JPS6157721A - Method of constructing underwater foundation of multipile jacket structure - Google Patents

Abstract

PURPOSE:To easily and highly precisely drive a steel pile and to produce resistance against a horizontal force such as earthquake, by a method wherein steel piles 5 are driven from a number of partition chambers around the interior of each of columns made of steel of a jacket structure. CONSTITUTION:A jacket structure body 4 made of steel for foundation is formed such that a number of partition chambers are formed around each of plural columns 2 made of steel coupled with each other through coupling members 1, and pile guide members are formed in the partition chamber. After the jacket structure body 4 is installed on a sea bottom ground, a steel pile 5 is engaged with each pile guide member and is griven in the seal bottom ground. The interior of the partition chamber or the interior of the upper part of the column 2 made of steel is filled with concrete, and the steel pile 5 is coupled to the jacket structure body 4 by means of the concrete. Further, the steel pile 5 is driven from the partition chamber in the column 2 made of steel into the seat bottom ground to produce resistance against a horizontal force such as earth quake, and the steel pile 5 is easily and highly precisely driven with the aid of the guide member.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an underwater foundation construction method for a multi-pile jacket structure, which is employed when constructing bridge piers and other structures in relatively deep waters. .

-1-^1 [Prior Art] Conventionally, when constructing an underwater foundation on underwater ground at a large water depth (for example, 20 to 30 fn), a multi-column foundation, a caisson foundation, etc. have been adopted. For example, April 1981, Public Works Research Institute, "Fundamentals", Volume 6, No. 4, No. 58-66.
See pages 91-97.

However, when the underwater ground is very weak and the layer of the soft ground is thick (e.g. 20m to 40m), if the above foundation is adopted, the horizontal displacement during an earthquake will be large in the case of a multi-column foundation, and in the case of a caisson foundation. There is a problem that the work of sinking a caisson is difficult. [Object of the invention, structure] The object of the invention is to provide an underwater foundation construction method for a multi-pile jacket structure that can advantageously solve the above-mentioned problems. The gist of this invention is,
A large number of compartments 6 are provided around a plurality of steel columns 2 interconnected by connecting members 1, and pile guide members are provided in the compartments 6 to constitute a foundation steel jacket structure 4. , After installing the jacket structure 4 on the underwater ground,
Insert the steel pile 5 into each pile guide member and drive it into the underwater ground,
Next, concrete 6 is filled into the compartment 3 or the upper part of the steel pillar 2, and the concrete 6 is used to form the steel pile 5.
An underwater foundation construction method for a multi-pile jacket structure is provided, which is characterized in that the above is connected to a jacket structure 4.

〔Example〕

Next, this invention will be explained in detail in Section 6 using the illustrated example.

6 to 9 show a basic steel jacket structure 4 used in an embodiment of the present invention,
Several (five in the case of illustration) steel columns 2 with a circular cross section are arranged at intervals in the front-rear and left-right directions, and the middle and lower parts of each adjacent steel column 2 are provided with a steel connecting member 1. The upper end of each steel column 2 is connected to a top plate 7 made of steel or steel frame concrete, and a steel inner column 8 disposed in the center of each steel column 2 is connected to the top plate 7 made of steel or steel concrete. and steel columns 2 are reinforcing and partitioning steel rib plates 9 arranged radially.
A truncated conical shape that gradually decreases downward is installed in the upper part of the multiple compartment chambers formed by the steel column 2, the steel inner column 8, and the multiple grate plates 9. A lower pile guide member 10 is disposed, and the lower pile guide member 10 is attached to the support member 1 against the peripheral wall of the compartment compartment.
1 and fixed by welding. This lower pile guide member 10 may be provided at a position further above the position shown in FIG. 8, for example near the secondmost part of the steel column 2, to enhance the pile guide function.

A lower pile guide member 12 consisting of a truncated conical portion that gradually contracts downward and a cylindrical body continuous to its lower end is arranged at the bottom of each compartment B, and the T-section pile guide member 12
is fixed to the peripheral wall of the compartment chamber by a support member 13 and welding, and a steel bottom plate 14 that closes the lower ends of the steel columns 2 and the steel inner columns 8 is the lower end of the steel columns 2 and the steel inner columns 8. A steel frame member 15 is further fixed to the lower part of the steel inner column 8 by welding, and the cylindrical body of the lower pile guide member 120 penetrates the steel bottom plate 14 and protrudes downward. There is.

A rubber water stop ring 16 is fixed to the inside of the cylindrical body of the lower pile guide member 12, and a steel reinforcing ring 17 is fixed inside the compartment between the upper guide member 10 and the lower guide member 12. Fixed by welding.

The jacket structure 4 having the above-mentioned configuration is manufactured under sufficient quality control in a factory, land yard, dock, etc. convenient for marine transportation. Naturally, if the top plate 7 is made of steel, even if the top plate 7 is made of steel concrete, it is possible to manufacture the jacket structure 4 by incorporating steel members as long as there are no restrictions on construction such as pile driving. can.

The connecting member 1 may be circular or rectangular in cross section and have the same cross section over its entire length, or may have a modified cross section in which the joint with the steel column is enlarged. f. A reinforcing steel plate rib may be fixed by welding to the joint between the steel column and the connecting part.

Since several steel columns 2 with a diameter of, for example, 10n1 are used, the weight of the jacket structure 4 is quite large (for example, 1000 to 2000 tons), but the weight of the steel inner columns 8 and the connecting member 1 is quite large. After the jacket structure 4 is floated and towed using buoyancy, water is poured into the steel inner column 8 to adjust the buoyancy, thereby making it possible to sink the jacket structure relatively easily.

As an example of the water stop ring 16, a rubber hollow ring is used, and after driving the steel pile 5, air is injected into the hollow ring and expanded, so that the hollow ring is attached to the outer peripheral surface of the steel pile 5. It may be pressed against the

When constructing an underwater foundation using the above-mentioned steel jacket structure, first install the jacket structure on the underwater ground at the planned location to support the jacket structure during the construction period, as shown in Fig. 10. After constructing the pedestal 22 supported by a pile, and placing the jacket structure 4 on the pedestal, the lateral position and level of the jacket structure are adjusted.

Next, the steel pile (steel pipe pile) 5 is inserted through the upper guide member 10, the lower guide member 12, and the water stop ring 16, and the steel pile is driven using the upper part of the jacket structure 4 as a foothold. This steel pile 5 can be fixed mainly at the top of the steel column 2 using concrete (6A) as shown in Fig. Pile 5
There is a method of cutting it and fixing it at the bottom of the steel column 2 with concrete 6. Here, a method for processing the steel pile 5 in the latter case where the steel pile 5 is cut at an appropriate position will be described.

First, the water stop ring 16 is operated to stop the water, and after draining the water in the compartment and making it dry,
Concrete 6 is placed in the compartment 3, and the head of the steel pile 5 is embedded in the concrete. In this way, after piling each compartment 3 one after another and placing concrete in a dry state, the inside of the steel inner columns 8 was drained and concrete IJ-) 18 was poured, and the steel frame It consists of the entire base of the concrete structure.

In order to further strengthen the bond between the steel pile 5 and the steel column 2, for example, as shown in FIG. It is a good idea to install several reinforcing bars 21 to fix the parts 20 and reinforce the concrete. Next, the lower end of the pier 19 is fixed to the top plate 7 of the jacket structure 4.

〔Effect of the invention〕

According to this invention, the steel piles 5 are driven into the underwater ground from a large number of compartments 3 around the steel column 2 in the steel jacket structure 4 installed on the soft underwater ground. The jacket structure 4 effectively concentrates the strength of a large number of steel piles 5 to resist a large horizontal load, and therefore the horizontal displacement of the jacket structure 4 can be reduced. Furthermore, since a large number of compartments 3 are provided around the steel column 2, when cutting the steel pile 5, the steel pile 5 and the steel column 2 are connected one by one using concrete B. Therefore, the construction is reliable, and the jacket structure 4 can be installed on soft ground with large water depth and thick water.
If a steel pile 5 is installed, the steel pile 5 will inevitably be long, but since the long steel pile 5 is guided and driven by the pile guide member provided in each compartment, a straight pile is not required. Not only can inclined piles be driven easily and accurately,
Therefore, effects such as being suitable for foundation construction in deep water and where the ground supporting the foundation is soft and thick strata can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side view of an underwater foundation constructed by the method of the present invention, and FIG. 2 is a longitudinal sectional side view showing a joint between a jacket structure and a steel pile in the underwater foundation. Figures 3 to 9 show a basic steel jacket structure used in an embodiment of the present invention, with Figure 6 being a side view, Figure 4 being a plan view, and Figure 5 being a side view. 6 is a cross-sectional view taken along the line A-A in Figure 6, Figure 6 is a cross-sectional view taken along the line B-B in Figure 3, Figure 7 is a cross-sectional view taken along the line C-C in Figure 6, and Figure 8 is the internal structure of the steel column. FIG. 9 is a sectional view taken along line D-D in FIG. 8. Figure 10 is a side view showing the jacket structure placed on a pedestal installed in the underwater ground, Figure 11 is a side view when a steel pile is fixed at the top of a steel column, and Figure 12 is FIG. 7 is a longitudinal side view showing another example of a joint between a steel pile and a jacket structure. In the figure, 1 is a connecting member, 2 is a steel column, 3 is a compartment,
4 is a steel jacket structure, 5 is a steel pile, 6 is concrete, 7 is a steel or steel concrete top plate, 8 is a steel inner column, 9 is a steel rib plate, 10 is an upper pile guide member, 12 14 is a lower pile guide member, 14 is a steel bottom plate, 16 is a rubber water stop ring, 18 is concrete, 20 is a dowel, 21 is a reinforcing bar, and 22 is a pedestal.

Claims (1)

[Claims] A large number of compartments 3 are provided around a plurality of steel columns 2 interconnected by connecting members 1, and pile guide members are provided in the compartments 3 to constitute a foundation steel jacket structure 4. , After installing the jacket structure 4 on the underwater ground,
Insert the steel pile 5 into each pile guide member and drive it into the underwater ground,
Next, the inside of the compartment 3 or the upper part of the steel pillar 2 is filled with concrete 6, and the concrete 6 is used to 5 the steel pile 5.
An underwater foundation construction method for a multi-pile jacket structure, which is characterized by combining the above with a jacket structure 4.