JPH045305A - Load test device in caisson sinking method - Google Patents

Abstract

PURPOSE:To perform an unmanned load test in a present position by suspending an excavator, in which a load test device is build, in a work room under a caisson. CONSTITUTION:An excavator 4 is moved integrally with a load test device transversely to a predetermined position along a rail 5. Next, a loading plate 6 is pressed to a test objective ground base while taking reaction force to the slab 2 of a caisson 1 by extending a testing cylinder 7. Then, the perpendicular displacement of the loading plate 6 is measured by linear displacement meter 8 while measuring a change of supporting force of the ground base as a change of oil pressure in the cylinder 7. Further a measured data is transmitted to a receiver 15 in a work room 3 from a transmitter 13 received thereafter and transmitted to a computer 18 to be processed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a caisson sinking technique, and more particularly to a loading test device for a caisson sinking management method in which the caisson is sunk while grasping the caisson load and the sinking resistance load.

<Prior Art> When sinking a caisson, it is important to accurately determine the caisson load and sinking resistance load.

Generally, instruments are attached to the side of the caisson or to the cutting edge of the caisson to measure frictional resistance and the supporting capacity of the ground.

<Problems to be Solved by the Present Invention> The conventional caisson sinking technique described above has the following problems.

<B> Rapid subsidence of the caisson tends to damage instruments, and measurement values vary, making data unreliable.

Therefore, it is difficult to continuously obtain accurate measurements up to the final sinking depth of the caisson.

<Exposure> In order to obtain highly reliable data, it is possible to conduct a loading test directly at the current location inside the caisson.

However, conventional loading testing methods require engineers to perform tests in a pressurized environment, resulting in limitations on work time and problems with pressure problems.

<Object of the present invention> The present invention was made in order to solve the above problems, and its purpose is to provide a loading test device for the caisson construction method that allows unmanned loading tests at the current location. It is in.

<Means for solving the problem> That is, the present invention has a hanging type excavator in the working chamber of the lower part of the caisson, and in a caisson sinking method in which the caisson is sunk while being excavated by the excavator, a load is placed on the excavator. It is characterized by a built-in testing device.

<Description of the present invention> The present invention will be described below with reference to the drawings.

<A> Caisson configuration Figure 1 shows the cutting edge of the caisson 1.

A slab 2 partitions the inner space of the caisson 1, and forms a working chamber 3 below.

Reference numeral 4 denotes a known excavator, which is movably suspended from a rail 5 on the lower surface of the slab 2 so as to be able to excavate the entire area inside the work chamber 3 by remote control.

The above configuration is the same as the conventional configuration.

In the present invention, a loading test device is built into the excavator 4, and a loading test can be performed at any position within the work chamber 3.

<Explanation> Loading test The loading test device includes a loading plate 6, a means for artificially loading the loading plate 6, a means for measuring the vertical displacement of the loading plate 6 and changes in the supporting force of the ground, and data processing of the measured data. It consists of a transfer means for wirelessly or wired transfer to the computer that is to be used.

That is, a test cylinder 7 is suspended vertically from the center of the excavator 4.

The free end (lower end) of the test cylinder 7 was connected to the center of a loading plate 6 of standard dimensions (a steel disc with a thickness of 22 mm and a diameter of 30 cm) with a bottle.

In the present invention, the slab 2 of the caisson 1 is loaded onto the loading plate 6 without taking the reaction force.

Further, the base ends of a plurality of sets of linear displacement meters 8 are fixed to the lower peripheral surface of the test cylinder 7, and the other ends are connected to the loading plate 6.

As the linear displacement meter 8, a known instrument incorporating a potentiometer, a differential transformer, etc., and capable of electrically measuring the amount of displacement of the loading plate 6 in the vertical direction can be used.

Incidentally, the M-line displacement meter 8 may be fixed to the excavator 4g4.

<C> Measuring means Figure 2 shows a measurement block diagram of the loading test device.

The expansion and contraction of the test cylinder 7 is controlled by a hydraulic unit 9.

A pressure sensor 11 that electrically measures the hydraulic pressure of pressure oil is provided in a part of the pipe 10 that connects the test cylinder 7 and the hydraulic unit 9.

The pressure sensor 11 is wired to a transmitter 13 via an amplifier 12.

In addition, each linear displacement meter 8 is also connected to a transmitter 12 via an amplifier 14.
It is wired to.

<2> Transfer means A receiver 15 is installed in a part of the work room 3.

A data transmission cable 16 is connected to the receiver 15,
Further, the cable 16 is wired to a computer 18 via an AD converter 17 outside the work room 3.

The test cylinder 7 and each linear displacement meter 8 are operated according to a program input into a computer 18 or the like so that automatic measurement can be performed.

Incidentally, excavation control of the excavator 4 may be performed using the transmitter/receiver 13.15.

Furthermore, the measurement data may be transferred either wirelessly or by wire.

<Operation> To conduct a ground loading test, the excavator 4 is moved laterally to a predetermined position together with the loading test device.

Then, the test cylinder 7 is extended, the loading plate 6 is pressed against the test ground while applying a reaction force to the slab 2, and the change in the supporting force of the ground is measured as the pressure change of the pressure oil in the test cylinder 7. The amount of vertical displacement of the loading plate 6 is electrically measured by a linear displacement meter 8.

Measurement data is transmitted from the transmitter 13, and after being received by the receiver 15 in the work room 3, it is transmitted to the computer 18 and predetermined data processing is performed.

<Effects of the Present Invention> Since the present invention is as described above, the following effects can be obtained.

<A> Loading tests can be performed under automatic control.

Therefore, loading tests can be performed automatically and unattended.

<Mouth> A loading test device was built into the excavator.

Therefore, the loading test can be carried out over a wide area within the work room.

<C> Since the test cylinder and linear displacement meter are integrated, the structure can be simplified.

<2> Applicable to many caisson construction methods such as pneumatic caisson and oven caisson.

[Brief explanation of drawings]

Fig. 1 Cross-sectional view of the lower part of the second caisson Figure 2 Explanatory diagram of the loading test device

Claims (2)

[Claims] (1) A method for sinking a caisson, in which a hanging type excavator is installed in the working chamber of the lower part of the caisson, and the caisson is sunk while being excavated by the excavator, characterized in that the excavator has a built-in loading test device. Loading test equipment for caisson submersion method. (2) In the loading test device of claim (1), a test cylinder is suspended from a part of the excavation rig, a loading plate is fixed to the free end of the test cylinder so as to be movable up and down, and the excavator and the loading plate are connected. A loading test device for the caisson submersion method, characterized in that a linear displacement meter is telescopically installed between the test cylinders and the linear displacement meter in a longitudinal direction, and the measurement operation by the test cylinder and the linear displacement meter can be automatically controlled.