 and / or the hydraulic sensor is used for the vibrator 1. The hydraulic pressure when compacting the concrete C is measured, and the degree of compaction of the concrete C is evaluated by the change of the hydraulic pressure of the vibrator 1 over time. The slope of the change of the hydraulic pressure or the hydraulic pressure is lower than a predetermined threshold value. Since it is determined that the compaction of the concrete C is completed at the point in time or when the rate of decrease in hydraulic pressure is reduced, the compaction of the concrete C can be evaluated more objectively and quantitatively, and there is less noise. Since there are few conditions other than the compaction of the oil pressure, there is an advantage that the data is stable. In addition, since only the hydraulic gauge 3 and / or the hydraulic sensor are installed in the hydraulic system of the vibrator 1, there is an advantage that it is simple and has few failures without using a complicated device.

1 Hydraulic vibrator 10 Hydraulic hose (hydraulic pipe)
DESCRIPTION OF SYMBOLS 11 Bar-shaped vibrator 2 Buyback 21 Crawler 22 Operation room 23 Machine room 24 Actuator 241 Cylinder 242 Boom 243 Cylinder 244 Arm 245 Cylinder 3 Oil pressure gauge C Concrete

Claims (3)

When the concrete is compacted by using a hydraulic vibrator that vibrates the vibrator with pressure oil supplied from the hydraulic pump through a hydraulic pipe by driving the hydraulic pump, In a concrete compaction management method for measuring the degree of compaction of concrete by measuring various data correlated with the load during operation of the vibrator,
A hydraulic meter and / or a hydraulic sensor for measuring the hydraulic pressure of the vibrator is installed in the hydraulic pipe,
While inserting the vibrator into the placed concrete and compacting the concrete, the hydraulic pressure when the concrete of the vibrator is compacted by the hydraulic meter and / or the hydraulic sensor is measured, and the time-dependent change in the hydraulic pressure of the vibrator, Evaluate the degree of compaction of concrete,
A concrete compaction management method characterized by that.   The hydraulic pressure of the vibrator starts to increase with the insertion of the vibrator in the oil pressure gauge and / or the hydraulic pressure sensor, increases with the passage of time, reaches a peak, and gradually decreases as the compaction of the concrete progresses. The change over time of the oil pressure approaching a certain value is displayed, and the point in time when the oil pressure or the slope of the oil pressure change falls below a predetermined threshold or when the rate of decrease in the oil pressure decreases is reduced. The concrete compaction management method according to claim 1, wherein it is determined that compaction has been completed.   The concrete compaction management method according to claim 1 or 2, wherein a warm-up operation of the vibrator is performed and the temperature of the pressure oil is made constant before measuring the hydraulic pressure of the vibrator.

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