JPS63118418A - Setting work of large-size caisson - Google Patents

Abstract

PURPOSE:To settle a large-size caisson into the ground by a method in which peripheral caissons are provided for the inner surface of a caisson body and only the peripheral caissons are settled into hard ground by compressed air. CONSTITUTION:A number of peripheral caissons 2 are provided for the inner surface of a large-size caisson body 1 to make up a composite caisson 4. The caisson 4 is settled into soft ground 5 until reaching hard ground 6 by an open caisson method. An air locker is attached to the bearing stage 14 of the caissons 2 to make them a pneumatic caisson. The composite caisson 4 having the central caisson 3 of open caisson type is settled. The caisson can thus be settled into the ground at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a construction method for sinking a large caisson across soft ground and hard ground below it.

[Prior art]

When a large caisson with a large cross section and high height is sunk over soft ground and hard ground below it, if the entire large caisson is sunk as a pneumatic caisson over the entire settling section, pressure will be applied to the entire excavation surface. Since the excavation has to be carried out at the same time, there are problems in that the construction period is long and the construction cost is high.

In addition, if the entire large caisson sinks as an open caisson over the entire settlement section, when the large caisson reaches hard ground and excavates underwater, it is difficult to excavate the hard ground directly below the cutting edge, so the large caisson The problem is that it is difficult to subside.

[Purpose and structure of the invention]

The object of the present invention is to provide a method for sinking a large caisson that can advantageously solve all of the above-mentioned problems. A composite caisson 4 is constructed by providing a peripheral caisson 2 and a central caisson 3 surrounded by each peripheral caisson 2, and sinking the composite caisson 4 as an open caisson between each peripheral caisson 2 and the central caisson 3t on the soft ground 5. When the composite caisson 4 reaches the hard ground 6, the surrounding caisson 2 is made into a two-mnemonic caisson, and the central caisson 5 is made into an open caisson and the composite caisson 4 is sunk. It's in the construction method.

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

5 and 6 show a large concrete composite caisson 4 used in carrying out the present invention, in which a pair of opposing caissons in the large caisson 1 are arranged in a large caisson main body 1 having a rectangular plane. A pair of partition walls 8 extending parallel to the short side wall 7 is provided, both ends of the partition wall 8 are integrally connected to the other pair of long side walls 9 of the large caisson main body 1, and a central portion of the partition wall 8 is provided. and said side wall 7
A partition wall 10 is integrally connected to the central portion of the partition wall 8, and both ends of a pair of partition walls 11 extending parallel to the pair of long side walls 9 are integrally connected to the partition wall 8, and further, a partition wall 10 is integrally connected to the central portion of the long side wall 9.
A partition wall 12 is integrally connected to the central part of the partition wall 11 and a central part of the partition wall 11, and a central partition wall 15 is integrally connected to the central part of the pair of partition walls 11. A large number of peripheral caissons 2 are arranged along the inner circumference of the central caisson 6, and a pair of partition walls 8 and a pair of partition walls 11 form a central caisson 6.

A bearing step 14 is located at the midpoint in the height direction within each peripheral caisson 2.
is provided, and a female screw member 15 for Zelto screwing is embedded and fixed in the support step 14, a lid 16 is removably screwed into the female screw member 15, and a blade opening is provided at the lower end of each peripheral caisson 2. A wedge-shaped portion 18 is formed at the lower end of the central partition wall 1, and the wedge-shaped portion 18 is arranged at a higher level than the cutting edge 17.

When the composite caissons 4 shown in Figures 5 and 6 are to be sunk over the soft ground and the hard ground below, first, as shown in Figure 1, each peripheral caisson 2 and the central caisson 3 are installed in the soft ground 5. Composite caisson 4 will be lowered as an open caisson.

Next, the cutting edge 17 of the peripheral caisson 2 in the composite caisson 4
After reaching the hard ground 6, as shown in FIG.
The base 20 is fixed to the support step 14 by means of bolts screwed onto the female threaded member 15, and then the peripheral caisson 2 is made into a pneumatic caisson, and the central caisson 3 is made into an open caisson to form a composite caisson. 4 to the hard ground 6. In this case, workers, soil removal packets, and other equipment are lifted into and out of the working chamber of the pneumatic caisson through a lifting shaft 1.9 and an airlock device.

When carrying out this invention, it is preferable to make the area of each peripheral caisson 2 as small as possible and make the area of the central caisson 60 as wide as possible in order to reduce construction costs.

〔Effect of the invention〕

According to this invention, a large number of peripheral caissons 2 are provided along the inner periphery of a large caisson main body 1, and a central caisson 5 is provided surrounded by each peripheral caisson 2 to form a composite caisson 4. In the soft ground 5 above the hard ground 6, the composite caisson 4 is lowered by using each peripheral caisson 2 and the central caisson 6 as an open caisson. It is possible to sink the composite caisson 4 while ensuring cost-effective excavation and an increase in the sinking speed.
After the cutting edge 17 reaches the hard ground 6, each peripheral caisson 2 is changed to a pneumatic caisson, the central caisson 3 is changed to an open caisson, and the composite caisson 4 is changed to a pneumatic caisson.
Since the lower part around the composite caisson 4 is kept dry, the hard ground 6 below the cutting edge 17 in each surrounding caisson 2 can be easily excavated, and the comparison The hard ground 6 at the bottom of the central caisson 5 with a wide area can be excavated at low cost, and the air pressure in the peripheral caisson 2 on one side in the left-right direction or front-back direction is different from the air pressure in the peripheral caisson 2 on the other side. By applying a pressure difference, effects such as being able to easily correct the inclination of the composite caisson 4 can be obtained.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a vertical sectional side view showing a composite caisson sinking into soft ground with peripheral and central caissons as open caisson, and Fig. 2 shows a peripheral caisson and a central caisson as open caisson. The caisson is a pneumatic caisson, and the central caisson is an open caisson and is sunk in the hard ground. The longitudinal side views, Figures 3 to 6, show the composite caisson used in this invention. Figure 5 is a plan view.
Figure 4 is a sectional view taken along line A-A in Figure 6, and Figure 5 is B in Figure 3.
6 is a vertical sectional side view showing a female threaded member for dirt screw engagement embedded and fixed in the support step. In the figure, 1 is a large caisson main body, 2 is a peripheral caisson, 5 is a central caisson, 4 is a composite caisson, 5 is a soft ground, 6 is a hard ground, 14 is a support step, 15 is a female screw member for bolt threading, and 17 is a The cutting edge 19 is a shaft for lifting and lowering. Figure 5

Claims (1)

[Claims] A large number of peripheral caissons 2 are provided along the inner circumference of the large caisson body 1, and a central caisson 3 surrounded by each peripheral caisson 2 is provided to form a composite caisson 4. The composite caisson 4 is lowered by using the caisson 3 as an open caisson, and when the composite caisson 4 reaches the hard ground 6,
This large caisson sinking method is characterized in that the peripheral caisson 2 is a new caisson, the central caisson 3 is an open caisson, and a composite caisson 4 is sunk.