JP2005180112A - Ground improvement structure and ground improvement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ground improvement structure which is suitable for improvement of a narrow ground under an existing construction, for example and is strongly efficiently installed in the ground to rigidly support the ground and further enables compactrization of execution space and simplification of execution and reduction of construction cost and shortening of construction term, and also provide a ground improvement method using the same. <P>SOLUTION: The ground improvement structure is configured to install a curved columnar reinforcement body 34 in the ground 2 to be improved under the existing construction 4. The whole area of the reinforcement body 34 is installed under a partition area Z<SB>2</SB>of the ground 1 in which the existing construction 4 is built and thus the reinforcement body is reasonably and finely installed in a partition area in a predetermined ground and ground improvement is practically realized. The reinforcement body is prevented from being installed outside of the partition area in an adjacent ground and is suitable for ground improvement of cities in which the existing constructions are densely built. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is suitable for, for example, narrow ground improvement under an existing structure, can be firmly and efficiently laid in the ground and can firmly support the ground, and the construction space can be made compact and the construction simplified. The present invention relates to a ground improvement structure and a ground improvement method capable of reducing the construction cost and shortening the construction period.

  Conventionally, various ground improvement methods have been proposed for the purpose of water stoppage and strength increase. For example, the injection pipe is inserted by drilling vertically to a predetermined depth with a boring machine or the like, and a pile is formed in the ground by pulling up the injection pipe while high-pressure spraying a curing agent or the like from the tip of the injection pipe. There is a so-called CCP method.

  The construction method has the advantage that the soft and viscous ground that has been difficult with the chemical solution injection method and the so-called jet grouting method can be strongly improved. However, the construction method needs to drill the ground vertically. For this reason, for example, when improving the ground below the region where existing structures and contaminated ground exist, there is a problem that the construction becomes practically difficult and the contaminated ground is drained to the ground as excavation sludge.

  In order to solve such problems, for example, a work shaft is formed on the side of the ground to be improved where the existing structure exists in the ground, and the ground below the existing structure is horizontally cut from this shaft. A hollow cylindrical casing is inserted, and after drilling a predetermined distance, a solidifying agent is injected at a high pressure from the tip while pulling out the casing, and a cylindrical improvement body extending horizontally is formed, There is one in which the ground below the existing structure is improved (for example, see Patent Document 1).

  However, since this construction method requires a shaft, it is necessary to secure the site, and there is a problem that the excavation work becomes large and the construction cost increases and the construction period is prolonged. In particular, this problem has become prominent in the construction of cities in which vertical shafts cannot be constructed in close proximity to existing structures.

  Therefore, as a solution to the above-described problem, for example, in a method for widening a drilling hole in a shield tunnel, a so-called curved boring device is installed inside the shield drilling hole, and the improved ground is provided from the boring device. A curved pipe is embedded toward the side, and the curved pipe is formed into an inner / outer double pipe structure by sequentially adding inner and outer curved short pipes having the same curvature. There is one in which a ground improvement injection pipe is inserted into the bent pipe instead, and an improvement agent such as cement milk is injected into the injection pipe to improve the widened ground (for example, Patent Document 2). reference)

  However, the construction method requires excavation of a large shield hole that can be installed with a curved boring device instead of the above-mentioned shaft, which increases the construction cost and lengthens the construction period. Since the curved pipe filled with cement milk etc. is laid, the ground can be firmly supported, but the curved pipe installation and construction becomes complicated and the construction cost increases, and the curved pipe is moved from the start side to the arrival side. Since the pipes are laid and installed, the bent pipes become longer, which increases the construction cost and prolongs the construction period.In addition, the construction target is limited to the ground with a certain area. Had problems such as being unable to hire.

  In order to solve such a problem, a curved boring device is installed on the ground surface around an existing structure, a curved embedding hole is excavated by the boring device, and the embedding hole is used for promoting drainage. Insert the casing pipe holding the drain material, then leave the drain material on the ground and pull out the casing pipe, and improve the ground through the drainage action of the drain material. There is something which is made to do (for example, refer patent documents 3).

  However, since the drain material of the construction method is exclusively used for drainage promotion and is made of a soft flexible material, it does not strengthen the strength of the ground itself, and does not increase the strength of the ground under the existing structure. It cannot be adopted for improvement.

Japanese Patent Laid-Open No. 10-183599 JP-A-4-281990 JP 2000-290989 A

  The present invention solves the above problems and is suitable for, for example, narrow ground improvement under an existing structure, can be laid in the ground firmly and efficiently and can firmly support the ground, and the construction space can be made compact and An object of the present invention is to provide a ground improvement structure and a ground improvement method capable of simplifying, reducing the construction cost and shortening the construction period.

The invention according to claim 1 is a ground improvement structure in which a curved columnar reinforcing body is laid on a ground area requiring improvement under an existing structure, and the entire area of the reinforcing body is laid under a partition area of the ground where the existing structure is located. In addition, the reinforcement body is rationally and finely laid in the predetermined ground area to improve the ground, and the reinforcement body is prevented from being placed outside the adjacent ground area, and the existing structures are densely packed. It is suitable for urban ground improvement.
According to a second aspect of the present invention, at least one end of the reinforcing body is provided with a curved columnar filler that is miscible with the ground, and the filler is extended and installed in a ground zone adjacent to the zone. In addition, it closes the extraction hole of the curved pipe used for the construction of the reinforcing body in each partition area, prevents the collapse of the extraction hole and the deformation of the ground, and adapts the filler to the ground over time, The original condition of the ground used for construction is restored.

According to a third aspect of the present invention, the reinforcing body and the filler are formed in the same curved shape, and these are laid on the same curve line, and the reinforcement and the filler are laid based on the same construction curve line. And streamline the construction.
According to a fourth aspect of the present invention, the reinforcing body and the filler are formed in a curved column shape, maintain their strength, and streamline the construction.
According to the invention of claim 5, a plurality of reinforcing bodies having different curvatures are laid out vertically or laterally apart from each other so as to enhance the effectiveness of narrow ground improvement.
According to a sixth aspect of the present invention, the reinforcing body is formed of a curved columnar rigid body projecting downward, and improves the strength against earth pressure and overload, thereby improving the effectiveness and efficiency of ground improvement.

  In the invention of claim 7, a construction base is provided on the ground having a ground required for improvement under the existing structure, a hole is drilled in a curved shape from the base to the ground required for ground improvement, and the curved hole is curved. In the ground improvement method of pulling out the curved pipe while spraying a curing agent from the tip of the curved pipe after inserting the pipe, and laying a curved columnar reinforcing body on the improved ground section, the entire area of the reinforcing body is When laying under the subdivision area of the ground where the existing structure is located and improving the ground under the existing structure from the ground surface, the reinforcement is rationally and finely laid in the predetermined subdivision area of the ground to effectively improve the ground. In addition, the reinforcement body is prevented from being laid out outside the partition area of the adjacent ground, making it suitable for improving the ground in cities where existing structures are densely packed.

  According to an eighth aspect of the present invention, after injecting the curing agent into a predetermined area in the partition area of the ground, the filler that is miscible with the ground is sprayed while pulling out the curved tube, and the filler is adjacent to the partition area. Extending and laying in the area of the ground to be closed, closing the extraction hole of the curved pipe used for the construction of the reinforcing body in each area, and preventing the collapse of the extraction hole and the deformation of the ground in advance. The filler is gradually adapted to the ground over time, so that the original state of the ground used for construction is restored.

The invention according to claim 9 may adopt the formation of the reinforcing body according to the ground by forming the reinforcing body by high-pressure injection of a curing agent or a curing agent and air or water while pulling out the curved tube. I have to.
According to a tenth aspect of the present invention, the cross-sectional shape of the reinforcing body is controlled by rotating or swinging the high-pressure jet of the hardener or the hardener and air or water, or by adjusting the jet pressure. The formation of a reinforcing body according to the ground can be adopted.

In the invention of claim 1, since the entire area of the reinforcing body is laid under the partition area of the ground where the existing structure is located, the reinforcing body can be reasonably and finely laid in the predetermined ground area, and the ground improvement In addition, it is possible to prevent the laying of the reinforcing body outside the partition area of the adjacent ground, and it is suitable for improving the ground of a city where existing structures are densely packed.
In the invention of claim 2, a curved columnar filler that is miscible with the ground is laid on at least one end of the reinforcing body, and the filler is extended and laid in a partition area of the ground adjacent to the partition area. Therefore, in each partition area, the extraction hole of the curved pipe used for the construction of the reinforcing body is closed to prevent the collapse of the extraction hole and the deformation of the ground, and to make the filling material familiar with the ground over time. It is possible to restore the original condition of the ground used for construction.

In the third aspect of the invention, the reinforcing body and the filler are formed in the same curved shape, and these are laid on the same curved line, so the reinforcing body and the filler are based on the same construction curved line. It can be installed and streamlined construction.
In the invention of claim 4, since the reinforcing body and the filler are formed in a curved columnar shape, the strength thereof can be maintained and the construction can be rationalized.
In the invention of claim 5, since the plurality of reinforcing bodies having different curvatures are laid out vertically or laterally from each other, it is possible to enhance the effectiveness of narrow ground improvement.
In the invention according to claim 6, since the reinforcing body is formed of a curved columnar rigid body protruding downward, it is possible to improve the strength against earth pressure and an overload, and to improve the effectiveness and efficiency of ground improvement.

  In the invention of claim 7, since the entire area of the reinforcing body is laid under the partition area of the ground where the existing structure is located, when the ground under the existing structure is improved from the ground surface, the reinforcement is reinforced in the predetermined ground partition area. The body can be laid down rationally and finely, making it possible to effectively improve the ground, while preventing the installation of reinforcements outside the area of the adjacent ground, and suitable for improving the ground in cities where existing structures are dense .

  According to an eighth aspect of the present invention, after injecting the curing agent into a predetermined area in the partition area of the ground, the filler that is miscible with the ground is sprayed while pulling out the curved tube, and the filler is adjacent to the partition area. Since it extends and lays in the partition area of the ground to be closed, the extraction hole of the curved pipe used for the construction of the reinforcing body is closed in each partition area, and the collapse of the extraction hole and the deformation of the ground are prevented in advance. The filler material can be adapted to the ground over time, and the original state of the ground used for construction can be recovered.

In the invention of claim 9, since the reinforcing body is formed by high-pressure injection of a curing agent or a curing agent and air while pulling out the curved tube, there is an effect that the formation of the reinforcing body according to the ground can be adopted. is there.
The invention of claim 10 controls the cross-sectional shape of the reinforcing body by rotating or swinging the nozzle for high-pressure injection of the curing agent or the curing agent and air, or by adjusting the injection pressure. There is an effect that the formation of a reinforcing body corresponding to the ground can be adopted.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of an illustrated embodiment in which the present invention is applied to ground improvement under an existing structure. In FIGS. 1 to 8, reference numeral 1 denotes a ground having an improved ground portion 2 such as a soft ground or a contaminated ground. The ground surface on the above-mentioned improved ground portion 2 is formed on a residential land, consisting of a sandy layer, a viscous soil layer, a gravel layer, a cobblestone layer, a hard soil layer, and the like.
The residential land is divided into a plurality of areas, and existing structures 3 and 4 such as houses are constructed in the divided areas Z ₁ and Z ₂ . In the figure, the zone Z ₃ is a vacant space 4 that is an unconstructed part of an existing structure.

In the embodiment, the required improvement ground portion 2 under the existing structure 4 is the target of ground improvement, and a known curved boring device 5 is used for the construction of the ground improvement, and this is applied to the adjacent zone Z ₃ . It is installed in open space 4.
That is, the curved boring device 5 is fixed to the frame 6 that is fixedly installed in the open space 4 that is the construction site, and the curved tube 7 is attached to the frame 6 via a hydraulic cylinder (not shown) during excavation. After the excavation and after excavation, the curved tube 7 and the curved tube propulsion device 8 capable of pulling out the distal end device, which will be described later, the curved tube 7 in which curved outer tubes are sequentially connected, and the distal end of the curved tube 7 are attached. And a tip device 10 having a drill bit 9 at the tip.
In this case, as the propulsion means for the curved tube 7, it is also possible to use a propulsion means such as a pulling method using a wire or a winch, a rack gear, a chain drive or the like instead of the aforementioned cylinder.

As shown in FIG. 4, the tip device 10 includes a bent tubular leading conduit 11 constituting the curved tube 7, and a leading inner tube 13 coaxially disposed inside the tube 11 via a mud passage 12. A rotation holder 14 is provided inside the inner tube 13, and a rotation rod 15 is supported at the tip of the holder 14 so as to be able to rotate forward and backward.
The rotary rod 15 is linked to a drive mechanism (not shown) such as a hydraulic motor so that it can be rotated forward and backward about the axis L of the front conduit 11, and most of the rotation rod 15 is accommodated in the front conduit 11. ing.

Small-diameter shaft portions 15a and 15b are provided at both ends of the rotating rod 15. The excavation bit 9 is pivotally attached to the distal end of the small-diameter shaft portion 15a on the distal end side, and a high pressure is provided at the intermediate portion of the small-diameter shaft portion 15a. A nozzle 16 that is an injection means is provided.
The excavation bit 9 is expanded at the time of excavation to increase the excavation diameter to facilitate the insertion of the leading conduit 11 and the curved tube 7, and is reduced at the time of excavation stop to facilitate the extraction of the curved tube 7 and the tip device 10. I have to. A water supply pipe (not shown) is piped near the excavation bit 9 so that the drilling water can be ejected toward the face during excavation.

The nozzle 16 has a nozzle hole that opens in a direction orthogonal to the axis L, and as shown in FIG. 5, the curing agent spray port 17 and the air spray port 18 are arranged concentrically. Is communicated with a hardener passage 19 and an air passage 20 formed inside the rotary rod 15.
The curing agent passage 19 is formed along the axial center of the rotating rod 15, and the rear end portion thereof communicates with a communication port 21 formed in the diameter direction in the small-diameter shaft portion 15 b on the rear end side. It is formed on the peripheral surface of the rotating rod 15 and is open to the annular groove 22.

A hardener passage hole 23 and an air passage hole 24 are formed in the rotary holder 14 in the axial direction, and these are arranged at symmetrical positions, and their tips are bent in the axial direction. .
Of these, the tip of the curing agent passage hole 23 opens into the annular groove 22, communicates with the curing agent passage 19 and the curing agent injection port 17 via the annular groove 22, and cures from the curing agent injection port 17. The agent can be sprayed.
On the other hand, the front end portion of the air passage hole 24 opens into an annular groove 25 formed in the peripheral surface of the small-diameter shaft portion 15b, and communicates with the air passage 20 via a passage hole 26 communicating with the annular groove 25. Air can be ejected from the mouth 18.

  The curing agent is not particularly limited. For example, as a main material, a cement milk type, a cement mortar type, a cement clay type, a lime type, and those obtained by adding fine particles such as fly ash, slag, bentonite, etc. Used as an auxiliary material, for example, rapid setting agents such as water glass, calcium chloride, aluminum hydroxide, calcium sulfoaluminate (CSA), separation inhibitors, dispersants, foaming agents, foaming agents, etc. Is possible.

One end of each of the hardener conduit 27 and the air conduit 28 is connected to each rear end portion of the hardener passage hole 23 and the air passage hole 24, and the other end thereof penetrates the partition piece 29 attached to the rear portion of the front conduit 11. It communicates with the holes 30 and 31.
A sludge pipe 32 is piped between the leading inner pipe 13 and the partition piece 29, one end communicating with the sludge passage 12, and the other end communicating with a guide hole 33 formed at the center of the partition piece 29. ing.
The conduits (not shown) are connected to the through holes 30 and 31 and the guide hole 33, so that a high-pressure hardener and air can be supplied from the ground, and excavated soil including mud at the time of excavation is supplied to the first conduit 11. The suction port 34 can be sucked out and discharged to the ground via a suction pump (not shown).

In the figure, reference numeral 34 denotes an improved ground portion required to be improved by the hardener or hardener and air or water, hardener and air and water, etc. ejected from the nozzle 16 when the leading pipe 11 or the curved pipe 7 is pulled out after the excavation is completed. 2 in reinforcement of laying has been curved columnar shape, the curved shape is approximately the position of the main improved ground portion 2, curve ball - and installation position of the ring 5, is determined by the correlation between the width of the compartment area Z ₂ The leading conduit 11 or the curved tube 7 is curvedly formed on the basis of the construction curved line L corresponding to the curved shape, and the leading conduit 11 or the curved tube 7 is propelled and dug along the construction curved line L. Yes.
Therefore, in the case where the reinforcing body 34 is further installed at the upper and lower positions of the reinforcing body 34 in FIG. 1 while maintaining the installation position of the curved bowling 5, and the improvement of the improvement ground portion 2 is promoted, the upper reinforcing body 34 is formed into a gentler curved line than the lower reinforcing body 34.

The length of the reinforcing member 34 is formed to short and small or slightly width approximately the same partition zone Z _2, to avoid protruding from the compartment area Z _2, and the cross-sectional shape, and a path of action of the nozzles 16, It is controlled by the ejection pressure of the curing agent or air and the type of ejected matter.
That is, when the nozzle 16 rotates together with the rotating rod 15, the operation locus of the nozzle 16 becomes a circle, and the cross-sectional shape of the reinforcing body 34 becomes a circle as shown in FIG.
In addition, when the nozzle 16 swings together with the rotating rod 15 and reciprocates by 180 °, for example, the operation locus of the nozzle 16 becomes a semicircle, and the cross-sectional shape of the reinforcing body 34 is shown in FIG. It becomes semicircular like.

Furthermore, the cross-sectional shape of the reinforcing body 34 has a larger diameter in the case where the curing agent and air are ejected together than in the case where only the curing agent is ejected from the nozzle 16 as shown in FIG. In addition, as shown in FIG. 7B, the higher the injection pressure, the larger the diameter compared to the lower case.
Therefore, by comprehensively controlling these relationships, it is possible to form an optimal reinforcing body 34 according to the situation of the ground portion 2 requiring improvement.

In the figure, 35 is a curved drawing hole formed from the section zone Z ₂ to the ground of the section zone Z ₃ when the leading pipe 11 or the curved pipe 7 is pulled out after the excavation is finished. 11 to the outer diameter of the curved pipe 7, and the drawing hole 35 is filled with a filler 36 such as earth or sand or clay.
That is, it is desirable that the filler 36 be mixed and homogenous with the ground, which can be ejected from the nozzle 16 when the leading pipe 11 or the curved pipe 7 is pulled out.

The laying position of the reinforcing body 34, that is, the propulsion position and the number of the curved pipes 7 are not particularly limited. In the embodiment, for example, the frame 6 of the curved bowling 5 is appropriately moved as shown in FIG. A plurality of curved tubes 7 are arranged in parallel to each other from the frame 6 toward the existing structure 4.
Further, as shown in FIG. 3B, the frame 6 is rotated by an appropriate angle, and a plurality of curved tubes 7 are arranged in a radial direction toward the existing structure 4, and further as shown in FIG. 3C. It is also possible to arrange the plurality of curved tubes 7 in parallel and in the radial direction toward the existing structure 4 by using the above-mentioned method in combination.
At that time, the curved pipes 7 arranged in parallel and the curved pipes 7 arranged in the radial direction are arranged up and down to reinforce the ground part 2 to be improved finely and avoid the crossing of the curved pipes 7. It is desirable to make it easier and more reliable.

  In addition, reference numeral 37 in the figure denotes a front end opening of the tip conduit 11, which sucks in excavated earth and sand mud water containing the earth and sand during excavation, through the mud passage 12 and the mud pipe 32 communicating therewith. It can be discharged to the ground. A seal packing 38 is interposed between the leading conduit 11 and the rear end of the leading inner tube 13.

In the above-described embodiment, the curved boring device 5 is used as a means for installing the curved pipe 7 in the improved ground portion 2, but depending on the situation of the ground 1 or the improved ground portion 2, Other means can be used.
For example, an injection mechanism such as a water jet can be used for excavating a sandy layer, and a percussion or impact mechanism such as a percussion can be used for excavating a hard soil layer or a rock.

When the ground is improved by using the construction method of the present invention configured as described above, a predetermined position of the zone Z ₃ adjacent to the zone Z ₂ of the ground 1 under the existing structure 4, that is, on the construction curve line L At this construction base, the frame 5 of the curved boring device 5 is installed, and the curved tube propulsion device 8 is installed downward on the frame 5. This situation is as shown in FIG.

Next, the curved pipe propulsion device 8 is provided with a leading pipe 11 equipped with a tip device 10 facing downward, and a hardener supply pipe, an air pipe, a mud pipe, a water supply pipe, a power cable, etc. When both are not connected), the excavation bit 9 is driven to excavate the ground 1 in the zone Z ₃ and the curved pipe propulsion device 8 is pushed in to drive the tip conduit 11 into the ground for the excavation. .
After the excavation is started, drilling water is sprayed from a water pipe (not shown) toward the face, and a vacuum pump (not shown) is driven to suck mud water including excavated sediment from the tip opening 37, Is discharged to the ground through the mud passage 12, the mud pipe 32 and the mud conduit.

Then, when the leading conduit 11 is dug for approximately the length and propelled into the ground, the driving of the excavating bit 9 and the curved tube propulsion device 8 is stopped, and a predetermined length is provided at the rear end of the leading conduit 11. The curved tube 7 is added by appropriate means. Thereafter, the driving of the excavation bit 9 and the curved pipe propulsion device 8 is resumed, the excavation is shifted to the zone Z ₃ or the zone Z ₂ , and the improved ground portion 2 is excavated. This situation is as shown in FIG.

Thereafter, the above operation is repeated, a required number of curved pipes 7 are added to the leading conduit 11, and the ground 1 immediately below the improved ground portion 2 in the partition zone Z ₂ is excavated over substantially the entire area. Is stopped, the excavation is finished, and the situation where the tip of the tip device 10 enters the adjacent compartment Z ₁ is prevented. This situation is as shown in FIG.

Thereafter, the excavation bit 9 is reduced, the rotary rod 15 is driven to rotate, the nozzle 16 is moved in accordance therewith, and the curing agent or the curing agent and compressed air are pumped to the nozzle 16.
That is, the curing agent is pumped to the curing agent conduit 27 through a pumping means (not shown), and the compressed air is pumped to the air conduit 28, and these are fed from the curing agent passage hole 23 and the air passage hole 24 to the curing agent passage. 19 and the air passage 20 are guided to the nozzle 16 and are ejected from the nozzles 17 and 18.
On the other hand, before and after this, the curved tube propulsion device 8 is pulled out, the leading conduit 11 and the curved tube 7 are pulled out together, and the tip device 10 including the excavation bit 9 is moved together.

  In this way, the extraction hole 35 is formed after the extraction of the leading conduit 11, and the curing agent and the compressed air are ejected in a radial direction from the nozzle 16 at the substantially center of the hole 35, and these are the ground 1 around the hole 35. The ground 1 is solidified while being stirred, and a large-diameter curved columnar reinforcing body 34 is formed around the extraction hole 35. This situation is as shown in FIG.

In this case, when the compressed air is not pumped to the nozzle 16, the diffusion effect of the curing agent by the compressed air disappears, the diffusion range becomes narrow, and the outer diameter of the reinforcing body 34 becomes smaller accordingly. This situation is as shown in FIG. 7 (a) and FIG.
Therefore, in this case, since the number of laying of the reinforcing bodies 34 can be relatively increased with respect to the unit area or the unit volume of the improved ground portion 2, the supporting strength of the required ground portion 2 can be increased accordingly.

On the other hand, along with the drawing operation, the curved tube 7 is sequentially drawn out on the ground surface of the zone Z ₃ , divided into a predetermined length and stored in a proper place.
Thereafter, the pulling-out operation of the curved tube propulsion device 8 is restarted, the leading conduit 11 and the curved tube 7 are pulled out, and the new pulling hole 35 is filled with the curing agent ejected from the nozzle 16 or the curing agent together with the compressed air. The reinforcing body 34 is extended in the drawing direction.
The withdrawal end of the reinforcing body 34, at close to the boundary of the compartment area Z _2, to stop the supply of the curing agent and compressed air to the nozzle 16. The rotation of the rotating rod 15 is stopped, and the rotation of the nozzle 16 is stopped. This situation is as shown in FIG.

After that, the extraction of the leading conduit 11 and the curved tube 7 is resumed by the curved tube propulsion device 8, and a new extraction hole 35 is formed.
In addition, an appropriate filler 36 such as earth or sand, bentonite or clay that is miscible with the ground 1 is pumped together with water to the mud conduit 32 or the air conduit 28 via a pumping means, and this is rotated under the nozzle. From 16 injection ports 17 or 18, the extraction holes 35 are ejected and filled. This situation is as shown in FIG.

Then, the pulling-out operation of the curved tube propulsion device 8 is continued, the leading conduit 11 and the curved tube 7 are pulled out to the ground surface of the partition zone Z ₃ , divided into a predetermined length, and the new pulling hole 35 is filled with the above-described filling. Fill material 36 with water.
Further, detaching the curve pipe propulsion device 8 from the gantry 6, if leveling the surface of the partition zone Z ₃ by removing the cross-platform 6, a series of ground improvement work is completed.
This situation is shown in FIG. 1, the reinforcing member 34 is laid on the main improved ground portion 2 of the partition zone Z _2, also has partition zone Z ₂ of the filler 36 over the compartment area Z ₃ from a boundary portion is laid .

  Thus, in the present invention, since the curved pipe 7 is laid from the ground using the curved boring device 5, no vertical shaft is required for laying the straight pipe horizontally as in the prior art. The construction from the inside is abolished and the construction is simplified without being overly large, and the construction cost can be reduced and the construction period can be shortened, the construction space can be made compact, and it is difficult to secure the construction site. Suitable for ground improvement.

  Further, after the curved tube 7 is pulled out or at the same time, the reinforcing body 34 is formed by high-pressure injection of the curing agent or air and the curing agent or these together with water and the like, and this is laid on the improved ground portion 2. Therefore, compared to the conventional case where curved pipes are placed inside and outside, and the filling material is filled into the outer pipe that is left after the inner pipe is pulled out, the use of the pipe material is reduced and the construction is simplified, and the construction cost is reduced. And shortening the construction period.

Thus, the reinforcing body 34 laid on the improved ground portion 2 firmly supports the improved ground portion 2 due to its rigidity, and improves its strength.
In addition, since the reinforcing body 34 is formed in the shape of a curved column protruding downward, it can secure a wide contact area with the ground portion 2 to be improved as compared to the linear reinforcing body, and can firmly support the ground. Biting against the ground 1 is strengthened.

In addition, since the reinforcing body 34 is laid in a predetermined zone Z ₂ to prevent intrusion outside the zone, troubles associated with the laying can be prevented and construction from the reinforcing body 34 can be performed. Since the filler 36 that is miscible with the ground 1 is installed until the base, it is possible to prevent deterioration of the ground 1 in the temporarily used zone Z ₃ and to restore the initial geology or soil condition reliably and quickly.

FIG. 9 and FIG. 10 show other embodiments of the present invention, and the same reference numerals are used for portions corresponding to the configurations of the above-described embodiments.
Among these, FIG. 9 shows 2nd Embodiment of this invention, and this embodiment replaces the structure on the ground as an existing structure, an underground tunnel, a sewer, a sewer pipe, a water pipe, a gas pipe, etc. installed underground. It is applied to improve the ground around the underground structure 37.
That is, in the case of this embodiment, for example, the above-described curve boring device (not shown) is installed at an appropriate place on the ground surface, and the device is directed toward the improved ground portion 2 or other ground surface from the ground portion 2. Drilling into a curved line toward the side point, laying a curved tube 7 in the drilled hole, laying out the curved tube 7 in a predetermined area, and then pulling out the tube 7, and at the same time, curing agent or curing agent and air or water Etc. are jetted at high pressure, a large-diameter reinforcing body 34 is formed around the underground structure 37, and the adjacent reinforcing bodies 34 are brought into close contact with each other, so that the ground of the improved ground portion 2 is efficiently improved.
In this case, for the ground 2 immediately above or directly below the underground structure 37, a reinforcing body 34 is laid from one side of the ground surface, and the ground 2 on both sides sandwiching the underground structure 37 is reinforced from both sides of the ground surface. The body 34 is laid.

  By doing so, the earth pressure and the load around the underground structure 37 are supported by the reinforcing body 34, and the load on the underground structure 37 is reduced. Therefore, the underground structure 37 is prevented from being damaged and its life is improved. it can. In particular, this effect is suitable for improving the lifetime of the aged underground structure 37.

FIG. 10 shows a third embodiment of the present invention. In this embodiment, the ground of the river bed 41 is a ground around the footing 39 and the foundation pile 40 constituting the foundation of the lower end of the pier 38 as an existing structure. Applied to improvement. In the figure, 42 is a river.
In this embodiment, a large-diameter reinforcing body 34 is laid on the riverbed 41 around the footing 39 and the foundation pile 40, the adjacent reinforcing bodies 34 are brought into close contact with each other, and the ground of the part is improved, so that the pier 38 is provided. The safety of the construction and the safety of the construction are ensured. In this case, the reinforcement body 34 is laid from one side of the river 42 separated from the footing 39.

  The ground improvement structure and the ground improvement method of the present invention can be laid in the ground firmly and efficiently and can firmly support the ground, and the construction space can be made compact, the construction can be simplified, the construction cost can be reduced and the construction period can be shortened. For example, it is suitable for narrow ground improvement under existing structures.

It is sectional drawing which shows the construction condition of the ground improvement by this invention, and has laid the reinforcement body formed by high pressure injection of a hardening | curing agent and air. It is sectional drawing which shows the construction condition of the ground improvement by this invention in order from (a) to (f).

It is a top view which shows the construction situation of the ground improvement by this invention, shows the installation situation of an existing structure and a curve boring apparatus, (a) shows the case of embodiment, (b) and (c) are the applications. The form is shown. It is sectional drawing which shows the assembly | attachment condition of the curved pipe applied to this invention, a tip conduit, and a front-end | tip apparatus. It is sectional drawing which follows the AA line of FIG. 4, and has expanded slightly.

It is sectional drawing in alignment with the BB line of FIG. 4, and has expanded slightly. It is sectional drawing which shows the various form of the reinforcement body applied to this invention, (a) shows the case of embodiment, (b) and (c) have shown the application form. It is sectional drawing which shows the construction condition of the ground improvement by this invention, and has laid the reinforcement body formed by high-pressure injection only of a hardening | curing agent.

It is sectional drawing which shows the 2nd Embodiment of this invention, and has shown the construction condition of the ground improvement around underground structures, such as a sewer. It is sectional drawing which shows the 3rd Embodiment of this invention, and has shown the construction condition of the ground improvement around the foundation of the lower end part of a bridge pier.

Explanation of symbols

1,41 Ground 2 main improved ground portion 3,4,37,38 existing structures 7 curve pipe 16 nozzles 34,34a reinforcement 35 withdrawal hole 36 filler Z ₁ to Z ₃ compartment area

Claims (10)

  In the ground improvement structure in which a curved columnar reinforcing body is laid on the ground required for improvement under the existing structure, the entire area of the reinforcing body is laid under a partition area of the ground where the existing structure is located. Improved structure.   The ground improvement according to claim 1, wherein a curved columnar filler that is miscible with the ground is laid at at least one end of the reinforcing body, and the filler is extended and laid in a partition area of the ground adjacent to the partition area. Construction   The ground improvement structure according to claim 2, wherein the reinforcing body and the filler are formed in the same curved shape, and are laid on the same curved line.   The ground improvement structure according to claim 2, wherein the reinforcing body and the filler are formed in a curved column shape.   The ground improvement structure according to claim 1, wherein a plurality of reinforcing bodies having different curvatures are laid apart from each other vertically or horizontally.   The ground improvement structure according to claim 1, wherein the reinforcing body is formed of a curved columnar rigid body protruding downward.   A construction base is provided on the ground having an improved ground portion under an existing structure, a curved hole is drilled from the construction base toward the improved ground portion, and a curved pipe is inserted into the drilled hole. In the ground improvement method in which the curved pipe is pulled out while spraying a curing agent from the tip of the pipe, and a curved columnar reinforcing body is laid on the ground area requiring improvement, the ground where the existing structure is located in the entire area of the reinforcing body A ground improvement method characterized by laying under a partition area.   After injecting the curing agent into a predetermined area in the subdivision area of the ground, a filler that is miscible with the ground is injected while pulling out the curved tube, and the filler is extended to the subdivision area of the ground adjacent to the subdivision area. The ground improvement method according to claim 7, wherein the ground improvement method is installed and installed.   The ground improvement construction method according to claim 7, wherein the reinforcing body is formed by high-pressure jetting of a curing agent or a curing agent and air or water while pulling out the curved pipe. The ground improvement of Claim 7 which controls the cross-sectional shape of the said reinforcement body by rotating or swinging the nozzle which carries out high-pressure injection of the said hardening | curing agent or hardening | curing agent and air or water, or adjusting the injection pressure. Construction method.

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