Earth bucket fly-prevention structure for caisson and earth removal method

Abstract

To provide an earth bucket fly-prevention structure for caissons that can certainly prevent the incident of earth buckets' flying and a soil removal method applied in a pneumatic caisson construction method.SOLUTION: An earth bucket fly-prevention structure for caissons prevents an earth bucket from being pushed out with compressed air and then flying even when the compressed air in a high-pressure work space is released upon the encapsulating door of a material lock being damaged and flows into a material shaft (2). In the structure, the material shaft (2) that is meant for an earth bucket transporting out the excavation soil excavated in the high-pressure work space to run through has openings 10a' formed on it that are capable of releasing the aforesaid compressed air from the inside of the shaft through the outside.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a structure for preventing the earth bucket of a caisson from flying away and a method for discharging earth in a pneumatic caisson construction method. [Background technology]

[0002] In the pneumatic caisson method, compressed air is sent into a high-pressure work chamber, and the soil excavated in the high-pressure work chamber is discharged to the outside using soil discharge equipment such as an earth bucket through a material shaft. In addition, when the earth bucket passes, a pair of upper and lower doors are opened and closed to allow for both the removal of soil and maintaining air pressure.

[0003] However, as the excavation depth increases with the pneumatic caisson method, the process of lifting the earth bucket from the high-pressure work chamber using the soil removal equipment becomes longer, and if the wire rope used to lift the earth bucket were to break, the height from which it would fall would also increase. In the worst case scenario, if the wire rope were to break, the earth bucket could fall from a high altitude with one of the material lock's two doors open, potentially destroying the door. In that case, the high air pressure inside the high-pressure work chamber could be suddenly released, flowing into the material lock, and the earth bucket loaded with soil could be pushed out of the material lock like a cannon, potentially resulting in a serious accident with serious consequences, potentially resulting in loss of life.

[0004] On the other hand, the exhaust noise and air leakage noise emanating from the material lock are loud, necessitating measures such as the installation of a sound-absorbing muffler. For example, Patent Document 1 discloses a material lock 9 having an airlock 17 provided between an upper hatch 15 and a lower hatch 16, with an air supply pipe 18 and an exhaust pipe 23 attached to the airlock 17, in which a sound-absorbing device for eliminating noise generated by the high-pressure air supplied from the air supply pipe 18 is provided in a substantially annular shape around the inside of the airlock 17 (see claim 1 in the scope of claims of Patent Document 1, paragraphs

[0023] to

[0044] of the specification, Figures 1 and 2 of the drawings, etc.).

[0005] Furthermore, Patent Document 2 discloses a material lock noise suppression device that has excellent sound-deadening and soundproofing functions, in which sufficient airtightness is obtained between the soundproof door and the cylindrical part in the noise suppression dome, the wire rope insertion holes provided in the noise suppression door are maintained at a substantially uniform size, an increase in the amount of air leakage is prevented, and the device can be made compact (see claim 1 in the scope of claims of Patent Document 1, paragraphs

[0023] to

[0032] of the specification, Figures 1 to 3 of the drawings, etc.).

[0006] However, the material lock with sound-absorbing function of Patent Document 1 and the sound-absorbing device of the material lock of Patent Document 2 are merely sound-absorbing devices that reduce the noise caused by air leakage, and are not designed to address the problem of the earth bucket flying off due to the wire rope being cut, as mentioned above, and naturally cannot prevent the earth bucket from flying off. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-143734 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-218790 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, the present invention was devised in consideration of the above-mentioned problems, and its purpose is to provide a caisson earth bucket flying prevention structure that can reliably prevent earth bucket flying accidents, and a soil removal method in pneumatic caisson construction. [Means for solving the problem]

[0009] The earth bucket flying prevention structure for a caisson according to claim 1 is a caisson earth bucket flying prevention structure that prevents the earth bucket from being pushed out by the compressed air and flying away even if the sealing door of the material lock is broken and the compressed air in the high-pressure work chamber is released and flows into the material shaft, and is characterized in that the material shaft, through which the earth bucket that transports excavated soil and sand excavated in the high-pressure work chamber is inserted, has an opening that connects the inside of the shaft to the outside and allows the compressed air to escape.

[0010] The caisson earth bucket flying prevention structure of claim 2 is characterized in that, in the caisson earth bucket flying prevention structure of claim 1, the opening is formed above the upper lock door of the sealing door.

[0011] The caisson earth bucket flying prevention structure of claim 3 is characterized in that, in the caisson earth bucket flying prevention structure described in claim 2, the total opening area of ​​the openings is approximately the same as the cross-sectional area within the material shaft.

[0012] The earth removal method according to claim 4 is an earth removal method in a pneumatic caisson construction method, The material shaft for inserting an earth bucket to transport excavated soil and sand excavated in a high-pressure work chamber has the caisson earth bucket flying prevention structure described in any one of claims 1 to 3, and is characterized in that when the earth bucket is hoisted up and discharged, when the earth bucket passes through the upper lock door of the sealing door, the upper lock door is closed even when the lower lock door of the sealing door is closed. [Effects of the Invention]

[0013] According to the inventions of claims 1 to 4, even if the wire rope of the earth bucket is cut and the heavy earth bucket loaded with soil falls, damaging the sealing door of the material lock and releasing the compressed air in the high-pressure work chamber and flowing into the material shaft, it is possible to prevent a serious accident with the risk of death, such as the earth bucket loaded with soil being pushed out of the material lock like a cannon and flying out. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a perspective side view that schematically shows the entire caisson shaft to which an earth bucket flying prevention structure for a caisson according to an embodiment of the present invention is applied. [Figure 2] Figure 2 is a perspective front view showing the general shaft alone of the caisson shaft. [Figure 3] FIG. 3 is a plan view showing the general shaft alone. [Figure 4] Figure 4 is an internal development view of the inner cylindrical part of the slit shaft of the caisson shaft. [Figure 5] FIG. 5 is a schematic cross-sectional view showing the opening and closing operation of the sealing door when the caisson shaft is hoisted up and unloaded using a conventional soil unloading method. [Figure 6] FIG. 6 is a schematic cross-sectional view showing the accident situation when the wire rope of the caisson shaft is cut. [Figure 7]FIG. 7 is a schematic cross-sectional view showing the opening and closing operation of the sealing door when the caisson shaft is hoisted and unloaded by the soil unloading method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of a structure for preventing an earth bucket from flying off a caisson and a method for discharging earth according to the present invention will be described in detail with reference to the drawings.

[0016] [Caisson earth bucket flying prevention structure] (Caisson shaft) First, a caisson shaft 100 to which an earth bucket flying prevention structure 1 for a caisson according to an embodiment of the present invention (hereinafter simply referred to as earth bucket flying prevention structure 1) is applied will be described using Figure 1. Figure 1 is a perspective front view that schematically shows the entire caisson shaft 100 to which an earth bucket flying prevention structure 1 for a caisson according to an embodiment of the present invention is applied. Note that reference numeral 5 denotes a high-pressure working chamber 5.

[0017] The caisson shaft 100 described as this embodiment is a type of slim caisson with a shaft cross-sectional area of ​​40 m 2 This section will explain the construction of a pair-shaft caisson shaft, which is an integrated structure consisting of a cylindrical material shaft 2 and a surrounding man shaft 3 with a doughnut-shaped cross section, enabling mechanized excavation even in small-diameter caissons of less than 100 mm. Of course, the earth bucket flying prevention structure for a caisson according to the present invention is not limited to small-diameter slim caissons, but can also be applied to a single material shaft 2 of a general-sized caisson in which the material shaft and man shaft are separated.

[0018] As shown in Figure 1, the caisson shaft 100 is a shaft whose basic form is a pair-shaft type general shaft 10 in which a man shaft is formed around a material shaft and integrated into it. Starting from the lower end connected to the caisson body 200, this caisson shaft 100 is equipped with a special shaft 11 that ensures space for an escape route, and a bottom door chamber 12 with a bottom door 12a. This bottom door 12a is a sealing door that seals off both the material shaft 2 and the man shaft 3.

[0019] The caisson shaft 100 is provided with a lower lock chamber 13 having a lower lock door 13a as a locking section, and an upper lock chamber 14 having an upper lock door 14a, and above these is provided an upper lock chamber shaft 15 to ensure operating space for the opening and closing mechanism of the upper lock door 14a.

[0020] The lower lock door 13a and the upper lock door 14a are sealing doors that seal the material shaft 2. The lower lock chamber 13, the upper lock chamber 14, and the lock chamber upper shaft 15 constitute a lock unit that is a lock mechanism.

[0021] Above (upper level) the lock chamber upper shaft 15, which is the top level of this lock section, is provided a general shaft section based on the general shaft 10 of the caisson shaft 100. At the bottom level of this general shaft section, there is provided a slit shaft 10', which is a characteristic feature of the present invention, in which an opening 10a' (see Figure 4) is formed in the general shaft 10, allowing compressed air to escape from inside the shaft to the outside.

[0022] Moreover, above (on the upper level of) the slit shaft 10', three levels of general shafts 10 are stacked.

[0023] At the top of the caisson shaft 100, an upper shaft 16 is provided in which a hydraulic unit and operating equipment are installed, and a landing 16a is formed around this upper shaft 16.

[0024] (General shaft and slit shaft) Next, the general shaft 10 and slit shaft 10' of the caisson shaft 100 will be described in more detail using Figures 2 to 4. As mentioned above, the difference between the general shaft 10 and the slit shaft 10' is whether or not there is an opening 10a', so the same components as those of the general shaft 10 will be denoted by the same reference numerals and will be described together. Figure 2 is a perspective front view showing the general shaft 10 alone of the caisson shaft 100, and Figure 3 is a plan view showing the general shaft 10 alone. Finally, Figure 4 is an internal development view of the inner cylindrical portion of the slit shaft 10'.

[0025] 2 and 3, the slit shaft 10' and the general shaft 10 are provided with a cylindrical inner cylinder 20 made of a 9 mm thick steel plate that constitutes the material shaft 2, an upper flange 21 made of a 75 mm wide, 19 mm thick flat bar welded to the upper end of the inner cylinder 20, and a lower flange 22 made of a 75 mm wide, 19 mm thick flat bar welded to the lower end of the inner cylinder 20. In the slit shaft 10' and the general shaft 10 according to this embodiment, the inner cylinder 20 has a height of 2000 mm and an inner diameter D1 of 860 mm.

[0026] As shown in Fig. 3, the upper flange 21 and the lower flange 22 are each provided with a plurality of bolt holes 21a (22a) for bolting to another shaft. Also, as shown in Figs. 2 and 3, the upper flange 21 and the lower flange 22 are joined perpendicularly to the inner cylindrical portion 20 via flange ribs 23 and 24 that serve as stiffening members.

[0027] Furthermore, the slit shaft 10' and the general shaft 10 are provided with a cylindrical outer cylinder 30 made of a 12 mm thick steel plate, an upper flange 31 made of a 90 mm wide, 25 mm thick flat bar welded to the upper end of the outer cylinder 30, and a lower flange 32 made of a 90 mm wide, 25 mm thick flat bar welded to the lower end of the outer cylinder 30. The outer cylinder 30 is set to a height of 2000 mm and an outer diameter D2 of 2100 mm.

[0028] As shown in Figure 3, the upper flange 31 and the lower flange 32 each have a plurality of bolt holes 31a (32a) for bolting to another shaft, and as shown in Figures 2 and 3, the upper flange 31 and the lower flange 32 are joined perpendicular to the outer tube portion 30 via flange ribs 33 and 34 which serve as stiffening materials.

[0029] In the slit shaft 10' and the general shaft 10, the donut-shaped cross-section space between the inner cylindrical portion 20 and the outer cylindrical portion 30 serves as the manshaft 3, and this manshaft 3 is not provided with a ladder but with a spiral staircase 35 with fixed width treads and risers. Therefore, unlike a vertical ladder, there is less risk of a fall accident and workers can safely and quickly ascend and descend to enter and exit the high-pressure work chamber 5.

[0030] The reference numeral 36 denotes a lifting fitting 36 made of a 16 mm thick steel plate for hanging shackles etc. when assembling the caisson shaft 100 and lifting the slit shaft 10' and general shaft 10. The reference numeral P denotes various piping P installed in the man shaft 3.

[0031] 4, the slit shaft 10' is formed with an opening 10a' that connects the inside of the shaft to the outside and allows the compressed air to escape. Therefore, as will be described later, even if the wire rope that hoists the earth bucket EB is cut and the earth bucket EB loaded with soil falls, causing the lower lock door 13a to be destroyed by the impact, the compressed air can be released from the material shaft 2 to the man shaft 3, which is a larger space, and an accident in which the earth bucket EB is thrown into the air can be reliably prevented.

[0032] As shown in Figure 1, the slit shaft 10' is provided above the upper lock door 14a. Therefore, the opening 10a' is formed above the upper lock door 14a, which is a sealing door, and in the unlikely event that the upper lock door 14a is damaged in an accident, the compressed air flowing in from the high-pressure work chamber 5 can escape from the material shaft 2 to the man shaft 3 directly above it (see also Figure 6).

[0033] In addition, the opening 10a' in this embodiment is a circular hole with a diameter φ=300 mm, as shown in Figure 4, and a fall prevention fence 10b' made of expanded metal or punched metal is attached to prevent workers from falling from the man shaft 3 into the material shaft 2.

[0034] 4, a total of eight openings 10a' according to this embodiment are provided, and considering that the inner diameter D1 of the slit shaft 10' is 860 mm, the total opening area of ​​the openings is approximately the same as the cross-sectional area of ​​the material shaft 2. (150 x 150 x π x 8 = 180,000π ≒ 430 x 430 x π = 184,900π) Therefore, even if compressed air flows into the material shaft 2, it can be instantly released into the man shaft 3, reliably preventing the earth bucket EB from flying off.

[0035] [Earth removal method] Next, an earth removal method according to an embodiment of the present invention will be described with reference to Figs. 5 to 7. An example of earth removal using a caisson shaft 100 to which the earth bucket flying prevention structure 1 described above is applied will be described. Fig. 5 is a schematic cross-sectional view showing the opening and closing operation of the sealing door when the caisson shaft 100 is hoisted up and removed using a conventional earth removal method, and Fig. 6 is a schematic cross-sectional view showing the occurrence of an accident when the wire rope is cut. Also, Fig. 7 is a schematic cross-sectional view showing the opening and closing operation of the sealing door when the caisson shaft 100 is hoisted up and removed using the earth removal method according to an embodiment of the present invention.

[0036] As shown in Figure 5, in the conventional earth removal method, in the operating conditions for opening and closing the sealing door when hoisting and discharging the caisson shaft 100, when earth and sand is loaded into the earth bucket EB and the wire rope is hoisted up by a structural crane (not shown), which is an earth removal facility, the lower lock door 13a, which is the material lock, is closed and the upper lock door 14a is open, and the earth is then hoisted up and discharged by the structural crane. The reason for this is that the compressed air in the high-pressure work chamber 5 is sealed by the lower lock door 13a, so the pressurized state is maintained, and there is no interference with the work of hoisting the earth bucket EB and discharging earth.

[0037] However, as mentioned in the background art, if a malfunction occurs in a structural crane or the like and the wire rope hoisting the earth bucket EB is cut, the earth bucket EB loaded with soil will fall, as shown in Figure 6, and the impact will destroy the lower lock door 13a, causing the high air pressure in the high-pressure work chamber 5 to be suddenly released and flow into the material shaft 2, and the earth bucket EB loaded with soil will be pushed out of the material shaft 2 like a cannon and thrown into the air, causing an accident. In particular, small caissons such as slim caissons are constructed in relatively narrow, densely populated residential areas, and there was a notable problem that if an earth bucket were to fly out, it could result in a serious accident.

[0038] However, in the caisson shaft 100 according to this embodiment, as described above, the slit shaft 10' is formed with an opening 10a' that communicates from inside the material shaft 2 to the external man shaft 3 and allows the compressed air to escape. Therefore, even if the wire rope that hoists the earth bucket EB is cut and the earth bucket EB loaded with soil falls, destroying the lower lock door 13a due to the impact, the compressed air can be released from the material shaft 2 to the larger space of the man shaft 3, thereby reliably preventing an accident in which the earth bucket EB is thrown into the air.

[0039] Furthermore, in the earth removal method according to the embodiment of the present invention, as shown in Figure 7, when the caisson shaft 100 is being hoisted and earth is being removed, the sealing door closes the lower lock door 13a, and then when the earth bucket EB passes through the upper lock door 14a, the upper lock door 14a also closes. Therefore, even if the upper lock door 14a is destroyed in the unlikely event that the wire rope lifting the earth bucket EB is cut, the lower lock door 13a can prevent the high air pressure in the high-pressure work chamber 5 from flowing into the material shaft 2.

[0040] In the earth bucket flying prevention structure 1 according to the embodiment of the present invention described above, the opening 10a' is formed in the slit shaft 10', so even if the wire rope hoisting the earth bucket EB is cut and the earth bucket EB loaded with soil falls, destroying the lower lock door 13a due to the impact, the compressed air can escape from the material shaft 2 to the man shaft 3, which is a larger space, and an accident involving the earth bucket EB flying can be reliably prevented.

[0041] Furthermore, in the earth removal method according to an embodiment of the present invention, when the caisson shaft 100 is hoisted and earth is removed, the lower lock door 13a is closed, and then when the earth bucket EB passes through the upper lock door 14a, the upper lock door 14a is also closed. Therefore, even if the upper lock door 14a is destroyed, the lower lock door 13a can prevent the high air pressure in the high-pressure work chamber 5 from flowing into the material shaft 2.

[0042] The above has described in detail the earth bucket flying prevention structure 1 for a caisson according to an embodiment of the present invention and the earth removal method using the same. However, the above-mentioned and illustrated embodiments are merely specific embodiments for carrying out the present invention. Therefore, the technical scope of the present invention should not be interpreted as being limited by these. [Explanation of symbols]

[0043] 100: Caisson shaft 200: Caisson body EB: Earth bucket P: Piping 1: Earth bucket (caisson) flying prevention structure 2: Material shaft 10: General shaft 10': Slit shaft 10a': opening 10b': Fall prevention fence 20: Inner cylinder 21: Upper flange 21a: Bolt hole 22: Lower flange 23,24: Flange rib 3: Manschaft 30: Outer cylinder 31: Upper flange 31a: Bolt hole 32: Lower flange 33,34: Flange rib 35: Spiral staircase 36: Hanging hardware 5: High-pressure work chamber 11: Special shaft 12: Bottom door chamber 12a: Bottom door 13: Lower lock room 13a: Lower lock door (sealing door for material lock) 14a: Upper lock door (sealing door for material lock) 15: Upper shaft of lock chamber 16: Upper shaft 16a:Landing

Claims

1. A caisson earth bucket flying prevention structure that prevents the earth bucket from being pushed out by the compressed air and flying away even if the sealing door of the material lock is broken and the compressed air in the high-pressure work chamber is released and flows into the material shaft, The material shaft, through which an earth bucket for transporting excavated soil excavated in the high-pressure work chamber is inserted, has an opening formed therein that communicates from the inside of the shaft to the outside and allows the compressed air to escape. A caisson earth bucket flying prevention structure characterized by the above.

2. The opening is formed above the upper lock door of the sealing door. The earth bucket flying prevention structure for a caisson according to claim 1, characterized in that:

3. The total opening area of ​​the openings is approximately the same as the cross-sectional area of ​​the material shaft. The earth bucket flying prevention structure for a caisson according to claim 2, characterized in that:

4. A method for discharging soil in a pneumatic caisson construction method, The material shaft for inserting an earth bucket for transporting excavated soil in a high-pressure work chamber has the earth bucket flying prevention structure for a caisson according to any one of claims 1 to 3, When the earth bucket is hoisted up and discharged, if the earth bucket passes through the upper lock door of the sealing door, the upper lock door is closed even if the lower lock door of the sealing door is closed. A soil removal method characterized by the above.

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