JPS61130518A - Improvement of underwater ground - Google Patents

Abstract

PURPOSE:To exactly and accurately improve the ground under water by a method in which a leader is kept in the fallen form on the hull during the period when an improvement ship is transported to an improving area, and when improving work is made, the leader is raised and the shaft is slidably lowered. CONSTITUTION:An improving ship 2' is towed under a condition that a leader 4' is kept in the horizontal state to the hull 3' and an arm 25 on one end is fixed to the bracket 27 of the hull 3' by a pin 28. When an aimed improving area is reached, the ship 2' is anchored by a wire 48, the leader 4' in erected attitude is kept in a fixed and stable attitude, and preplanned improving work is made. The shaft 9 is penetrated with stirring into the ground 10 for improving the ground, and then drawn out of the ground 10. The anchoring of the ship 2' is released and the ship 2' is advanced by a given distance. The ship 2' can thus be towed smoothly to the desired improving area, and the leader can be easily erected on site.

Description

[Detailed description of the invention] Industrial application field> The disclosed technology can be applied to the ground beneath the water surface of the sea, rivers, lakes, etc.
It belongs to the field of technology that improves the ground by supplying improvement materials such as powdered cement by gas transport using a soil improvement ship.

Therefore, this invention is equipped with a leader that slides a shaft to feed improvement materials such as powdered cement from above the water surface to the ground under the water surface such as the sea, rivers, lakes, etc. This invention relates to a ground improvement method in which a shaft for improvement work for the leader is slid to feed an improvement area inserted into the ground below the water surface. It has an open part to the water surface in the center, and a pair of bearings on the left and right sides of the open part, and a square frame-shaped leader can be freely pivoted along the vertical surface with respect to the bearings. The ground-penetrating part at the tip of the leader can be freely moved in and out of the water surface through the open part, and a luffing device such as a winch is installed between the leader and the hull to move the desired improvement area. When navigating on water up to The improved material is conveyed from the improved material plant installed in the ship's hull through pneumatic transport through the shaft into the ground through a shaft that is erected upright and penetrated into the ground below the water surface. The ground should be improved, and furthermore, a tilting position device should be interposed between the hull and the leader, the shaft should be placed in a predetermined tilted state, and the improvement work should be carried out diagonally at a set angle with respect to the ground. This invention relates to an underwater ground improvement method that allows for.

<Prior art> As is well known, improvement work on soft ground is widely carried out, but when large-scale ground improvement is carried out by reclamation in lakes and coastal areas with large areas, it is necessary to Unlike ground improvement, there are various restrictions and conditions.

Recently, the area where ground improvement is possible on land has become smaller, and the area for underwater ground improvement has been expanded based on national land planning, etc., and the above-mentioned constraints and conditions have been eliminated, making it possible to carry out smooth ground improvement "accurately and quickly." There is a growing demand for this to be done.

For example, in ground improvement on land, injection methods that use water glass-based chemicals are widely used from the perspective of pollution problems, but there are problems with groundwater in the ground, so it is more effective than injection of liquid chemicals. There has been remarkable development of so-called injection agitation methods, in which hydrophilic powder improvers such as cement are pneumatically transported into the ground, mixed with the soil, and agitated to promote reactions in groundwater and coagulate. ing.

In particular, various technical issues in transporting powder improvers and numerous bottlenecks in post-floating treatment of transport gas are being resolved.

In this way, ground improvement technology on land is transitioning from the liquid-based chemical-based construction method to the injection stirring method, but the above-mentioned underwater ground improvement for underwater, rivers, and lakes has not yet improved the water environment of the ground. From this point of view, ground improvement technology that feeds improvement materials such as powder cement is potentially more compatible than liquid-based injection ground improvement technology, and for this reason, there is a strong demand for its introduction.

Therefore, it has become desirable to further develop and expand underwater ground improvement technology to meet the expanding needs as described above.

As a matter of course, in this type of underwater soil improvement, a construction barge or other ship is towed to the improvement area, or is self-propelled, takes the anchor, and removes the shaft from the hull. In principle, it descends into the water, penetrates the ground below the surface of the water, and pneumatically transports the improvement material from the ship to supply it to a specified location.

Therefore, the mode of soil improvement using a soil improvement boat that has been generally adopted up to now will be briefly explained with reference to Figures 23 and 24.
Alternatively, it can be positioned by self-propulsion, anchored and set with the hull 3, a guide casing 5 attached to a tower-type leader 4 fixed in advance on the hull 3, and a guide casing 5 placed in the water from the leader 4. The sub-leader 6 is extended downward in a comb-like manner, and the shaft 9 having the penetration device 8 is inserted into the soft layer 7 such as sludge along this, and the shaft 9 is penetrated into the ground and improved by the improvement material plant 11. material tank 1
Two predetermined improvement materials are fed into the ground 10 by a shaft 9 via the guide shaft and foot 5 to perform predetermined ground improvement.

<Problems to be Solved by the Invention> However, although the facilities such as the leader 4 provided on the hull 3 are attached with sufficient rigidity, the sub-leader 6 extending downward into the water has the above-mentioned problems. Since it is a so-called cantilever one-way type of comb type, it cannot have sufficient rigidity, so theoretically it extends vertically from the leader 4 and penetrates statically using the shaft 9 or the penetrating device 8. However, the ground improvement method itself has a considerable heavy enclosure, and the inertia force is large. The relative position of the sub-leader 6 and the improved ship 2 changes due to the shaking due to the impact and the photography of various equipment during construction, etc., and as a result,
There was a drawback that accurate improved piles etc. could not be made, and in particular, construction accuracy was poor because it was not possible to confirm the construction status underwater.

On the other hand, the leader 4 that is assembled and fixed on the hull 3 has a considerable height, and especially in the improved ship 2 for large-scale construction, the height is extremely large, and the improved material plant 1
Since it is incomparably larger than 1 and the operation part 13, the center of gravity is quite high and it is extremely unstable, causing a lot of sway when being towed or traveling, so the hull must be made wider. This has the disadvantage of high costs,
Furthermore, during docking and hull assembly, the process of towing or self-propelling from the quay to the designated target improvement area may cause the leader to interfere with bridges such as suspension bridges installed at river mouths or inlets, or interfere with port facilities. There was a negative point in that the height was limited because there was a risk that the

As a result, the scale of underwater ground improvement work, which was originally intended to be carried out, was restricted, which was an undesirable constraint that caused a significant delay compared to land-based construction.

In particular, construction methods such as the powder injection stirring method in which cement is transported pneumatically require high accuracy during construction, as remarkable results can be obtained in land construction. There is a problem that it obstructs the

In addition, even when building an improved ship 2 of a desired size that can withstand these restrictions and adverse conditions, the leader is quite expensive, so not only construction but also so-called high-altitude work is required during maintenance, inspection, etc. This is unavoidable and involves danger, and it also has the disadvantage that it is difficult to ensure perfect accuracy in supporting work at high places.

Furthermore, in addition to the constraints of working at heights, there was also the negative point of reduced efficiency in that many parts of the work could not be performed simultaneously, resulting in poor work efficiency.

The purpose of this invention is based on the above-mentioned prior art and is in extremely high demand, and even though the construction technology of powder injection agitation ground improvement work on the original ground has been developed with many excellent points, The problem of underwater ground improvement using a soil improvement ship, which is simply due to the obstruction of the leader to the ship's hull, is a technical issue that must be solved, and during construction, the leader must not only be placed on the ship's hull, but also be lowered into the water. The extending parts should also have sufficient rigidity so that essential ground improvement can be carried out reliably and accurately, and above all,
Work has been carried out to improve high precision and effective powder injection, and the leader is low enough to maintain a stable attitude when towing or self-propelling to the target improvement area, and the leader is designed to be able to maintain a stable attitude when towing or traveling to the target improvement area. It is an excellent method that benefits the field of underwater ground improvement technology application in the construction industry by not causing any hindrance to facilities, making it easier to construct ships, maintain and inspect them, and make it easier to carry out incidental work on quays. The purpose is to provide a ground improvement method.

<Means/effects for solving the problems> In accordance with the above object, the structure of the present invention, which is summarized in the above-mentioned claims, is as follows:
In order to solve the above-mentioned problems, the leader, who takes the highest position, is placed in a reclined position with respect to the ship's hull, and various tasks are carried out simultaneously, allowing safe and highly efficient work.
Therefore, when performing underwater ground improvement, when towing or self-propelling the improved ship to the target improvement area, the long leader is laid down parallel to the ship's hull, that is, the center of gravity is in a low position. With a low and stable posture, it is unaffected by wind and waves,
Therefore, there is little rocking, and it is possible to move smoothly without interfering with suspension bridges and port facilities installed at river mouths and inlets. The leader is rotated vertically parallel to the vertical plane via a pair of bearings provided on the hull, and the leader below the bearings is placed in an opening or the like provided at approximately the middle of the hull. The open part faces into the water and extends downward from the hull at a predetermined distance so that the upper and lower parts of the hull have sufficient rigidity.Then, the shaft is slid down along the leader to connect the ground beneath the water surface. The improvement material is penetrated into the ground and delivered from the improvement material plant on the ship's hull into the ground via gas transport, etc., to perform ground improvement such as building piles.
In this process, the leaders above and below the hull are extended with sufficient rigidity, so the shaft maintains its penetration into the ground as desired, allowing accurate ground improvement work to be carried out with high precision. Underwater ground improvement using powder and injection agitation work was carried out as designed, and furthermore, the tilting position device installed between the ship's hull and the leader tilted the leader at the desired angle relative to the ship's hull in accordance with the design. As a result, improvements to the sloped ground such as diagonal piles on the ground below the water surface can be carried out smoothly without any problems. Furthermore, technical measures have been taken to enable the leader to be moved and replaced while turning, thereby maintaining the leader's attitude and position relative to the ship's hull in an optimal state.

<Example> Next, an example of the present invention will be described below based on FIGS. 1 to 22. 23 and 24 will be described using the same reference numerals.

In the embodiment shown in Fig. 1.2, 2' is a soil improvement ship, and in this embodiment, it pneumatically transports powdered cement as an improvement material for the ground 10 in seawater. Technical powder injection fJJ1g! It is used for construction work to perform high-precision underwater ground improvement using the mixing method, and its hull 3' is formed in the shape of a mouth (also included in the catamaran type, as described later). An opening 14 as an open part is opened approximately in the center, and around the opening 14 there is an improved material plant 11 equipped with a compressor, etc. for transporting improved material for powdered cement, and a cement tank connected to these by pipes. 12, 12..., an operating section 13, and a housing 15 for equipment such as an engine.

A pair of rails 16, 16... are laid along the longitudinal direction on both sides of the frontage 14 of the hull 3'.
．． 17... are provided with exchangeable bearings 18, 18 which are movable in the longitudinal direction.

Further, as shown in FIG. 2.8, for each bearing 18, a hydraulic cylinder 19 is pivotally supported at its rond end via a pin 20, and its rear end is connected between each rail 16 and 16. Screw holes 21, 21, etc., which are bored stepwise at set pitches along the longitudinal direction, are selectively connected and disconnected via screw pins (not shown), so that each bearing 18 can be adjusted to move forward and backward in the longitudinal direction along each rail 16 by the repetitive movement of the hydraulic cylinder 19.

A leader 4' having a rectangular frame shape and having an opening in plan view has a shaft 22.22 integrally fixed to the bearing 18.18, and is rotatable with respect to a vertical plane, that is, can be laid down. It is pivotably supported so that it can stand up freely.

In this embodiment, as shown in Fig. 1.2, a pair of short pipes 24, 24 with a circular cross section and a predetermined length are connected to one unit via horizontal reinforcing girders 23, 23. Set length leader 4 through flange 25.25...
', and arms 2 are attached to both ends of the leader 4'.
6.26 are installed across the building to form a rectangular framework overall.

Therefore, by adding or removing each unit via the flanges 25, 25, etc., it is possible to form the leader 4' to a predetermined length when building an improved ship 2' or rearranging the unit. It is like that.

In this embodiment, as shown in FIG. 1.2, one side of the leader 4' faces the proximal end of the opening 14, and the arm 26 on the other side lies horizontally. In one position, the bracket 2 provided on the hull 3'
7 with a removable pin 28 and is prevented from rotating.

A stand 29 provided near the center on one side of the opening 14 of the hull 3' is pivotally supported to a bracket 36 at the top of the stand 29, and can be raised and lowered freely, and can be raised or lowered by a stopper (not shown). , and a winch 33 provided at the rear of the stand 29 via a pulley 32 provided at the upper end of the sub-stand 31 that is maintained in a collapsed position.
A wire 34 from the leader 4' is engaged with the arm 26 at the other end of the leader 4' to form a hoisting device 35, and by activating the winch 33, the leader 4' is raised to the shaft 22. 22 and bearings 18, 18, it is possible to pivot and stand up on the hull 3' about this.

Bearings 37, 37, etc. are provided along the reinforcing beam 23 of the leader 4' and are fixed to a horizontal bracket 36 that is slidable along the leader 4', and the other end of the bearing 37, 37 on the side opposite thereto. The powder cement improvement material is pneumatically transported between the drive mechanism 38, 38, etc. of a rotary set such as a hydraulic motor installed on the side arm 26, and underwater ground powder injection agitation work is carried out. Shafts 9.9... are rotatably supported.

Further, at the tip of each shaft 9, stirring blades 39 are integrally fixed at a predetermined number of stages and extend laterally, for spouting the pneumatically transported powder cement into the ground 10 and stirring and mixing the soil and powder cement. Further, a well-known swivel joint 40 is provided on the base end side, which is connected to the improvement material plant 11 by an air transport pipe (not shown).

Furthermore, on both sides of the tip of the leader 4', there are provided hydraulic spuds 41, 41 which are telescopically telescopic and retractable by appropriate means by remote control.
As shown in the figure, when the leader 4' is laid down horizontally with respect to the hull 3', it is retracted, and when it is erected and used for ground improvement work, it is protruded and pierced into the ground 10, and the leader 4' is placed in the water. As shown in Figure 13, the ground g! 110 to maintain a stable standing posture of the leader 4'.

A winch 42 provided on the arm 26 at the other end of the leader 4' is attached to a boot 9 provided on the bracket 36 slidably provided with respect to the leader 4'.
43, and in the upright state of the leader 4' shown in FIG. 13, the shafts 9.9...
It forms a pulling mechanism for the

A wire 41 is stretched between another winch 45 provided at the other end of the bracket 3B and a pulley 46 provided on the arm 26 on the base end side of the leader 4'. As shown in Figure 13, with the leader 4' in the upright position, the ground 1 of the shaft 9.9...
It is said to be a forced penetration mechanism for zero.

Therefore, when constructing the improved ship 2', as shown in Figure 3.4, the hull 3' was completed in advance at the quay of the shipyard.
Meanwhile, the leader 4' is attached to the similar vibrator 24.24 and the reinforcing girder 23.2 by a small crane or the like installed on the quay.
A leader 4' of a predetermined number of stages, that is, a predetermined length, is constructed simultaneously and horizontally on the hull 3' in a horizontal position through flanges 25, 25, etc. .

Of course, during this time, the bearing 1 of the shaft 22, 22 of the leader 4'
8. Assembly to 18 and its roller 17.17...
Similarly, the sets for the rails 16, 16, etc. are performed concurrently.

Therefore, since all construction work for assembling these leaders 4' is done in a low position, there is no need for work at heights, work efficiency is improved, and it can be done safely. Because it is easy to perform such operations, accuracy is increased, and inspections can be performed accurately.

Each task can be performed simultaneously and efficiently.

Of course, the construction work of other improvement material plants 11, operation section 13, improvement material tank 12, etc. can also be carried out simultaneously.

The improved ship 2' constructed in this way has the leader 4' horizontal to the hull 3', as shown in FIG. It is fixed to the bracket 27 with a bin 28 and transported by water, such as towing or traveling, to the target improvement area.

During this time, as shown in Figure 3.4, that is, Figure 1.2, the leader 4' remains in the attitude at the time of construction and remains horizontal with respect to the hull 3'; Since the sub-stand 31 of the stand 29 is also in a collapsed position and fixed by a stopper (not shown), the height does not exceed the height of the operating part 13, and therefore, it cannot be used on a considerably low bridge such as a suspension bridge at an estuary or an inlet. It is possible to navigate without interfering with other protruding 1M facilities such as port decks and cranes, and since the leader 4' is in a horizontal position,
The center is extremely low, it is not affected by waves or wind, it does not sway or tilt, and it can be walked safely.Therefore, there is almost no problem even if the speed is increased considerably, and as a result, it quickly stabilizes to the target improvement area. It can be transported by sea.

When the target improvement area is reached, as shown in Fig. 5, the ground is improved by properly anchoring it with a wire 48 and using the leader 4' in a vertical position, as will be described in detail later. The spuds 41 and 41 are pierced into the ground 10 by remote control, and the leader 4' is fixed in a fixed position, that is, the improved ship 2' is also fixed, so that it is almost unaffected by wind and waves and has a stable position. and perform the prescribed ground improvement.

In addition, the ground improvement work is not necessarily carried out in a vertical position; depending on the design, the construction may be performed by driving diagonal piles in an oblique position, as shown in Figure 6. As detailed below, the spud 41 is stuck into the ground 10 when the leader 4' is erected and tilted to a predetermined posture, and the posture at the predetermined angle is maintained by cooperating with the anchor via the wire 48. Ground improvement is carried out by diagonal construction using leader 4'.

To explain in detail the principle of the above-mentioned construction, first, after reaching the improved area and anchoring the improved ship 2' with the wire 48, as shown in Fig. 5, the arm 2 of the leader 4' is
6 and the bin 28 of the bracket 27 and remove the leader 4'
The sub-stand 31 of the stand 29 provided at the contact portion of the hull 3' is brought into a vertical position 4 as shown by the solid line in FIG. 1, and fixed by a stopper (not shown).
The hole on the base end side of the hydraulic cylinder 19 provided in each bearing 18 is
As shown in FIG. 8, by alternately inserting and inserting the screw holes between the screw holes provided in the hull 3', that is, by expanding and contracting the hydraulic cylinder 19 and extracting and detaching the screw bottles each time, the so-called length is fixed. Each bearing 18 is moved along the longitudinal direction of the hull 3' through a sliding movement, and the itching blade 39 at the tip of each shaft 9 is placed in a position where it fully faces the opening 14 of the hull 3' and can easily enter. attitude and thereupon, by activating the winch 33 provided at the aft end of the hull 3', the wire 34 pulls the arm 26 at one end of the leader 4', so that the leader 4' has its position relative to each bearing 18. The winch 33 pivots around the shaft 22 and assumes a standing position.
The leader 4' stands up as a result of the continuous operation, and when it reaches a predetermined angle, if the slope construction shown in FIG. 1l1110 by remote control as appropriate to fix the inclined posture of the leader 4' at the set angle.

In addition, when performing construction in the vertical state shown in FIG. The spud 41 is made to penetrate into the ground 10 in an upright position.

Then, by operating the winch 46 provided on the arm 26 on the lower end side of the leader 4', the bracket 36 provided on the upper part is forcibly pulled down along the leader 4 via the pulley 45 and the wire 47, and each shaft is moved down. 9 into the ground 10, and the arm 26 on the lower end side of the ground.
Each shaft 9, that is, the stirring blade 39, is rotated through a rotary complete rotation mechanism 38 such as a hydraulic motor installed in the ground 10 to penetrate into the ground 10 and stir it. The powdered cement is transported by air from the compressor and passed through each shaft, and is ejected into the ground from the stirring blade 39 rotating at a predetermined depth, and at the same time, the winch 45 that had been operating until then is stopped. together with the upper arm 26 of the leader 4'.
The other winch 42 provided in The soil and spouted cement are mixed and stirred while swirling inside.

During this time, the air that transported the powder cement ascends and dissipates along the shafts 9 via spills (not shown).

Incidentally, the construction can be carried out in exactly the same manner in the inclined construction shown in FIG. 6.

After each shaft 9 has been pulled out of the ground 10, the anchors are released, the improved ship 2' is advanced a predetermined distance, the anchors are removed again, and the above-mentioned construction is repeated to remove the anchors from the ground 10.
We will carry out ground improvement for this area.

During this period, the leader 4' is connected to the ground 10 from the hull 3' during construction through the spud 41.
Because the upper aerial part and the lower underwater part of the ship 2' have the same rigidity, unlike the weak auxiliary leader of the conventional cantilever set described above, the modified ship 2'
It is possible to securely penetrate each shaft 9, perform powder cement injection, and perform Ill construction by sufficiently maintaining the vertical or inclined position of the leader 4' without accepting any shaking. It is something.

Therefore, in the above embodiment, the hull 3' and the ground 10
This is a case where the depth in the construction area is constant, and in this case, the flange 25 formed by each short pipe 24 and reinforcing girder 23 is installed at the shipyard to the same length as the above depth according to the survey of the leader 4'. Although this mode can be carried out by predetermining the length from the shaft 22 to the lower arm 26, that is, the spud 41, by assembling the unit through the hull 3'
If the depth of the ground 10 changes or varies, the shaft 22 and spud 41 should be removed at the construction site.
The length may have to be adjusted depending on the depth.

In such cases, for example, if the depth is shallow as shown in Figure 14, or deep as shown in Figure 15, each type of vibrator of the leader 4' should be installed at the shipyard in advance. 24
By adjusting the installation of the reinforcing girder 23, the position of the shaft 22 is adjusted to the bearing 1.
This can be solved by assembling 8 to a length corresponding to the corresponding depth.

Of course, the similar vibrator 24 and the reinforcing girder 23 can be assembled in a horizontal state using a low crane on the quay, as described above, and the accuracy of the assembly can be controlled extremely accurately as described above. This can be done in a horizontal position.

In this aspect, for example, as shown in FIG.
If the distance between the spud 2 and the spud 41 is long and there is interference with the opening 14 of the hull 3', the hydraulic cylinder 19 of each bearing 18 operates to close each bearing 18 to the hull 3'.
The leader 4' can be towed in an optimal position relative to the hull 3' by adjusting the length of each screw hole 21, and by expanding and contracting the hydraulic cylinder 19, the spud 41 and Stirring blades 39 on each shaft 9
It is possible to make it easy for people to face the frontage and enter the water easily.

Of course, in this embodiment, it is possible to adopt a mode in which the shaft 22 is replaced and inserted into a predetermined position of the leader 4' depending on the design.

However, there are cases where it is necessary to adjust the distance between the shaft 22 and the spud 41 steplessly depending on the depth at the site of the improvement area. As shown in the figure, a slider 50 is inserted into the slit 49 of each bearing 18.
A worm 53 provided at the upper end of a shaft 52 that is loosely inserted into the slider 50 of a motor 51 with a reducer provided below the worm 53 is inserted into a rack 54 formed in the slit 49 so as to be slidable up and down. By engaging and operating the motor 51, the slider 5° moves up and down a predetermined minute distance, and therefore, the leader 4' moves up and down via the shaft 22 mounted on the slider 50. Therefore,
The distance between the shaft 22 and the spud 41 can be adjusted in response to the depth of the construction site, and furthermore, the spud 41 can be forcibly penetrated into the ground after coming into contact with the ground 10.

Incidentally, this embodiment can be applied to both cases where the leader 4' is in an upright position and an inclined position.

In this way, the axis 4 of the leader 4' relative to the hull 3'
By changing and adjusting the position of the leader 4, the aerial part and the underwater part of the leader 4' can be made almost equal, as shown in FIG. 10, and the aerial part is longer, as shown in FIG. The underwater portions are short, and the ridges shown in Figure 12 can be arranged to take an intermediate position, thereby reducing the length of the leader 4' relative to the depth between the hull 3' and the ground 110 at the site. The height can be adjusted steplessly.

The embodiment shown in FIGS. 18 to 20 is a mode in which a tilting position device is attached, and hydraulic cylinders 55 are provided on both sides of the leader 4', and the tip of the iron 56 is connected to the leader 4'. The cylinders are pivotally supported on a bracket 57 fixed to the side surface, and each hydraulic cylinder 5 is connected to a screw hole 58 with a predetermined pitch provided on both sides of the opening 14 of the hull 3'.
By aligning the pin holes 60 of the bracket 59 on the base end side of the bracket 5 and screwing them together, as shown in FIG. 19, the leader 4' in the upright state is supported and the winch shown in FIG. 33, it is possible to support and maintain the predetermined standing posture of the leader 4' via the wire 34, especially when the height of the aerial part of the hull 3' of the vertical posture of the leader 4' is high. Make sure to maintain your posture and spud 41.
This makes the posture fixed state by 41 more reliable.

Therefore, in this embodiment, the hull 3' of the leader 4'
In the horizontally collapsed state, as shown in FIG. 18, the retracted hydraulic cylinder 55 is parallel to the leader 4' and fixed at the side using a fixed chain 61 or the like between the hydraulic cylinder 55 and the leader 4'. I can do it.

In addition, an air cylinder or the like may be provided between the hydraulic cylinder 55 and the leader 4' so that they are positioned parallel to each other, or the leader 4' may be opened in a V-shape and fixed between the leader 4' and the hull 3'. can also be fully adopted.

By doing this, as shown in FIG. 21, the posture of the leader 4' can be reliably fixed in the upright position, and as shown in FIG. It is possible to maintain a stable condition from start to finish during slope construction in an inclined position.

It goes without saying that the embodiment of the present invention is not limited to the above-mentioned embodiment. For example, the embodiment shown in FIG. If a moving mechanism etc. is provided, the bearing 18.18 is mounted on the hull 3'.
It is possible to adopt an aspect in which the vessel is constructed with equal diameters, such as by turning the vessel along a circular rail provided around the opening 14, or by making the hull into a catamaran type.

In addition, it is applicable not only to the ground improvement using powder injection and agitation mentioned above, but also to ground improvement using sand drains, paper drains, quicklime, etc., and the applicable water area is 2N.
It can be applied not only inside, but also in rivers and lakes.

<Effects of the Invention> As described above, according to the present invention, it is basically possible to improve the underwater ground using a soil improvement vessel equipped with a leader, which is used for ground improvement such as underwater powder injection stirring work in rivers, underwater lakes, etc., which is in extremely high demand these days. In the improved construction method, the leader is laid down in a horizontal position parallel to the ship's hull during transportation on water, and at the site of the improvement area it can be tilted or vertically placed against the ship's hull. When building or remodeling, construction can be easily and safely carried out using a crane or the like with a low quay in a horizontal position, and can be carried out simultaneously with other work, improving work efficiency. The excellent effect of being able to do this is achieved.

In addition, water transportation has the excellent effect of being able to smoothly navigate to a designated improvement area without interfering with suspension bridges or other port facilities installed at river mouths, inlets, etc.

In addition, because the height is low and the center of gravity is low and the posture is stable, it is not affected by wind or waves, and there is little swaying, making it extremely safe. It can be transported at a considerable speed and therefore has the advantage of being extremely effective in shortening the construction period.

Furthermore, since the length of the leader 4 is not restricted by obstructions to suspension bridges during navigation or safety during construction, it has the effect of providing freedom in designing the height, that is, the length. , the excellent effect of reducing costs is achieved due to ease of construction.

In addition, since the length of the leader can be adjusted freely, the length can be infinitely extended regardless of the size of the construction project, making it an excellent product that can also contribute to the development of underwater ground improvement work. The effect is produced.

In addition, by providing a lifting device for the leader between the hull and the leader, the above-mentioned lying position of the leader during navigation is guaranteed, and furthermore, the leader can be easily erected at the site. It is played.

In addition, by installing an improved material plant in the hull, it has the excellent effect of being able to apply the powder injection stirring method and deep mixing method, which uses powder pneumatic transport to transport cement, etc., without using the chemical injection method mentioned above. Qin will be conquered.

Therefore, the leader is different from the case where the ears are simply able to lie down and stand up with respect to the hull, but because the lower part of the leader underwater is also one body of the leader because it rotates and stands up through the shaft. Not only is the upper portion of the hull in the air rigid, but the underwater portion is equally rigid, and therefore, unlike traditional cantilever sets, which are not rigid and unstable, It is possible to reliably maintain the posture of the improvement material transport shaft against the ground, and as a result, ground improvement work can be carried out with high precision as designed, and, for example, piles in the ground can be formed accurately, which is an excellent effect. Even if there are some waves or wind during construction, the rigidity of the leader in the water is sufficient, and on the other hand, it has the excellent effect of being able to maintain the improved structure itself in a low position on the water surface. Ru.

As a result, problems that would previously have required construction to be stopped even if there was a slight change in the weather have been resolved all at once, and construction can now continue without being affected by weather changes, unless the weather changes drastically. Excellent effects can be achieved.

By providing a tilting device on at least one side of the hull and the leader, it is possible to stably maintain not only the vertical position of the leader but also the tilted position at the set tilt angle. It is possible to perform slope construction, and has the excellent effect of dramatically improving ground improvement underwater, where freedom of construction is originally restricted.

Therefore, in recent years, excellent improvement materials such as powdered cement have been developed that can accurately perform predetermined ground improvement by ejecting excellent improvement materials such as powder cement into the underwater ground as designed and mixing it with the soil. The effect is produced.

[Brief explanation of drawings]

1 to 22 are detailed explanatory diagrams of the present invention, in which FIG. 1 is a partially transparent side view of the hull of one embodiment, FIG. 2 is a plan view of the same, and FIG. 3 is a schematic diagram of an improved water transportation posture. 4 is a schematic plan view of the same, FIG. 5 is a schematic side view of the leader in the vertical position in the construction area, Fig. 6 is a schematic side view of the leader in the same inclined position, and Fig. 7 is a schematic perspective front view of the improved hull. Fig. 8 is a plan view of the horizontal movement mechanism of the bearing, Fig. 9 is a partially sectional front view of the bearing, Figs. Figures 14 and 15 are front views of a part of the reader with its posture fixed relative to the ground in a vertical position; Figures 14 and 15 are front views of the adjustment of the leader set corresponding to changes in water depth; Figure 16 is a schematic part of the lifting mechanism for the reader's bearings. 17 is an enlarged partial sectional view of FIG. 16, FIG. 18 is a plan view of another embodiment equivalent to FIG. 2, FIG. 19 is a schematic front view of the vertical position fixing mechanism of the reader, and FIG. Figure 21 is a perspective view of the hydraulic cylinder, Figure 21 is a transparent side view of the leader fixed in an upright position, Figure 22 is a transparent side view of the leader fixed in an inclined position, and Figure 23 is a ground improvement method based on conventional technology. A schematic side view of the underwater ground improvement, and FIG. 24 is a schematic plan view thereof. 1... Water surface, 10... Ground, 9... Shaft, 4'... Leader, 33... Operating device, 2'... Ground improvement ship Figure 10 Figure 13 Figure 1u 39 Procedure amendment (1 button December 20, 1980 Manabu Shiga, Commissioner of the Patent Office 1, Display of $ 1980 Patent Application No. 250546 2, Title of invention Underwater ground improvement method 3, Amendment with the person making the amendment) Related Patent Applicant Address: 3-30 Fujimidai, Fuji City, Shizuoka Prefecture
Name Ken Mitani

Claims (10)

[Claims] (1) In a ground improvement method in which an improved material shaft is extended from an improved ship floating on the water surface through a leader provided on the improved ship, and inserted into the ground below the water surface to feed the improved material, the improvement described above is carried out. When transporting the ship to the improvement area, the leader is laid down on the ship's hull, and when carrying out the improvement work, the leader is erected, and the shaft is then slid down along the leader and inserted and fixed into the ground, allowing the improvement material to be placed in the ground. An underwater ground improvement method characterized by feeding water into the water. (2) The underwater ground improvement method according to claim 1, wherein the leader is moved relative to the ship's hull during the period from when the leader is lowered to when it is raised. (3) The underwater ground improvement method according to claim 2, wherein the movement is one of horizontal, turning, and vertical movement. (4) The underwater ground improvement method according to claim 1, wherein the standing position of the leader is a vertical position. (5) The underwater ground improvement method according to claim 1, wherein the standing position of the leader is an inclined position. (6) The underwater ground improvement method according to any one of claims 4 and 5, wherein the leader maintains a fixed posture with respect to the ship's body after standing up. (7) Claim 1, characterized in that the improvement material is a powder, and is fed into the ground by gas transport, and is injected into the ground and mixed with the ground soil. Underwater ground improvement method described in section. (8) The underwater ground improvement method according to claim 1, wherein the ground improvement is performed by using a sand drain. (9) The underwater ground improvement method according to claim 1, wherein the ground improvement is performed using quicklime. (10) The underwater ground improvement method according to claim 1, wherein the ground improvement is performed using a paper drain.