JPH08165643A - Concrete pouring height measuring device and measuring method - Google Patents

Abstract

(57) [Abstract] [Purpose] Since there is no moving part, the sensor part can be stably and accurately arranged, and the height of concrete pouring can be measured in real time quickly and accurately, and as a result, the formwork It is possible to prevent accidents that frequently occur in the past, such as slipping off of concrete and leakage of concrete. [Structure] An optical fiber 2 serving as a sensor is attached along a pre-assembled rebar, and the optical fiber 2 is vertically arranged at a place for placing concrete together with the rebar, and one end of the optical fiber 2 is used to measure a backscattering distribution. The optical fiber reflectometer 4 is connected to the personal computer 5 for calculating the point where the backscattering amount changes abruptly, and the concrete 10
When the aggregate or the like hits the optical fiber 2 in response to the driving, the backscattering phenomenon occurs due to the impact and the amount of backscattering is measured by the optical fiber reflectometer 4, and the distribution of this backscattering is measured. Is calculated by the personal computer 5 to obtain a point where the backscattering amount changes abruptly, and this is set as the driving height.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concrete pouring height measuring device and a measuring method used for managing concrete pouring at construction sites of civil engineering and construction.

[0002]

BACKGROUND ART As is well known, an underground continuous wall is a wall made of a single reinforced concrete by excavating a deep groove from the ground above the ground, inserting a reinforcing cage into it, and placing concrete. The wall body is connected to each other without any gaps and is constructed.It is widely used for its low vibration and low noise construction, high rigidity, large water blocking effect, suitable for a wide range of ground, etc. It's being used. However, it is important to control the pouring of concrete, and if it is poorly controlled, the wall will be inhomogeneous and will not be useful as the target wall.

[0003] In this underground continuous wall, generally, in the concrete pouring management, the top of the pouring height is visually controlled. However, if the depth of the continuous underground wall is large, or if the top of the concrete pouring height cannot be visually controlled when pouring concrete in water or in a narrow construction site other than the continuous underground wall, a weight was used. It is estimated and measured with substitute characteristics such as a sneak hunt and the sound of hitting a mold.

That is, in pouring underwater concrete, it can be estimated by measuring with a weight or ultrasonic waves reflected by an ultrasonic oscillator, or in a narrow place, by water seeping out from the mold, Hitting with a hammer etc., the sound quality is used to guess the crown.

[0005]

However, both the weight method and the ultrasonic method have moving parts, and there is a risk of being caught by an underwater obstacle such as a reinforcing bar. For deep depth measurement, it is difficult to get a feel for landing on a concrete surface, which requires skill. In addition, a high degree of skill is required to accurately measure the concrete pouring height even when measuring in a narrow space.

The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, and since there is no moving part, the sensor part can be stably and accurately arranged, and the height of concrete pouring can be quickly and in real time.
Another object of the present invention is to provide a concrete pouring height measuring device and a measuring method capable of accurately controlling and measuring.

[0007]

In order to achieve the above-mentioned object, the present invention provides a concrete pouring height measuring device, including an optical fiber as a sensor attached along a reinforcing bar or the like arranged at a concrete pouring place, A measuring instrument connected to one end of an optical fiber to measure the distribution of backscattering; and a personal computer connected to the measuring instrument to perform arithmetic processing on a point at which the amount of backscattering suddenly changes; The gist of the present invention is to connect a plurality of optical fibers attached along a line to one measuring instrument via an optical fiber switch.

As a concrete pouring height measuring method, an optical fiber serving as a sensor is attached along a pre-assembled reinforcing bar, and the optical fiber is vertically arranged at the concrete pouring place together with the reinforcing bar. One end of the instrument is connected to a measuring instrument that measures the distribution of backscattering, and that instrument is connected to a personal computer that processes the point where the amount of backscattering changes abruptly. The backscattering phenomenon occurs due to the impact on the fiber, and the backscattering amount fluctuates. It is measured with a measuring instrument, and the backscattering amount is suddenly changed by computing the distribution of this backscattering with a personal computer. The point is to find the point and use this as the driving height.

[0009]

According to the present invention as set forth in claims 1 and 3, the optical fiber serving as a sensor is attached along a pre-assembled rebar and is placed at a concrete pouring place together with the rebar, so that the optical fiber can be accurately arranged vertically. Set up. Then, when concrete is poured into the optical fiber, the aggregate or the like hits the optical fiber, and the impact causes a backscattering phenomenon, and the amount of backscattering varies. When concrete is driven in and the position of its top is changed, the position at which the optical fiber is impacted by aggregates will also gradually change.However, this signal is sent to the measuring instrument as the backscattering distribution, and the backscattering is sent. Then, the distribution of the backscattering is calculated by a personal computer to obtain a point where the backscattering amount changes abruptly, and this can be set as the driving height. Further, it is conceivable that the fiber is cut by the impact of the driving, but in that case, the cutting point may be considered to be almost equal to the driving height.

According to the second aspect of the present invention, in addition to the above operation, the optical fibers arranged at a plurality of places can be switched by the optical fiber switch and the measurement can be performed by one measuring instrument.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view showing an embodiment of a concrete pouring height measuring device and measuring method of the present invention, and FIG. 2 is a sectional view of an optical fiber used in the present invention.

First, the concrete pouring height measuring apparatus of the present invention will be described. An optical fiber 2 serving as a sensor,
An optical fiber, which is a measuring instrument connected to the optical fiber 2 to obtain the backscattering distribution from the signal from the optical fiber 2.
It is composed of a reflectometer 4 and a personal computer 5 connected to the optical fiber reflectometer 4 for data processing.

The optical fiber 2 is a thin glass fiber or a plastic fiber having a hair-like shape, and is composed of a core 6 forming a central part and a clad 7 forming a peripheral part as shown in FIG. Is the reinforcement of the optical fiber,
The buffer layer 8 and the coating layer 9 are made of silicone, nylon or the like according to the purpose of use such as improvement of mechanical properties.

The type of the optical fiber 2 is an SI fiber (step index type multimode fiber) or a GI fiber (graded) depending on the refractive index distribution shapes of the core 6 and the cladding 7 and the number of modes propagating in the core 6.・ Index type, multimode fiber), SM
It is classified into a fiber (single mode fiber), and in this embodiment, it is preferable to use a GI fiber as a sensor.

The optical fiber reflectometer 4 is a measuring device for obtaining the backscattering distribution from the signal of the optical fiber 2 as described above. For example, an optical fiber reflectometer Q8460A manufactured by Seiko Denshi Kogyo Co., Ltd. is used. This is suitable, but it is capable of detecting fault position and distance measurement of medium / short-distance optical fiber lines with high resolution and high accuracy, and can also measure adjacent connection points separately.
It is a measuring instrument that can automatically measure the distance between connection points and break points, connection loss, etc. by using the function.

The personal computer 5 is a personal microcomputer which basically has an output device such as a display, an input device such as a keyboard, and an input / output interface, and an auxiliary storage device and other peripheral devices can be added as necessary. Is.

The optical fiber 2 is attached along a pre-assembled reinforcing bar such as a reinforcing bar cage 1 of a continuous underground wall, and a plurality of optical fibers 2 are connected via an optical fiber switch 3 to one optical fiber reflectometer. 4 may be connected.

The optical fiber switch 3 is similar to an electric circuit changeover switch for switching the signals of a plurality of optical fibers 2 and sending the signals to the optical fiber reflectometer 4. The optical fiber switch 3 is mechanical or electro-optical depending on the operating method. formula,
There is an acousto-optic type. In this embodiment, a mechanical mechanical optical switch SW-011 was used.

Next, the concrete pouring height measuring method of the present invention will be described for the case of construction of an underground continuous wall. The optical fiber 2 serving as a sensor is provided along the side portion of the rebar cage 1 with the most tip being the rebar cage 1. Install so that it reaches the bottom of the. For this attachment, a method of binding with a wire material such as a binding wire or a method of joining with an adhesive tape or the like can be considered.

The rebar cage 1 to which the optical fiber 2 is attached is hung down in the excavation hole, but the optical fiber 2 is also set vertically in the excavation hole by the rebar cage 1 being accurately built.

The other end of the optical fiber 2 exposed to the outside is connected to the input side of the optical fiber switch 3, and the output side of the optical fiber switch 3 is connected to the input side of the optical fiber reflectometer 4. The output side of the reflectometer 4 is connected to the input side of the personal computer.

In this way, the concrete 10
When the top end of the concrete 10 of the optical fiber 2 built with the rebar cage 1 rises, the aggregate or the like hits the optical fiber 2 and the impact causes the optical fiber 2
The backscattering phenomenon occurs at this point due to the collapse of the backlash, and the amount of backscattering fluctuates.

Further, when the concrete 10 is cast and the position of the top end changes, the impact position of the optical fiber 2 from the aggregate and the like also gradually changes, but this signal is reflected by the optical fiber reflect. It is sent to a meter (OTDR measuring device) 4, where the distribution of scatter is obtained. Further, a point at which the backscattering amount changes abruptly is obtained by calculating the distribution of this scattering with a personal computer, and this is taken as the driving height. Further, the fiber may be cut by the impact of the driving, but in that case, the cutting point is considered to be almost equal to the driving height.

The optical fiber switch 3 switches signals from a plurality of optical fibers 2 and sends the signals to an optical fiber reflectometer (OTDR measuring device) 4, and one optical fiber reflectometer is provided at a plurality of measuring locations. When the meter 4 is shared, it is possible to sequentially switch and send.

Although the above-mentioned embodiments have been described with respect to the construction of continuous underground walls, the present invention can be applied to the case where concrete is placed in other water or in a narrow construction site. In addition to a rebar cage or the like as a rebar preassembled on the ground, a steel frame, a steel pipe, or the like may be used. Furthermore, the rebar, the steel frame, the steel pipe, etc. are first placed in concrete pouring and then the optical fiber 2 is attached. Good.

[0026]

As described above, according to the concrete pouring height measuring apparatus and method of the present invention, since there is no movable part, the sensor section can be stably and accurately arranged, and the concrete pouring height can be measured in real time. This enables quick and accurate control measurement, and as a result, it is possible to prevent accidents that frequently occurred in the past, such as mold slippage and concrete leakage.

[Brief description of drawings]

FIG. 1 is an explanatory view showing one embodiment of a concrete pouring height measuring device of the present invention.

FIG. 2 is a sectional view of an optical fiber used in the present invention.

[Explanation of symbols]

1 ... Rebar cage 2 ... Optical fiber 3 ... Optical fiber switch 4 ... Optical fiber reflectometer 5 ... Personal computer 6 ... Core 7 ... Clad 8 ... Buffer layer 9 ... Coating layer 10 ... Concrete

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Miyoshi Victory 1-2-7 Moto Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Kazutaka Nakano 1-2-7 Moto-Akasaka, Minato-ku, Tokyo No. Kashima Construction Co., Ltd. (72) Inventor Ikuo Yamamoto 10-27 Daimachi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Toyoko Hermes Co., Ltd. No. 12 Iei Building, 3rd floor, Oyama Construction Co., Ltd.

Claims (3)

[Claims] 1. An optical fiber as a sensor attached along a reinforcing bar or the like arranged at a place for placing concrete, a measuring device connected to one end of the optical fiber to measure the distribution of backscattering, and connected to the measuring device. However, the concrete pouring height measuring device is characterized by comprising a personal computer that performs arithmetic processing on a point where the backscattering amount changes abruptly. 2. The concrete pouring height measuring device according to claim 1, wherein a plurality of optical fibers attached along the reinforcing bars are connected to one measuring device through an optical fiber switch. 3. An optical fiber to be used as a sensor is attached along a pre-assembled reinforcing bar, the optical fiber is vertically arranged at a place for placing concrete together with the reinforcing bar, and the backscattering distribution is measured at one end of the optical fiber. Connect to the measuring instrument,
The measuring instrument is connected to a personal computer for processing the point where the backscattering amount changes abruptly, and the aggregate or the like hits the optical fiber according to the concrete placing, and the backscattering phenomenon occurs due to the impact, and the amount of backscattering Is measured by a measuring instrument, the backscattering distribution is calculated by a personal computer, and the point where the backscattering amount changes abruptly is determined. Measuring method.