JPS61142218A - Improver for seabed soft ground - Google Patents

Abstract

PURPOSE:To easily perform delivery and improving operations by a method in which a working ship is divided into a semi-diving ship and a support ship, main working equipments such as stirring shaft, etc., are attached to the semi- diving ship, and auxiliary equipments such as an improving agent supplier, power source, etc., are attached to the support ship. CONSTITUTION:On the tip of a semi-submerged ship 10, a stirring shaft 50 with a stirring blade 51 and an improving agent discharger, a supporter 42 for the shaft 50, a rotary driver 60 for the shaft 50, and an elevating driver for the shaft 50 are provided. A buoyancy regulator 15 to hold the ship 10 at a semi-diving position, a stationary spud 30 movable only vertically to the ship 10, and a driver for the spud 30 are also provided. In addition, a movable spud 31 to be moved vertically or horizontally to the ship 10, a driver 36 for the spud 31, and a means to alter the relative position in the horizontal direction for the ship 10 and the spud 31 are provided. Furthermore, an improving agent supplier and a power source for each driver of the ship 10 are provided to the support ship 20.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a device for improving soft ground on the seabed. This relates to a completely new type of submarine soft ground improvement equipment that is operated while being held by a ship.

(Prior Art) Conventionally, as shown in Fig. 10, as a construction method for improving the soft ground on the seabed, a work barge 1 floating on the sea is lowered into the sea while rotating a hollow stirring shaft 2, and then the lower end is lowered into the sea. The provided stirring blade 3 is placed at a predetermined depth D1 into the soft ground C on the seabed.
After penetrating up to the point, the soil improvement material is pulled out, and in either the penetration or withdrawal process, the ground improvement material is pneumatically fed to the improvement material supply passage provided inside the stirring shaft 2, and then the ground improvement material is fed through the discharge passage provided at the lower end of the stirring shaft 2. A jet stirring method (DJMT method) is known in which the material is discharged from the outlet into the soft ground C and the stirring blades 3 stir and mix the ground improvement material and the soft ground soil on the ocean floor to improve the soft ground.

However, with conventional submarine soft ground improvement equipment, a single work barge 1 floating on the sea can be used to improve the soft ground I on the seabed. A
In order to carry out all operations such as inserting and pulling out the stirring shaft 2 from C and supplying the ground improvement material to the stirring@2, the stirring shaft 2 and the stirring shaft 2 are installed on the work barge 1. A supporting leader 4, a rotating and elevating drive device for the stirring shaft 2,
a tank 5 for storing soil improvement material; an improvement material supply device 6 for supplying the soil improvement material from the tank 5 to the stirring shaft 2;
It is necessary to mount all related equipment such as a generator unit as a power source and a control room 7 equipped with their control equipment, and as a result, the work barge 1 becomes very large and equipment costs are extremely high. It was expensive. Moreover, all the work is done from the work barge 1 floating on the sea.
It is necessary to make the total length L1 of the stirring shaft 2 longer than the sum of the water depth Do from the sea surface A to the seabed surface B and the actual improved depth D1 from the seabed surface B, and accordingly, the leader 4 is also made taller. Therefore, the total height Ho of the work barge 1 is the sum of the water depth Do, the soil improvement depth D1, the total length L1 of the stirring shaft 2, and the allowance length L2 of the rotational drive part of the stirring shaft 2 and the leader top. At corresponding heights, the whole becomes very high and unstable;
This caused various problems in transportation and ground improvement work.

In particular, in this type of ground improvement method, by sequentially displacing the penetration position of the agitation 13 in the radial direction and repeating the above steps, a large number of pile-shaped improved ground C1 are placed adjacent to each other to improve the ground in a predetermined range. , and in order to increase the strength of the improvement, construction may be carried out so that the adjacent improved ground is partly concave in the radial direction. In the case of this lap construction, the positional accuracy of the lap m is on the order of several α. However, when working from above the sea surface as in the conventional method, if there is a slope of 10 on the sea surface at a deep depth of 30 m, the seabed surface will have a slope of 50C1.
Errors may occur. Furthermore, in the above-mentioned conventional device, the height Ha of the work barge 1 is high and it is unstable and easily affected by wind, rain, tides, and waves, so the lap m tends to be uneven, and the work The tide level changes depending on the date and time, and the water depth Do from the work barge 1 to the seabed surface B changes, so the improvement depth D1 also becomes uneven, making it impossible to work, especially on days with strong wind, rain, currents, and waves. There were problems such as very poor operation efficiency.

(Purpose of the Invention) The present invention was developed to solve these conventional problems, and aims to reduce the size of work boats, reduce equipment costs, simplify transportation, and improve tide level and wind and rain, tides,
To enable work to be carried out without being affected by waves, to greatly increase the operating rate of machines, and to easily equalize the lap amount and improvement depth of adjacent improved ground to obtain very high quality improved ground. The purpose is to provide a device that can do this.

(Structure of the Invention) The present invention provides nine semi-submersible vessels capable of semi-submerged and surfacing, a stirring shaft having a stirring blade at the tip, a support means for supporting the stirring shaft so as to be rotatable and vertically movable, and a rotating drive for the stirring shaft. a means for driving the stirring shaft up and down, a means for discharging the ground improvement material into the stirring section by the stirring shaft, and nine semi-submersible vessels held at a semi-submerged position at a predetermined height from the seabed surface. A buoyancy adjustment means, a fixed spud that can only be raised and lowered for the nine semi-submersible ships, a driving means that allows the fixed spud to be inserted into and removed from the seabed surface from the nine semi-submerged ships, and a fixed spud that can be lifted and lowered for the nine semi-submersible ships. A movable spud that is movable and horizontally movable, a driving means that allows the movable spud to be inserted into and removed from the seabed surface from the nine semi-submarine vessels, and a horizontal relative position between the nine semi-submersible vessels and the movable spud is changed. On the other hand, a support ship configured separately from the nine semi-submarine ships is provided with an improved material supply device for the improved material discharging means, and a drive for each means provided in the nine semi-submarine ships. It is characterized by being equipped with a power source for the parts.

That is, the present invention divides the work vessels into nine semi-submersible vessels and a support vessel, and equips the nine semi-submersible vessels with main working equipment such as stirring shafts for penetrating the stirring blades into the soft ground of the seabed. By equipping the support vessel with auxiliary equipment such as a supply device for improvement materials and a power source for the equipment, each can be made smaller for convenience in transportation, and the semi-submersible equipment can be kept at a predetermined height from the seabed. This allows accurate work to be carried out from a semi-submersible facility without being affected by tide levels, wind and rain, currents, and waves while holding it in a semi-submersible stage position, and allows for rough movement of semi-submerged facilities and wrapping construction. It was made easy.

(Embodiment) FIG. 1 is a front view of the entire structure showing an embodiment of the present invention. In the figure, 10 indicates a semi-submerged installation and 20 indicates a support ship. As shown in FIGS. 1 and 2, the semi-submerged installation 10 has a rectangular frame-shaped lower hull installed around a midship 12 having a through hole 11 for raising and lowering the stirring shaft in the center via radial bracing 13. Stabilizing columns 15 are provided at the four corners of the column 14 as buoyancy adjustment means, and by adjusting the buoyancy by supplying and discharging water or air into the columns 15, semi-submersible The device 10 can be adjusted to a state where it is floating on the sea, a semi-submerged state where it is at a predetermined height hl from the seabed surface B, and other submerged states. In addition,
Bracing 16 and upper gutter 17 are provided between each column 15 as necessary, as shown by the dashed lines in Figure 1.

As a means for fixing and changing the position of the semi-submerged installation 10, the semi-submerged installation 10 is used as shown in FIGS. 2 and 5(a) to (b).
For example, fixed spuds 30 and movable spuds 31 are installed at several locations in the center of the lower hull 14 facing each other left and right.
is provided. The fixed spud 30 is attached to the lower hull 1
The hydraulic cylinder 3 for pouring is fitted into the through hole 18 provided in the lower hull 14 and is attached to the support frame 32 fixed to the lower hull 14.
3 so that it can be raised and lowered freely. moving spud 3
1 is an elongated through hole 19 provided in the lower hull 14.
The movable support frame 35 is fitted into the lower hull 14 and is horizontally movable via a horizontally moving hydraulic cylinder 34, and is movable up and down via a pouring hydraulic cylinder 36. .

A beamer 40 is erected on the midship 12 of the semi-submerged installation 10. The leader 40 may be provided in the semi-submerged installation 10 via a trolley so as to be able to change its position front and rear, left and right, or both.

The stirring shaft 50 is hollow and has a rectangular cross section, has an improvement material supply passage formed therein, and has a ground improvement material injection port and stirring blades 51 at its lower end.

The upper end of the stirring shaft 50 is rotatably supported by the upper holder 41 via a swivel joint or the like, the middle part is supported by the intermediate holder 42 so as to be rotatable and movable up and down, and the upper holder 41 is movable up and down by the leader 40. The intermediate holder 42 is fixed to the leader 40.

The rotational drive device @60 of the stirring shaft 50 has a motor with a speed reducer, a transmission gear, etc., and is installed on a fixed frame 43 provided at the bottom of the leader 40, and allows movement in the axial direction with respect to the stirring shaft 50. while transmitting rotational torque.

The lifting drive device ft70 for the stirring shaft 50 includes a pair of upper and lower lifting frames 71 and 72, as shown in FIGS. 3 and 4. Each of the lifting frames 71 and 72 has a stirring shaft 50. A chuck structure 73, 74 is provided for detachably holding the stirring shaft 50 while allowing rotation of the stirring shaft 50. Both lifting frames 71.7
2 are connected to the ends of the ronds of hydraulic cylinders 75 and 76 for raising and lowering, respectively, and are provided so as to be freely raised and lowered.
76 is fixed to fixed frames 44 and 43 provided at the middle and lower portions of the leader 40.

On the other hand, the support ship 20 is equipped with an improvement material supply device 1, an improvement material storage tank 21, and an improvement material pneumatic feeder @ 22, as well as a power source for each device installed in the semi-submerged facility 10. A control room 23 is equipped with a generator unit, a hydraulic power source, an air source, and control devices for each device. 24 is a support hose that supplies power such as electricity, hydraulic pressure, air, etc. and improvement materials from each device of the support ship 20 to each device of the semi-submersible facility 10.

Next, the ground improvement work using the above device will be explained.

■ The water in the transport stabilizing column 15 is drained to increase the buoyancy of the semi-submersible facility 10, and while the semi-submersible facility 10 and the support vessel 20 are floating on the sea, the ground is improved using a tugboat (not shown). transport to the location. In this case, the support ship 20 may be provided with a propulsion device, and the semi-submersible ship 10 may be towed and transported by the support ship 20. Further, the semi-submersible vessel 10 may be transported in a semi-submerged state, which is submerged to some extent. In this way, the protruding height of the leader 40 from the sea surface can be lowered, and it can be passed under bridges without any trouble. can.

On the other hand, before or after the above-mentioned transportation, each device provided in the support ship 20 and each device provided in the semi-submersible ship 10 are connected by the support hose 24.

Next, at the ground improvement position, the buoyancy of the semi-submersible vessel 10 is gradually reduced by supplying water into the stabilizing column 15 of the semi-submersible vessel 10, and the semi-submersible vessel 1o is gradually lowered to the seabed surface while maintaining its levelness. It is stopped at a predetermined height h from B. Thereafter, as shown in FIG. 5(a), each spud 30, 31 is driven from the semi-submersible vessel 10 into the seabed surface B by each spud-casting cylinder 33, 36, and the semi-submersible vessel 10 is removed from the water. It is fixed at the above height position in the child state. Note that the support ship 20 remains floating on the sea. At this time, if necessary, several anchors are dropped from the semi-submersible ship 10 and the support ship 20 using winches, and the anchors are brought to the bottom.

■ Ground improvement work After fixing the semi-submersible vessel 10, the stirring shaft 50 is lowered by the lifting drive device 70 while being prevented from rotating by the rotary drive device 60, and the stirring blade 53 at the tip is rotated to improve the soft ground on the seabed. Penetrate C. At the time of this penetration, when lowering the stirring shaft 50 from the state shown in FIG. The lower lifting frame 72 is lowered by the lower lifting hydraulic cylinder 76, and the stirring shaft 5 is integrated with the lower lifting frame 72.
Lower 0.

In this case, the stirring shaft 50 is held by the lower chuck mechanism 74, but this chuck mechanism 74 is attached to the lower lifting frame 72.
The stirring shaft 50 is provided so that it can only rotate relative to the rotary drive bag @60, and the stirring shaft 50 is slidable in the axial direction relative to the rotary drive bag @60, and rotates by receiving rotational torque from the rotary drive bag @60. are doing. Therefore, the stirring shaft 50 is lowered while rotating. On the other hand, the upper lifting frame 71 is raised by the upper lifting hydraulic cylinder 75 with the chuck mechanism 73 released so as not to interfere with the rotation and lowering of the stirring shaft 50.

When the lower elevating frame 72 descends by a predetermined stroke Sb and the upper elevating frame 71 rises by a predetermined stroke Sa, the chuck mechanism 73 of the upper elevating frame 71 closes at that position.
After grasping the stirring shaft 50 with the
By lowering the upper elevating frame 71, the stirring shaft 50 is lowered while rotating. At this time, the lower lifting frame 72 is raised and lowered back to its original position by the lower hydraulic cylinder 76 with the chuck mechanism 74 released so as not to interfere with the rotation and lowering of the stirring shaft 50.

Thereafter, by repeating the above steps, while rotating the stirring shaft 50, the chuck mechanisms 73 and 74 of the upper and lower lifting frames 71 and 72 grip the stirring shaft 50 alternately.
By raising and lowering each lifting frame 71, 72, the stirring shaft 50
As a result, the stirring shaft 50 is lowered almost continuously, and the stirring blades 51 are rotated to penetrate into the soft ground C.

In this way, the predetermined depth D is reached while rotating the stirring W151.
After penetrating up to 2, stir! Pull out I51 while rotating it. At this time, as above, the lifting hydraulic cylinder 75
．． 76 is extended and contracted to raise and lower each lifting frame 71.72, and when the lifting frame 71.72 is raised, the chuck mechanism 73 or 74 provided on the frame is turned on to grip the stirring shaft 50, and when lowered, the chuck Release mechanism 73 or 74.

As a result, the stirring shaft 50 is raised almost continuously, and the stirring blades 51 are pulled out while being rotated.

On the other hand, in either the process of penetrating or pulling out the stirring blade 51, the improvement material supply passage in the stirring shaft 50 passes through the improvement material supply tank 21 provided in the support ship 20, the air pressure feeding device 22, and the support hose 24. The soil improvement material is supplied to the soil improvement material, the improvement material is discharged into the soft ground from the tip outlet of the stirring shaft 50, and the soil improvement material and the soft ground soil are stirred and mixed by the rotation of the stirring shaft 51, and the following steps are carried out. Therefore, we will improve the soft ground.

In this way, the nine semi-submersible vessels 10 are placed at a predetermined height h from the seabed surface B.
By working fixed in a semi-submerged position at a distance of
Work can be performed smoothly without being affected by wind and rain, tides, and waves, and the ground improvement depth D2 can be easily made uniform without being affected by changes in the tide level, that is, the water depth Do.

Furthermore, the total length of the stirring shaft 50 can be significantly shortened compared to the conventional method in which work is carried out from a work barge floating on the sea. Along with this, the leader 40 can also be lowered, and the total height Hl of the nine semi-submersible vessels 10 can be lowered, making it possible to make the entire structure smaller. Moreover, since it is only necessary to install improving materials and power source supply equipment on the support ship 20, the height H2 of the support ship 20 can also be reduced.

■ Prevention of seawater pollution During the above-mentioned work, the spent air used to air-feed the ground improvement material rises along the outer circumferential surface of the stirring shaft 50 through the ground soil that is stirred during penetration and extraction. However, as shown in the figure, from nine semi-submersible vessels 10 to sea surface A.
By setting up a curtain 26 made of a plastic sheet or the like via a float 25 so as to surround the sea area above the ground improvement area, seawater pollution can be minimized.

■ Changing the ground improvement position The ground improvement position is changed by moving the nine semi-submersible vessels 10 as shown in FIGS. 5(a) to (f).

First, (a) extend the horizontal movement hydraulic cylinder 34, shorten the distance between the fixed spud 30 and the movable spud 31, and drive both spuds 30 and 31 into the seabed surface B using the respective casting hydraulic cylinders 33 and 36. With the sub 9 vessel 10 fixed, perform the ground improvement work described in (3) above, and when the ground improvement work is completed, (b) once remove only the fixed spud 30 from the seabed surface using the cylinder 33, and (C) move it. spud 31
By moving the movable spud 31 in the direction of separating it from the fixed spud 30 using the cylinder 34 while driving the movable spud 31 into the seabed surface B, the movable spud 31
Move it by a predetermined amount to the right in the drawing based on , then (
d) The fixed spud 30 is driven into the seabed surface B by the cylinder 33, (e) The moving spud 31 is pulled out from the seabed surface B by the cylinder 36, (f) The cylinder 34
The movable spud 31 is moved and both spuds 30.
31, and then return to the step (a) above, drive the moving spud 31 into the seabed surface B using the cylinder 36, and move the semi-submersible 9 vessels 10 horizontally by a predetermined amount from the previous working position. Fixed to.

In this way, by repeating steps (a) to (f),
The nine semi-submersible vessels 10 are moved horizontally by a predetermined distance, and at each position (a), the soil improvement work is performed by partially indenting the previously constructed improved ground in the radial direction. During this wrap construction, the ground improvement work is carried out with the nine semi-submersible vessels 10 fixed at the predetermined semi-submerged positions as described in (■) above. It is possible to easily equalize the radial lap rate of the improved ground.

Next, another example will be described.

In FIG. 6, a rod 82 is protruded from both upper and lower ends of a hydraulic cylinder 81 for lifting and lowering that is mounted on a fixed frame 45, and a movable pulley 83 is provided at each of the upper and lower ends of the rod. The pair of upper and lower lifting wires 85 passed to the upper lifting frame 71 having an upper chuck mechanism 73
This upper elevating frame 71 and the lower chuck mechanism 7
4 is connected to a fixed pulley 86 by a pair of upper and lower interlocking wires 87, and by raising and lowering the upper and lower movable pulleys 83 by the hydraulic cylinder 81, the upper The elevating frame 71 is raised and lowered, and in conjunction with this elevating, the lower elevating frame 72 is moved up and down in a direction opposite to that of the upper elevating frame 71 via an interlocking wire 87. According to this embodiment, both the upper and lower lifting frames 71,
72 can be raised and lowered in opposite directions.

FIG. 7 shows that the rotational drive system of the stirring shaft 50 is similar to the above-described embodiment, in which a rotational drive device 60 is mounted at the middle part of the stirring shaft 50.
A winch 70a is used as the lifting/lowering drive system. In this case, air recovery efficiency can be increased by using a cylindrical leader 40a that also serves as an air recovery tube.

FIG. 8 shows an upper drive system in which a rotation drive device 60a is connected to the upper end of the stirring shaft 50, and the stirring @1150 and rotation drive device 60a are raised and lowered together by a winch 70a. In this way, the rotational drive torque can be transmitted more reliably, and the weight of the rotational drive device 60a can be added at the time of penetration. Also in this case, as in FIG.
0a can be used.

FIG. 9 shows a tip drive system in which a cylindrical elevating body 52 is raised and lowered from the semi-submersible vessel 10 by an elevating drive device 70b, and a required number of stirring shafts are connected to the tip of the elevating body 52 via a rotary drive device 60b. According to this, the leader can be omitted and the center of gravity of the semi-submersible vessel 10 can be lowered to improve stability.

In addition, by providing fixed spuds 30 and movable spuds 31 on all sides of the semi-submersible vessel 10 as means for horizontally moving the semi-submersible vessel 10, the semi-submersible vessel 10 can be freely horizontally moved forward, backward, left and right. can.

(Effects of the Invention) As described above, according to the present invention, a work vessel is divided into a semi-submersible vessel and a support vessel, a working vessel such as a stirring shaft is supplied to the semi-submersible vessel, and improvement materials and a power source are supplied to the semi-submersible vessel. By separately equipping each support ship with equipment, semi-submersible ships and support ships can be made smaller.
Not only can transportation be simplified, but equipment costs can also be reduced.

In particular, since ground improvement work is carried out by fixing a semi-submersible vessel in a semi-submerged state at a predetermined height from the seabed, it is not affected by changes in tidal level (water depth), wind, rain, currents, or waves. , the work can be done smoothly, the operating efficiency of the machine can be greatly increased, and the radial lap amount and soil improvement depth of the adjacent improved ground can be easily uniformized, and highly accurate improved ground can be obtained. . In addition, by moving the semi-submersible ship in a semi-submerged state at a predetermined height from the seabed surface, it is possible to prevent sludge from floating up on the seabed and prevent seabed pollution as much as possible. It can be moved smoothly with less resistance, greatly increasing work efficiency.

[Brief explanation of drawings]

Fig. 1 is an overall front view showing an embodiment of the device of the present invention, Fig. 2 is a plan view of the semi-submersible vessel, Fig. 3 is a front view of the main parts showing the rotation of the stirring shaft and the elevation drive unit, Figure 4 is its side view.
5(a) to 5(f) are operational explanatory diagrams showing the horizontal movement direction of the semi-submersible vessel, FIG. 6 is a cross-sectional view of main parts showing another example of the stirring shaft lifting/lowering drive means, and FIGS. 7 to 7. FIG. 9 is a schematic explanatory view showing yet another example of the stirring shaft rotation and lifting/lowering driving means, and FIG. 10 is an overall side view showing a conventional example. 10...Semi-submersible ship, 15...Stabilizing column, 20...Support ship, 21...Improvement material supply tank,
22... Pneumatic feed location of improved material, 23... Control room,
24... Support hose, 30... Fixed spud, 31
... Moving spud, 33... Hydraulic cylinder for pouring,
34... Hydraulic cylinder for horizontal movement, 36... Hydraulic cylinder for pouring, 40... Leader, 50... Stirring shaft,
51... Stirring blade, 60.60a, 60b-... Rotating drive device, 70, 70a, 70b... Lifting drive device,
71... Upper lifting frame, 72... Lower lifting frame, 73.
74... Chuck liI! s. 75.76.81...Hydraulic cylinder for lifting. Patent applicant: Kobe Steel, Ltd.
Mitsui Engineering & Shipbuilding Co., Ltd. 1 Mitsui Fudosan Construction Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Chief 1
) Positive amount Patent attorney Yasuo Itaya No. 61 Threshold No. 7 Figure 8 Figure 10

Claims (1)

[Claims] 1. A semi-submersible vessel capable of floating semi-submersively, with a stirring shaft having a stirring blade at the tip, supporting means for supporting the stirring shaft so as to be rotatable and movable up and down, means for rotationally driving the stirring shaft, and raising and lowering of the stirring shaft. a driving means, an improvement material dispensing means for discharging the soil improvement material into a stirring section by a stirring shaft, a buoyancy adjustment means for holding the semi-submersible vessel at a semi-submerged position at a predetermined height away from the seabed surface; A fixed spud that can only be raised and lowered relative to the sunken ship, and a driving means that drives the fixed spud so that it can be inserted into and removed from the semi-submerged ship on the seabed surface.
A movable spud that is movable up and down and horizontally movable relative to a semi-submersible ship, a driving means for driving the movable spud into and out of the seabed surface from the semi-submersible ship, and a connection between the semi-submersible ship and the movable spud. and position changing means for changing the relative position in the horizontal direction,
On the other hand, a support ship configured separately from the semi-submersible ship is equipped with an improvement material supply device for the improvement material discharging means and a power source for the drive units of each means provided in the semi-submersible ship. A submarine soft ground improvement device that is characterized by the ability to