JPH0345179B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a construction method and apparatus for completing an embankment, seawall, etc. constructed offshore within a short period of time.

[Conventional technology]

When constructing seawalls, breakwaters, etc. in offshore waters,
Conventionally, caisson construction method and cell construction method are mainly used.

In the caisson construction method, a caisson box is manufactured in a dry dock, floated to the surface, towed to the construction site, then sunk at the construction site, and finished by filling the inside with sand. Since caisson boxes are manufactured using dry docks, the manufacturing precision is high, and large-scale items can also be manufactured.

Two types of cell construction methods are known: steel sheet pile cell construction method and steel plate cell construction method, both of which involve assembling the cell shell at a land base, placing it on a barge and towing it, or
This construction method involves hoisting it using a floating crane and transporting it to the construction location, then driving it into the seabed using a vibro hammer suspended from the floating crane, and then filling the interior with sand.

[Problem that the invention seeks to solve]

Incidentally, there has recently been a demand for shortening the construction period for offshore embankment and seawall construction. On the other hand, in the conventional caisson construction method, as the scale of the caisson box increases, the cost of producing it using dry docks increases, and it takes time to manufacture the caisson box, which poses a problem in terms of rapid construction.

In addition, rapid cell construction has recently been developed, and if the construction site is close to a land base, the construction period is relatively short, but if the construction site is far away, the towing time becomes longer and rapid construction is not possible. . Also, considering the tensile strength of the steel material, the practical water depth is limited to 20 meters at most.

The present invention aims to provide a rapid construction method for embankments and seawalls that solves the problems of the conventional construction methods, and an apparatus therefor.

[Means for solving problems]

It has a U-shape, and is equipped with multiple ballast tanks on each side, a formwork forming section at the opening, and a material storage tank, mortar mixing plant, pump, portal crane, control room, and residence on the deck. A large work boat equipped with rooms, etc. is transported to the construction site of the embankment body or seawall and is seated on the seabed. Next, a formwork is formed on the embankment body or revetment using the work boat, and the levee body or revetment is constructed using the so-called pre-pact concrete construction method, in which coarse aggregate is first poured into the formwork and then mortar mixed on the work boat is poured into the formwork. Concrete is poured, the work boat is floated after the concrete is cured, and the concrete hardens, and the same work is repeated to construct the embankment body or revetment.

[Effect]

As mentioned above, the construction of the embankment body and revetment is carried out by repeatedly using a large work boat to create the formwork for the embankment body and revetment at the construction site, and then pouring pre-pact concrete inside it. Since we will do
The construction period will be greatly shortened.

[Embodiments of the invention]

A height of 20 km in the offshore area about 2 to 5 km from the land.
Consider an example of constructing a trapezoidal seawall with a width of approximately 30 m.

Figures 1 and 2 are a perspective view and a sectional view of a large working boat used for the construction of the seawall. In the figure, 1 is a work boat, 2 is a formwork forming part, 3 is a ballast tank, and 4
is a formwork, 5 is a formwork operation arm, 6 is coarse aggregate, 7 is mortar, 8 is a tremie pipe, 9 is a mortar mixing plant, 10 is a coarse aggregate tank, 11 is a portal crane, 12 is a control room and Living room, 13 is a cement tank, 14 is a pump, 15 is a hydraulic cylinder, 16
is bearing, 17 is sprayed sand, 18 is existing seawall, 19 is
20 is a newly constructed seawall, and 20 is a seabed.

As shown in the figure, the work boat 1 has a U-shape, and is equipped with a formwork forming section at its opening, and has a mortar mixing plant 9, a coarse aggregate tank 10, a portal crane 11, and a control room on the deck. A living room 12, a cement tank 13, a pump 14, etc. are provided.
Also, a plurality of ballast tanks 3 are provided on both sides, and a large number of hydraulically driven formwork operating arms 5 are arranged in parallel on the formwork forming section 2.

When the work boat 1 reaches the seawall construction site by self-propulsion or towing, the ballast is injected into the ballast tank 3 and the hull is brought to the bottom of the seabed 20. At this time, a plurality of hydraulic cylinders 15 installed on the ship's hull are temporarily set on a support 16 that has been sunk on the seabed in advance, leaving a gap that is large enough to prevent the ship's hull from coming into contact with the seabed surface, and earth and sand 19 are poured into the gap. After eliminating the effects of blowing and unevenness, the hydraulic cylinder 15 is housed in the hull, the hull is placed on the seabed, and the amount of ballast is adjusted in consideration of the working force during construction to stabilize the hull.

Next, the formwork operation arm 5 is operated in the formwork forming section 2 to form the formwork 4 in accordance with the predetermined shape of the seawall. The shape of the formwork is a flat surface or a curved surface with a certain degree of curvature in the vertical direction. The formwork as a whole is 2
There will be two opposing templates, but since they are large, they may be divided into several pieces in the vertical direction.

Once the formwork 4 is formed, coarse aggregate 6 for prepact concrete is put into the formwork from the workboat 1, and the tremie pipe 8 is set using the portal crane 11 of the workboat 1. The number of tremie tubes 8 is the working time,
It is determined by the capacity of the mortar mixing plant 9, etc. Next, the mortar 7 blended in the mortar mixing plant 9 is pumped into the formwork 4 through the tremie tube 8, and is filled between the coarse aggregates 6 that have already been filled. The fine aggregate used for the mortar 7 may be transported from land to the work boat 1, or if good seabed sand is available locally, it may be washed and used.

After pouring the mortar 7 and placing the so-called pre-pact concrete, the tremie pipe 8 is pulled up, and the work boat 1 remains seated on the seabed to cure the concrete, allowing it to solidify and reach the required strength. When this is reached, the formwork operation arm 8 is operated to separate the formwork 4 from the concrete, and the seawall is completed. Next, the water in the ballast tank 3 is drained, the work boat 1 is floated forward, and a new seawall is installed following the existing seawall 18.

It is desirable to replenish cement hardening material and aggregate during concrete curing, and weight loss due to consumption of cement and aggregate can be adjusted by injecting ballast water.

〔Effect of the invention〕

As described above, the present invention utilizes a large work boat for constructing embankments and seawalls in offshore waters, so the construction period is greatly shortened compared to the conventional caisson construction method or cell construction method. It is particularly effective for constructing sea walls and breakwaters with the same cross section over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a seawall construction work performed by a large work boat showing an embodiment of the present invention, and FIG. 2 is a sectional view of the work boat. In the figure, 1 is a work boat, 2 is a formwork forming section, 3 is a ballast tank, 4 is a formwork, 5 is a formwork operation arm, 6 is coarse aggregate, 7 is mortar, 8 is a tremie tube, and 9 is a mortar mixing Plant, 10 is a coarse aggregate storage tank, 11 is a portal crane, 12 is a control room and living area, 13
is a cement storage tank, and 14 is a pump.

Claims (1)

[Claims] 1. In the construction work of an embankment body and seawall offshore, a large work boat is seated on the seabed at the construction site,
Operate the formwork support device installed on the work boat,
A formwork is formed to create the above-mentioned embankment body and revetment in the required shape, and prepact concrete is placed inside the formwork, and after being cured and hardened, the formwork is peeled from the concrete and the work boat is installed. 1. A rapid construction method for offshore embankments and revetments, characterized in that the embankments and revetments are constructed by floating and moving and repeating the same operation. 2. During construction work for offshore embankments and seawalls, large work vessels sit on the seabed at the construction site, form the formwork for the embankment and seawall, and place pre-pact concrete into the formwork. It has a square shape, and is equipped with multiple ballast tanks on each side, a formwork forming part at the opening, and a material storage tank, mortar mixing plant, pump,
A portal crane, control room, living room, etc. will be installed.
By pouring water into the ballast tank,
A rapid construction device for offshore embankment bodies and seawalls, characterized by being configured to be able to sit on or float on the seabed.