JPH0532532B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an underwater concrete placing device used in continuous underground wall construction methods and the like.

Conventional technology Normally, when placing underwater concrete such as underground continuous walls and cast-in-place piles, there is no problem even if a vibrator is not used, but recently there has been an increase in the use of large amounts of reinforcing bars to increase rigidity. .

Problems to be solved by this invention When there are many reinforcing bars, the concrete does not wrap around easily, so it is necessary to use a vibrator to improve fluidity and compact the concrete to avoid creating cavities. Although it cannot be seen visually because it is in muddy water, it is necessary to maintain the vibrating part of the vibrator at a constant depth from the top of the concrete.

In other words, if the insertion depth is too deep, the compaction effect will be reduced and it will be impossible to pull up the vibrator, and if the insertion depth is too shallow and it is at the boundary between the muddy water and the top of the concrete, the problem will be that muddy water will be drawn into the concrete and cause concrete deterioration. It was hot.

Until now, when using a vibrator like the one mentioned above, there was no way to properly grasp the concrete pouring surface in muddy water, so the positioning of the vibrator's excitation part depended on the experience and intuition of site workers. There were also problems in terms of workability and quality control of poured concrete.

Therefore, this invention solves the above-mentioned problems that occur when using a vibrator for underwater concrete pouring, and as the top of concrete pouring rises, the vibrator is automatically raised to a certain depth. Gives concrete proper fluidity,
An object of the present invention is to provide an underwater concrete placing device capable of controlling the position and operation of a vibrator in order to fill concrete around reinforcing bars.

Structure of the Invention The underwater concrete placing device according to the present invention includes a cable reel that can freely feed a hanging cable from the ground side into an excavation hole, and a cable reel that is attached to the tip of the suspension cable and guided up and down inside the excavation hole. a vibrator, a plurality of electrodes mounted on a hanging cable a predetermined length above the vibrator and arranged at predetermined intervals for detecting the boundary between concrete and muddy water, and a conductivity meter connected to the electrodes. A concrete top detection sensor consisting of a concrete top detection sensor, and a vibrator provided above to control winding and unwinding of the cable reel, and only when the output of the concrete top detection sensor is input and the top of the concrete is detected. It is characterized in that it is equipped with a control device that operates the .

Embodiments The present invention will be explained below with reference to illustrated embodiments.

FIGS. 1 and 2 show the installation state of a tremie pipe 2 in an excavated hole 1 and a pouring device described later when pouring underwater concrete for an underground continuous wall using the pouring device according to the present invention. A plan view and a sectional view are shown.

Here, details of the casting device disposed near the tremie tube 2 will be explained based on FIG. 3. Drill hole 1
A cable reel 6 is disposed near the above-ground opening of the cable reel 6, and this cable reel 6 is drive-controlled by a control device 7, which will be described in detail later, so that the hanging cable 9 can be fed out into the excavation hole 1 and wound up. There is. The suspension cable 9 is composed of a multicore cable with a steel core, and functions as a suspension load support at the tip of the cable, power supply, and a signal cable.

A vibrator 11 is attached to the lower end of the suspension cable 9, and is vibrated by power supplied through the suspension cable 9 to compact the surrounding concrete 5.

Furthermore, a concrete top detection sensor 10 is attached to a portion of the hanging cable 9 above the vibrator 11 by a predetermined length. As shown in detail in FIG. 4, this concrete top detection sensor 10 has three electrodes suspended above the vibrator 11 by a predetermined length: an upper electrode 10 _U , a lower electrode 10 _L , and a lower limit electrode 10 _LL . They are arranged at predetermined intervals in the length direction of the cable 9.

These three electrodes 10 _U , 10 _L , and 10 _LL are connected to conductivity meters 12 and 12 ′ provided in the control device 7 , and use the difference in conductivity between the muddy water 4 and the concrete 5 to Based on the electrical conductivity readings between the three electrodes, it is detected whether concrete 5 exists between each electrode 10 _U , 10 _L , and 10 _LL .

Further, a control device 7 is installed near the above-ground opening of the excavation hole 1. As shown in the block configuration in the system configuration diagram of FIG. 4, this control device 7 is equipped with the conductivity meters 12, 12' and comparison/judgment circuits 13, 13' that input these outputs and compare and discriminate them. It is being This comparison/discrimination circuit has an upper electrode of 10 _U.
Conductivity 12 measures the conductivity between the lower electrode 10 _L and the lower electrode 10 _L in the same way _.
The measured values of the conductivity measuring device 12' which measures the conductivity between _L and L are compared with respective preset values. When both of these conductivity values exceed a predetermined value, a concrete 5 detection signal is output to the sequence control panel 23.

As described above, this sequence control panel 23 receives the concrete top detection signal from the comparison/discrimination circuits 13, 13' and the vibrator 11 from the depth sensor (encoder) 16 attached to the cable reel and the cable reel motor 15 driving the cable reel. It operates by inputting a depth signal that indicates the position. The sequence control panel 23 processes the input signal according to a set sequence, and appropriately energizes the vibrator motor 14 and cable reel motor 15 to control the vibrator 11 and the cable reel 6.

Furthermore, this pouring device is equipped with a data management mechanism centered on a microcomputer 17, and the microcomputer 17 has conductivity meters 12, 12 which are converted into digital values via an A/D converter 18. The measured value of ' and the value of the depth sensor 16 are inputted via the DI 19. A display device 20, a floppy disk 21, and a printer 22 are provided as peripheral devices for the microcomputer 17, and are capable of monitoring concrete placement status, recording data, and printing out daily reports.

In the above configuration, when using this device, before pouring concrete into the tremie pipe 2, the start button of the control device 7 is pressed and the vibrator 11 is lowered.

It is detected by the output from the depth sensor 16 whether or not the depth has fallen to a preset depth, and the lowering of the cable reel 6 is automatically stopped at the set depth.
Next, start pouring concrete. Here, the lower limit electrode 10 _LL of the concrete top detection sensor 10
The motor 14 of the vibrator 11 is stopped until the concrete 5 is filled between the concrete 5 and the lower electrode _10L . The conductivity between these electrodes is low in muddy water 4 and high in concrete 5, so comparison discrimination circuit 1
The presence or absence of concrete 5 can be determined through 3 and 13'.

The driving of the vibrator 11 is started when the concrete 5 is filled between the lower limit electrode 10 _LL and the lower electrode 10 _L.

Concrete 5 is poured in succession, and the upper electrode 10
When the space between _U and the lower electrode _10L is filled with concrete 5, the cable reel motor 15 is driven,
Wind up the vibrator 11.

When concrete can no longer be detected between the lower electrode _10L and the lower limit electrode _10LL , the hoisting is stopped and at the same time the vibrator motor 14 is stopped.
Thereafter, this process is repeated until the predetermined amount of concrete is poured.

Effects of the Invention The embodiments of the underwater concrete placing apparatus according to the present invention are as described above, and the following effects can be achieved.

During underwater concrete placement work, as the top of concrete placement rises, the vibrator is automatically raised to a certain depth, giving appropriate fluidity to the concrete, and filling the area around the reinforcing bars with concrete. , can manage the position and operation of the vibrator.

[Brief explanation of the drawing]

Figures 1 and 2 are a plan view and a cross-sectional view showing an example in which this device is applied to a continuous underground wall;
Figure 4 is a diagram of the equipment configuration, Figure 4 is a diagram of the principle of the concrete top detection sensor, and Figure 5 is a diagram of the overall system configuration of the vibrator load detection method. 1... Excavation hole, 2... Tremy pipe, 3... Guide wall, 4... Mud water, 5... Concrete,
6... Cable reel, 7... Control device, 8...
Microcomputer, 9...hanging cable,
10... Concrete top detection sensor, 11...
Vibrator, 12, 12'... Conductivity meter, 13,
13'... Comparison/discrimination circuit, 14... Vibrator motor, 15... Cable reel motor,
16...Depth sensor, 17...Microcomputer, 18...A/D converter, 19...DI, 2
0... Display device, 21... Floppy disk, 22... Printer, 23... Sequence control panel, 24... Motor output detection circuit, 25... Comparison circuit, 26, 26'... Detection vibrator, 2
7...Warning buzzer.

Claims (1)

[Scope of Claims] 1. A cable reel that is installed on the ground side of an excavation hole and can freely feed a suspended cable into the excavation hole; a vibrator that is guided up and down within the suspension cable; a plurality of electrodes that are installed above the vibrator on the suspension cable and are arranged at predetermined intervals to detect the boundary between concrete and muddy water; and a conductive electrode that is connected to the electrodes. a concrete top detection sensor, which is installed on the ground side of the excavation hole and controls winding and unwinding of the cable reel, and inputs the output of the concrete top detection sensor to determine the top of the poured concrete. and a control device configured to operate the vibrator only when the vibrator is detected.