EP4726106A1

EP4726106A1 - Buried object removal method, contaminated ground containment method, and buried object removal system

Info

Publication number: EP4726106A1
Application number: EP23940725.7A
Authority: EP
Inventors: Taichi Yamashita; Hiroaki Watanabe
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-06-08
Filing date: 2023-06-08
Publication date: 2026-04-15
Also published as: WO2024252627A1; JPWO2024252627A1

Abstract

A method of removing a buried object according to the present invention includes: placing a filler tube (30, 60) within a ground including a first buried object being buried; pulling the first buried object 10 and drawing a filler 31 by negative pressure, from the filler tube (30, 60) located apart from the first buried object 10, via an interface or a boundary plane in underground compositions having different characters, into a negatively-pressured void formed by the pulling, thereby filling the void with the filler 31; and gelling the filler 31 and then forming a wall of the filler extending up to a ground surface.

Description

Technical Field

The present invention relates to a removal method of a buried object, a confinement method of a contaminated ground, and a removal system of a buried object.

Background Art

Construction of burying a water pipe, a sewage pipe, a gas pipe, a box culvert, or the like includes operation of placing earth retaining members, such as steel sheet piles (sheet piles) or H-shaped steel beams, as buried objects at a site where sidewalls are to be constructed on both sides of a ditch; supporting the ditch walls so as to prevent their collapse; digging the earth to form the ditch; and laying a water pipe or another component in the ditch. After the laying operations, the earth retaining members are pulled out and removed from the earth.
Stakes for supporting a structure, such as a building, to the ground or another component like that is also removed from the earth in demolition of the structure and recovery to a vacant lot.
There has been a problem in that these processes of pulling out and removing buried objects such as sheet piles or stakes produce a void within the ground, causing shifting of the circumjacent earth and sand to fill the void and thereby generating sinking of or a crack in a structure build in a surrounding area. Such sinking or a crack occurs just from after pullout of a buried object.
In view of such a problem, a method has been proposed in which along with pulling a buried object, a void produced by the pulling is filled instantaneously with an injection material (see, e.g., Patent Literature 1).

Citation List

Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No. 2020-125613

Summary of Invention

Technical Problem

However, since the conventional method described above takes a long time until installation of a filler tube, because of a process of boring the ground near an buried object and inserting a filler tube to be installed, and has a problem in, e.g., quality of a continuous wall formed of a filler (hereinafter referred to as a continuous wall), there has been need for further modification of a construction method for removing a buried object and improving the ground.

Solution to Problem

The present invention was made in view of the aforementioned conventional art, and the present invention provides:
a method of removing a buried object, comprising: placing a filler tube within a ground including a first buried object being buried; pulling the first buried object and drawing a filler by negative pressure, from the filler tube located apart from the first buried object, via an interface or a boundary plane of underground compositions having different characters, into a negatively-pressured void formed by the pulling, thereby filling the void with the filler; and gelling the filler and then forming a wall of the filler extending up to a ground surface.

Advantageous Effects of Invention

The present invention enables promoting efficiency of ground improvement after removal of a buried object, as well as providing higher quality.

Brief Description of Drawings

FIG. 1 illustrates a shape and an exemplary installation of a sheet pile.
FIG. 2 depicts an exemplary configuration of a pulling machine to pull out a sheet pile.
FIG. 3 illustrates a process of removing a sheet pile.
FIG. 4 depicts an exemplary configuration of a plant facility for feeding a filler.
FIG. 5 depicts an exemplary connection between a filler tube and two feed pumps.
FIG. 6A illustrates a structure of a conventional filler tube.
FIG. 6B illustrates another structure of a conventional filler tube.
FIG. 6C illustrates another structure of a conventional filler tube.
FIG. 7 illustrates an installation position of a conventional filler tube.
FIG. 8 illustrates a structure of a tip member of a filler tube according to the embodiment.
FIG. 9 illustrates an installation position of a filler tube according to the embodiment.
FIG. 10 shows a flowchart illustrating a construction work procedure before pullout of a sheet pile.
FIG. 11 shows a flowchart illustrating a flow of simultaneous-pulling-and-filling operation of a first group of sheet piles.
FIG. 12A illustrates simultaneous-pulling-and-filling operation of the first group of sheet piles.
FIG. 12B depicts an order of sheet piles to be pulled out.
FIG. 13 shows a flowchart illustrating simultaneous-pulling-and-filling operation of a second and subsequent groups of sheet piles.
FIG. 14 illustrates simultaneous-pulling-and-filling operation of sheet piles in the second group.
FIG. 15A illustrates simultaneous-pulling-and-filling operation of sheet piles in the third group.
FIG. 15B is a schematic view of a configuration for confining a contaminated ground.
FIG. 16 illustrates installation of a filler tube to be used in removal of sheet piles placed for confining a contaminated ground.

Description of Embodiments

The following embodiments employs a sheet pile as a buried object and is described for removal of a sheet pile, but the buried object may be a stake or another component and is not limited to a sheet pile.
Since earth and sand from a dug slope or inclined face potentially collapses without any measure, there builds a linked structure that prevents the collapse and is referred to as an earth retainer. An earth retainer includes an earth retaining wall and a falsework. As the earth retaining member, a sheet pile is used.
Referring to FIG. 1, description will now be made for a sheet pile 10 as a representative example. The sheet pile 10 is classified into a U-shaped type, a Z-shaped type, a straight type, an H-shaped type, or the like based on a cross-sectional shape as cut perpendicularly to its longitudinal axis, and a plurality thereof is aligned to a single line and driven into an appropriate stratum, such as a support stratum, in the ground, thereby building a firm wall face with no gap. Such a shape is provided for strength durable to earth pressure, water pressure, or another factor received by the sheet pile 10, and for rigidity durable to repeated use for driving and pullout in temporary work. As used herein, the term "ground" means a soil stratum above a support stratum. A support stratum means a soil stratum having high strength to support the ground.
The sheet pile 10, illustrated in FIG. 1(a), is a U-shaped steel sheet pile in which a cross-sectional shape is U-shaped. Hereinafter, the sheet pile 10 will be described as a U-shaped steel sheet pile, but the sheet pile 10 may have a shape other than a U-shape.
The sheet pile 10 includes a joint 11 on each side for making a catch to create a linkage. The sheet piles 10 are linked to each other via catches between the joints 11, and as viewed from above, form a wall face having projections and cavities as shown in FIG. 1(b). Formation of such a wall face can provide higher strength than that of a simply straight wall face.
The sheet pile 10 is made of steel; but can contain copper and may also have a surface coated with polyethylene-based resin, polyurethane-based resin or the like, for preventing corrosion.
Construction for installing a water pipe or the like is conducted after digging a ditch, and then linking a plurality of the sheet piles 10 to each other via the joints 11 and building an earth retaining wall so as to cover a side wall face of the ditch. After completion of the installing construction, a plurality of the sheet piles 10 is pulled out and remove when no structure or other buried object is located nearby. The sheet pile 10 thus removed undergoes checking for damage or the like and then reused.
On the other hand, when there is a structure and/or another buried object around, a void generates in the ground at pulling and then collapses to cause ground sinking and/or another event, thereby possibly making a structure fall and crash. Therefore, when there is a structure and/or another buried object around, the sheet pile 10 is often not pulled out and left to stand.
Most of the sheet piles 10 remaining in the ground are reusable, and such reuse enables effective use of resources and reduction in generation of greenhouse gas, such as carbon dioxide, in manufacture of the sheet pile 10. Now, description will be made in detail as below on a method by which the sheet pile 10 can be pulled out and removed even when there is a structure and/or another buried object around.
First, a pulling machine for pulling out the sheet pile 10 will be described. FIG. 2 depicts an exemplary configuration of Silent Piler^® as the pulling machine. A Silent Piler 20 is a known machine that is prevalent as a machine for press-driving and pulling a stake material with no noise and vibration. The Silent Piler 20 hydraulically press-drives and pulls out the sheet pile 10 and includes a chuck 21 to grab the sheet pile 10, and a lifting and lowering device 22 to move the chuck 21 up and down. The upper part of the chuck 21 has a small circular opening enough for the sheet pile 10 to pass through.
The Silent Piler 20 includes a plurality of clamps 23 to grab the top of the sheet pile 10 buried in the ground. The clamp 23 grabs the top of the sheet pile 10, thereby receives reaction force from the sheet pile 10, and allows the chuck 21 to press-drive into or pull out from the ground the sheet pile 10. The Silent Piler 20 is also configured to be capable of shifting on each top of the sheet piles 10 aligned in a single line and moving in the direction of the alignment.
Although the description above has referred to the Silent Piler 20 as the pulling machine, the pulling machine is not limited to the Silent Piler 20, and a hydraulic vibratory hammer or the like can also be used. A hydraulic vibratory hammer is a machine that is hung from a crane or the like in use, operates hydraulically, grabs the sheet pile 10, applies vibration to the sheet pile 10 forcefully, thereby reduces frictional resistance and performs pullout.
The Silent Piler 20 enables the sheet piles 10 to be pulled out serially from one side, but mere pullout has a problem in that a trace of the sheet pile 10 after the pullout (a void) lets the circumjacent earth and sand flow therein and generates ground sinking, a crack, or the like.
To deal with this, the void can be filled with a filler to prevent the circumjacent earth and sand flowing into the void. Since the flow of the circumjacent earth and sand into the void begins just after generation of the void, it is necessary to fill it with a filler simultaneously with generation of the void.
Referring to FIG. 3, removal of the sheet pile 10 will be described. A plurality of the sheet piles 10 is buried into the ground so as to form a single line with exposing only each top portion. Without depicted in FIG. 3, a pulling machine such as the Silent Piler 20 is set on the exposed top. Meanwhile, with a predetermined number of the sheet piles 10 grouped, one filler tube 30 is placed for each of the groups, and a filler 31 is discharged from the filler tube 30 to fill a void 32, which is formed by pullout of the sheet pile 10. A support stratum, exemplarily employed as an indicator for evaluating hardness of the ground, is a stratum having an N-value of 50 in gravel soil and an N-value of 20-30 in viscous soil. The sheet pile 10 may be embedded into the aforementioned-support stratum and used, or construction work may proceed without such embedment depending on a construction work condition. Note that the support stratum and the ground have a difference in soil properties and is thus expected to form a water path, and the embodiment actively uses, in addition to this water path, an interface or a boundary plane in underground compositions having different characters as a path for the filler 31.
In installation of the filler tube 30, a construction method that fixes the filler tube 30 to the sheet pile 10 can be employed, or construction work can proceed without fixation to the filler tube 30 so as to allow the filler tube 30 to be removed and placed independently from pullout of the sheet pile 10. In the example shown in FIG. 3(a), one filler tube 30 is allocated to five sheet piles 10. The filler tube 30 is placed near the third sheet pile 10 from one side, in the middle of the five sheet piles 10. Although the third sheet pile 10 from one side is mentioned here, the position is not limited thereto and may be adjacent to another one among the five sheet piles 10.
The sheet piles 10 can be pulled out in an order from one side to the other side. As shown in FIG. 3(b), once the sheet pile 10 is pulled up, discharge pressure from the filler 31 and negative pressure in the void 32 cause, in addition to a boundary plane or a boundary stratum between the top of a support stratum and the ground, a boundary plane between the sheet pile 10 and soil to provide a flow path that allows suction of the filler 31 from a discharge outlet to the void 32, resulting in filling with use of at least an interface between the support stratum and the ground, and a boundary plane between an end face of the sheet pile 10 or the like and the ground as flow paths in the lower part of the filler tube 30. Accordingly, without spreading in the ground, the filler 31 is induced into the void 32 having negative pressure generated by pullout of the sheet pile 10 and fills the void. Hereinafter, a path to flow the filler 31 refers to an interface or a boundary stratum in an underground structure. This interface or boundary stratum means an interface or boundary plane in a structure present underground; example thereof include a boundary plane between the ground and a support stratum; an interface or a boundary plane of strata with different soil properties such as an interface or boundary plane between a gravel stratum and a sand stratum; and an interface or boundary plane between soil properties of the ground and a sheet pile.
Consequently, the embodiment provides formation of a firm continuous wall of the filler 31 gelled and extending to a support stratum. Further, the embodiment uses, as a flow path, an interface or boundary plane of a structure present underground such as a boundary plane between a support stratum and the ground, between the ground and a sheet pile, between a support stratum and a sheet pile, or between strata having different soil properties, and thus allows the filler 31 to reach the void 32 even away from a discharge outlet as long as a boundary stratum is present, thereby providing filling of the filler 31 that permeates well into the support stratum. In the embodiment, a filler "automatically searches" a negatively-pressured area and flows into an adjacent, negatively-pressured site. As shown in FIG. 3(c), along with pulling of the sheet pile 10, the filler 31 is discharged from the filler tube 30 and gradually fills the void 32, and finally, the sheet pile 10 is pulled out.
These processes are repeated to pull out a group of the sheet piles 10, and then the filler tube 30 is pulled out and recovered. To pull out the next group of the sheet piles 10, the filler tube 30 is placed at a predetermined position, and then the group of sheet piles 10 is all pulled out in the same manner as described above. By repeating these processes, all the sheet piles 10 are removed. Note that in the embodiment, the filler 31 filled in the void 32 passes along with an interface or a boundary plane in an underground structure having different properties and enters a support stratum, resulting that gel of the filler 31 filled in the void 32 extends into the support stratum, thus allowing formation of a firmer continuous wall structure. Accordingly, the method according to the embodiment enables more effective control of a problem, such as ground transition or ground sinking, as compared to other construction method.
In other embodiments, before the filler 31 is gelled and exerts strength after pullout of the sheet pile 10, the filler tube 30 is placed again into an ungelled filler 30; this enables continuous extension of a construction work area without preplacement of the filler tube 30.
Referring to FIG. 4, description will be made for a plant facility for feeding the filler 31. As the filler 31, either chemical-based materials or non-chemical-based materials can be used. The non-chemical-based materials may be cement-based materials, including cement, clay, and mortar. The chemical-based materials may be solidification agents other than cement-based materials and be classified into liquid glass-based, specialty silica-based, and polymer-based materials.
The filler 31 should be a material that can be filled to fill a void after pullout of the sheet pile 10 and prevent collapse of the circumjacent ground. Thus, once solidified, the filler 31 should have a predetermined strength. Despite low strength when solidified, polymer-based fillers can also be used singly or in combination with another filler as long as difference in strength is not an issue.
Examples of the chemical-based filler include a mixture liquid of silica sol and cement, a mixture liquid of silica sol and a gelling agent, a mixture liquid of liquid glass and carbon dioxide gas, hybrid silica, and Permarock^®. Permarock^® is active composite silica grout based on active silica colloid derived by removing alkali using ion exchange.
Examples of the non-chemical-based filler include cement milk, a mixture liquid of cement and bentonite, and a cement milk setting accelerator. As the cement milk setting accelerator, a two-component type to undergo mixing just before discharged can be used. A two-component filler consists of liquid A and liquid B; liquid A containing cement, an accelerator, and water, and liquid B containing a mixture of a curing agent, water, and the like can be used. Note that a material used herein is not particularly limited, and that cement, grout, and other inorganic curable materials such as liquid glass can be used as appropriate in construction work.
As the accelerator, preferably used are high-safety materials majorly containing sodium carbonate and/or sodium aluminate, and no poisonous or toxic substance. As the curing agent, preferably used are high-safety materials majorly containing calcium hydroxide, and no poisonous or toxic substance.
Although the filler 31 may be any filler, description will be herein exemplarily made for use of the two-component filler described above.
A plant facility includes feed pumps 40 and 41, mixers 42 and 43, containers 44 to 47, an underwater pump 48, and an electricity generator 49. The feed pump 40 feeds liquid A into the filler tube 30. The feed pump 41 feeds liquid B into the filler tube 30. A mixer 42 receives and mixes an accelerator and water, and prepares liquid A. The mixer 43 receives and kneads any materials to form liquid B, and prepares liquid B. The containers 44 to 47 contain cement, an accelerator, a curing agent, and water, respectively. The underwater pump 48 feeds water from the container 47, which contains water, to each of the mixers 42 and 43. The electricity generator 49 supplies electrical power to the feed pumps 40 and 41, the mixers 42 and 43, the underwater pump 48, and a water meter (not depicted). The pumps 40 and 41 can be substituted with a single large pump, and fully automatic mixers can be used as the mixers.
The plant facility is preferably mounted on a vehicle such as a truck and relocatable, because this facilitates transfer of the plant facility to a construction work site, and allows elimination of operation for installing the plant facility, thereby providing reduced construction period. Nevertheless, the plant facility may also be a stationary plant, depending on circumstances of a construction work site.
The feed pumps 40 and 41 are pumps capable of feeding two liquids separately, and a volumetric reciprocating pump can be exemplarily used. The volumetric reciprocating pump to be used can be a two-component plunger pump that easily changes a discharge amount. The two-component plunger pump includes two machineries to reciprocally move a rod-shaped piston by a cam or a crank. A liquid feed rate is set to a feed of 20 L/min or less in a chemical injection method, but is preferably set to provide a feed that enables access to a target void with flowability not sufficient to allow gelling to a void away from a discharge outlet of the filler tube 30, and is preferably a rate of more than 20 L/min per pump, e.g., 40 to 200 L/min.
The amount of water to be added in liquid A or liquid B affects a result of kneading and thus requires a certain accuracy and is preferably measured using a water meter.
Liquid A and liquid B are fed separately into the filler tube 30 by the feed pumps 40 and 41 and mixed in the filler tube 30 just before discharge. The filler 31 is prepared by mixing liquid A and liquid B and discharged from a discharge outlet.
The two-component plunger pump, which is used for the feed pumps 40 and 41, pumps a liquid by reciprocal motion of a piston, and thus forms a pulsating liquid flow. Once a liquid pulses, the liquid cannot be sent constantly and becomes unstable, thereby affecting a gelling quality of a chemical. Furthermore, hoses connecting the filler tube 30 to the feed pumps 40 and 41 may swing, thus be rubbed and damaged, and burst. Therefore, the feed pumps 40 and 41 can include an accumulator in a discharge outlet for a liquid in order to prevent a liquid from pulsing. The accumulator is an air-containing container that works so as to contain a portion of a discharge liquid by compressing the inner air at push of a piston and to push out the inner compressed air at return of a piston, thereby reducing pulsating of the liquid. The resulting reduction in pulsating of the liquid allows prevention of breakage of a hose.
The filler 31 can be discharged from the filler tube 30, then permeate less widely into the ground, and be appropriately filled in a void having negative pressure generated by pullout of the sheet pile 10. Thus, the filler 31 efficiently flows into the void by cooperation with discharge pressure and negative pressure in the void and then is gelled to achieve filling. To prevent permeation into the ground, the time until the filler 31 loses flowability and rapidly increase in viscosity (gelling time) is preferably about 10 to 150 seconds, and more preferably about 60 to 90 seconds.
Additionally, to provide a void with appropriate negative pressure, the sheet pile 10 is preferably pulled out at a moderate rate corresponding to soil properties; for this purpose, continuous pullout may be performed at a moderate speed, or processes can be repeated that performs pullout to a constant height at a constant rate and waits for the filler 31 to flow into a void and permeate the circumjacent ground, and then further performs pullout at an appropriate rate. A pullout speed of the sheet pile 10 is susceptible to ventilation in the ground where the sheet pile 10 is buried and thus can be appropriately adjusted. A pullout speed of the sheet pile 10 as a standard in the embodiment must conform to a filling rate for sending a filler in an amount capable of filling a volume of a void generated at pulling of the sheet pile by 50 cm, so that filling can be made at a rate of 8 liter/min to 120 liter/min. The volume of a void described above varies depending on the size of a sheet pile, H-steel, or the like.
Once liquid A and liquid B are mixed together, they are gelled in a short time. Change of their proportion enables adjustment of the gelling time. Owing to the rapid gelling, liquid A and liquid B are mixed just before discharge from a discharge outlet. Note that the gelling does not occur during flowing of the filler 31. Thus, it is also possible to feed the filler 31 consisting of a single liquid into the filler tube 30 and discharge it in the ground. The filler 31 is not gelled during flowing in the ground and then gelled upon further flowing into the void 32 away from the filler tube 30 and stopping flowing. Furthermore, at a site adjacent to a support stratum carrying the filled void 32, the filler 31 remaining ungelled is present that has flowed through an interface or a boundary plane in underground compositions having different properties, in addition to through a boundary stratum to the support stratum and the like, as long as the void 32 to be filled is formed; thus, filling can continue to reach a remote site determined by a gelling time and a rate of a filler in a boundary stratum, as long as the sheet pile 10 at an adjacent site is kept pulled.
FIG. 5 depicts an exemplary connection between a filler tube 30 and two feed pumps 40 and 41. The feed pumps 40 and 41 have two discharge outlets to discharge liquid A and liquid B, respectively. The filler tube 30 has two introducing inlets to receive liquid A and liquid B.
The feed pumps 40 and 41 are connected to the filler tube 30 through two connecting tubes 50 and 51 each having a branch, in order to separately feed liquid A and liquid B prepared in mixers 42 and 43. The connecting tubes 50 and 51 are hoses or the like made of rubber, plastic, or the like and branched into two in the middle. The connecting tubes 50 and 51 can be formed by joining three hoses with use of e.g., a Y-shaped or T-shaped joint. In such case, two hoses in the connecting tubes 50 and 51 are connected to respective discharge outlets to discharge liquid A contained in the feed pumps 40 and 41, and the residual one hose is connected to an introducing inlet to introduce liquid A contained in the filler tube 30.
At that time, the connecting tubes 50 and 51 each has a tube length determined in consideration of viscosity of each liquid and the diameters of the feeding tubes 50 and 51 so as to provide approximately the same feeding proportion until reaching a mixing chamber of the filler tube 30. The same applies to liquid B.
In the embodiment with increase in feed, liquid A and liquid B additively fed from the feed pump 40 to the connecting tubes 50 and 51 extending from the feed pump 41 are additionally supplied from the feed pump 40 in consideration of pressure loss generated by a characteristic, viscosity, and thixotropy of each of the liquids. The feed pump 40 is controlled by adjusting a controller for pumping action and valve opening so as to provide pressure and feed corresponding to pressure loss generated between the feed pump 41 and each joint site joining the feed pump 40 to the connecting tubes 50 and 51, and feeds each of the liquids to the connecting tubes 50 and 51. By employing this configuration, liquid A and liquid B can be fed in a quantitative ratio designed in such a way that no trouble occurs in a mixing chamber formed at the tip of the filler tube 30, thereby providing the filler 31 with a good gelling property in a mixing chamber of the filler tube 30.
In the embodiment described herein, liquid A fed from the feed pumps 40 and 41 passes through two respective hoses of the connecting tube 50, joins together at a joining part in the middle, then passes through the remaining hose portion, and is fed from one introducing inlet into the filler tube 30. Liquid B fed from the feed pumps 40 and 41 passes through two respective hoses of the connecting tube 51, joins together at a joining part in the middle, then passes through the remaining hose portion, and is fed from the other introducing inlet into the filler tube 30. Subsequently, liquid A and liquid B are separately fed in the filler tube 30 and mixed in a mixing chamber just before discharge from a discharge outlet, thereby preparing the filler 31.
The filler 31 thus prepared is discharged to the outside via a discharge outlet that extends perpendicularly to a longitudinal axis of the filler tube 30.
At the mixer 42, small cement solids (cement residues) adhered and solidified inside the mixer 42 fall off every time when liquid A is prepared. Without covering the top of the mixer 42 with a lid or the like, dust and other substances enter the mixer 42. Feed of cement residues, dust, and other substances together with liquid A thus prepared to the feed pumps 40 and 41 leads to breakage of a packing, a valve, a valve sheet, a piston and the like used in the feed pumps 40 and 41.
To deal with this, a net, a strainer, or the like with pluralities of approximate square openings with a size of about 0.6 to 1 mm can be used to remove cement residues, dust, and the like.
Referring to FIG. 6A, description will be made for a structure of a filler tube 60 fixed to the sheet pile 10 in use. Conventionally, the filler tube 60 is placed by forming a hole using a boring device that bores the ground, and then inserting the filler tube 60 into the hole using an erecting device. The boring device and the erecting device are briefly described below.
The boring device has a sharp cone-shaped tip, and a monitor that is a boring member having a spiral groove, a pole rod connected to the monitor, and a clamping unit that clamps a rod so as to be capable of rotating and moving up and down the rod. The monitor is not limited to one having a sharp cone-shaped tip and a spiral groove, and may be e.g., a bit having a plurality of blades (tips) that cuts and intrudes the ground. Note that the filler tube 60 having the structure shown in FIG. 6A can be preferably used in the following conditions:

(a) having a high N-value such as sand and gravel or cobblestones;
(b) incapable of installing a boring machine;
(c) diverting a sheet pile to multiple on-site use; or
(d) capable of attaching a filler tube to a sheet pile beforehand at another site.

Next, referring to FIG. 6B and FIG. 6C, description will be made for a filler tube 60-1 for performing separate driving and pullout without being fixed to the sheet pile 10.
As the filler tube 60-1, available are a steel tube, a tube formed of plastic resin such as a polyvinyl chloride tube, and the like, and furthermore, a tube with the tip shaped into various forms can be used. An exemplary tube that can be used has an outer shape formed as in FIG. 6B and an inner structure enclosing a cylindrical plug 62-1 and an elastic body 63-1. Exemplary cases to which the filler tube 60-1 in FIG. 6B and FIG. 6C is applicable can be as follows:

(a) a sheet pile is previously driven and placed; and
(b) A simultaneous-pulling-and-filling construction method can be used to deal on site.

A hole to insert the filler tube 60-1 was formed using the boring device described above and insertion is performed into the hole using the filler tube erecting device described above, thereby installing the filler tube 60-1. The tip of the filler tube 60-1 thus preferably has a shape tapered toward the tip so as to facilitate insertion into the hole thus formed. The tip also includes a drain outlet 61-1 that is directed horizontally to the ground surface and functions to drain an injection material to a tube wall, and further includes the cylindrical plug 62-1, and the elastic body 33 that is coupled to an end of the plug 62-1 and extendable along a longitudinal axis of the filler tube 60-1.
The plug 62-1 has an outer wall face placed close to the inner wall face filler tube 60 so as not to form a gap; when no injection material is fed, the elastic body 63-1 extends to move up, and thereby closes the drain outlet 61-1 as depicted in the upper panel in FIG. 6B. By contrast, when a filler is fed into the filler tube 60, a load thus generated contracts the elastic body 63-1 and cause the plug 62-1 to move down, thereby opening the drain outlet 61-1 and draining the continuously fed filler into the circumjacent soil as indicated by an arrow, as depicted in the lower panel in FIG. 6B.
As the elastic body 63-1, a coil spring can be exemplarily used. An O-ring can also be provided between the plug 62-1 and the inner wall face of the filler tube 60-1 to better ensure preventing a filler from leaking.
Although description has been made as performing boring with a rod having a monitor at the tip, followed by insertion and installation of the filler tube 60-1 in the hole, but a method of placing the tube is not limited thereto. For example, a monitor to be used for boring is attached onto the tip of the filler tube 60-1, and only a boring device is used to insert and place the filler tube 60-1 simultaneously with boring, thereby allowing shortening of construction work time and reduction in construction work cost. The monitor can be removed later at recovery of the filler tube 30, subjected to inspection, and then used again.
In a soil having a high N-value such as cobblestone-soil mixture or sand, the filler tube 60-1 having a structure as depicted in FIG. 6B is required to perform boring along with receiving vibration, and has a problem in that the elastic body 63-1 moves to lower the plug 62-1, thereby opening the drain outlet 61-1 and allowing earth and sand to flow back, causing closure of the inside with the earth and sand. This needs pull-up to the ground surface, cleaning, and re-insertion, which are laborious. Thus, an operation in soil having high N-value can employ the filler tube 60-1 having a structure as depicted in FIG. 6C.
The filler tube 60-2 depicted in FIG. 6C includes none of the plug 62-1 and the elastic body 63-1 and has a drain outlet 61-2 including a first hole 61a-2 with a first diameter, and a subsequent second hole 61b-2 continuing thereto with a diameter larger than the first diameter. The second hole 61b-2 is closed inside with a lid 64-2, which is a disk-shaped closing member. Because of this, the lid 64-2 can provide prevention even when earth and sand flow back and enter the filler tube 60-2, while the lid 64-2 can be pushed out by an injection material and automatically removed from the second hole 61b-2 in drain of the injection material.
Although a single lid 64-2 is used in FIG. 6C, a double lid 64-2 may be used to form a structure that has more increased sealing and allows secure prevention of flowback. In this case, the inner lid can be a lid made of a plastic resin having a predetermined strength durable to pressure from earth and sand flowing back, and the outer lid can be a lid made of a silicon resin to enhance sealing. In FIG. 6C, a boring member 65-2 is attached onto the tip of the filler tube 60-2, and the tip is closed. FIG. 6C also depicts a joining part 66-2 where two injection materials combine together.
An erecting device includes a clamping unit to clamp the filler tube 60, and examples can include a device that adjusts force for clamping the filler tube 60 and thereby moves down and inserts the filler tube 60 at a constant speed to place the filler tube 60 inserted in a hole. This is an example, and the erecting device is not limited to thereto. A boring device and an erecting device may not be separate devices, and a device having both functions such as a boring machine may be used. The filler tube 60 may be fixed to a buried object or may have a form to be buried into a hole independently bored by a boring machine, simultaneously with or after boring.
The filler tube 60 includes rods 61 and 62, which are two cylindrical pipes arranged parallelly. The rods 61 and 62 form flow paths for separately feeding liquid A and liquid B. In feed of only one liquid, one rod may be used. As appropriate, the rods 61 and 62 are divisible on their longitudinal axes into a plurality of segments that can be concatenated with connecting members by, e.g., longitudinal insertion.
In the concatenation of the rods 61 and 62, an anti-shifting member 63 having circular holes with approximately the same sizes as the outer diameters of the rods 61 and 62 is attached at joint sites. The anti-shifting member 63 fixes positions of the rods 61 and 62 relative to each other and prevents the rods 61 and 62 from shifting in installation of the filler tube 60 or the like. The top of the filler tube 60 includes an introducing member 64 having introducing openings for connecting the rods 61 and 62 to the connecting tubes 50 and 51, respectively. Between the introducing member 64 and each of the connecting tubes 50 and 51, connecting members 52 are used to make linkages by longitudinal insertion.
The filler tube 60 contains a tip member 65, which is connected at the lower end of the rods. The tip member 65 includes an upper member 66 and a lower member 67. The upper member 66 has an approximate rectangular solid form and includes introducing inlets 68 and 69 for respective liquid at the top. The backside of the upper member 66 is flatly formed so as to closely attach to a surface of the sheet pile 10 on a contact area contacting with the sheet pile 10.
Inside the upper member 66, a space continuing to the introducing inlets 68 and 69 is formed to serve as a mixing chamber 70 for mixing each liquid to prepare a filler. The upper member 66 includes a discharge outlet 71, which communicates the mixing chamber 70 to an outer ground. The mixing chamber 70 has an approximate circular form with a constant cross-sectional diameter. The discharge outlet 71 extends vertically to longitudinal axes of rods and discharges a filler in a direction of consecutive installation of the sheet piles 10.
The lower member 67 is connected to the upper member 66 via a connecting member 72. The lower member 67 is shaped to include an upper portion having an approximate rectangular solid form, and a lower portion slantly cut and tapered to the tip with a decreasing thickness. The backside of the lower member 67 is also flatly formed so as to closely attach to a surface of the sheet pile 10 on a contact area contacting with the sheet pile 10, as similar to the upper member 66.
The discharge outlet 71 extends in a radial direction from the mixing chamber 70 in the cross-sectional center of the filler tube to the outer side face of the filler tube 60, and internally includes a check valve 73 for preventing flowback from the outside. The check valve 73 may be placed at any position, such as close to the ground or the mixing chamber or in the center, as long as within a discharge outlet. The check valve 73 is a valve that works to cause a valve body to prevent flowback by back-pressure of a filler in the mixing chamber 70, and is classified into lift-type valves, swing-type valves, and the like according to the type of a valve body. The lift type is a type that opens and closes by vertically moving a valve body, and the swing type is a type that opens and closes by rotating a valve body like a door with a hinge as a fulcrum.
At that time, a gap is generated between a filler and the check valve 73, and a sealant member (seal material) 74 is thus provided for filling the gap and fixing the check valve 73 so as not to allow a filler to push and eject the check valve 73 to the outside. The seal material 74 has, e.g., a cylindrical hollow shape, and can be used by being fitted into the discharge outlet 71. The seal material 74 generates frictional resistance against the discharge outlet 71 and resists the push of the check valve 73 due to a filler. Within a feeding pressure of a filler (1 MPa or less), the seal material can sufficiently fix the check valve 73.
However, when a pressure several to several ten times higher than a feed pressure of a filler is applied, the seal material 74 is pushed to the outside together with the check valve 73. The check valve 73 is placed for the purpose of avoiding flowback of soil, a filler, or another component, and the check valve 73 and the seal material 74 can be washed, dried, and then easily attached by only being fitted into the discharge outlet 71.
A configuration of the tip member 65 in a conventional filler tube is as described above, includes three members of the upper member 66, the connecting member 72, and the lower member 67, and has a short longitudinal length in the tapered portion. The reason is that since a hole is formed in a direction of the ground depth, followed by insertion and installation into the hole, a filler tube can be inserted as long as it is tapered toward the tip even slightly. Moreover, a configuration formed of a plurality of members causes reduced strength; but does not press-drive itself into the ground, and makes its own conveyance easy by separation into small pieces.
A filler moves toward a void generated by pullout of the sheet pile 10, a ground surface, and the like, all of which have low pressure, and thus is preferably discharged from a position as deep as possible. Nevertheless, when a configuration includes three members in which the upper member 66 has the discharge outlet 71, the discharge outlet 71 is provided at some distance from the tip of the filler tube 60.
Conventionally, a boring device and an erecting device have been used to place a filler tube close to the sheet pile 10, discharge a filler from the discharge outlet 71 in the filler tube 60 along with pulling the sheet pile 10, and fill a void generated by the pullout with a filler.
A long distance between the sheet pile 10 to be pulled out and the filler tube 60 leads to long time to flow a filler to a void generated by pullout of the sheet pile 10. On the other hand, installation of a large number of the filler tubes 60 causes corresponding reduction in construction work efficiency. Accordingly, the filler tube 60 is placed for every three to eleven of the sheet piles 10.
For example, as shown in FIG. 7, in installation of the filler tube 60 for every five of the sheet piles, five of the sheet piles are grouped in which an end of the consecutive alignment of the sheet piles 10 is defined as a first pile, then a hole is formed near the sheet pile 10 at the third position from the end, and the filler tube 60 is inserted and placed into the hole. Then, while the piles are serially pulled out from the end, a filler is filled from the filler tube 60. After pullout of the sheet pile 10 at the last fifth position, the filler tube 60 is pulled out along with discharging a filler.
Subsequently, to pull out sheet piles in the next group, a hole is formed near the sheet pile 10 at the eighth position, and the filler tube 60 is inserted and placed into the hole. The sheet piles 10 in the group are pulled out and finally the filler tube 60 is pulled out, in the same manner as described above. These processes are repeated to pull out all the sheet piles 10. In another embodiment, before a filler filled in a trace of the sheet pile 10 at the last position exerts sufficient strength, the filler tube 60 can be placed at a position of a void filled with a filler, thereby conducting construction work consecutively. In other described embodiments, a construction work area is easily, freely expanded corresponding to the shape of an on-site ground without determining a construction work area beforehand.
Note that the example described above provides the filler tubes 60 at the third, eighth, thirteenth, ... positions, but the filler tube 60 may be placed at any of the first to fifth positions, and the same applies to the sixth to tenth positions and the eleventh to fifteenth positions.
In a described embodiment, a hole is formed for each group, and a filler tube is inserted and placed into the hole. A ground has varied geology depending on its location and is not always capable of being bored easily. A hard ground, a clayey and silty ground, and the like resist boring, and requires a considerable amount of time for boring. Moreover, for boring, a boring device needs to be moved and placed at a predetermined site. An operation of installing a filler tube includes such ground boring, thus takes some time for processes, and also needs workers for performing a boring process.
Therefore, in other embodiments, to simplify an operation of installing a filler tube, the filler tube is inserted and placed at a filling completion site before exertion of high strength, rather than placed after ground boring. While a filler is gradually solidified and exhibits strength, a filler tube can be inserted and placed easily into the filler remaining unsolidified. This eliminates need for a boring device and enables reduction in wear of a boring member used for boring by a boring device. Note that the first filler tube needs to be placed in the same manner as conventional methods, because there is no site filled with a filler.
Referring to FIG. 8, description will be made for a tip member 80 of the filler tube 30 according to the embodiment. A configuration other than the tip member 80 is the same as a conventional one. The tip member 80 may employ the conventional tip member 65, which needs manufacture of three members. Since larger numbers of members leads to higher cost of materials, processing, administration, and the like, as well as lower strength, the tip member 80 is made of a single member.
As shown in FIG. 9, the filler tube 30 is placed so as to be inserted at a site filled with the filler 31 before exertion of strength. Thus, for ease of the insertion, a tip can employ a shape in the conventional filler tubes 60, 60-1, and 60-2 depicted in FIG. 6A, FIG. 6B, and FIG. 6C, or a filler tube retaining a configuration of the conventional filler tube 60, 60-1, or 60-2 and having a more tapered tip can be used. The residual configuration can be the same as conventional configurations except for being formed of a single member.
Nevertheless, the filler tube 30 can be formed of a single member, and thus can include discharge outlets 81 and 82 closer to a tip as compared to the conventional filler tube 60.
When a mixing chamber to mix two liquids is provided as in the conventional filler tube 60, the mixing chamber needs to be so large in bulk as to sufficiently mix the two liquids. Thus, the mixing chamber 70 has conventionally had a space largely extending beyond the discharge outlet 71 toward a tip.
For this reason, when formed of a single member, the tip member 80 would be too large and create difficulty in its conveyance, administration, and the like.
Therefore, for the purpose of enabling sufficient mixing without a large space, introducing openings 83 and 84, to which two rods are to be joined, and a linking tube 85, which links two discharge outlets 81 and 82, are connected via connecting tubes 86 and 87, which do not join parallelly and directly to the linking tube 85 but intersect with each other to allow two liquids to collide and combine together. Such a configuration eliminates need for a space largely extending toward a tip of the filler tube 30, thus makes the size of the tip member 80 smaller, ensures sufficient mixing, and enabling reduction in cost of materials, processing, and administration.
The connecting tubes 86 and 87 have an inner space with an approximate triangular prism shape after the intersection in the middle, and liquid A and liquid B are fed so as to intersect with each other. This causes liquid A and liquid B to well collide with each other rather than flow in layers and to then undergo mixing and stirring, thereby allowing sufficient homogenization in a short section from the intersection point to the linking tube 85. The mixing modality depicted in FIG. 8 can also be used in the conventional filler tubes 60, 60-1, and 60-2 depicted in FIG. 6A, FIG. 6B, and FIG. 6C.
Referring to FIG. 10 to FIG. 14, detailed description will be made for a removal method for the sheet pile 10. FIG. 10 is a flowchart illustrating a construction work procedure before pullout of the sheet pile 10. The procedure starts at step 100, and a plant facility is set at a predetermined position at step 101. At step 102, a boring machine is placed as a boring device at a predetermined position, because there is no site to be filled with a filler in the beginning group.
At step 103, a boring machine performs boring operation. At step 104, the filler tube 30 is inserted and placed into a hole formed by the boring. At step 105, a special swivel is employed as the connecting member 53 and attached to the filler tube 30 in order to connect the filler tube 30 to the connecting tubes 51 and 52. Then, the connecting tubes 51 and 52 are connected. At step 106, the boring machine is relocated, and at step 107, preparation before pullout is finished. These processes are effectively used in installation of the filler tube 30 for boring to a deep depth in a gravel stratum. By contrast, in boring to a small depth or as soil properties and condition permit, step 103 and step 104 can be combined to place the filler tube 30 simultaneously with boring by the boring machine.
In preparation before pullout, liquid A and liquid B were separately produced in a plant facility, and the feed pumps 40 and 41 are started up to be ready to feed liquid A and liquid B into the filler tube 30.
Referring to FIG. 11 and FIG. 12, description will be made for a construction work procedure for a first group of the sheet piles 10. For the following construction work procedure, a buried object removal system includes each tool described above in the embodiment. FIG. 11 is a flowchart illustrating a flow of simultaneous-pulling-and-filling operation of the first group of the sheet piles 10, and FIG. 12A illustrates simultaneous-pulling-and-filling operation of the first group of sheet piles 10 beginning with installation of the filler tube 30. The filler tube 30 is placed by the operation shown in FIG. 10.
Operation starts at step 200, and a pulling machine 24 is placed at predetermined position. At step 201, one sheet pile 10 is pulled out to form a void with negative pressure and allow the filler 31 to discharge from the filler tube 30, thereby filling the void 32, which is generated by pullout of the sheet pile 10, with the filler 31. In view of construction work efficiency, this pullout process is preferably performed by repeating the following steps: pulling the sheet pile 10 to a certain height, filling the filler 31 in an amount required and sufficient to fill a void formed by pullout and having negative pressure, completing the filling of the void area, then pulling the sheet pile 10 to a predetermined height to generate negative pressure, and filling the filler 31 again.
Note that the formation of negative pressure occurs when a volume increase rate of a void generated by pullout of the sheet pile 10 is larger than a feed rate of the filler 31, which is a viscous fluid that flows and enter along a boundary between a buried object and the ground. Accordingly, as long as the condition is met, the sheet pile 10 may be pulled out continuously, or the sheet pile 10 may be pulled out in stages. These embodiments of pullout can be appropriately set corresponding to on-site environment, performance of a buried object removal system.
An order of pullout of the sheet piles 10 will now be described with reference to FIG. 12B. The order of pullout of the sheet piles 10 can be conceived as three embodiments. For instance, assume that N sheet piles 10 are numbered as sheet piles 10-1 to 10-N, and the filler tube 30 is placed, e.g., closest to sheet pile 10-M. In this case, the sheet piles 10 can be pulled out in order of sheet pile 10-1 to sheet pile 10-N (a first embodiment, FIG. 12B(a)). In a second embodiment, the pullout can be carried out in order of sheet pile M-1, sheet pile 10-1, sheet pile 10-(M+1), and sheet pile 10-N (a second embodiment, FIG. 12B(b)). In a third embodiment, the pullout can be carried out in order of sheet pile 10-(M-1), sheet pile 10-1, sheet pile 10-N, and sheet pile 10-(M) (FIG. 12B(c)).
In the embodiment, it is possible to pull out the sheet piles 10 in a flexible order as described above. The reason is because pullout of the sheet pile 10 generates a void having negative pressure and leads to cooperative action of discharge pressure of a filler from the filler tube 31 and the negative pressure of the void, thereby efficiently inducing the filler 31 to the void.
At step 202, the pulling machine 24 is relocated for pulling the next sheet pile 10. In this case, six sheet piles are grouped in one group, and the filler tube 30 is placed adjacent to a third sheet pile 10. This is an example and the number of sheet piles to be pulled out is not limited to six per filler tube, and the position of the filler tube 30 is also not limited to a position adjacent to the third sheet pile.
At step 203, whether all the sheet piles 10 in the first group are pulled out is checked. If pullout is not completed, the process returned to step 201 to pull out the next sheet pile 10. By contrast, if pullout is completed, the process proceeds to step 204 and water is fed into the filler tube 30 to wash the inside. Then, at step 205, simultaneous-pulling-and-filling operation of the sheet piles 10 in the first group is finished.
Next, referring to FIG. 13 to FIG. 15, description will be made for a construction work procedure for the sheet piles 10 in a second and subsequent groups. FIG. 13 is a flowchart illustrating a flow of simultaneous-pulling-and-filling operation of the sheet piles 10 in the second and subsequent groups. FIG. 14 illustrates simultaneous-pulling-and-filling operation of the sheet piles 10 in the second group. FIG. 15 illustrates simultaneous-pulling-and-filling operation of the sheet piles 10 in the third group.
A process started at step 300, and the filler tube 30 is lifted and recovered by a lifting machine such as a crane at step 301. At step 302, whether all the sheet piles 10 are pulled out is checked. If all the sheet piles 10 are not pulled out, the process proceeds to step 303, in which a boring machine 25 clamping the filler tube 30 is lifted by a lifting machine such as a crane, placed at a predetermined position, and then allowed to insert and place the filler tube 30 at a predetermined site filled with a filler before exertion of strength. In further embodiments, in addition to the boring machine 25, the filler tube 30 can also be lifted by e.g., a crane, conveyed to a predetermined installation position, and inserted by self-weight of the filler tube 30 and manual rotation with a pipe wrench.
The predetermined site is preferably as close to the sheet pile 10 in the next group as possible. In this case, since pullout and filling with a filler are performed for the first to sixth sheets in the first group, the filler tube 30 is placed at the sixth sheet pile, which is closest to the seventh to twelfth sheet piles in the next group.
At step 304, while one sheet pile 10 is pulled, the filler 31 is discharged from the filler tube 30 to fill the void 32, which is generated by pullout of the sheet pile 10, with the filler 31. At step 305, the pulling machine 24 is relocated for pulling the next sheet pile 10. At step 306, whether all the sheet piles 10 in the group are pulled out is checked. If pullout is not completed, the process returned to step 304 to pull out the next sheet pile 10.
By contrast, if pullout is completed, the process proceeds to step 307 and water is fed into the filler tube 30 to wash the inside. Then, turning to step 301, the filler tube 30 is lifted and recovered with a lifting machine such as a crane. Again, at step 302, whether all the sheet pile 10 are pulled out is checked.
Once all the sheet piles 10 are pulled out at step 302, the process proceeds to step 308 to finish simultaneous-pulling-and-filling operation.
FIG. 14 and FIG. 15 illustrate removal of the sheet piles 10 in the first to third groups. In other words, the filler tube 30 used in the first group is lifted and recovered with a crane, then clamped by the boring machine 25, lifted together with the boring machine 25 using a crane, placed at a predetermined position close to the sheet pile 10 in the second group, and inserted and installed so as to be driven at the filled site in the first group with the boring machine 25. While the sheet piles 10 in the second group are pulled out one-by-one with the pulling machine 24, the filler 31 is filled from the filler tube 30 to fill the void 32, which is generated by pullout of the sheet pile 10, with the filler 31. Once all the sheet piles 10 in the second group, the filler tube 30 is recovered. To pull out the sheet piles 10 in a third group, the filler tube 30 is placed at the filled site in the second group in the same manner as described, and then the sheet piles 10 in the third group are pulled out.
Meanwhile, a plurality of the sheet piles 10 are linked via the joints 11 and can be used not only to prevent collapse of earth and sand in a slope or inclined face, but also to separate areas in the ground and, e.g., perform confinement of the ground so as not to allow contaminants to migrate from one ground to another ground.
The confinement of the ground can be performed by e.g., erecting a plurality of the sheet piles 10 so as to surround a certain area of a contaminated ground, exchanging the contaminated ground in the certain area within a continuous wall 77 which is formed by a cured filler after pullout, to a fresh ground, and then simultaneously pulling the sheet pile 10 and filling the filler 31 into a void. This can prevent contaminants in the circumjacent ground from entering the certain area.
A clay stratum 76 and the like lie at a certain depth in the ground, and groundwater flows through the clay stratum 76 and the like to a ground surface. Therefore, building a cured form of the filler 31 to a depth extending to an impervious stratum or a support stratum of the clay stratum 76 and the like can offer insulation against a circumjacent ground 75, and prevent inflow of contaminants in the circumjacent ground 75. This is because the circumjacent contaminants will not flow against a flow of groundwater and under the clay stratum 76 and the like to enter again the area surrounded by the cured form through the clay stratum 76 and the like.
Thus, building a cured form surrounding a predetermined area by simultaneously pulling the sheet pile 10 and filling the filler 31 enables removing the sheet pile 10 along with retaining a confinement function. This makes the sheet pile 10 reusable.
Referring to FIG. 16, description will be made for installation of the filler tube 30 in confinement of a contaminated ground. FIG. 16(a) illustrates a position of the filler tube 30 in removal of the sheet piles 10 in the first group. The sheet piles 10 are buried so as to surround a predetermined area. The number of the sheet piles 10 to be pulled out by one filler tube 30, i.e., the number of the sheet piles 10 in one group, is prescribed. Then, to pull out the sheet piles 10 in the first group, the filler tube 30 is placed adjacent to any of the sheet piles 10 in the first group.
The filler tube 30 is placed by boring the ground with the boring machine 25 and inserting the filler tube 30.
The sheet piles 10 in the first group are serially replaced with the filler 31 by simultaneously pulling the sheet pile 10 in the first group and filling the filler 31 from the filler tube 30 with the pulling machine 24.
After the sheet piles 10 in the first group are replaced with the filler 31, then for the purpose of pulling out the sheet piles 10 in a second group adjacent to the first group, the filler tube 30 is inserted and installed at a filled site of the sheet pile 10 in the first group closest to the sheet pile 10 in a second group as shown in FIG. 16(b). The filler tube 30 can be installed by using the boring machine 25 to simultaneously move down and rotate the filler tube 30. At this time, the filler 31 has not exerted strength yet, and thus has a paste shape, a semi-gelled form, or a highly thixotropic form, i.e., has substantially no flowability but takes a form with tofu-like plastic deformability. This enables the filler tube 30 to be simultaneously rotated and moved down easily.
Similarly, with regard to the sheet piles 10 in a third and subsequent groups, the sheet pile 10 can be pulled out while the filler 31 is discharged from the filler tube 30. In this manner, a wall made of a cured form of the filler 31 can be build, and the thickness of the wall is sufficient to confine contaminants.
As has been described so far, the filler tube 30 can be easily installed, thereby allowing shortening of a construction period and reduction in the number of workers. Furthermore, the number of boring with a boring member is reduced, and wear of a boring member can also be eliminated. Accordingly, construction periods for removal operation of a buried object, confinement operation of a contaminated ground, or another operation can also be shortened.
In addition to the configuration described above, a configuration according to the present invention can be used for driving a sheet pile in the ground along with filling a filler, to prevent displacement in early phase of driving of the sheet pile, as described in e.g., Japanese Patent Application Laid-Open No. 2023-54602 . Moreover, in an embodiment in which a filler is filled simultaneously with driving of a sheet pile, it is possible to prevent continuous displacement after driving of the sheet pile, and further to prevent deformation, collapse, or the like of a void generated upon pullout of a sheet pile.
An installation method for a filler tube, a removal method for a buried object, and a confinement method for contaminated ground according to the present invention have been described in detail with reference to the aforementioned embodiments so far, but the present invention is not limited to the aforementioned embodiments, and another embodiment or a variation such as addition, change, or deletion can be made as far as it would be contemplated by those skilled in the art. Any embodiment falls within the scope of the present invention as long as it offers an action and/or an effect of the present invention.

Reference Signs List

10: sheet pile
11: joint
20: Silent Piler
21: chuck
22: lifting and lowering device
23: clamp
24: pulling machine
25: boring machine
30: filler tube
31: filler
32: void
40, 41: feed pump
42, 43: mixer
44-47: container
48: underwater pump
49: electricity generator
50, 51: connecting tube
60: filler tube
61, 62: rod
63: anti-shifting member
64: introducing member
65: tip member
66: upper member
67: lower member
68, 69: introducing inlet
70: mixing chamber
71: discharge outlet
72: connecting member
73: check valve
74: seal material
75: contaminated soil
76: clay stratum (support stratum)
77: continuous wall
80: tip member
81, 82: discharge outlet
83, 84: introducing opening
85: linking tube
86, 87: connecting tube

Claims

A method of removing a buried object, comprising:
placing a filler tube within a ground including a first buried object being buried;

pulling the first buried object and drawing a filler by negative pressure, from the filler tube located apart from the first buried object, via an interface or a boundary plane in underground compositions having different characters, into a negatively-pressured void formed by the pulling, thereby filling the void with the filler; and

gelling the filler and then forming a wall of the filler extending up to a ground surface.
The method of removing a buried object according to claim 1, comprising:
pulling a second buried object adjacent to the first buried object and filling the filler via the boundary plane into a second void formed by the pulling of the second buried object; and

forming a corresponding continuous wall of the filler at sites of the first buried object and the second buried object.
The method of removing a buried object according to claim 1, comprising:
inserting and placing a filler tube for injection of the filler, before a gelled filler exerts strength within a void formed by the second buried object pulled out;

pulling a third buried object buried at a site away from the filler tube; and

filling the filler at a site of the third buried object and extending the wall, without placing a second filler tube beforehand.
The method of removing a buried object according to claim 3, wherein the placing is performed by moving down the filler tube clamped by an erecting device with keeping the erecting device hanging, thereby inserting the filler tube into a filled site.
The method of removing a buried object according to claim 1, comprising recovering the filler tube at least after pullout of the second buried object.
A confinement method of a contaminated ground, comprising:
placing a plurality of buried objects at a boundary between a contaminantcontaining area and a contaminant-free area;

placing a first filler tube in a hole in a bored ground;

forming a negatively-pressured void along with pulling one first buried object after another, discharging a filler from the filler tube placed away from the buried object being pulled, and drawing the filler via an interface or boundary plane in underground compositions having different properties to the negatively-pressured void, thereby filling the void; and

discharging a filler from the second filler tube placed, along with pulling a second buried object adjacent to a second filler tube.
The confinement method of a contaminated ground according to claim 6, wherein the placing is performed by moving down the filler tube clamped by an erecting device with keeping the erecting device hanging, thereby inserting the filler tube into a filled site.
The confinement method of a contaminated ground according to claim 6 or 7, further comprising after pulling out the first buried object and completing filling, and before allowing the filler gelled to exert strength, inserting the second filler tube into the filler before the gel exerts strength.
A buried object removal system comprising:
a first two-component feeding device to apply pressure to and provide a curable composition and an accelerator,

a plurality of connecting tubes to feed the accelerator and the curable composition separately from the two-component feeding device,

an injection tube placed in a ground above a support stratum and including a mixing chamber to mix the accelerator and the curable composition inside and form a filler, and

a filler to flow via a boundary stratum between the buried object and the ground or a boundary stratum between a support stratum and the ground, to a negatively-pressured void formed by pulling a buried object buried in the ground, and to form a continuous wall extending to a ground surface after gelling.
The buried object removal system according to claim 9, further comprising:
a second two-component feeding device to apply pressure to and feed the curable composition and the accelerator; and

an unit to control pressure of and feed from the second two-component feeding device in correspondence with pressure loss corresponding to properties of the curable composition and the accelerator from the first two-component feeding device.