JPS6326432Y2 - - Google Patents

Description

[Detailed explanation of the idea] The drain method is known as a method for improving soft ground that contains a large amount of moisture. For onshore construction, drains such as sand piles, paper drains, and plastic drains are installed at desired intervals in the ground, the ground surface is covered with bedding sand, and then embankment is placed on top of it. The ground is compressed by the gravity of the soil, and the moisture contained in the soil is forced out through the drain and toward the sand. In addition, if you cover the ground where the drain is installed with an airtight sheet, bury the area around the sheet deep enough into the ground, and then exhaust the inside of the sheet, negative pressure will be created inside the drain, which will effectively seal the ground. Contained moisture can be expelled.

However, in the case of underwater construction, even if a loaded embankment is placed on top of the sand, the difference in specific gravity between the embankment and water is not very large, so it is not possible to effectively compress the ground and drive out the moisture contained in it. Ta. However, since there are no other suitable methods, this method has been relied upon exclusively, which has led to problems such as uneven ground subsidence. Note that the method of using a sheet has not been put into practical use because it is extremely difficult to construct it at the bottom of the water.

The purpose of this idea is to effectively expel moisture contained in the ground during underwater drainage construction.

The work boat of this invention has an airtight submarine box with no bottom surface and an ark. Multiple pillars extend upward from the box, and the ark is supported by these pillars. On top of the ark, there is a hoisting machine for hoisting the ark above the pillars and for pulling the subcase close to the ark, a pump for draining the inside of the subcase, and these hoisting machines and pumps. A prime mover is installed to drive the motor.

This invention will be explained below based on the illustrated embodiments.

Reference numeral 1 denotes a submarine box, which consists of only an upper wall and side walls, has an open bottom surface, and is sufficiently reinforced with reinforcing beams (not shown) or the like to withstand external pressure. The size of the box 1 is arbitrary, but an example is 25m x 25m x
It is 4m. On the top of the box 1, there are four pillars 2,
2 have been planted.

3 is an ark, and four vertical holes 4, 4 penetrating from the deck to the bottom of the ship are provided, and the columns 2, 2 of the submersible 1 are inserted into these vertical holes 4, 4. On the deck, a prime mover 5, a drainage pump 6 and a hydraulic pump 7 driven by the prime mover, and hoisting machines 8, 8, etc. driven by the hydraulic pressure of the pump 7 are installed. Wire ropes 9 , 9 extending from the hoisting machines 8 , 8 are connected to the upper ends of the columns 2 , 2 and the upper surface of the subcase 1 , and the drain pump 6 is communicated with the internal space of the subcase 1 through a hose 10 .

Next, the usage of the above-mentioned work boat will be explained.

As shown in Figure 2, sand piles 12,1 with a diameter of 20 to 50 cm and a length of 5 to 20 m are placed on the water bottom 11 of the work site.
2... are installed in advance at intervals of about 1 to 4 m, and the sand bed 13 is laid down to a thickness of 1 to 2 m. As shown in Fig. 1, the work boat is towed to the work site with the submersible 1 raised close to the bottom of the ark 3, and there, the submersible 1 is lowered by the operation of the hoisting machines 8, 8, and the sand 13 is lowered. sit on the bottom of the water, surrounding it.
When the hoisting machines 8, 8 are further operated, the ark 3 is hoisted above the water surface 14 as shown in FIG. In addition to this, when the pump 6 is operated, the pressure inside the submersible case 1 is reduced, so that the moisture contained in the underwater ground is effectively expelled through the sand piles 12, 12, . . .

The workboat described above is not only effective not only for sand pile construction methods but also for paper drain construction methods, plastic drain construction methods, etc.
When the clay layer at the bottom of the water is thin, it is also effective for direct water supply from the surface of the clay layer, and its range of applications is extremely wide.

In addition, when hoisting the ark 3 above the water surface 14, it is possible not only to use its weight to compress the ground as described above, but also to prevent the ark 3 from being shaken by waves and interfering with the work. can.

As described above, with this invention, it is possible to efficiently improve the effectiveness of ground improvement by water pumping at the bottom of the water, which has been difficult to achieve results compared to land-based work. It has a large contribution to make.

[Brief explanation of the drawing]

The figures show a working boat in which this invention was implemented, with FIG. 1 being a longitudinal cross-sectional view during movement, and FIG. 2 being a longitudinal cross-sectional view during work. 1... Submarine, 2... Support, 3... Ark (hull),
5... Prime mover, 6... Drain pump, 8... Hoisting machine, 9... Wire rope, 10... Hose.

Claims (1)

[Scope of utility model registration request] A plurality of vertical supports are installed in a submersible having an airtight upper surface and side surfaces and an open bottom surface, the ship's body is supported by these supports so as to be able to be raised and lowered, and the ship's body is raised and lowered along the pillars. A ground drainage work boat comprising an upper machine and a pump provided in the hull or the subcase for draining the inside of the subcase.