JP2010281149A - Caisson immersion method and water gauge for caisson - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a caisson immersion method by which a pneumatic caisson construction method can be easily and accurately performed and a water gauge for caisson. <P>SOLUTION: In this caisson immersion method, the level of the water in a working chamber 3 is measured with a water gauge 10 for caisson attached to the cutting edge 2 of a caisson 1, and the caisson 1 is immersed while the barometric pressure in the working chamber 3 is regulated according to the results of the measurement of the water level. The water gauge 10 for caisson includes a first electrode 12a, a second electrode 12b shorter than the first electrode 12a, and a protective cover 11 for storing the first electrode 12a and the second electrode 12b. The barometric pressure in the working chamber 3 is regulated so that the first electrode 12a detects water and the second electrode 12b does not detect water. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a caisson laying method and a caisson water level meter in a pneumatic caisson method.

  In the pneumatic caisson method, excavation work is performed while keeping the air pressure in the work chamber below the caisson constant and controlling the inflow of water into the work chamber.

  In the pneumatic caisson method, it is important to keep the air pressure in the working chamber at an appropriate level by keeping the water level in the box appropriate in order to prevent the air blow and oversinking of the caisson.

  Conventionally, as a method for measuring the water level in the working chamber, for example, as shown in Patent Document 1, there is a case where the water level of the water surface of the potyard formed in the excavation ground is measured by a water level meter installed in the working chamber.

  As another conventional method for measuring the water level, there is a case where a borehole is formed in the ground surrounding the caisson and the water level in the borehole is measured.

JP 2006-348482 A

However, the measurement with a water level meter installed in the work chamber may interfere with excavation work, and the measurement is generally performed while the work is suspended. For this reason, it may not be possible to cope with a sudden change in water level (atmospheric pressure).
In addition, when setting up a kettle, it is necessary to provide a plurality of kettles prior to caisson excavation, which requires time and effort.

Moreover, the measuring method using a boring hole has a problem that it takes labor and cost for boring holes, installing a measuring instrument, and measuring a water level.
Also, when air blow occurs, accurate measurement may not be possible because air blow pressure and groundwater pressure cannot be distinguished.

  This invention is made | formed in order to solve such a problem, and makes it a subject to provide the caisson installation method and the water level meter for caisson which were able to perform construction easily and with high precision.

  In order to solve the above-described problem, the caisson laying method of the present invention measures the water level in the water storage section formed along the caisson blade edge by water detection means installed in the caisson blade edge, and the water level in the water storage section. The caisson is set while adjusting the atmospheric pressure in the work chamber according to the measurement result.

  In the caisson laying method, the water detection means includes a first electrode rod inserted into the water storage section and a second electrode rod having a length shorter than the first electrode rod, and the first electrode rod May detect water and adjust the atmospheric pressure in the working chamber so that the second electrode rod does not detect water.

  According to the caisson laying method, since the water storage part formed along the caisson blade edge is used, the excavation work is not hindered. In addition, it is not necessary to form a pot hall or a boring hole, and it is possible to measure easily. Moreover, since the measurement is performed at the caisson blade edge, the water level gauge is not affected by the atmospheric pressure due to air blow.

  The water level gauge for caisson of the present invention includes a protective cover fixed to the caisson blade, water detection means accommodated in the protective cover, and fixed to the lower end of the protective cover and communicated with the protective cover. And a filter material filled in the tip protection material, wherein the tip protection material has a water inlet, and water flowing in from the water inlet is It flows into the protective cover through the inside of the tip protective material.

Such a water level meter for caisson measures the water level of water penetrating into the protective cover by means of a water detection means.
According to the water level meter for caisson, the water level can be measured with high accuracy because the water detecting means is prevented from coming into contact with the earth and sand by the tip protective material and the protective cover.
In addition, the filter material in the tip protective material prevents soil particles from entering the protective cover.

  Further, if the water detection means of the caisson water level meter is composed of a plurality of electrode rods with different lengths inserted from the upper part of the protective cover, the water level is measured by a resistance value between the electrode rods. It becomes possible. Moreover, since it is possible to attach and detach the electrode rod as necessary, it is possible to easily adjust the water level, clean the inside of the protective cover, and the like.

  According to the caisson laying method and the caisson water level meter of the present invention, it becomes possible to easily and accurately manage the water level in the work chamber.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the installation condition of the water level meter for caisson concerning the suitable embodiment of this invention, Comprising: (a) is sectional drawing, (b) is a top view which wants (a) from the downward direction. It is a figure which shows the water level meter for caisson, Comprising: (a) is sectional drawing, (b) is a front view. It is a figure which shows the detail of the water level meter for caissons, Comprising: (a) is an enlarged front sectional view, (b) is an AA arrow view of (a), (c) is an arrow BB view of (a). FIG.

Preferred embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, as shown in FIG. 1A, the caisson 1 is measured while measuring the water level in the work chamber 3 with the caisson water level meter 10 fixed to the blade edge (caisson blade edge) 2 of the caisson 1. The case of sunk will be described. In the present embodiment, as shown in FIG. 1B, caisson water level gauges 10 are installed at four locations on the inner surface of the blade edge 2.

  As shown in FIGS. 2A and 2B, the caisson water level gauge 10 includes a protective cover 11 fixed to the blade edge 2 and water detection means (electrode rods 12, 12) accommodated in the protective cover 11. ), A tip protection member 13 fixed to the lower end of the protective cover 11, a filter member 14 filled in the tip protection member 13, and a cable protection member 15 for protecting the cable 16 connected to the water detection means. I have.

  As shown in FIGS. 2 (a) and 3 (a), the protective cover 11 accommodates water detection means composed of two electrode rods 12, 12 so that earth pressure acts on the electrode rods 12, 12. To prevent.

  In the present embodiment, the protective cover 11 is constituted by a steel pipe having a rectangular cross section (see FIG. 3C). In addition, the material which comprises the protective cover 11 will not be limited if it has the intensity | strength which does not deform | transform by the earth pressure at the time of caisson 1 setting.

  In this embodiment, although the protective cover 11 is fixed to the blade edge 2 by welding, the fixing method of the protective cover 11 is not limited.

  As shown in FIG. 2A, the upper end of the protective cover 11 is shielded by the upper lid member 11a. A through hole for installing the water detection means is formed in the upper lid member 11a. The electrode rod 12 is fixed to the protective cover 11 via a jig 17 installed in the through hole of the upper lid member 11a.

At the lower end of the protective cover 11, a lower lid member 11b is installed as shown in FIG. A through hole is formed in the center of the lower lid member 11b, and the protective cover 11 and the tip protective member 13 are communicated with each other.
The water that has flowed into the tip protective material 13 enters the protective cover 11 from the through hole of the lower lid material 11b. Thereby, water is stored in the protective cover 11, and a water storage section is configured in the caisson water level gauge 10. In the water reservoir, the water level in the work chamber permeates through the tip protection member 13 so that the same water level as the work chamber is maintained.

As shown in FIG. 3C, a filter medium 11c is installed in the through hole of the lower lid member 11b.
Although the material which the filter medium 11c comprises is not limited, in this embodiment, a porous filter material is used.

As shown in FIG. 3C, the water detection means is composed of a first electrode rod 12a and a second electrode rod 12b having a shorter length than the first electrode rod 12a.
As shown in FIG. 3A, the first electrode rod 12a and the second electrode rod 12b are arranged in the protective cover 11 in a state in which the height position of the tip (lower end) is shifted.

  In the present embodiment, the base end portions of the two electrode rods 12 and 12 are fixed to the upper lid member 11b of the protective cover 11 via a jig 17 (see FIG. 2A). In addition, the fixing method of the electrode rod 12 is not limited.

  In this embodiment, two electrode rods 12 and 12 having different lengths are used as the water detection means, but the configuration of the water detection means is not limited, and may be, for example, a resistance wire, a laser beam, or an electromagnetic type. Detection means may be used. Further, a plurality of types of detection means may be used in combination as the water detection means.

The tip protection member 13 is a steel member fixed to the tip of the protective cover 11 as shown in FIGS.
The tip protection member 13 is formed in a trapezoidal shape in cross section, and the tip (lower end) is formed at an acute angle corresponding to the shape of the blade edge 2. Thereby, the front end surface of the front end protection member 13 is flush with the front end surface of the blade edge 2.

  As shown in FIG. 2B, the tip protection member 13 is formed wider than the protection cover 11 in a front view, and is connected to the protection cover 11 in a state of projecting left and right at the lower end of the protection cover 11. Has been.

The upper end of the tip protection member 13 is shielded by a lid member 13a. The protective cover 11 and the tip protection member 13 are connected in a state where the lower cover member 11b of the protection cover 11 and the lid member 13a of the tip protection member 13 are overlapped.
The tip protection member 13 may be formed integrally with the protective cover 11 in advance, or may be formed by fixing different members to the tip of the protective cover 11.

  As shown in FIGS. 3A and 3B, the cover member 13a is formed with water outflow holes 13b corresponding to the through holes (filter material 11c) of the lower cover member 11b of the protective cover 11. A plurality of water inflow holes 13c, 13c,... (Water inlets) located on the outer peripheral side of the protective cover 11 are formed. Thereby, the water which flowed into the front-end | tip protective material 13 from the water inflow holes 13c, 13c, ... penetrates into the protective cover 11 through the water outflow holes 13b.

  In addition, a filter material 14 is filled in the tip protection material 13. The filter material 14 excludes muddy soil particles that have flowed into the tip protection material 13. In the present embodiment, a sponge-like porous material is used as the filter material 14, but the material constituting the filter material 14 is not limited. For example, the tip protective material 13 may be filled with a granular material such as sand. In addition, by using a strong filter material 14, the strength of the tip portion (tip protective material 13) of the caisson water level gauge 10 is enhanced, and the filter member 14 is prevented from being damaged by the pressure during caisson installation. It is good.

  As shown in FIGS. 2A and 2B, the cable protection member 15 is a steel member installed so as to cover the upper portion of the protective cover 11.

  The cable protector 15 protects the cable 16 by covering the cable 16 that extends from the side surface of the caisson 1 and is connected to the electrode rod 12.

The cable protection member 15 is composed of a tube material having a lower end opened and a top end shielded, and is installed in a state in which the upper portion of the protective cover 11 is inserted into the lower end opening.
The cable protection member 15 is fixed to the surface of the blade edge 2 with bolts via attachment portions 15a, 15a,. In addition, a cable hole 15 b is formed in the cable protection member 15 corresponding to the position of the cable 16 extending from the side surface of the caisson 1.

  The cable 16 is embedded in the side wall of the caisson 1 to connect the electrode rod 12 to the relay circuit or computer on the ground. The measurement result by the electrode rod 12 is output to the ground part via the cable 16. The cable 16 is not necessarily embedded in the side wall of the caisson 1 and may be wired in the inner space of the caisson 1.

  The caisson 1 is set while adjusting the atmospheric pressure in the work chamber 3 by measuring and managing the water level in the vicinity of the blade edge 2 stably and accurately.

  In the present embodiment, the atmospheric pressure is adjusted so that the water level in the protective cover 11 is between the lower end of the first electrode rod 12a and the lower end of the second electrode rod 12b. That is, the atmospheric pressure is adjusted so that the first electrode rod 12a detects water and the second electrode rod 12b does not detect water.

When the first electrode rod 12a does not detect water, the caisson water level meter 10 may notify the operation room of an abnormality because the water level may be lowered due to the atmospheric pressure in the work chamber 3 being too high. The worker who is informed of the abnormality lowers the pressure of the pressure and adjusts the water level to an appropriate position.
Further, when the second electrode rod 12b detects water, an abnormality due to the rise in the water level is notified to the working room. Thereby, the worker raises the air pressure in the work chamber 3 to lower the water level.

Since the water inflow hole (water inlet) 13 c is formed at the upper end of the tip protection member 13, the earth pressure at the tip and side surfaces of the blade edge 2 is prevented from acting on the caisson water level gauge 10.
Moreover, since the water inflow hole 13c is formed in the upper end of the front-end | tip protective goods 13, it is prevented that the water inflow hole 13c is shielded by earth pressure.

  Since the water flowing in from the water inlet hole 13c is inserted through the filter material 14 filled in the tip protective material 13 and further through the filter material 11c, it is prevented that soil particles enter the protective cover 11. ing. Therefore, it is possible to prevent the soil particles from adversely affecting the detection of the water level by the electrode rod 12, such as changing the resistance value of water.

  Since the electrode rod 12 is detachably fixed to the protective cover 11 via the jig 12b, maintenance of troubles such as removal of deposits caused by intrusion of muddy water into the protective cover 11 is possible. The electrode rod 12 may be attached / detached with the cable protection material 15 removed.

Since the cable 16 of the detection rod 12 is protected by the cable protection member 15, it is prevented from being damaged by the work in the work chamber 3.
Since the cable 16 is embedded in the caisson 1 in advance, the cable 16 is connected to a relay circuit or a computer on the ground, and the measurement result of the caisson water level gauge 10 can be used immediately for control of excess or deficiency of pressure. .

It is possible to prevent injuries such as air blow to the surrounding ground by appropriately performing pressure management in the work chamber 3.
Moreover, it is also possible to grasp the inclination of the caisson 1 based on the water level measurement results of the caisson water level meters 10, 10,.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that the above-described constituent elements can be appropriately changed without departing from the spirit of the present invention.

For example, the installation location and the number of installations of the caisson water level gauge 10 are not limited and can be set as appropriate.
Moreover, the formation method of a water storage part is not limited to the said thing.

  Moreover, in the said embodiment, although the water level was measured with the two electrode rods 12 and 12, the number of the electrode rods 12 is not limited, By installing three or more electrode rods, a water level is stepwise. It is good also as what measures the change of.

  Further, the caisson water level meter 10 may be used to measure the water level in the working chamber and to measure the air blow in the surrounding area, for example, and may be combined with other measuring methods and measuring devices as appropriate to enhance safety.

  In the above embodiment, the protective cover 11 and the tip protective member 13 are connected in a state where the lower end of the protective cover 11 and the upper end of the tip protective member 13 are brought together. The connection method of the protective cover 11 and the tip protection material 13 is not limited, for example, it connects in the state inserted in the upper part of the tip protection material 13.

1 Caisson 2 Cutting edge (Caisson cutting edge)
3 Working room 10 Water level meter for caisson 11 Protective cover 12 Electrode rod (water detection means)
13 Tip protection material 13c Water inlet hole (water inlet)
14 Filter material

Claims (4)

Measure the water level in the water reservoir formed along the caisson blade by means of water detection means installed in the caisson blade,
A caisson laying method characterized in that the caisson is laid while adjusting the atmospheric pressure in the working chamber according to the measurement result of the water level in the water reservoir. The water detection means comprises a first electrode rod inserted into the water reservoir and a second electrode rod having a length shorter than the first electrode rod;
The caisson laying method according to claim 1, wherein the air pressure in the working chamber is adjusted so that the first electrode rod detects water and the second electrode rod does not detect water. A protective cover fixed to the caisson blade,
Water detection means housed in the protective cover;
A tip protective material fixed to the lower end of the protective cover and communicated with the protective cover;
A water level meter for caisson comprising a filter material filled in the tip protection material,
The water tip for caisson is characterized in that a water inlet is formed in the tip protective material, and the water flowing in from the water inlet flows into the protective cover through the inside of the tip protective material. . The water level meter for caisson according to claim 3, wherein the water detection means is composed of a plurality of electrode rods having different lengths inserted from the upper part of the protective cover.

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