JPH06116936A - Ground restoration method - Google Patents

Abstract

PURPOSE:To provide flat leveling of a ground surface layer like a design by a method wherein the local sedimentation portion of a ground surface layer owing to unequal settling is capable of rising to the flat level of a necessary portion, and an excessive rise and unequal restoration are prevented from occurring. CONSTITUTION:An anchor 10 is anchored through a head part 14 from the portion, except a portion to be recovered, of a settled ground surface layer 3 and the anchored part 13 is extended down to a support layer 2. Forced injection is effected at the given number of stages such that the lowermost layer of a non-fluid self-curable consolidating material injected with a pressure by compaction grouting execution is situated between the support layer and the ground surface layer. The ground surface layer 3 is brought into a pressurized state to generate a reaction force. The density of a consolidating material 7 is increased through compression of a peripheral ground with a given pressure through a top-down system, and the ground of a portion is forced to rise to restore sedimentation. In this case, since the ground surface layer is brought into a pressurized state by means of the anchor 10, a rise to a level higher than a flat level does not occur and restoration of the ground surface layer like a design is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The disclosed technology belongs to the field of ground restoration technology in which an unexpectedly inclined ground surface layer is restored to a flat surface layer by compaction grouting.

[0002]

2. Description of the Related Art As is well known, effective use of national land is extremely important for Japan, which is restricted by the terrain in which there are many mountainous areas and the plains distributed along the rugged coastline are extremely narrow. It is extremely beneficial to use the land developed by ground improvement and land reclamation as much as possible. Therefore, various ground improvement techniques have been developed, but even for the effectively utilized land once formed, its uneven settlement When deformation occurs due to dents, depressions, irregularities, liquefaction, etc. (Of course,
Although it should be prevented at the time of initial construction), it is at least a negative factor for the various facilities to be constructed, and must be promptly repaired and restored, and the ground due to such uneven settlement and depression. The change of (surface layer) is mainly that the uppermost layer generally has high hardness, and the lowermost support layer also has high strength, but the weak layer between them has low strength and there is groundwater etc. In some cases, it causes subsidence phenomena through consolidation and groundwater escape, resulting in unequal subsidence locally or locally, which is unexpected for construction facilities such as airports, roads, factories, and housing complexes. There is a problem that can cause a situation.

In order to deal with this, various ground restoration techniques including primitive means such as so-called replacement and underpinning accompanied by excavation have been developed and partially put into practical use.

Thus, for example, techniques such as so-called pulse consolidation by injecting a solidifying material such as cement milk, permeation consolidation by injecting a chemical solution such as water glass, or so-called jet grout discharge replacement have been developed. However, since the soil restoration methods using these conventional techniques use a relatively high-fluidity solidifying material, even if it is press-fitted or injected into the soil, the solidifying material There is a potential drawback that stray or escape may occur, and it is difficult to restore the surface to the design flat level by lifting the surface layer that tends to sink over time.

On the other hand, a so-called compaction grouting method as shown in FIG. 3 has been developed. For example, the ground 2 on which the shield tunnel 1 is formed has a depression or the like at the upper portion of the shield tunnel 1 and is not formed on the surface layer 3. When equal subsidence occurs, fine ash and fluidity of fly ash, bentonite, sand, fine gravel, etc. into cement mortar by a predetermined pressure pipe 6 through a device 5 such as a grout pump by a predetermined construction carriage 4 on the surface of the earth A low-slump (0-6 cm slump, etc.) non-fluidic, self-hardening consolidation material 7 in which a given amount of added earth or the like is mixed is used, for example, 40 kgf / cm ²
To form a homogeneous solidified body 8 by extruding as a laminated bulb type block which is stepwise joined to each other in a plurality of stages so as to reach the lowermost support layer 2 at a predetermined pressure such as The surrounding soft layer 2'is compressed by non-discharging displacement to increase the density and self-cure over time, thereby lifting the surface layer 3 in a pressurized state, and restoring the surface layer 3 to the overall design flat level. The technology to do so has come to be used.

[0006] Such a compaction grouting method is a so-called bottom-up method (a top-down method is intentionally used in some cases) in which stages are gradually changed from a lower stage to an upper stage to improve the ground through a consolidation phenomenon over a wide area. Although it has been provided, the reinforcement and repair work for changes in the surface layer 3 due to uneven settlement and depression as described above is not only the repair work associated with the construction of the shield tunnel, but also the slope of the foundation ground of large structures such as oil tanks and airports. It is being applied to extremely important works such as restoration work due to earthquakes and reinforcement work against liquefaction of the ground due to earthquakes, etc., and it is a so-called top-down method that gradually takes stages from the upper stage to the lower stage (in some cases it is a design bottom There is also an up method.) Is adopted in terms of local effects.

[0007]

Therefore, the construction by the compaction grouting, especially the ground restoration construction mainly by the top-down method is a low slump (0-6 cm slump) and is non-fluid. Since it uses a self-hardening solidifying material, it does not cause stray or runaway in the ground, does not cause pollution problems such as groundwater pollution, and enables construction of tunnels etc. that cannot be constructed due to soft ground In addition, since it is possible to perform construction and work from the inner bottom of an existing structure and there is almost no noise or vibration, it is an inherently excellent construction technique.

However, a low slump (0) is applied to the surface layer that has been concavely deformed or inclinedly deformed due to uneven subsidence or depression.
(6 cm slump), even in compaction grouting work by non-fluidizing and self-hardening solidifying material such as top-down method, the surrounding material is covered by the expressing material. Since it becomes a pressure state and is compressed (causing a consolidation phenomenon), and there is no stray or escape of the solidifying material in the ground, and because it is a non-discharge filling method, sometimes the surface layer is There is a case in which there is a disadvantage that an overhang causes a swelling phenomenon, locally bulges, and as a result, uneven deformation occurs, which is not suitable for flattening the entire original area.

[0009] Such a point is a particularly unfavorable problem for local surface deformation in a considerably large area such as an airport or road interchange, and once the surface of lining concrete or asphalt is peeled off. In addition, it is extremely troublesome in construction to carry out backfilling by locally jacking up a plurality of points, and to perform compaction grouting again, which is disadvantageous in that it is not suitable in terms of cost.

Moreover, once the surface layer is deformed due to unequal subsidence or the like, it may lead to the same deformation over time thereafter, and thus the repeated construction must be repeated over and over again. There was also a negative point that it could hinder the stable and constant operation of the structure due to the absence.

By the way, as shown in FIG. 4, various techniques have been developed for constructing the anchor 10 on the sloping ground 3 in order to maintain a stable function of structures such as a dam body and a steel tower. It is in the stage of being put into practical use as.

As shown in FIG. 5, the anchor 10 is connected to the PC through the grout 11 in the drilled hole in the ground.
A steel head 12 is inserted and a ground head 14 is provided so that the fixing portion 13 serves as an anchor body at the tip, and rustproof treatment is surely performed, and a technique that can be used as a permanent structure has reached the completion area. This contributes significantly to maintaining the stable function of the target in various construction works and has a considerable track record.

[0013]

OBJECT OF THE INVENTION The object of the invention of this application is the problem of surface deformation, bulging, etc. due to compaction grouting through a top-down method such as repair work for dealing with uneven settlement or depression of the ground based on the above-mentioned prior art. Taking the advantage of the compaction grouting into full use as a technical issue to be solved, and paying attention to the point of maintaining a stable function for the construction object of the anchor as another civil engineering construction technique described above, the initial design Predetermined area on the flat level of the ground,
The target ground is pressed and the design is flat while restoring the non-fluid and self-hardening solidification material including the local area by compressing the surrounding ground and restoring it through the consolidation phenomenon due to the increase in density. The purpose of the present invention is to provide an excellent method for ground restoration that can reliably maintain the level and maintain the restoration over time and benefit the field of civil engineering applications in the construction industry.

[0014]

In order to solve the above-mentioned problems, the structure of the invention of the present application, which is based on the above-mentioned object and has the above-mentioned object as a gist, is an uneven settlement or a depression in the ground in a predetermined region. ， In case of concave deformation or inclination due to liquefaction phenomenon etc., when restoring it to the flat level of the initial design, the compaction grouting method via top-down method (bottom-up method can be adopted in some cases) A low slump (0-6 cm slump) non-fluidic, self-hardening binder is locally applied at a predetermined pressure so that it reaches the supporting layer inside the ground at the deformation site. In order to apply pressure by means of the anchor, an anchor is provided on the support layer from the ground or from another site, and the anchor is applied to the support layer below the solidified solidified material of the non-flowable solid material. The non-fluid and self-hardening solidifying material is used to achieve the compression of the ground and the increase of the density by the non-discharging displacement, and the pressure of the surface layer is revealed by the anchor, and the swelling of the surface layer is reduced. In addition, it is possible to suppress it at the relevant part, and the solidification is solidified by the solidification through the self-hardening of the solidifying material over time, and the surface layer is flattened as designed to the flat level. ,
This construction is performed on all of the deformed parts, and technical measures are taken so as to maintain a stable flat level of the ground surface layer over time.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the invention of this application is shown in FIGS.
The explanation is as follows.

The same parts as those in FIG. 3 and subsequent figures will be described using the same reference numerals.

The embodiment shown in FIG. 1 is a mode in which it is constantly required to maintain a flat level of a vast effective use area such as an airport or a road. From the right side to the left side of the figure, the surface layer 3 of the ground is unsuitable for the reasons described above. In order to restore the flattened state (indicated as deformed in the figure) to a flat level as much as possible as originally designed, anchor from other parts such as the ground in advance. 10 (which is a known technique per se as described above) is connected so that the fixing portion 13 exists in the portion of the support layer 2, and the head portion 14 is formed at a portion where it is not desirable to cause excessive swelling. The anchor 10 is formed in advance, and the compaction grouting method based on the above-mentioned top-down method is used there. A mixture of fine particles such as tontonite, sand, and fine gravel (also including locally procured materials), and silt (the composition is determined by the situation of each construction site), etc. A block in which a non-fluid, self-hardening solidifying material 7 of slump (0 to 6 cm slump) is mutually joined by a predetermined number of stages, and is solidified so as to reach the lower support layer 2. The surface layer 3 is raised by forming the body 8 and compressing the ground of the portion to raise the density to raise the subsidence portion, but in this embodiment, the portion other than raising the sinking portion Since the head portion 14 of the anchor 10 is provided at a portion where swelling is not desired and the surface layer 3 of the portion is in a pressurized state to take a reaction force, it is non-fluid and self-curing. Solidifying material 7 By compaction grouting the pressure injection through a reciprocating grout pump, the surface layer 3 rises and rises in the pressure injection portion as shown by the alternate long and short dash line, and the other portions do not rise, and therefore the surface layer 3 covers the entire area. Be flattened.

In this case, the size of the fixing portion 13 of the anchor 10 and the tension of the PC steel wire 12 are adjusted in advance according to the design, and the non-fluid and self-hardening non-fluid binding material 7 is formed. Adjust the size of the bulb-shaped block of the solidified body 8 for each stage by adjusting the injection pressure,
The swelling of the surface layer 3 is adjusted to a predetermined level so that overswelling does not occur, secondary uneven deformation is avoided, and a constant flat level is achieved in the entire area.
Since the solidified body 8 is formed by self-curing of the solidifying material 7 over time, and because the anchor 10 is a permanent structure, the flat level position / posture state of the surface layer 3 once flattened is over time. The stable flat level will be maintained by one compaction grouting work.

At the end stage, the anchor can be removed.

Next, the embodiment shown in FIG. 2 is caused by unequal subsidence of the bottom portion of the bottom portion of the structure 9 such as an airport building and the end edge portion.
Alternatively, it is a mode in which a depression due to a liquefaction phenomenon is repaired,
Aspects of performing the compaction grouting construction by a top-down method, and regarding the construction of the anchor 10, the anchor 10 that can be constructed from the inner bottom portion of the structure 9 described above,
And, the anchor 10 reaching the support layer 2 from the surface layer 3 outside the predetermined area is laid to prevent excessive bulge repair of the construction area and other areas, and a flat level surface layer as designed in the predetermined area. The repair of No. 3 is possible, and there is substantially no difference between the above-described embodiment and the function and effect.

The embodiment of the invention of this application is not limited to the above-mentioned embodiments, and various embodiments can be adopted, for example, an anchor is provided so as to reach the same portion as the press-fitting and solidifying material. Is.

Further, it is needless to say that the object of application can also be applied to the time-dependent repair after construction of uneven settlement due to sedimentation due to the difference in specific gravity of the slurry at the time of landfill through the discharged mud and sand due to dredging. .

[0023]

As described above, according to the invention of this application, basically, when the surface layer is deformed due to uneven settlement due to natural phenomenon of the ground formed, depression due to construction, liquefaction phenomenon, etc. In the ground restoration method that restores to a flat level by compaction grouting construction via the down method, etc., fly ash on cement mortar,
Bentonite, sand, fine particles such as gravel, components such as silt,
Depending on the situation, multiple non-fluid, self-hardening binders with a low slump (0 to 6 cm slump) that is as close to zero as possible with locally procured materials and the like are mixed in the ground at a predetermined pressure. On the stage, it is pressed into a block shape that is joined and laminated to each other by a top-down method, etc. to form a solid body over time with the lower support layer, and the surrounding ground is compressed by non-discharging displacement, When increasing the density and repairing the subsidence and slope due to swelling, prevent swelling of unnecessary parts,
Also, it is possible to avoid the protrusion due to excessive swelling even in the necessary part, and additionally to suppress the swelling of the necessary part and to cover the surface layer with the anchor so as to prevent the swelling beyond the design flat level even in the unnecessary part. By applying a reaction force between the lower support layer and the pressure state, it is possible to restore the flat level of the entire desired site as much as possible, and the anchor itself is a permanent structure. A flat level is formed at the same time through the solidification of a fluid and self-hardening solidifying material over time, so that it is possible to reliably restore the flatness of the ground surface layer with a single construction. Therefore, it is possible to prevent the inclination, the fall, and the collapse of the building constructed on the ground, and to maintain the designed function stably and fully over time.

Therefore, there is an advantage that construction work can be completed by one restoration work and post-construction work is not performed plural times, and the construction cost can be reduced. Moreover, in addition to the airport or road on the ground, Furthermore, the excellent effect that the function of the construct can be stably maintained is exhibited.

Then, according to the scale of repairing uneven settlement, inclination or depression, the pressure of the consolidation material, the mixing ratio, the number of stages,
Further, there is a degree of freedom that the design of the tension of the anchor can be changed as appropriate, and there is an effect that the versatility is extremely high.

At the present level, the compaction grouting technology has reached the perfection level almost completely in the actual construction work. Therefore, not only the ground restoration by the combined use of both can be surely performed, but also the ground surface layer There is also an effect that smooth concavo-convex molding can be appropriately performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the invention of this application.

FIG. 2 is a vertical cross-sectional view of another embodiment.

FIG. 3 is a vertical cross-sectional view of a general aspect of a compaction grouting method using a top-down method.

FIG. 4 is a cross-sectional view of anchor application to the construct.

FIG. 5 is a schematic cross-sectional view of an anchor.

[Explanation of symbols]

 3 Ground surface layer 7 Non-fluid and self-hardening solidifying material 2 Support layer 2'Ground 10 Anchor

Claims (4)

[Claims] 1. A low-slump, non-fluid, self-curing solidifying material having a low slump from the upper surface of the ground is pressed into a block of mutual joining through a plurality of steps into a space between the supporting layers, and the surrounding ground is compressed to a high density. In the method for ground restoration, the anchor is attached to the supporting layer from the ground surface before or after the non-fluid and self-hardening binder is injected. Ground restoration method. 2. The ground restoration method according to claim 1, wherein the plurality of steps are performed in a top-down manner. 3. The ground restoration method according to claim 1, wherein the anchors are connected to a level below the lowermost portion of the block. 4. The non-fluidic, self-hardening solidifying material is locally injected to anchor the anchor from another site. Ground restoration method.