JPH0424487B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method of depositing dredged sludge, etc. on a reclaimed land, or on a part of a river or coastline that has been sectioned off and dammed, or in a pond after water has been pumped out. The present invention relates to a method for dewatering soft mud so that the ground can be stabilized and used for later use of various sites, etc., for ultra-soft ground such as mud.

The following methods are known as methods for dewatering soft mud.

The first is that by forming a drainage ditch in the soft mud, the water in the soft mud will naturally flow down into the drainage ditch, and the water will evaporate from the surface of the soft mud that is exposed to the atmosphere. This is a synergistic method of dehydration.

The second method, for example, as seen in Japanese Patent Application Laid-open No. 53-85910, is to form a drainage ditch in the soft mud and backfill the drainage ditch with a soil covering layer, and similarly, the drainage via the ditch and the atmosphere are This is a method of dehydration by evaporation from the facing surface.

The third method is a method of burying a drainage pipe in soft mud to dewater it, as disclosed in, for example, Japanese Patent Application Laid-Open No. 47-44912.

The fourth method is to lay a water-permeable, water-absorbing membrane on the surface of the soft mud and remove water by evaporation, as disclosed in, for example, Japanese Patent Application Laid-Open No. 102308/1983.

When using the first method, the surface area of the soft mud that faces the atmosphere and acts as a water evaporation surface can be increased by forming drainage channels, thereby increasing the amount of water evaporation from the surface of the soft mud. be able to. However, since drainage from the soft mud to the drainage ditch depends only on gravity, the area around the drainage ditch where water can efficiently flow out of the soft mud is a relatively narrow area, resulting in ,
To efficiently drain soft mud into drainage ditches,
It was necessary to reduce the distance between adjacent drainage ditches, and as the number of drainage ditches increased, it became more labor-intensive to form them, resulting in a longer construction period. Moreover, the discharge of water from the soft mud into the drainage ditch involves the water in the soft mud flowing out to the sides of the drainage ditch and then flowing down the sides, but the sides of the drainage ditch are exposed to the atmosphere. Therefore, the surface layer of soft mud that forms the sides is easily washed away by running water, causing the sides to collapse at an early stage, making the drainage channels shallower and resulting in poor drainage.

When using the second method, the drainage ditch is backfilled with a soil covering layer, which can restrict the movement of soft mud located on the surface of the sides of the drainage ditch and suppress early collapse of the drainage ditch. The disadvantage was that the soil covering layer acted as a drainage resistance in the drainage ditch, resulting in poor drainage efficiency. Moreover, by backfilling with the soil covering layer, the surface area facing the atmosphere is reduced to the same area as before the drainage ditch was formed, resulting in less water evaporation. In other words, although dehydration is performed through drainage and evaporation, the efficiency of both drainage and evaporation is low, and dehydration takes a long time.

In the third method, water is removed by drainage and evaporation, but since the evaporation area is small like the second method, the evaporation efficiency is poor and dehydration takes a long time. Ta.

The fourth method has the disadvantage that dehydration takes time because it relies only on evaporation.

The object of the present invention is to provide a method for dewatering soft mud that does not have the above-mentioned disadvantages.

The characteristics of the method for dewatering soft mud according to the present invention are as follows:
The method consists of forming a drainage ditch with sloping sides in the soft mud, and pasting a hydrophilic, porous, and water-permeable membrane on the side of the drainage ditch with its surface exposed to the atmosphere; The resulting effects are as follows.

By forming drainage channels in the soft mud, dewatering is performed through drainage and evaporation, and the membrane attached to the sides of the drainage channels serves as a support to suppress the movement of the surface layer of the soft mud that forms the sides of the drainage channels. As a result, it is possible to prevent the surface layer of the soft mud from being washed away by water flowing out of the soft mud and flowing down the sides.

Since the membrane is made of a hydrophilic, porous, and water-absorbing material, the water absorption effect of the membrane causes a flow of water from the soft mud to the drain side, and in combination with natural flow, the soft mud is removed. To make it possible to drain water from inside objects to a drainage ditch, to enlarge the range in which water can be efficiently discharged to the drainage ditch, and to reduce the amount of water that flows down the sides of the drainage ditch.

Since a water-permeable membrane is used and the surface of the membrane is exposed to the atmosphere, water absorbed by the membrane flows down inside the membrane.
The water that reaches the surface of the membrane body is discharged into the drainage ditch, and the water that reaches the surface of the membrane body evaporates, thereby continuously maintaining the water absorption effect of the membrane body.

As described above, according to the present invention, by forming a drainage groove in soft mud and pasting a water-absorbing and water-permeable membrane on the side surface of the drainage groove, the collapse of the side surface of the drainage groove is suppressed and drainage through the drainage groove is improved. While maintaining good performance,
Achieving an increase in the amount of evaporation by expanding the evaporation area by forming a drainage ditch, and the synergistic effect of this good drainage performance and evaporation performance allows for efficient dewatering of soft sludge. It has become possible to shorten the construction period by expanding the drainage range and reducing the number of drainage ditches.

Hereinafter, embodiments of the present invention will be described in detail based on illustrative drawings.

First, a landfill site will be described as an example of soft mud material to which the present invention is applied.

As shown in Figures 1 and 2, an outer dam 1 is constructed surrounding the planned reclamation site, and an inner dam 2 is constructed to appropriately divide the planned reclamation site. Ultra-soft mud-like soft mud 5 such as underwater sludge is deposited in a dumping ground 6 surrounded by dams 1 and 2.

In order to carry out the dehydration method of the present invention,
A self-propelled vehicle 8 equipped with a winch 7 is placed at each of the weirs 1 and 2 facing the soil dumping site 6, and
A boat-like float-like groove-making device 11 equipped with a groove-making device 9 and a membrane supply mechanism 10 is floated on the mud surface of the soft mud material 5, and the groove-making device 11 and both winches 7, 7 are connected to a wire or the like. They are connected via a rigging 12.

By driving both winches 7, 7 and moving the self-propelled vehicles 8, 8 by appropriate distances on the dams 1, 2, the trenching device 11 is moved along the mud surface, and the trenching device 9 is moved. With the formation of the drainage groove R, the inclined side surfaces F, F are formed, and as shown in FIG. Accordingly, the membrane bodies 13, 13 drawn out from there are adhered.

The membrane body 13 is made of a hydrophilic porous and water-permeable material in the form of a band, such as a so-called paper drain or a fiber drain.
As it is attached to the sloped side surfaces F, F, the water contained in the soft mud material 5 is drawn out and oozes out to the surface and flows down to the bottom of the drainage ditch R.

As shown in FIG. 1, the drainage groove R is not limited to one formed in a parallel shape, but may be formed in a zigzag shape.
1 can be formed into a spiral shape if it is configured to be self-propelled.

In addition, excavation work vehicles 14 such as crane trucks with clam shells and backhoe work vehicles are used to excavate the dams 1 and 2.
At this time, a groove R ₁ is formed around the entire circumference of the soil dumping site 6, either in parallel with the formation of the drainage groove R by the groove-forming device 11, or at the rear of the drainage groove _R. communicate with each other.

The working device 11 is used to form the groove R ₁ extending all around the soil dumping site 6, and not only the groove R ₁ for the dams 1 and 2 is formed, but also the groove R ₁ for the dams 1 and 2 is formed. The film body 13 may be attached only to the inclined surface F on the side farther away than 2.

After forming the sloped side surface by making grooves as described above, the water in the soft mud 5 is allowed to flow into the drainage grooves R and _R1 for a suitable number of days, for example about 50 days, and the water is drained by the drainage equipment 15 etc. The soft mud 5 is dehydrated by draining water from the groove _R1 .

Furthermore, if necessary, similar to the above, drainage ditches R, _R
The step of sequentially increasing the depth of the dewatering process is performed once or multiple times, and the dewatering process of the soft mud 5 is completed.

In the above embodiment, the groove forming device 11 is equipped with the membrane supply mechanism 10, and immediately after the inclined side face F is formed, the membrane body 1 is
3 is pasted, but in the present invention, groove making device 9 is attached.
and a device for supplying the membrane body are configured separately, and after forming the sloped side surfaces F, F to a certain length, the membrane body supplying device is moved along the sloped side surface F by another transfer means, and the sloped side surface is The film body 13 may be attached to F.

Next, the groove forming device 11 of the present invention will be explained.

A tapered mud draining section 16 is provided at the front part to drain mud from both the left and right sides as it moves into the soft mud. Inclined plate 17 protruding outward by a certain distance
is provided, the mud is moved to both left and right sides by the mud draining part 16, and the mud is pushed in by both inclined plates 17, 17, forming a drainage groove R, and sloped side surfaces F, F are formed on both left and right sides. The groove creator 9 is configured to form the groove. The mud removal section 16 and the inclined plates 17, 17
A flat top plate 18 extends between the upper ends of the
A flat bottom plate 19 extends between the lower ends.
are connected to each other, and the front end of the mud removal section 16 is inclined so that the lower part is located at the rear, and the whole structure is formed into a boat-shaped float shape. 20, 20 in the figure
is a locking member that locks the rigging 12.

In the internal space S formed by the mud removal section 16, the left and right inclined plates 17, 17, the top plate 18, and the bottom plate 19, a pair of left and right rotation plates are provided on the front side thereof across the top plate 18 and the bottom plate 19. The drums 21, 21 are rotatably mounted on shafts, and an inclined plate 1 is provided on the rear end side.
A pair of left and right rubber rollers 22, 22 are rotatably mounted close to the inner surfaces of the drums 7, 17, respectively, and a roll of a membrane 13 such as a paper drain is attached to each of the rotating drums 21, 21. The end of the membrane 13 is led out between the rollers 22 and 22 and through a slit (not shown) drilled in the rear side plate, and is fixed by appropriate means, so that the groove-forming device 11 is moved. , membrane body 1
The membrane supplying mechanism 10 is configured such that the membranes 3 and 13 are drawn out and adhered to both inclined side surfaces F and F. 22a is a roller that regulates the upper end position of the membrane body 13.

A sled body 23 is attached to the upper side of the outer surface of each of the inclined plates 17, 17, and the sliding of the sled bodies 23, 23 prevents the groove-making device 11 from sinking due to its own weight while forming a predetermined depth. It is configured to form a drainage groove R. These sled bodies 23, 23 are
It is detachably attached to the inclined plates 17, 17 so that the groove making device 11 can be easily used even when forming deeper grooves.

In the figure, reference numeral 24 denotes an opening/closing lid for an opening for entering and exiting the internal space S for attaching the membrane body 13 and the like.

A frame 27 having a handrail 25 and a scaffolding board 26 is attached to the top plate 18, and is configured so that a worker can board the frame 27 to manage the dehydration state.

On the top plate 18, for example, a mounting part for a drum or weight that can freely contain water is provided, and the groove making device 11
By changing the weight of the soft mud material 5, a desired settling state may be obtained in response to changes in the properties of the soft mud material 5.

FIG. 7 shows another embodiment, in which the rotating drum 21,
21 are arranged side by side in the front-rear direction, and are configured so that a roll of the membrane body 13 having a large winding diameter can be attached thereto.

FIG. 8 also shows another embodiment, in which the rotating drum 21,
21 is provided on the upper side of the top plate 18, and the groove making device 1
1 is placed in the soft mud 5 and the work is temporarily interrupted, muddy water enters the internal space S and the roll of the membrane body 13 gets stuck in the muddy water and swells. configured to prevent

FIG. 9 shows a modified example, in which a wing body 28 is attached to the lower part of the front end side of the outer surface of each of the inclined plates 17, 17 so as to be able to change the angle and fix the blade body 28, and the work begins when the groove making device 11 is placed in the soil dumping site 6. Initially, the wing body 28,
By moving the trench forming device 11 with the trench 28 in an inclined position with the front end facing downward, the trench can be quickly settled to a predetermined level.
However, after descending to a predetermined level, the wing bodies 28, 2
Change 8 to horizontal position and fix it.

FIG. 10 shows a modification of the membrane body 13.
A reinforcing portion 29 with a thick wall structure is provided at a predetermined interval in the longitudinal direction on the side that is not attached to the inclined side surface F.
is provided, and in the pasted state, the membrane body 13
However, it is configured to maintain a well-stretched state in the width direction.

In the groove forming device 11, left and right membrane bodies 13, 13
If a deck is to be installed between the holes, as shown in Fig.
0, and a predetermined number of reinforcing portions 29, 29 may be fitted into the recessed portions 31 formed at each longitudinal end thereof, thereby improving the shape retention of the drain groove R. This brace member 30 may be made of hard vinyl or the like.

FIG. 11 also shows a modified example of the membrane body 13.
A weight 32 is attached to one side in the width direction at a predetermined interval in the longitudinal direction, and when attaching to the inclined side surfaces F, a part of the attachment side of the weight 32 is attached to the mud surface. , After the pasting, the weights 32 are settled into the soft mud material 5 by their own weight, thereby locking one side edge of the membrane body 13 to the soft mud material 5, and pasting the membrane body 13 onto the inclined surface F. It is constructed to maintain good wearing condition over a long period of time.

In order to stick a part of the membrane 13 on the mud surface of the soft mud material 5 as described above, for example, it is necessary to extend the membrane body 13 horizontally from near the upper end of the rubber rollers 22, 22 to the outside in the horizontal direction. A pair of rollers is provided, and a rotating wheel for pushing is provided at the rear near the outer end of the horizontal roller, and the end portion of the membrane body 13 is pressed into soft mud by using the weight of the weights 32 of the above-mentioned embodiment. Instead of pushing the membrane body 13 into the
It is also possible to forcibly push the end portion into the soft mud material 5.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a plan view showing a landfill site and an outline of the method of the invention; FIG. 2 is a longitudinal sectional view showing an outline of the method of the invention; and FIG. 4 is a partially cutaway side view of the groove making device, FIG. 5 is a plan view of the groove making device, and FIG. 6 is a sectional view taken along line A-A in FIG. 5. , FIG. 7 is a plan view showing another embodiment, FIG. 8 is a partially cutaway side view showing another embodiment, FIG. 9 is a side view showing another embodiment, and FIG. 10 is a diagram showing the membrane body. FIG. 11 is a perspective view showing a modification, and FIG. 11 is a sectional view showing a modification of the membrane body. 5... Sooty mud, 13... Membrane body, F... Side, R
...Drainage ditch.

Claims (1)

[Claims] 1 A drainage groove R having an inclined side surface F is formed in the soft mud material 5, and a hydrophilic porous material is formed on the side surface F of the drainage groove R.
In addition, a method for dewatering soft mud, in which a water-permeable membrane 13 is attached with its surface facing the atmosphere.