JPH0363640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a compaction device for cast-in-place concrete for constructing shield tunnels.

Conventionally, shield tunnel construction has been a complex method consisting of three steps: primary lining, backfill injection, and secondary lining. The tunnel lining is constructed using a single cast-in-place concrete casting method. In cast-in-place concrete, a large amount of concrete is injected at once, so compaction of the lining concrete during tunnel construction is an important factor in maintaining the strength and quality of the concrete.

Conventionally, the compaction of concrete lining in tunnels has mostly been carried out using vibrators attached to the formwork, and empirical values have also been adopted for the compaction time. Therefore, it has disadvantages such as (1) compaction is concentrated only near the surface of the formwork, and (2) it is difficult to quantitatively determine whether or not compaction has been sufficiently achieved.

The object of the present invention is to provide a concrete compaction device that can improve the above-mentioned conventional drawbacks and perform efficient compaction. A device used for compacting lining concrete, which includes a detector that detects the input current of the vibrator, a power unit and a solenoid valve that control the insertion and withdrawal of the vibrator jack, and a signal from the above detector. This is a concrete compaction device that is composed of a control mechanism that calculates the operating time of a vibrator and controls insertion and withdrawal by a vibrator jack. 1 and 2 are schematic cross-sectional and control block diagrams showing the operation, in which 1 is a skin plate of a shield machine for tunnel excavation, 2 is a formwork for tunnel lining, 3 is a concrete lining part where pouring has already been completed, Reference numeral 4 indicates an uncompacted area where concrete has just been poured, and the gable formwork 5 prevents the concrete from flowing into the tunnel. Fig. 2 is a partial front view of the end formwork 5, and the front part of the end formwork 5 has a closing plate with an appropriate interval maintained around its circumference in order to insert a vibrator for compacting the poured concrete. 6 is installed. The closing plate 6 is made of a material that has a certain degree of strength and elasticity, such as hard rubber, and has a notch 7 in its center as shown in Figure 3 to prevent the concrete poured inside from flowing out. Although it has sufficient strength to prevent this, it is easy to insert a rigid push rod such as a vibrator. The vibrator thrust rod 8 is inserted into the uncompacted portion 4 of the concrete through the notch 7 in the elastic portion of the closing plate 6. The vibrator is composed of a thrust rod 8, an electric oscillator 9, and a vibrator jack 10 whose propulsion and extraction are controlled by hydraulic or pneumatic pressure. Reference numeral 11 denotes a power source, and power is supplied to a power unit 14 for the vibrator jack 10 via a detector 12, an oscillator 9, and a calculation mechanism 13. The detector 12 detects the current value of the power sent to the oscillator 9 and sends this current signal to the calculation mechanism 13. The calculation mechanism 13 has a mechanism for operating the electromagnetic valve 15 based on the above-mentioned current signal to control the propulsion and extraction of the vibrator jack 10, and for calculating the compaction time from the load current value of the oscillator 9.

When operating the device configured as described above, first press the vibrator's push rod 8.
is propelled by the vibrator jack 10 and inserted into the uncompacted part 4 of the poured concrete through the closing plate 6, and the oscillator 9 transmits vibrations to the thrust rod 8 to start compaction. In this case, the push rod is 8
The load current of the oscillator 9 is small in the process where the rod is not fully inserted into the concrete or the concrete is not sufficiently compacted, and then the ramming rod 8 is sufficiently inserted into the concrete and compaction progresses. At the same time, the load current of the oscillator 9 increases. Therefore, by detecting the current value sent to the oscillator 9 by the detector 12, the degree of compaction can be detected. Furthermore, regarding the amount of concrete to be compacted by this single ramming rod 8, if this amount is large, it will take time to compact, and if this amount is small, compaction will be completed quickly.
This tendency allows the compaction time to be calculated even during compaction by detecting the rate of increase in the current value detected by the detector 12 over time. When the current value of the oscillator 9 reaches the optimum compaction value determined from the insertion degree of the ramming rod 8 and the compaction degree, the work is completed and the calculation mechanism 13
Vibrator jack 1 via solenoid valve 15
0 is activated, the thrust rod 8 is extracted, and one cycle of compaction work is completed.

The concrete compaction device according to the present invention has the above-mentioned configuration and function, and therefore it has been found that conventionally it has been difficult to quantitatively understand the compaction of concrete and it has largely relied on empirical intuition. By quantitatively determining the current value, compaction can be performed reliably and unnecessary compaction will not be performed.Also, since the vibrator reaches the inside of the concrete, it is possible to compact not only the surface but also the inside. It can be compacted, shorten work time, and produce high-quality concrete lining.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view and control block diagram showing the structure and operation of the apparatus of the present invention, FIG. 2 is a partial front view of the gable form shown in FIG. 1, and FIG. 3 is an enlarged front view of the closing plate. 8... Thrust rod, 9... Oscillator, 10... Jacket, 1
1...Power supply, 12...Detector, 13...Calculation mechanism, 14
...Power unit, 15...Solenoid valve.

Claims (1)

[Claims] 1. A device used for compaction of cast-in-place concrete lining concrete for shield tunnels, which includes a detector that detects the input current of a vibrator, a power unit and a solenoid valve that controls the insertion and withdrawal of the vibrator jack, A concrete compaction device comprising a control mechanism that calculates the operating time of a vibrator based on the signal from the detector and controls the insertion and withdrawal of the vibrator jack.