JPS6132457B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel caisson embankment and method of constructing the same.

Generally, when constructing a caisson embankment in deep water areas, conventionally, as shown in Figure 1, a large amount of rubble is poured in to create a high rubble foundation 1, and a normal caisson 2 is installed on top of it. Or, as shown in Figure 2, the rubble foundation 3 was set at the normal height and a large caisson 4 was installed to adapt to the water depth. However, in the method shown in Figure 1, the rubble foundation 3 This method requires a large amount of rubble, and has the disadvantage of requiring a great deal of labor and time. In addition, with the method shown in Figure 2, the deeper the water gets, the larger the caisson becomes, making it impossible to manufacture the caisson in facilities of conventional size, requiring a great deal of labor to move it, and also requiring a lot of effort when installing it. There were problems such as the need for a larger work boat.

In view of the above-mentioned problems, the present invention has developed a caisson that does not require a large amount of rubble, can be manufactured and installed using conventional facilities and work boats, and can be constructed in deep sea areas. The purpose of this project is to provide a construction method for a caisson embankment suitable for the construction of an embankment, and its gist is to provide a lower caisson in which a closed caisson is sunk and filled, and a caisson embankment installed on the upper surface of the lower caisson. , a caisson embankment having an upper caisson narrower than the lower caisson, wherein a tenon formed on the upper surface of the lower caisson is fitted into a tenon fitting recess formed on the bottom surface of the upper caisson so as to engage with each other; It lies in the way it is constructed.

Next, an embodiment of the present invention will be described with reference to FIG. 3 and the following drawings.

FIG. 3 shows a sectional view of a caisson embankment according to the present invention, in which 10 is a lower caisson, 11 is an upper caisson, and 12 is an upper concrete.

The lower caisson 10 uses a closed caisson,
A foundation skirt 13 is integrally formed on the lower end surface and is press-fitted into the soil. In addition, there are four tenons 14 on the upper end surface of the lower caisson 10.
is integrally molded, and this tenon 14 connects to a tenon fitting recess 15 formed at the bottom of the upper caisson 11.
The gap between the two is filled with grout and the two are integrated.

The tenons 14 are important parts for mutually transmitting horizontal forces, and are arranged evenly on a plane so that horizontal forces do not concentrate on any one part or couple forces occur on the whole.

Furthermore, the tenon 14 is tapered to reduce the tolerance as much as possible to ensure the stability of the upper caisson 11 against external forces during construction.

In this embodiment, the tenons 14 are provided at four locations, but they may be provided at three, five, or more locations, and their shape may be the truncated cone mentioned above or the truncated pyramid shape. It's good.

Further, the lower caisson 10 is divided into four separate sealed chambers 17, 17, .
8, 18... are formed, and a through hole (not shown) is formed in this partition wall.

On the other hand, the upper caisson 11 is of an upwardly open type like a conventional caisson. Both caissons 10 and 11 are each filled with filler sand 19 after installation.

In addition, in the above-mentioned embodiment, the skirt 1 is used as the basis.
3 is used, but a rubble foundation 19 may also be used as shown in FIG.

Next, a method of constructing the above-mentioned caisson embankment will be explained.

Both caissons 10, 11 are fabricated at a dock or other conventional caisson making yard, floated on the water, and towed to the desired installation site.

When installing the lower caisson 10 after being towed, a buoyancy tower 20 is attached to its top surface.
This buoyancy tower 20 has four hollow tubes 21, 21...
..., and each hollow tube 21 has a hook 2 at its lower end.
2 are attached, and the upper ends of the hollow tubes 2 are connected to each other with bolts 23, 23...
A tie bar 24 is stretched between 1 and 21, and by tightening the tie bar 24, the lower ends can be brought closer to each other.

Each hook 22 is provided on the horizontal side, and the lower ends of the hollow tubes 21 and 21 are brought close to each other by a tie bar 24 with respect to an inverted U-shaped hanging ring 25 protruding from the upper surface of each tenon 14. It is designed to be locked by. There is a rope 26 on the back of the hook 22.
The lower ends of the rope 26 are connected, and the rope 26 is passed around a pulley 31 attached to a weight 32 and extended upward, and by pulling the upper end, the rope 26 is connected to the hook 22.
is pulled outward and removed from the hanging ring.

In addition, each hollow tube 21 has a structure that allows water to be poured into the inside thereof, and after pouring water into the inside, loosening the tie bar 24 and pulling the rope 26 allows removal by effectively utilizing buoyancy. Work efficiency can be improved.

Further, although this embodiment shows the case where four hollow tubes are used, it is sufficient to use two or more hollow tubes.

Further, the lower caisson 10 has its respective sealed chambers 17
Inlet/outlet ports 27a, 27b are formed in advance for each port, and inlet/outlet pipes 29a, 29b leading to the pump (not shown) of the immersion barge 28 are formed in advance.
are connected to each other so that water and air can be injected and discharged from each sealed chamber 17.

By discharging air and injecting water through these injection ports 27a and 27b, the buoyancy of the caisson is reduced and the caisson sinks. Then, adjust the position and lower it to the desired position.

At this time, since the buoyancy tower 20 is erected, the caisson is lowered while maintaining an appropriate posture.

After sinking and installing in this way, the lower caisson 10 is filled with filling and the buoyancy tower 20 is removed.

To remove the buoyancy tower 20, loosen the tension on the tie bar 24 mentioned above and pull the rope 26 above the water surface, so that the hook 22 comes off from the hanging ring and floats above the water surface due to the buoyancy of the hollow tube 21. In addition, the filling is performed by using the above-mentioned pouring/discharging ports 27a and 27b, injecting the filling sand 19 from one side using a water stream, and extracting it from the other side.

After performing the filling in this way, the upper caisson 11 is installed. The installation of the upper caisson 11 is carried out by floating it above the water surface and injecting water into the interior to allow it to settle. After settling, the upper caisson 11 is filled with filling from the upper opening, and the upper surface is filled with the upper concrete. 12 is installed on-site or by placing a precast board.

In addition, although the above-mentioned embodiment shows the case where the devices are stacked in two tiers, they may also be stacked in three or more tiers.

The caisson embankment and its construction method of the present invention are constructed as described above, and the structure of the embankment is made into a multi-stage structure consisting of a lower caisson and an upper caisson. Since it does not require a large amount of rubble or a particularly large caisson, it can be manufactured in the conventional caisson manufacturing yard, and it also requires a work vessel such as a particularly large crane ship. It has now become possible to construct one without having to do so.

Furthermore, by connecting the upper and lower caissons to each other with tenons, it not only provided good stability after completion, but also ensured stability during construction.

Furthermore, by using a buoyancy tower when sinking the caisson, the posture of the caisson could be easily maintained after being submerged, making the work more efficient.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing different examples of conventional deep-water caisson embankments, FIG. 3 is a cross-sectional view of an example of the caisson embankment of the present invention, and FIG. 4 is another cross-sectional view, Figure 5 is a cross-sectional view of the lower caisson settling process;
FIG. 6 is a cross-sectional view of the buoyancy tower in an attached state, FIG. 7 is a plan view thereof, and FIG. 8 is a cross-sectional view of an example of the lower caisson. 10... lower caisson, 11... upper caisson, 12... upper concrete, 14... tenon,
15... Recess for tenon fitting, 17... Sealed chamber, 19
... Packing sand, 20 ... Buoyancy tower, 21 ... Hollow pipe, 25 ... Suspension ring, 27a, 27b ... Injection and discharge port, 28 ... Immersion barge, 30 ... Towing boat.

Claims (1)

[Scope of Claims] 1. A lower caisson in which a sealed caisson is sunk and filled, and an upper caisson installed on the upper surface of the lower caisson and narrower than the lower caisson, and formed on the upper surface of the lower caisson. A caisson embankment in which the tenons are fitted into tenon fitting recesses formed on the bottom surface of the upper caisson and engaged with each other. 2. A closed caisson having a plurality of tenons integrally formed on its upper end surface is floated on water, and a buoyancy tower whose lower end is supported by the tenons is erected, and water is poured into the closed caisson to sink it to a predetermined installation position. Then, the lower caisson is filled with filling material, the buoyancy tower is removed, and the upper caisson, which has a recess for mortise and tenon fitting formed in advance on the bottom surface, is lowered onto the lower caisson, and the upper caisson is fitted with a recess for mortise and tenon fitting. A method for constructing a caisson embankment characterized by installing an upper caisson by fitting a tenon into a joint recess.