JP2014136896A - Reclamation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reclamation method capable of efficiently making soil improvement on a reclamation ground.SOLUTION: Around top edges 7 of vertical direction drain materials 5 are connected to a floating body 3. Drains 1 previously installed in which a lead 11 is provided in a bottom edge 9 of the vertical direction drain materials 5 are installed in a scheduled landfill site 17 where water is stored by floating the floating body 3 on a water surface 21, installing the lead 11 on a soil 19, and suspending the vertical direction drain materials 5 in underwater. Landfill soil 25 is sequentially put into the scheduled landfill site 17. While accelerating own-weight compaction of the landfill soil 25 by discharging water from the vertical direction drain materials 5, a reclaimed ground 18 is formed. Afterwards, a sheet 27 is placed between the landfill soil 25 and the floating body 3 to reinforce the surface of the reclaimed ground 18 by the floating body 3.

Description

  The present invention relates to a land reclamation method.

  When construction is performed on landfills made of ultra-soft soil such as dredged soil, the stability of the ground becomes a problem, so the ground needs to be improved. As a method for improving the ground, for example, an artificial drainage layer is provided to promote consolidation. For viscous soils with low hydraulic conductivity, as the layer thickness increases, the time required for consolidation becomes longer.Therefore, a number of vertical drains typified by sand drains are placed in the soft viscous soil in the vertical direction, and the drainage distance. Consolidation is promoted by shortening the length.

  When many drains are placed, the construction period becomes longer. Therefore, for the purpose of installing a large number of drains at once, a plurality of drain materials are connected by a linear body in a direction intersecting this, and the drain material is folded and placed at the bottom of the landfill, A method has been proposed in which the drain material is extended by floating the upper part on the upper surface of water or soft soil in the landfill using a floating body (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-323897

  In such ground, it is required to improve the ground more efficiently. For example, when placing vertical drains on soft, viscous ground, temporary surface improvement was required prior to vertical drains for the purpose of entering heavy machinery and securing scaffolding for ground construction. In addition, when soil is squeezed on the surface layer, it is necessary to pay close attention so that the ground does not break down due to the load of soil or the weight of the scouring machine and will not sink or mix with soft soil. Was difficult.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a landfill method that can efficiently improve the ground of a landfill.

  In order to achieve the above-described object, the present invention includes a step (a) of installing a pre-installed drain having a drain material in a planned landfill site, and a drainage material from the drain material by introducing the landfill soil into the planned landfill site. And a step (b) of forming a landfill ground while performing a step (c) of reinforcing the landfill ground using the pre-installed drain.

  By installing the pre-installed drain with drain material in the planned landfill site, and then putting in the landfill soil, drainage can be performed during the reclamation of the landfill and the self-consolidation of the landfill soil such as ultra-soft clay can be promoted. Therefore, when the creation is completed, the weight consolidation of the soft ground progresses considerably and the stability of the ground is improved. Moreover, the landfill can be easily reinforced by diverting the pre-installed drain to the reinforcing material. Even if consolidation occurs after loading or the like, the drain is already in place, which is effective for promoting consolidation.

The pre-installed drain further includes a rigid floating body, and the drain material is connected to the floating body, and in the step (c), it is desirable to reinforce the ground layer using the floating body.
By performing surface layer reinforcement of the ground using a floating body that is a part of the pre-installed drain, it is possible to greatly improve the workability of surface layer reinforcement. Moreover, the separation management of the upper end of the drain material can be easily performed by attaching the drain material to the floating body at a predetermined interval.

The drain member is preferably connected to the floating body via a slide mechanism and is slidable in the vertical direction with respect to the floating body.
By providing the slide mechanism, it is possible to prevent the drain material from being burdened when the floating body is shaken by waves or the like. It is also possible to relieve the tension acting on the drain material as the landfill sinks due to its own weight consolidation.

The floating body is preferably a lattice frame, for example.
By using a grid-like frame, it is possible to reduce the weight while securing rigidity, and the workability is improved.

In the planned landfill site, water is accumulated. In the step (a), it is desirable that the floating body is suspended on the water surface or in water, and a weight is provided at the lower end of the drain material to suspend it in the water.
In the case of underwater reclamation, a pre-installed drain can be suitably installed in the planned reclamation site in this way. Moreover, the distance management of the lower end of a drain material can be performed suitably with a weight.

The floating body and the weight are preferably connected using a connecting material.
By connecting the floating body and the weight using a connecting material such as a chain, it is possible to prevent the floating body from moving due to waves or the like and applying an excessive load to the drain material.

The drain material is connected to the floating body so that it can be unwound downward in the floating body, and in the step (a), the lower end of the drain material is installed at the bottom of the planned landfill, and in the step (b), As the landfill is introduced, the drain material is preferably unwound and extended into the landfill with the floating body positioned on the surface of the landfill.
In the case of air reclamation, a drain set in advance can be installed in the planned reclamation site, and the drain material can be extended along with the reclamation. Moreover, the drain material can be suitably managed by attaching the drain material to the floating body and determining the installation position of the lower end of the drain material.

In the step (a), the floating body is preferably supported at a predetermined height by a temporary support member.
As a result, the landfill that has been initially introduced into the planned landfill pushes up the floating body, and the floating body can be reliably raised.

The drain material is a three-dimensional lattice-shaped bag formed using a tubular woven fabric, and in the step (c), the landfill can be reinforced by filling the bag with a filler. desirable.
Also in this case, it is possible to promote drainage during land reclamation and promote self-consolidation of the landfill, and after completion of reclamation, by filling and filling a filler such as mortar into a three-dimensional lattice bag body, The ground can be reinforced three-dimensionally.

It is desirable that a vertical reinforcing material is attached to the bag body.
Thereby, the three-dimensional shape of a bag body can be hold | maintained reliably.

  ADVANTAGE OF THE INVENTION According to this invention, the landfill method which can perform the ground improvement of a landfill site efficiently can be provided.

Diagram showing pre-installed drain 1 Figure showing landfill method The figure which shows reinforcement of the landfill ground 18 The figure which shows the example which floated the floating body 3 in water Diagram showing pre-installed drain 33 Figure showing landfill method The figure which shows reinforcement of the landfill ground 44 Diagram showing pre-installed drain 59 Figure showing landfill method Figure showing landfill method

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
(1. Configuration of pre-installed drain 1)
FIG. 1 is a diagram showing a pre-installed drain 1 according to the first embodiment of the present invention. As shown in FIG. 1, the pre-installed drain 1 includes a floating body 3, a vertical drain material 5, a weight 11, a slide mechanism 13, a chain 15, and the like.

  The floating body 3 is, for example, a lattice frame-shaped member in which woods such as bamboo and plastic materials are assembled vertically and horizontally. However, the floating body 3 is not limited to this as long as it has a small specific gravity and floats in water and has sufficient rigidity.

  The vertical drain material 5 is a member for draining the landfill, and for example, a known vertical drain can be used. The vicinity of the upper end 7 of the vertical drain material 5 is connected to the intersection of the lattices of the floating body 3 via the slide mechanism 13, and the interval between the upper ends of the adjacent vertical drain materials 5 is maintained at a predetermined value. This interval is determined according to the expected consolidation promoting effect, and is, for example, about 2 to 6 m.

  The upper end 7 of the vertical drain member 5 can be slid in the vertical direction with respect to the floating body 3 by the slide mechanism 13. The vertical drain material 5 secures a certain amount of extra length above the slide mechanism 13 according to the estimated amount of settlement.

  The weight 11 is provided at the lower end 9 of the vertical drain material 5. The weight 11 is a bar such as a reinforcing bar having a sufficient weight, and the lower ends 9 of the plurality of vertical drain members 5 are attached at a predetermined interval, and the interval between the lower ends 9 of the adjacent vertical drain members 5 is set as described above. The distance between the upper ends 7 is secured.

  However, the weight 11 is not limited to a bar. For example, the same lattice frame shape as that of the floating body 3 may be used. In this case, by attaching the lower end 9 of each vertical drain material 5 to the intersection of the lattice, the interval between the lower ends 9 of the adjacent vertical drain materials 5 is ensured according to the interval between the upper ends 7. .

  The chain 15 is a connecting material that connects the floating body 3 and the weight 11. By connecting the floating body 3 and the weight 11 by the chain 15, the movement of the floating body 3 can be limited, and excessive tension is applied to the vertical drain material 5 due to the movement of the floating body 3, or the vertical drain material 5 is attached to the floating body 3 or the weight. 11 is prevented from coming off. It should be noted that other connecting materials can be used in place of the chain 15.

(2. Landfill method)
Next, a reclamation method using this pre-installed drain 1 will be described with reference to FIGS. Here, an example will be described in which underwater reclamation is performed in a planned reclamation site in which a bank body is built around and water is accumulated inside. 2 and 3, the illustration of the chain 15 is omitted.

  In this embodiment, first, as shown in FIG. 2A, the pre-installed drain 1 is transported, and the weight 11 is sunk on the ground 19 at the bottom of the water with the floating body 3 suspended on the water surface 21. The pre-installed drain 1 is installed at the planned landfill site 17 with the material 5 suspended in water. As described above, the interval between the adjacent vertical drain materials 5 is maintained by the floating body 3 and the weight 11.

  Note that the pre-installed drain 1 is desirably arranged over the entire planned landfill site 17 in consideration of subsequent processes. For this reason, for example, the pre-installed drain 1 can be enlarged by setting an appropriate size with good workability as one unit and juxtaposing and joining the floating bodies 3 in a plane. However, if the landfill is transported by an earth ship, it may be partially arranged if it is subject to construction conditions.

  Next, as shown in FIG. 2B, the landfill 25 is put into the planned landfill 17 and the landfill 25 is thrown to a predetermined height as shown in FIG. 2C to form the landfill 18. To do.

  The reclaimed soil 25 is, for example, ultra soft clay such as dredged earth sand, and can be input using a sand discharge pipe or the like. At this time, drainage is performed from the vertical drain material 5 installed in advance, and self-weight consolidation of the landfill soil 25 is promoted. The drainage from the vertical drain material 5 can be forcibly performed by attaching a pump or the like to the vertical drain material 5. Further, since the amount of water above the landfill 25 increases with drainage, it is discharged to another location as necessary.

  In the present embodiment, tension may act on the vertical drain material 5 due to factors such as movement of the floating body 3 due to waves on the water surface 21, subsidence due to self-weight consolidation of the landfill 25, or rising of the water surface 21. However, since the pre-installed drain 1 is provided with the chain 15 (see FIG. 1) as described above, the distance between the floating body 3 and the weight 11 is kept constant, and an excessive burden is placed on the vertical drain material 5. It can be prevented from occurring. In addition, when the vertical drain material 5 slides up and down with respect to the floating body 3 by the slide mechanism 13 (see FIG. 1), the tension is relieved and the vertical drain material 5 can be prevented from being broken.

  In addition, although the vertical direction drain material 5 anticipates margin length above the slide mechanism 13, there exists a possibility that the upper end 7 may fall off still. Therefore, the slide mechanism 13 may be provided with a gripping mechanism that grips the vertical drain material 5 with an appropriate gripping force and prevents the vertical drain material 5 from falling off.

  When the landfill ground 18 is formed as described above, finally, the landfill ground 18 can be reinforced as shown in FIG.

  Here, the sheet 27 is laid between the landfill 25 below the floating body 3. The sheet 27 is a general water-permeable civil engineering sheet, for example. Further surface layer reinforcing effect of the landfill ground 18 is exhibited by the floating body 3, and the covering soil 29 can be safely and reliably constructed on the floating body 3. The sheet 27 may be disposed on the floating body 3.

  As described above, in the first embodiment, after the pre-installed drain 1 is installed in the planned landfill site 17, the landfill 25 is introduced, so that the drainage distance during the landfilling operation is shortened and the landfill ground 18 is being created. The self-weight consolidation of the landfill 25 can be promoted. Therefore, when the creation is completed, the self-weight consolidation of the landfill soil 25 proceeds considerably, and the stability of the landfill ground 18 is improved. Further, the sheet 27 can be laid under the rigid floating body 3 to reinforce the surface layer, and the cover soil 29 can be safely and reliably applied on the floating body 3. By the above, the reclamation ground 18 can be easily reinforced at the time of underwater reclamation. Even if consolidation occurs after loading or the like, the drain is already in place, which is effective for promoting consolidation.

  Further, the floating body 3 is floated on the water surface 21 and the weight 11 provided at the lower end 9 of the vertical drain material 5 is arranged on the bottom of the landfill 17 so that the water is accumulated in the landfill 17 where the water is accumulated. The pre-installed drain 1 can be suitably installed by suspending the drain material 5.

  Furthermore, the vertical drain material 5 is attached to the floating body 3 and the weight 11 at predetermined intervals, so that the separation management between the vertical drain materials 5 can be suitably performed.

  In the first embodiment, the floating body 3 is suspended on the water surface 21, but the position of the floating body 3 is not limited to this. FIG. 4 is a diagram illustrating an example in which the floating body 3 is suspended in water. When the dredged soil is transported to the planned landfill site 17 by a ship, not by a sand pipe, when the construction conditions are restricted, as shown in FIG. It may be lowered. The position of the floating body 3 can be determined by, for example, the length of the chain 15 (see FIG. 1). If the floating body 3 can be placed in the water and the draft line of the ship can be secured, it is possible to place the pre-installed drain 1 over the entire planned landfill 17 even when the construction conditions are restricted.

  In the first embodiment, the lattice frame-like floating body 3 is used, but the shape of the floating body 3 is not limited to this. For example, it may be a plate. However, when the lattice frame is used, the weight is reduced and the workability is improved.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, differences from the first embodiment will be mainly described, and the same points will be denoted by the same reference numerals in the drawings and the like, and description thereof will be omitted.

(1. Configuration of the pre-installed drain 33)
FIG. 5 is a diagram illustrating a pre-installed drain 33 according to the second embodiment. As shown in FIG. 5, the pre-installed drain 33 includes a floating body 3, a vertical drain material 5, a weight 11, a slide mechanism 13, and the like. In the present embodiment, the vertical drain material 5 is wound around the slide mechanism 13 as shown in the roll-shaped portion 39 in the figure. This roll-shaped portion 39 can be unwound in the downward direction of the floating body 3.

(2. How to improve landfill)
Next, a landfill method using this pre-installed drain 33 will be described. In the present embodiment, an example of performing landfill in the air will be described.

  In the present embodiment, as shown in FIG. 6A, a pre-installed drain 33 is first installed on the ground 45 at the bottom of the planned landfill 43 in the air.

  At this time, the weight 11 is disposed on the ground 45 of the planned landfill 43. The weight 11 can also be fixed to the ground 45 using a fixing tool. Then, the floating body 3 is supported at a predetermined height from the ground 45 using the temporary support member 49.

  Next, as shown in FIG. 6B, the landfill 25 having a high water content is put into the planned landfill 43. At the same time, the floating body 3 ascends while being positioned on the upper surface of the landfill 25. In this embodiment, since the floating body 3 is previously arranged at a certain height from the ground 45, the landfill 25 that is initially input to the planned landfill 43 pushes up the floating body 3, and the floating body 3 is reliably raised. Can do.

  As the floating body 3 rises, the vertical drain material 5 is unwound from the roll-shaped portion 39 below the floating body 3 and extends into the landfill 25. Similar to the above, the vertical drain material 5 promotes drainage in the landfill 25 and promotes self-weight consolidation.

  It is also possible to raise the floating body 3 using a winch or the like as needed. It is also possible to provide a plate material such as an iron plate on the floating body 3 and arrange necessary equipment such as dehydration equipment and heavy machinery.

  Thus, when the landfill 25 is formed by introducing the landfill 25 to a predetermined height as shown in FIG. 6C, finally, the landfill 44 can be reinforced as shown in FIG. Also in the present embodiment, similarly to the above, if the sheet 27 is laid between the landfill 25 and the landfill 25 below the floating body 3, the surface layer of the landfill 44 can be reinforced by the body 3, and the covering soil 29 is formed on the body 3. Construction can be done safely and reliably.

  Thus, also in 2nd Embodiment, the effect similar to 1st Embodiment is acquired by installing the preliminary installation drain 33 in the planned landfill 43 in the air, and performing landfill.

[Third Embodiment]
Subsequently, a third embodiment of the present invention will be described.

(1. Configuration of the pre-installed drain 59)
FIG. 8 is a diagram illustrating a pre-installed drain 59 according to the third embodiment. As shown in FIG. 8, the pre-installed drain 59 includes a drain material 61, a reinforcing material 63, and the like.

  The drain material 61 is a three-dimensional lattice bag formed using a tubular woven fabric. As such a bag body, the thing of patent 4115922 is applicable, for example.

  The drain material 61 includes a horizontal drain material 61a and a vertical drain material 61b. The inside of the horizontal drain material 61a and the inside of the vertical drain material 61b communicate with each other.

  The reinforcing material 63 is, for example, a reinforcing bar, and is arranged in the vertical direction to hold the three-dimensional shape of the drain material 61. The reinforcing material 63 is disposed along, for example, the vertical drain material 61b at the planar corner of the drain material 61, and is attached to the vertical drain material 61b.

(2. Landfill method)
Next, a landfill method using this pre-installed drain 59 will be described with reference to FIGS. In this embodiment, an example in which underwater landfilling is performed will be described. 9 and 10, the illustration of the reinforcing material 63 is omitted.

  In the present embodiment, as shown in FIG. 9A, first, a pre-installed drain 59 is installed in a planned landfill 65 where water is accumulated. The pre-installed drain 59 can be installed, for example, by providing a weight (not shown) at the lower end of the reinforcing material 63 (see FIG. 8) and sinking it on the ground 67 at the bottom of the planned landfill site 65.

  Next, as shown in FIG. 9B, the landfill 25 is put into the planned landfill 65 to the height of the pre-installed drain 59. Also at this time, due to the drainage from the drain material 61, the self-weight consolidation of the landfill 25 is promoted.

  When the landfill 25 is poured up to a predetermined height to form the landfill 66, the landfill 66 can be finally reinforced as shown in FIG. 9C.

  Here, a filling material 81 such as mortar is injected and filled into a three-dimensional lattice-shaped bag body which is a drain material 61, and the landfill ground 66 is reinforced three-dimensionally. Further, if the sheet 27 is laid above the horizontal drain material 61a (see FIG. 8) on the upper surface of the pre-installed drain 59, the surface layer of the landfill 66 can be reinforced, and the covering soil 29 can be safely and reliably placed on the sheet 27. Can be constructed.

  In addition, it is also possible to provide a reinforcing material for retaining the cylindrical shape so as not to be crushed by earth pressure or the like at the time of landfilling, if necessary. Thereby, the filling material 81 can be injected smoothly.

  In addition, from the relationship between the water depth and the self-standing height of the pre-installed drain 59, when the water depth is deep, the pre-installed drain 59 is installed by the same procedure as described above as shown in FIGS. After filling the landfill 25 to the height, the next pre-installed drain 59 is installed on the pre-installed drain 59 initially arranged as shown in FIG.

  At this time, first, a sheet 77 is laid on the upper surface of the pre-installed drain 59 disposed above the horizontal drain material 61a. As the sheet 77, for example, a water-permeable civil engineering sheet is used so that drainage continuity between the landfill 25 already filled and the landfill 25 to be introduced later is maintained.

  Thereafter, the next pre-installed drain 59 is installed on the pre-installed drain 59. At this time, the continuity of the drainage is maintained through the sheet 77, but the vertical drain members 61b of both the pre-installed drains 59 are connected vertically by sockets (not shown) or the like so that the interiors communicate with each other. You can also.

  In addition, as the pre-installed drain 59, a sheet 77 attached in advance on or below the horizontal drain material 61a on the upper surface may be used.

  When the next pre-installed drain 59 is installed in this manner, the landfill 25 is subsequently charged in the same manner as before, and the landfill 25 is loaded to a predetermined height as shown in FIG. Form. Finally, reinforcement of the landfill 66 can be performed in the same manner as described above as shown in the figure.

  Thus, also in the third embodiment, the same effects as those of the first and second embodiments can be obtained by performing the reclamation by installing the preinstalled drain 59 in the planned reclamation site 65. In addition, by filling the filling material 81 into the three-dimensional lattice-shaped bag body that is the drain material 61 after the landfill ground 66 is formed, the landfill ground 66 can be reinforced three-dimensionally.

  In the third embodiment, an example of underwater reclamation has been described. However, the present invention is not limited to this, and a pre-installed drain 59 is installed in a planned land reclamation site, and a reclamation ground is formed in the same procedure as described above. Is also possible.

  In the third embodiment, the pre-installed drains 59 are arranged in one or two stages, but the number of pre-installed drains 59 is not limited to this. The number of installation stages of the pre-installed drain 59 can be set in consideration of the thickness of the landfill.

  In the pre-installed drain 59, the reinforcing material 63 is installed along the vertical drain material 61b at the corner, but the arrangement is not limited to this. Further, if the three-dimensional lattice can be maintained by the buoyancy or rigidity of the bag body of the pre-installed drain 59, the reinforcing member 63 may be omitted. Moreover, it is also possible to suspend the pre-installed drain 59 from the floating body 3 as in the first embodiment, or to extend the three-dimensional lattice together with the reclamation using the floating body 3 as in the second embodiment.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

1, 33, 59 ......... Pre-installed drain 3 ......... Floating body 5, 61b ......... Vertical drain material 11 ......... Weight 13 ......... Slide mechanism 15 ......... Chains 17, 43, 65 ......... Planned landfill site 18, 44, 66 ……… Reclaimed ground 19, 45, 67 ……… Ground 21 ……… Water surface 25 ……… Reclaimed soil 27, 77 ……… Sheet 29 ……… Soil 39 ……… Roll 81 ……… Filler

Claims (10)

A step (a) of installing a pre-installed drain having a drain material in a planned landfill site;
(B) forming a landfill ground while throwing a landfill into the landfill site and draining from the drain material;
Step (c) of reinforcing the landfill using the pre-installed drain;
The landfill method characterized by comprising. The pre-installed drain further has a rigid floating body,
The drain material is connected to the floating body;
The landfill method according to claim 1, wherein in the step (c), surface layer reinforcement of the ground is performed using the floating body.   The landfill method according to claim 2, wherein the drain material is connected to the floating body via a slide mechanism and is slidable in the vertical direction with respect to the floating body.   The landfill method according to claim 2 or 3, wherein the floating body is a lattice frame. Water is collected in the planned landfill site,
5. The landfill according to claim 2, wherein in the step (a), the floating body is floated on a water surface or in water, and a weight is provided at a lower end of the drain material to be suspended in water. Method.   The landfill method according to claim 5, wherein the floating body and the weight are connected using a connecting material. The drain material is connected to the floating body so that it can be unwound in the downward direction of the floating body,
In the step (a), the lower end of the drain material is installed at the bottom of the planned landfill site,
In the step (b), the drain material is unwound and extended into the landfill with the floating body positioned on the surface of the landfill as the landfill is charged. Item 5. The landfill method according to any one of Items 2 to 4.   The landfill method according to claim 7, wherein in the step (a), the floating body is supported at a predetermined height by a temporary support member. The drain material is a three-dimensional lattice-shaped bag formed using a tubular woven fabric,
The landfill method according to claim 1, wherein in the step (c), the landfill is reinforced by filling the bag with a filler.   The landfill method according to claim 9, wherein a vertical reinforcing material is attached to the bag body.

Images