JPH08184022A - Method of aerial reclamation construction - Google Patents

Abstract

PURPOSE: To enable reclamation having high quality, and to facilitate maintenance after completion by a method wherein a reclamation zone is coffered, water in the zone is drained, the ground is exposed, the ground is improved and the inside of a coffering is reclaimed. CONSTITUTION: Cut-off steel sheet-piles 7, 7 are driven to an improved field ground 6 as a revetment section 2 single or doubly, and the outer circumference of a reclamation zone A is coffered. A rubble-stone 13 is also charged on the outsides of the coffering sheet-piles 7 and the insides as required, and covering stone and precast concrete armour blocks are installed, thus constituting a revetment. All drainage in the reclamation zone A is conducted and the ground 1 is exposed, and a weak stratum is improved by using a stabilizer, etc. A deep well is installed as necessary, and spring water treatment and consolidation promotion are executed. The inside of a coffering zone is reclaimed through the same construction method as a method of banking construction on a land section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air reclamation method which can be used for reclamation of a shallow water area for both water depth and foundation ground where a water stop revetment or temporary cutoff can be constructed.

[0002]

2. Description of the Related Art The conventional landfill method used for the construction of artificial islands on the sea is based on Tsukishima, which involves dumping earth and sand into the water to a uniform ground level above the sea level.

[0003]

The underwater landfill method as described above has the following problems. Extend the settlement time of the foundation ground or increase the ground improvement. Insufficient strength of landfill due to underwater landfill, risk of liquefaction, and increase in ground improvement. Water pollution and ecosystem destruction due to the dumping of sediment into the water. Deterioration of landfill board quality due to bad soil reclamation and difficulty of early use. Extension of the construction period due to the inability to work parallel between Tsukishima and the building. Repair work such as mountain stopping and re-drilling in the construction of underground facilities.

An object of the present invention is that landfill can be constructed not by dumping earth and sand into water but by adopting the same embankment construction method as that used on land, which makes it possible to solve the above problems in the underwater landfill construction method. To provide a new air reclamation method.

[0005]

According to the present invention for the above object, the landfill area is closed, the drainage within the deadline is performed to make the ground in the landfill area appear, and the ground of the site ground is improved before the deadline is reached. The landfill will be carried out.

[0006]

[Working] With the above method, since the soil that has emerged from the drainage can be reclaimed while compacting the soil, it is possible to create a well-compacted ground with less subsidence. In addition, since the landfill soil is loaded in advance, it is possible to promote consolidation and settlement of the local soil and improve bearing capacity. Furthermore, by returning water after the landfill is completed, the weight of the landfill soil can be reduced by buoyancy, and the amount of consolidation settlement and the consolidation time can be shortened, and the landfill site can be used early. On the other hand, since the landfill soil is not dumped underwater, water pollution around the landfill area will be reduced.

[0007]

EXAMPLES FIGS. 1 to 9 show a process sequence of a case where an artificial island is to be reclaimed, in the order of steps.

Revetment Partial Ground Improvement Process (Fig. 1) The water area of the terrain where the water revetment or temporary deadline and its reinforcement can be constructed is set as the landfill area, and the ground 1 of the water area is set.
If the geology of is weak and the ground subsidence of the revetment part 2 is for a long time, or if the revetment part 2 is too soft to build,
First, the ground improvement of the water bottom which becomes the revetment part 2 of the landfill area A is performed. However, if the ground in the water area is of good quality or long-term land subsidence time can be secured, the improvement of the ground at the bottom of the water can be omitted.

In this ground improvement, the work boat 3 is used to drive a required number of vertical drain piles 4 at regular intervals. At the time of ground improvement, the pollution prevention curtain 5 is stretched from the work boat 3 to the surrounding water of the pile under construction to prevent the seawater from being polluted by the rising sand. By constructing the vertical drain pile 4, the consolidation of the soft layer is promoted, the supporting force is improved, and the strength of the field board 6 of the revetment portion 2 is increased.

Shutoff sheet pile driving step (FIG. 2) A water-stopping steel sheet pile 7 is struck in a single or double manner on the ground-improved site 6 which becomes the revetment portion 2, and the outer circumference of the landfill area A is shut off. In order to place the steel sheet pile 7, the steel sheet pile 7 is hung from the turret of the crane-equipped barge 8 that is anchored offshore.
Vibro hammer or hydraulic hammer 9
Type in.

Deadline filling process (Fig. 3) When the double steel sheet pile is used for shutting, the steel sheet piles 7 inside and outside the portion where the driving is completed are connected by the tie rods 10 at regular intervals and then carried by the gut ship 11. The resulting filled sand 12 or rubble stones are put into the space between the steel sheet piles 7 to make a watertight cutoff.

Closure Reinforcement Step (FIG. 4) In order to further dissipate the waves and stabilize the seizure, a rubble 13 is put on the offshore side of the cut-off sheet pile, and a covering stone and a wave-dissipating block are installed thereon to form a revetment 14. In some cases, rubble stones or earth and sand may be applied to the inside for embankment to ensure stability.

On-site ground soil improvement process in the landfill area (FIG. 5) All the drainage in the closed landfill area is performed to expose the ground 1, and the soft layer is improved by using the stabilizer 15 or the like. In addition, a deep virus 16 for the purpose of treating spring water and promoting consolidation is installed if necessary.

On-site board improvement process in the landfill area (Fig. 6) For the purpose of consolidation settlement and improvement of bearing capacity in the thick soft layer,
Ground improvement piles 17 such as vertical drains are piled into the pile driver 18
Install by.

Landfilling process (FIG. 7) After the improvement of the on-site board is completed, the landfilled sand 19 transported by the soil carrier is unloaded by the hoisting ship 20 into the deadline for landfilling. The landfilled sand at this time is not limited to mountain soil, but may be construction-generated soil containing defective soil, and the defective soil is laid by the bulldozer 21 alternately in a sandwich with high-quality sandy soil and sufficiently compacted.

Facility construction process (FIG. 8) Construction of the artificial island-related facility 22 is started at the same time as the landfill within the deadline. The construction of the facility is based on the direct foundation 23 or the pile foundation 24 depending on the ground condition of the water bottom.

Closing Sheet Pile Removal Step (FIG. 9) After the landfill is completed, the cutting sheet pile is removed if necessary. Superstructure with revetment block 25 after this removal 2
Build 6 and. If not removed, a revetment block and superstructure will be built on the temporary cut-off sheet pile. With these completions, all landfill processes will be completed.

Since this method can be applied in the same manner if the planned site is shallow in both the water depth and the foundation ground, the present invention is not particularly limited to landfilling of the outer periphery of the island or the like.

[0019]

As described above, the present invention has the following effects because the landfill area can be closed and then the landfill can be drained and the landfill can be constructed by the same embankment construction method as the land portion.

Since the deadline is drained and then compacted, landfilling is performed one by one, the landfill does not need to be improved and high-quality landfilling with less subsidence can be performed. Therefore, the maintenance work after completion is reduced, and the landfill board can be used early.・ Because of the preceding load due to air reclamation, which increases the amount of landfilled sand, the pressure density of the on-site ground is promoted, and ground improvement is unnecessary or less necessary.・ Since the deadline is drained before landfilling, water pollution is reduced compared to when dumping sand into the water.
The impact on the environment and fisheries around the landfill area due to changes in water quality will almost disappear.・ It is possible to use bad soil such as construction soil. In addition, since land reclamation work and facility construction can be done at the same time, the work can be shortened.・ No need for mountain retaining work and secondary excavation work for facility construction, and no or short facility foundation piles.

[Brief description of drawings]

FIG. 1 is a process diagram of revetment partial ground improvement in the air reclamation method of the present invention.

FIG. 2 is a process diagram of placing a cutoff sheet pile.

FIG. 3 is a deadline filling process diagram.

FIG. 4 is a deadline reinforcement process diagram.

FIG. 5 is a process diagram for improving the on-site bad soil in the landfill area.

FIG. 6 is a process diagram for improving the on-site board in the landfill area.

FIG. 7 is a landfill process diagram.

FIG. 8 is a facility construction process chart.

FIG. 9 is a process drawing of removing a cutoff sheet pile.

[Explanation of symbols]

 1 Ground in reclaimed area 2 Revetment part 4 Vertical drain pile 6 Local plate of revetment part 7 Water-stop steel sheet pile 12 Filling sand 13 Discarded stone 14 Revetment 17 Ground improvement

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Onishi 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Co., Ltd. (72) Inventor Yuichiro Someba 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction stock company

Claims (1)

[Claims] 1. A method for closing a landfill area, draining the landfill area to expose the ground in the landfill area, improving the ground on the site, and then landfilling the landfill area. Medium landfill method.