JP6468981B2 - Pneumatic caisson and method of suppressing sudden sinking of pneumatic caisson - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a pneumatic caisson and a method for suppressing the rapid sedimentation of a pneumatic caisson.

  Conventionally, in a pneumatic caisson, the caisson enclosure sometimes subsided suddenly as the ground such as soft ground subsided. As a pneumatic caisson provided with a mechanism for suppressing such sudden settling, for example, one disclosed in Patent Document 1 is known. In Patent Document 1, a caisson housing having a side wall having a blade edge on a lower end side and a ceiling portion formed on an upper portion of the side wall, and a work chamber is formed below the ceiling portion, and a side wall of the caisson housing A pneumatic caisson is disclosed in which a sandle is provided in a part on the side of the working room.

JP-A-10-37203

  In the pneumatic caisson shown in Patent Literature 1, when a sudden subsidence of the ground occurs, the subsidence is suppressed by supporting the caisson enclosure with a sandal. However, in such a pneumatic caisson, even if it is supported by a sanddle, it may be difficult to adjust the settlement speed once the settlement starts. In addition, since it is necessary to keep a large sanddle in the work room during excavation, there is a problem that the work room space cannot be used effectively.

  The present invention has been made to solve such a problem, and improves the certainty of rapid sedimentation suppression and can effectively use the space in the work room, and the pneumatic caisson. The purpose is to provide a method for suppressing the rapid sedimentation.

  A pneumatic caisson according to the present invention includes a side wall having a blade edge at a lower end side, and a ceiling part formed at an upper part of the side wall, and a caisson body in which a working chamber is formed below the ceiling part, and a caisson body An expansion / contraction member provided on the working chamber side and expandable / contractible by supply / discharge of gas, and a gas flow pipe that penetrates the caisson housing and is connected to the expansion / contraction member. Elongates by supplying high-pressure gas.

  According to the pneumatic caisson of the present invention, a telescopic member that can be expanded and contracted by supplying and discharging gas is provided on the work chamber side of the caisson housing, and a gas flow pipe that penetrates the caisson housing is connected to the elastic member. The Therefore, when the caisson housing suddenly sinks due to the rapid settlement of the ground, the telescopic member can be extended by supplying the high-pressure gas from the gas flow pipe. Thereby, since the lower end part of an expansion-contraction member can be pressed on the ground, progress of the sinking of a caisson housing can be suppressed. Moreover, since the expansion / contraction member can be shrunk in normal times, it can be suppressed that the expansion / contraction member becomes an obstacle in the space of the work chamber. As described above, it is possible to improve the certainty of suppression of sudden settling and to effectively use the space of the working chamber.

  In the pneumatic caisson according to the present invention, a valve may be provided in the middle of the gas flow pipe, and the expansion / contraction of the expansion / contraction member may be adjusted by opening / closing the valve. Thereby, the elastic member can be expanded and contracted in an appropriate manner in accordance with the state of settlement.

  In the pneumatic caisson according to the present invention, a hydraulic jack may be provided on the side wall of the caisson housing, and the elastic member may be provided on the hydraulic jack. According to this, compared with the case where an elastic member is provided in the ceiling surface of the work room of a caisson housing, for example, an elastic member can be arrange | positioned in the position close | similar to the bottom face of a ground. Therefore, the lower end portion of the expansion / contraction member can be quickly pressed against the ground. Moreover, it can suppress that it becomes an obstacle of the space of a working chamber by shrinking | contracting an expansion-contraction member and a hydraulic jack normally.

  In the pneumatic caisson rapid depression suppression method according to the present invention, a caisson housing having a side wall having a blade edge on a lower end side and a ceiling part formed on an upper part of the side wall, and a work chamber is formed below the ceiling part. A pneumatic caisson that includes a telescopic member that is provided on the work chamber side of the caisson housing and can be expanded and contracted by supplying and discharging gas, and a gas flow pipe that penetrates the caisson housing and is connected to the telescopic member. In the sinking suppression method, when the caisson housing is rapidly sinking, the expansion member is extended by supplying high-pressure gas from the gas flow pipe, and the lower end of the expansion member is pressed against the ground.

  According to the method for suppressing the rapid collapse of a pneumatic caisson according to the present invention, it is possible to achieve the same actions and effects as the above-described pneumatic caisson.

  ADVANTAGE OF THE INVENTION According to this invention, while improving the certainty of rapid sedimentation suppression, the space of a working chamber can be used effectively.

FIG. 1 is a schematic cross-sectional view showing a state of a pneumatic caisson according to an embodiment of the present invention in a normal state. FIG. 2 is a schematic cross-sectional view showing a state of the pneumatic caisson shown in FIG. FIG. 3 is a schematic cross-sectional view showing a normal state of a pneumatic caisson according to a modification. FIG. 4 is a schematic cross-sectional view showing a state in which the pneumatic caisson according to the modification is rapidly submerged.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic cross-sectional view showing a state of a pneumatic caisson according to an embodiment of the present invention in a normal state. FIG. 2 is a schematic cross-sectional view showing a state of the pneumatic caisson shown in FIG. As shown in FIGS. 1 and 2, the pneumatic caisson 1 includes a caisson housing 2, an elastic member 10, and a gas flow pipe 15.

  The caisson housing 2 has a side wall 2b having a blade edge 4 on the lower end side, and a ceiling portion 2a formed on an upper portion of the side wall 2b. The side wall 2b extends downward from the outer peripheral edge of the ceiling portion 2a. The outer peripheral surface of the side wall 2b extends in the vertical direction. The inner peripheral surface of the side wall 2b extends so as to be tapered so as to taper from the bottom to the top. The caisson housing 2 is embedded in the ground G, and the bottom surface GF of the ground G is disposed at the height position of the blade edge 4. Further, an opening 2c penetrating in the vertical direction is formed at a substantially central position of the ceiling 2a. A shaft 6 is provided in the opening 2c. A space surrounded by the bottom surface GF, the ceiling portion 2a, and the side wall 2b is configured as a work chamber 3.

  The expansion / contraction member 10 is a member that is provided on the side of the work chamber 3 in the caisson housing 2 and can be expanded and contracted by supplying and discharging gas. For example, a folding airbag or the like can be adopted as the elastic member 10. A high-pressure gas is preferably used as the gas. Specifically, high-pressure air can be employed, but any gas may be employed as long as it is harmless to the human body. The elastic member 10 has an annular shape that is open at the center and surrounds the central axis over the entire circumference. The elastic member 10 is attached to the ceiling surface of the work chamber 3 (that is, the lower surface of the ceiling portion 2a). The elastic member 10 is extended by supplying high-pressure gas from the gas flow pipe 15.

  The gas flow pipe 15 penetrates the caisson housing 2 and is connected to the expansion / contraction member 10 at the end on the working chamber 3 side. The gas flow pipe 15 is connected to a device that supplies high-pressure gas and a device that sucks the gas in the elastic member 10 on the upstream side. Further, the gas flow pipe 15 includes a main pipe 12 connected to these devices, and a branch pipe 11 branched from the main pipe 12 into a plurality of pipes and connected to the expansion and contraction members 10 respectively. Each branch pipe 11 is connected to the elastic member 10 so as to be separated from each other in the circumferential direction. The number of branch pipes 11 (that is, the number of connection points with the elastic member 10) is not particularly limited. The branch pipe 11 is embedded in the ceiling portion 2a of the caisson housing 2, and is connected to the extensible member 10 fixed to the ceiling surface at the tip portion. Further, a valve 14 is provided in the middle position of each branch pipe 11. An electromagnetic valve can be employed as the valve 14. The expansion and contraction of the elastic member 10 can be adjusted by opening and closing the valve 14.

  In the pneumatic caisson 1 as described above, during normal times (when there is no sudden ground subsidence), the elastic member 10 is folded and contracted, as shown in FIG. On the other hand, as shown in FIG. 2, when the caisson housing 2 suddenly sinks, the elastic member 10 extends by supplying high-pressure gas from the gas flow pipe 15 and presses the lower end portion against the bottom surface GF. Note that the method for determining whether the caisson housing 2 is rapidly sunk is not particularly limited. For example, a control unit (not shown) may monitor the settlement speed and make a determination based on the settlement speed. Alternatively, the control unit may monitor the pressure in the work chamber 3 and make a determination based on a sudden change in pressure. Alternatively, the sudden sink may be determined based on the judgment of the worker. When the control unit determines the sudden settling, the control unit supplies the high-pressure gas to the expansion member 10 by opening the valve 14. At this time, the gas flow pipe 15 upstream from the valve 14 is kept in a high pressure state. Or you may supply high pressure gas to the expansion-contraction member 10 by operation of a worker. In this case, the control unit may notify the worker in the work room 3 or the operation room by voice, a lamp, or the like when the sudden settling is determined.

  In the state shown in FIG. 2, the expanded elastic member 10 may be suddenly pressed, and the pressure of the elastic member 10 may increase rapidly. In such a case, an accumulator (not shown) may be provided in the gas flow pipe 15 to prevent breakage. When the subsidence of the ground G becomes stable and it is not necessary to press the expansion / contraction member 10 against the bottom surface GF, the expansion / contraction member 10 can be obtained by suctioning the gas with the equipment upstream of the gas flow pipe 15 and opening the valve 14. The gas is discharged from. As a result, the elastic member 10 is folded, and the state shown in FIG. 1 is restored. In order to prevent malfunction during manned work, a bypass valve or an air relief valve may be provided as a safety device.

  Next, functions and effects of the pneumatic caisson 1 according to the present embodiment will be described.

  As a mechanism for suppressing the sudden settling according to the comparative example, there is a mechanism in which a sandle is provided on the side wall of the caisson housing 2. In such a configuration, when the caisson housing 2 sinks to a certain extent, the sanddle and the bottom surface GF come into contact with each other, so that the sinking speed is adjusted by adjusting the width of the remaining moat. However, in the case of a soft ground soil layer, there is a problem that it is difficult to adjust the settlement speed once the caisson housing 2 starts to sink. In addition, since it is necessary to keep a large sanddle in the work room during excavation, there is a problem that the work room space cannot be used effectively.

  According to the pneumatic caisson 1 and the method for suppressing the rapid caking of the pneumatic caisson 1 according to the present embodiment, the telescopic member 10 that can be expanded and contracted by supplying and discharging high-pressure gas is provided on the work chamber 3 side of the caisson housing 2. The gas flow pipe 15 penetrating the caisson housing 2 is connected to the elastic member 10. Therefore, when the caisson housing 2 suddenly sinks due to the rapid settlement of the ground G, the telescopic member 10 can be extended by supplying the high-pressure gas from the gas flow pipe 15. Thereby, since the lower end part of the expansion-contraction member 10 can be pressed against the ground, the progress of the sinking of the caisson housing 2 can be suppressed. Moreover, since the expansion / contraction member 10 can be contracted during normal times, the expansion / contraction member 10 can be prevented from becoming an obstacle in the space of the work chamber 3. As described above, it is possible to improve the certainty of suppression of sudden settling and to effectively use the space of the work chamber 3.

  Further, in the pneumatic caisson 1 according to the present embodiment, a valve 14 is provided in the middle of the gas flow pipe 15, and the expansion / contraction of the expansion / contraction member 10 is adjusted by opening / closing the valve 14. Thereby, the expansion-contraction member 10 can be expanded-contracted in a suitable aspect according to the condition of subsidence.

  As an example of the present invention, a hydraulic jack (for example, as shown in FIG. 3 which will be exemplified later as a modified example) is provided on the side wall 2b, and when the hydraulic jack is suddenly depressed, the hydraulic jack is stretched and pressed against the bottom surface GF. There is something that suppresses settling. However, this configuration requires an excessive hydraulic device. There is also a possibility of oil leakage. In addition, since the expansion / contraction stroke of the hydraulic jack becomes slow, the bottom surface GF cannot be pushed immediately, whereas if the speed is increased, the force becomes weak. Moreover, since the hydraulic jack main body is exposed in the working chamber 3, it may become an obstacle. Also, it may be difficult to install and remove the hydraulic jack body. In addition, a banded lifter or the like for installing the hydraulic jack is required, but there is a problem that it cannot be used in the case of soft ground (however, as will be described later, the combination of the hydraulic jack and the telescopic member 10 is not hindered. ).

  On the other hand, in the present embodiment, the telescopic member 10 using an air bag or the like uses the high-pressure gas of the existing gas flow pipe 15 and thus does not require a separate device. In addition, oil leakage does not occur because it is pneumatic. Even if the internal gas leaks due to damage to the airbag, there is no problem if it is a gas such as air. In addition, since it is a gas, it can be inflated instantly, so it is easy to cope with rapid settlement. For example, if a mechanism in which the telescopic member 10 automatically swells when it suddenly sinks with an accelerometer or the like, the excavator can be protected by the air cushion effect. Further, if a folding airbag is employed as the elastic member 10, the space in the work chamber can be effectively used. Further, when stress is necessary as in the settlement control, the interior of the elastic member 10 can be filled with water, and the housing settlement can be controlled like a water jack. Moreover, by using a ceiling retractable type, it can be moved at any time without selecting a ground such as a soft ground. Moreover, since the installation and removal work is unnecessary, the concern about decompression sickness (latent illness) can be eliminated (the work in the high-pressure room can be reduced).

  The present invention is not limited to the embodiment described above.

  For example, a pneumatic caisson 50 as shown in FIGS. 3 and 4 may be employed. In the pneumatic caisson 50 according to this modification, the hydraulic jack 20 may be provided on the side wall 2 b of the caisson housing 2, and the telescopic member 10 may be provided on the hydraulic jack 20.

  Specifically, the hydraulic jack 20 includes a cylinder 21 whose end is fixed to the side wall 2 b and a rod 22 that advances and retreats along the cylinder 21. The tip of the rod 22 is connected to an annular plate-like support plate 23. The elastic member 10 is provided on the lower surface of the support plate 23. In addition, with the said structure, the branch pipe 11 of the gas distribution pipe 15 penetrates the inside of the ceiling part 2a and the side wall 2b.

  The timing for expanding and contracting the elastic member 10 of the pneumatic caisson 50 is the same as that of the pneumatic caisson 1 shown in FIG. Note that the timing for expanding and contracting the hydraulic jack 20 may be the same as the timing for expanding and contracting the expandable member 10.

  According to the pneumatic caisson 50 which concerns on a modification, the expansion-contraction member 10 can be arrange | positioned in the position close | similar to the bottom face GF of the ground G compared with the case of FIG. Therefore, the lower end part of the elastic member 10 can be quickly pressed against the ground. Moreover, it can suppress becoming the obstruction | occlusion of the space of the working chamber 3 by shrinking the expansion-contraction member 10 and the hydraulic jack 20 normally.

  The above-described embodiment is merely an example, and for example, the configuration of turning the gas flow pipe may be changed as appropriate.

DESCRIPTION OF SYMBOLS 1,50 ... Pneumatic caisson, 2 ... Caisson housing | casing, 2a ... Ceiling part, 2b ... Side wall, 2c ... Opening part, 3 ... Work room, 4 ... Cutting edge, 6 ... Shaft, 10 ... Extending member, 11 ... Branch pipe , 12 ... main pipe, 14 ... valve, 15 ... gas flow pipe, 20 ... hydraulic jack, 21 ... cylinder, 22 ... rod, 23 ... support plate, G ... ground, GF ... bottom face.

Claims (4)

A caisson housing having a side wall having a blade edge on the lower end side and a ceiling part formed on the upper part of the side wall, and a work chamber is formed below the ceiling part,
An expansion / contraction member provided on the side of the working chamber in the caisson housing that can be expanded and contracted by supplying and discharging gas,
A gas flow pipe penetrating the caisson housing and connected to the telescopic member;
A control unit for determining the caisson housing suddenly sinks ,
The elastic member is a pneumatic caisson that is extended by supply of a high-pressure gas from the gas flow pipe when the caisson housing is rapidly submerged . A valve is provided in the middle of the gas flow pipe,
The pneumatic caisson according to claim 1, wherein expansion and contraction of the elastic member is adjusted by opening and closing the valve. A hydraulic jack is provided on the side wall of the caisson housing,
The pneumatic caisson according to claim 1, wherein the elastic member is provided in the hydraulic jack. A caisson housing having a side wall having a blade edge on the lower end side and a ceiling part formed on the upper part of the side wall, and a work chamber is formed below the ceiling part,
An expansion / contraction member provided on the side of the working chamber in the caisson housing that can be expanded and contracted by supplying and discharging gas,
A pneumatic caisson rapid sink suppression method comprising a gas flow pipe that penetrates the caisson housing and is connected to the elastic member,
At the normal time when the caisson housing has not suddenly sunk, the telescopic member is in a contracted state, and when the caisson housing is rapidly sunk, the telescopic member is extended by supplying high-pressure gas from the gas flow pipe, A method for suppressing a sudden collapse of a pneumatic caisson, wherein the lower end of the elastic member is pressed against the ground.

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