JPH0723022U - Breakwater structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an inexpensive breakwater structure with a simple structure and excellent durability. [Structure] In a breakwater structure in which a gravity dam is installed on an underwater foundation composed of multiple foundation piles and footings connected by the heads of the foundation piles, an upright portion is provided at the footing side end, and the footing upper surface and upright portion are provided. It is characterized in that a mound layer forming space surrounded by is provided.When necessary, an outer cylinder steel pipe with a diameter larger than that of the foundation pile is embedded in the footing foundation pile connection, and the space between the outer cylinder steel pipe and the foundation pile is filled with solidifying material. However, the breakwater structure is characterized in that it is fixed or the upper surface of the footing is inclined forward to the wave pressure acting side so as to have an inclination with respect to the sea surface.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a breakwater structure constructed on soft ground for use in port construction, artificial island construction, etc.

[0002]

[Prior art]

 Conventionally, in a breakwater structure constructed on soft ground, for example, as disclosed in Japanese Utility Model Laid-Open No. 63-136020 shown in FIG. 6, a plurality of breakwaters mounted on a support ground b via a soft ground a are used. There is known a structure in which a gravity type bank body g such as a concrete block f is installed on an underwater artificial ground e composed of a support pile c and a footing d. Further, as disclosed in Japanese Patent Laid-Open No. 63-27539 shown in FIG. 7, a steel jacket h is used as an artificial ground, and the steel jacket is fixed to a support ground j via a support pile i. A structure is known in which a concrete pedestal k is fixed on the concrete pedestal k, and the concrete caisson is fixed on the concrete pedestal by using anchor bolts or the like.

[0003]

[Problems to be solved by the device]

 Conventionally, in structures where a gravity dam is installed on an underwater artificial ground, (1) When the water depth is deep and concrete caisson is installed as a gravity dam, the ground pressure of the concrete caisson is the end of the caisson bottom. Since it concentrates on such positions, concrete caisson or artificial ground footing is easily damaged. (2) Gravity type When a concrete caisson is installed as a dam g and a mound m such as abandoned stone layer is provided between the top surface of the artificial ground e and the bottom surface of the concrete caisson, the mound should not collapse as shown in Fig. 5. In addition, it is necessary to provide the slope t on the side surface of the mound. In addition, it is necessary to make the width of the artificial ground wider because it is necessary to prevent the discarded stones from being scattered from the artificial ground.

Further, in a structure in which a steel jacket is used as the artificial ground and the concrete caisson is fixed to the artificial ground using anchor bolts or the like, (3) the design of the breakwater is within a range where safety can be ensured. In order to pursue economic efficiency, some deformation of the breakwater due to waves above a certain design wave height is allowed. In a gravity breakwater such as a concrete caisson, if the wave force exceeds the frictional resistance of the caisson and the foundation work, the caisson only needs to move horizontally over the foundation work, and due to the structure, it will not be affected by waves that exceed the designed wave height. However, a safety mechanism that does not lead to major changes is incorporated in the structure.

However, in the structure in which the concrete caisson and the artificial ground are fixed, there is no such safety mechanism, and when waves more than the design wave are applied, the foundation pile will be damaged due to plastic deformation, etc. There is a risk of causing changes that would necessitate major repairs. (4) The cost of construction is high because it is necessary to protect steel members facing seawater. There was such a problem.

The present invention provides an inexpensive breakwater structure having excellent wave resistance and durability as a simple structure that simultaneously solves the problems in the conventional breakwater structure.

[0007]

[Means for Solving the Problems]

 According to claim 1 of the present invention, in a breakwater structure in which a gravity dam is installed on an underwater foundation constituted by a plurality of foundation piles and footings supported by the foundation piles, upright portions are provided on both sides of the footing, A breakwater structure is characterized in that a mound layer forming space surrounded by an upright wall inside the upright portion and a footing upper surface is formed, and claim 2 is the joint between the footing and the foundation pile head in claim 1. In addition, an outer cylinder steel pipe having a diameter larger than that of the foundation pile is embedded, and the space between the outer cylinder steel pipe and the foundation pile is fixed with a filling and solidifying material. It is a breakwater structure characterized by being inclined forward to the wave pressure side.

[0008]

[Action]

 In the present invention, (1) Since the artificial ground has an upright wall at the end on the footing side, the constituent material of the mound layer provided between the artificial ground and the gravity dam is dissipated during construction and during service. The function can be stably maintained over a long period of time. (2) Since a mound layer can be structurally and reliably provided between the man-made ground and the gravity dam, the ground contact pressure of the gravity dam is dispersed and relaxed and transmitted to the footing of the artificial ground. This can be done and the footing load can be reduced. (3) Since the artificial ground and the concrete caisson are not fixed, and the horizontal force acting on the caisson is transmitted by the frictional force, even if the wave pressure more than expected in the design is applied, the friction does not occur. Since horizontal force above the force is not transmitted to the foundation pile of artificial ground, the load on the foundation pile can be reduced.

(4) When an outer cylinder steel pipe having a diameter larger than that of the foundation pile is embedded in the joint between the foundation pile and the footing, and a solidifying material is fixed between the foundation pile and the outer cylinder steel pipe with a filling and solidifying material, The outer steel tube can reinforce the footing foundation pile connection. (5) As shown in Fig. 3, when the footing top surface of the seabed artificial ground is tilted forward to the wave pressure acting side, horizontal force due to the dam body and wave pressure acts on the foundation pile in mutually opposite directions. Therefore, the acting force on the foundation pile can be reduced as compared to the case where there is no forward lean. The present invention will be described below based on its embodiments.

[0010]

【Example】

 FIG. 1 shows a first embodiment of a breakwater structure constructed on soft ground 1. The footing 2 is as shown in Fig. 2 and has a reinforced concrete structure and is manufactured in advance in the yard. An upright portion 3 is provided at a side end portion of the footing, and an outer cylinder steel pipe 5 having a diameter larger than that of the foundation pile is embedded in the footing at a joint portion of the footing with the foundation pile 4, and the outer cylinder steel pipe is The inside of 5 should not be filled with concrete in the yard, but should be hollow.

For the outer tubular steel pipe 5, a steel pipe with an inner surface protrusion may be used in order to increase the adhesion strength of cast concrete on site, and a protrusion such as a ring rebar, a headed dowel, or a shaped steel may be used on the inner surface of the steel pipe. It may be fixed by welding or the like. Further, the footing 2 may be preliminarily manufactured in a yard by using steel shells such as a reinforcing bar, an outer cylinder steel pipe, and a discarding form on the premise that the footing 2 is manufactured by in-situ pouring concrete.

Steel pipe piles are used as the foundation piles 4, and the piles are driven into the seabed 6 using a tool such as a Yatco and stopped near the sea bottom. The setting sand 7 for adjusting the footing 2 installation height on the seabed 6 may be carried out prior to the work for placing the foundation pile 4 or after the foundation pile 4 is placed. When using steel pipe piles, steel pipes with external projections may be used in order to increase the adhesion strength with concrete cast on site, and the pile heads may be made of ring reinforcement, headed dowels, shaped steel, etc. The protrusion may be fixed by welding.

Next, a hoisting ship is used to transport the footing 2 manufactured in advance in the yard to the site, and the head of the foundation pile 4 placed in the seabed 6 is placed in the outer tubular steel pipe 5 embedded in the footing. The footing 2 is hung on the bottom of the sea so that the part can fit within the specified length. After that, the concrete 8 is poured and filled in the gap between the outer tubular steel pipe 5 and the foundation pile 4 in water, and it is sufficiently cured until the concrete is solidified.

In the case of a method of manufacturing a steel shell such as a reinforcing bar, an outer cylinder steel pipe, and a discard form in a yard in advance, in the outer cylinder steel pipe 5 in which the steel shell is embedded in the footing 2, the seabed 6 The footing 2 was hung on the seabed so that the head of the foundation pile 4 placed in the area would fit within the specified length, and the underwater concrete was placed in the steel shell. Concrete 8 is poured into the gap in water.

Next, a mound layer 10 is constructed in water by using a waste stone or gravel 9 on the upper surface of the footing 2. Although the thickness of this mound layer depends on the scale of the breakwater and the particle size distribution of gravel, a thickness of about 200 to 1000 mm is sufficient. Next, using a hoisting ship, etc., install a concrete caisson (heavy-weight dam body) 12 with concrete 11 filled in it on the footing 2. The parapet 13 on this concrete caisson is made of in-place concrete or the like. To build.

FIG. 3 shows a second embodiment of the breakwater structure of the present invention. As shown in FIG. 4, the footing 2 has an upper surface inclined at an angle of 10 to 20 degrees with respect to a horizontal plane, and the wave pressure is applied to the front side. A breakwater structure constructed on soft ground characterized by tilting is shown. The basic configuration and construction procedure are almost the same as those in the first embodiment. Here, the inclination of the upper surface of the footing 2 is provided to incline forward to the wave pressure acting side. When, for example, a concrete caisson is placed on the footing 2 via sand and gravel, the concrete caisson is applied to the foundation pile. Since horizontal forces in opposite directions are applied between the wave pressures, this can reduce the load on the foundation pile when the waves are applied, as compared to the case where the waves are not tilted forward.

The breakwater is formed by connecting a plurality of breakwater structures of the present invention in series. The breakwater can be constructed either on land or independently in the sea. Therefore, the structure, the material, the characteristics, the shape, etc. are not limited to the above-described embodiment, but within the scope of the configurations of claims 1 to 3, depending on the scale of the breakwater, the place of installation, the ground conditions, the conditions of wave generation, etc. It will be changed if necessary.

[0018]

[Effect of device]

 In the present invention, (1) Since the artificial ground has an upright side wall on the footing side, the constituent material of the mound layer provided between the man-made ground and the gravity dam is not dissipated during construction or during service. Therefore, not only the construction work of the mound layer in water is easy, but also the maintenance of the mound layer becomes easy. (2) Since the mound layer can be structurally provided between the artificial ground and the gravity dam, the ground contact pressure of the gravity dam can be dispersed and relaxed and transmitted to the footing of the artificial ground. Therefore, stress concentration on concrete caisson or footing part of artificial ground can be relaxed and damage during service can be prevented. Therefore, no structural reinforcement is required, which simplifies the design and facilitates maintenance.

(3) In the current design, waves above the design wave height are allowed, and there is a certain probability that waves above the design wave height will act, but in the structure of the present invention, the artificial ground and concrete case are fixed. Instead, the horizontal force acting on the caisson is transmitted by the frictional force, so even if the wave pressure exceeds the design's assumption, the horizontal force exceeding the frictional force is applied to the foundation pile of the artificial ground. Since it cannot be transmitted, minor changes such as horizontal movement of the caisson will not occur, and the foundation piles of the seabed artificial ground will not be damaged. Therefore, maintenance management can be significantly simplified.

(4) For fixing the foundation pile to the footing, an outer cylinder steel pipe having a diameter larger than that of the foundation pile is embedded at the head fixing position of the footing foundation, and the space between the foundation pile and the outer cylinder steel pipe is solidified. When fixed by filling with material, the outer tubular steel pipe reinforces the footing of the foundation pile fixing part, which makes it extremely easy to process the reinforcing bar and steel frame of the footing. (5) In the structure in which the footing of the artificial ground is also provided on the seabed, the steel pipe pile is embedded in the seabed and the footing is supported by its own weight on the seabed, with almost no influence of the waves. Since the steel pipe pile and footing do not sway due to waves, the filling concrete at the site joint between the steel pipe pile and footing can secure good curing conditions and the steel pipe pile and footing can be firmly connected. it can. As a result, on-site quality control becomes significantly easier.

(6) In the structure in which the footing of the artificial ground is provided on the seabed, the foundation piles are almost embedded in the seabed, and the vicinity of the seabed is hardly affected by the waves, so at the time of temporary construction Even in the sea area where large waves are expected, the foundation piles do not have the possibility of bending failure or low cycle fatigue failure due to waves, resulting in significantly easier construction management. In addition, since there is no exposed steel material in seawater, no anticorrosion measures are required, which not only reduces construction costs but also facilitates maintenance.

(7) When an inclination is provided on the upper surface of the footing of the seabed artificial ground, horizontal forces can be applied to the foundation piles in opposite directions due to the dam body and the wave pressure. The acting force on the foundation pile during wave action is smaller than that without. Therefore, the caisson's own weight can be reduced and the number of foundation piles can be reduced, which enables economical design. And the like.

[Brief description of drawings]

FIG. 1 is an explanatory side sectional view showing a first embodiment of a breakwater structure of the present invention.

2A and 2B are explanatory views showing a footing example used in the embodiment shown in FIG. 1, in which FIG. 2A is a plan explanatory view, FIG.
FIG. 7C is a cross-sectional view taken along the line Aa-Ab of FIG.

FIG. 3 is a side sectional view showing a second embodiment of the breakwater structure of the present invention.

4A and 4B are explanatory views showing an example of footing used in the embodiment shown in FIG. 3, in which FIG. 4A is a plan explanatory view, FIG.
FIG. 6C is a cross-sectional explanatory view taken along the line Ba-Bb of FIG.

FIG. 5 is an explanatory side sectional view showing a conventional breakwater structure example (1).

FIG. 6 is an explanatory side sectional view showing a conventional breakwater structure example (2).

FIG. 7 is an elevational view showing a conventional breakwater structure example (3).

[Explanation of symbols]

 1 Soft ground 2 Footing 3 Upright part 4 Foundation pile 5 Outer cylinder steel pipe 6 Seabed ground 7 Laying sand 8 Concrete 9 Sand gravel 10 Mound layer 11 Filled concrete 12 Concrete caisson 13 Parapet a Soft ground b Support ground c Underground pile d Footing Artificial ground f Concrete block g Gravity dam h Steel jacket i Support pile j Subsea ground k Concrete cradle l Concrete caisson m Mound t Gradient

Claims (3)

[Scope of utility model registration request] 1. In a breakwater structure in which a gravity-type dam body is installed on an underwater foundation constituted by a plurality of foundation piles and footings supported by the foundation piles, an upright portion is provided on both sides of the footing, and an inside of this upright portion is provided. A breakwater structure characterized by forming a mound layer formation space surrounded by an upright wall and a top surface of a footing. 2. The joint between the footing and the foundation pile head,
The outer cylinder steel pipe having a diameter larger than that of the foundation pile is embedded, and the outer cylinder steel pipe and the foundation pile are fixed by a filling and solidifying material.
Breakwater structure described in. 3. A breakwater structure in which the upper surface of the footing is inclined forward to the wave pressure acting side.