JP2014111893A - Method and device for constructing hydraulic solidification material liquid-substituted column - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for constructing a hydraulic solidification material liquid-substituted column, which can constructing a substituted column free from inclusion of soil mass, the substituted column having a stable quality and improved in extraction yield strength regardless of the properties of a target ground, and having a uniform diameter from the leading end to the terminal end of the column.SOLUTION: An excavating auger having a supply passage for hydraulic solidification material liquid includes at least an excavating claw and a discharge port for the hydraulic solidification material liquid at the leading end thereof. The excavating auger is propelled to a predetermined depth with rotation by a construction device provided with an auger motor. Thereafter, the excavating auger is pulled up with or without rotation while discharging the hydraulic solidification material liquid mixed with magnesium carbonate from the discharge port to fill a predetermined section of an excavation part with the hydraulic solidification material liquid, and then a core material is inserted into the liquid while the hydraulic solidification material liquid is unhardened.

Description

  The present invention relates to a method for constructing a hydraulic solidifying material liquid replacement column used for the foundation of a relatively light structure such as a detached house, a low-rise building, or a dirt slab, and a relatively small size for constructing a hydraulic solidifying material liquid replacement column. It relates to the construction equipment.

Various types of soft ground have been developed that are suitable as the basis for relatively minor structures such as detached houses, low-rise buildings, and soil slabs.
For example, as in the deep mixing method, cement slurry or cement powder is stirred and mixed with the original ground to form a cylindrical soil cement solidified body in the ground, which is used as the foundation of the structure (for example, Patent Document 1). reference).

JP2003-247228A

  However, in the general deep mixing method shown above, if the soil of the ground to be constructed is organic soil or peat, solidification failure due to harmful components contained in the ground tends to occur, so a large amount of solidified material slurry is injected. Necessary. When the ground is highly viscous clay, the excavated clay lump adheres to the stirring device, and stirring and mixing does not proceed well, so that a so-called co-rotation phenomenon occurs, and the soil cement tends to be low-quality soil cement. In addition, if the ground is organic soil, you can get the required strength and quality by injecting a large amount of solidified slurry, but a large amount of generated residual soil is generated, not only increase the environmental load, Remaining soil disposal costs will increase and become uneconomical.

  The present invention has been proposed to solve such a problem, and its purpose is that there is little contamination of the soil in the replacement column, and it is not affected by the soil properties of the target ground, and it is stable. Another object of the present invention is to provide a method for constructing a hydraulic solidifying material liquid replacement column having a substantially uniform diameter from the lower end portion to the upper end portion of the replacement column and a construction apparatus thereof.

  In order to achieve the object, the hydraulic solidifying material liquid replacement column construction method shown in claim 1 includes at least a drilling claw and the water at the tip of the excavating auger having a hydraulic solidifying material liquid supply passage inside. The hard solidifying material liquid is provided with a discharge port of the hard solidifying material liquid, and the excavating auger is dug up to a predetermined depth while rotating (forward or reverse rotation) with an auger motor. While discharging from the discharge port, the excavation auger is pulled up while rotating (forward or reverse rotation) or without rotating, and a predetermined section of the excavation part is filled with the hydraulic solidified material liquid mixed with the magnesium carbonate. A hard solidifying material liquid replacement column is constructed, and a core material is arranged in the hydraulic solidifying material liquid replacement column.

With this configuration, it is possible to build a replacement column made of hydraulic solidifying material liquid, and this built-in hydraulic solidifying material liquid replacement column can be used while discharging the earth while rotating the excavating auger or depending on the shape of the excavating auger. After excavating to a predetermined depth with no or very low soil removal, supply the hydraulic solidified liquid mixed with magnesium carbonate to the predetermined section of the excavation part while rotating the excavation auger or without rotating it. And build. Therefore, unlike the deep mixing method, it does not involve agitation and mixing with the in-situ soil, so it will always be a column with the same or similar quality as the hydraulic solidification material liquid produced in the mixing plant, without selecting the soil quality and its properties. .
In the present invention, “non-exhaust soil” is naturally used as a term encompassing a case where there is no earth removal, but there is earth removal but the amount is extremely small compared to complete earth removal. Yes.

In addition, the hydraulic solidifying material liquid always causes bleeding after the replacement column is cast. If there is a large bleeding that requires the addition of hydraulic solidifying material liquid, the replacement column will have insufficient shape, so the hydraulic solidifying material liquid must be added and the amount of addition required. Become very large. Moreover, the pouring work must be waited until the bleeding is completed, so that the efficiency of the construction is greatly reduced, not only is troublesome, but also the bleeding of the added hydraulic solidifying material liquid may be unacceptable. . In order to take these measures, the construction period is extended, which in turn increases costs. In the present invention, since magnesium carbonate (basic magnesium carbonate) is mixed as a bleeding reducing material, the amount of bleeding can be reduced to such a small amount that the work is unnecessary, and the above problem can be solved.
Bentonite as a bleeding reducing material has the advantage of being easily available and relatively inexpensive, but the water absorption / swelling effect is reduced by the fact that the amount added must be relatively large and the order of introduction into the mixing plant. There is a problem. Magnesium carbonate is relatively expensive, but not only can a relatively small amount be mixed with the cement slurry to increase its viscosity and reduce bleeding, but it can also reduce bleeding termination time compared to using bentonite. it can. In addition, the magnesium carbonate here is defined as containing basic magnesium carbonate.

  The excavation auger for the construction of the hydraulic solidifying material liquid replacement column includes both a spiral screw auger and a excavation rod that does not have a mechanism for extruding excavation sediment to the side of the hole wall and discharging the excavation sediment to the ground. When using this screw auger type, rotate the screw auger and excavate while excavating the excavated soil on the ground, or reverse rotate the screw auger and excavate while pushing the excavated soil into the hole wall side, After reaching the predetermined depth, the hydraulic solidification material liquid is discharged from the discharge port, and the excavation auger is pulled up with or without being rotated, and the predetermined section of the excavation part is filled with the hydraulic solidification liquid. And build. Unlike a screw auger, when using a drilling rod type that has a simple cylindrical part that does not have screw-like wings at least on the side of the auger, even if the drilling rod is rotated during drilling, Excavated soil is not discharged to the ground but pushed to the side of the hole wall, and there is little or no generated residual soil discharged to the ground. In addition, since the hole wall is pressed by the excavation rod, the hole wall becomes strong, and the hole wall collapse is preferable.

  Further, with this configuration, it is possible to build a replacement column made of a hydraulic solidifying material liquid in which a core material is arranged. The hydraulic solidifying material liquid replacement column of the present invention can support a vertical load (downward load), but the column of the present invention cannot support a pull-out load (upward load) because of its low tensile strength. Absent. By inserting the core material into the column of the present invention, the pulling resistance can be greatly improved to a practical level. As the core material, reinforcing bars, iron bars, mold steel, steel pipes, FRP and the like can be used. Although a straight type is possible as a shape, it is more preferable to use a deformed type with a high anchor effect or to take measures to improve the adhesion of the core material itself or to increase the anchor effect, such as attaching an anchor plate.

  As a method of arranging the core material, after filling a predetermined section of the excavation portion with the hydraulic solidification material liquid, the replacement column of the hydraulic solidification material liquid is uncured, and the core is manually or mechanically attached to the replacement column. A method for inserting a material, and a core material is previously inserted in the excavation auger, and the excavation auger is rotated while discharging the hydraulic solidified material liquid from the discharge port while rotating the excavation auger. Examples thereof include a method of leaving the core material in the hydraulic solidifying material liquid filled in the section.

Moreover, the construction method of the hydraulic solidification material liquid replacement column shown in claim 2 is characterized in that the outer diameter of the excavation auger is 100 mm to 300 mm.
If the outer diameter of the excavating auger is less than 100 mm, the outer diameter of the column to be built is also less than 100 mm, and the vertical supporting force performance as the column is small, and the reliability of its continuity is low, so the load of the superstructure is supported It is unsuitable as a foundation structure. If the outer diameter of the excavation auger exceeds 300 mm, when using the excavation rod type, not only soilless construction will be difficult, but also the force to displace the ground sideways will increase, so adjacent peripheral structures There is a high possibility of causing problems such as deforming, deforming a replacement column immediately after construction in the vicinity, or causing collapse of the hole wall. In the case of the screw auger type that involves excavation of the excavated soil, the weight of the excavated earth and sand is added to the load when the auger is pulled up, increasing the burden on the small construction machine.

Further, the construction method of the hydraulic solidifying material liquid replacement column shown in claim 3 is characterized in that the rotation diameter of the excavation claw is not more than the rotation diameter of the excavation auger and does not protrude from the outer diameter of the excavation auger.
When the rotation diameter of the excavation claw is equal to or larger than the rotation diameter of the excavation auger, the excavation auger is improved, but the effect of the peripheral surface of the excavation auger pressing the excavation soil against the hole wall is reduced. Therefore, the hole wall is not strengthened and the possibility of hole wall collapse increases. Further, when the excavating auger is rotated (forward or reverse) or pulled up without being rotated, the portion of the excavating claw that protrudes from the auger rotation diameter of the excavating claw scrapes off the hole wall. As a result, the quality of the column will be deteriorated, such as the remaining clots remaining and the column shape diameters varying. On the other hand, if the rotation diameter of the excavation claw is made smaller than the rotation diameter of the excavation auger, the excavation performance of the excavation auger is lowered and the construction efficiency is lowered. Therefore, it is more desirable that the rotation diameter of the excavation claw is equal to or less than the rotation diameter of the excavation auger and is substantially the same as the rotation diameter of the excavation auger.

The construction method of the hydraulic solidifying material liquid replacement column according to claim 4 is characterized in that the excavation auger has a cylindrical shape in which at least a part or all of the peripheral side surface is flat.
The excavation auger used for this invention is demonstrated based on FIG. Note that the excavation augers shown in this figure all have hooks as shown in FIG. 2 (b) and the rotating body has an inverted conical shape, but are merely examples and have no particular meaning.
(A) Normal spiral auger (Fig. 4 (a)): A drilling auger having a function of actively discharging excavated soil to the ground by a spiral screw blade soil removal mechanism. The excavation excavation is good, but the amount of soil is the largest. The strength of the hole wall is the weakest.
(B) Thick shaft spiral auger (FIG. 4 (b)): By increasing the auger shaft diameter relative to the outer diameter of the spiral screw blade, the excavating soil can be removed while maintaining the excavability of the spiral screw blade. The function to press against the hole wall side is strengthened, and the amount of soil removal is less than (a) and more than (c). The strength of the hole wall is intermediate between (a) and (c).
(C) Cylindrical excavation auger (Fig. 4 (c)): The spiral screw blades are completely removed, and almost all of the earth and sand excavated by the excavation claws are pressed against the hole wall, thereby strengthening the hole wall and eliminating soil discharge. Drilling auger with the function of. The excavation ability is only the function of the excavation claw and has no soil removal function, so it is inferior to (a) and (b), but the amount of soil removal is the smallest and the strength of the hole wall is the strongest. The production cost of the excavation auger is the cheapest among (a), (b) and (c).
(D) Cylindrical excavation auger with spiral at tip (FIG. 4D): Improved excavation excavation in (c) by arranging spiral screw blades at the tip. Therefore, the tip has the function (a), and the other part has the function (c). The amount of soil removed is greater than (c) but less than (a) and (b). The strength of the hole wall is relatively weak in the spiral screw blade portion at the tip, but strong in the cylindrical portion. Therefore, a strong part and a weak part are mixed.
(E) Short cylindrical excavation auger (FIG. 4 (e)): The cylindrical portion of (c) is shortened, and a small-diameter rod that can be connected to an auger motor is connected to the upper part via a reducer. A cylindrical part with a large diameter is made the minimum necessary length, making it easy to handle during construction. Like (c), since there is no soil removal function, the amount of soil removal is small.
The fundamental technology for constructing a replacement column in the present invention is to reliably achieve the strength of the hole wall that controls the finished shape of the replacement column. The strength of the hole wall is stronger when the cylindrical excavation auger shown by (c), (d), and (e) is used than when the spiral screw blade shown by (a) and (b) is used.

  According to the construction of this fourth aspect, the excavation auger has a cylindrical shape with at least a part or all of the peripheral side surface of which is flat. There is very little or no generated residual soil discharged to the ground. In addition, since the surrounding ground is constantly pressed by the excavation auger, the hole wall becomes strong and the hole wall collapse hardly occurs. The cylindrical drilling auger has a flat and smooth peripheral wall when drilling, so the frictional force between the drilling auger and the drilling wall is not so great, and the hole wall collapses even when pulled up with rotation stopped. Since the hydraulic solidified material liquid corresponding to the lifting volume of the excavating auger is discharged from the tip of the excavating auger, no suction (negative pressure) that collapses the hole wall is generated. A hard solidifying material liquid replacement column can be built. In this way, the pore wall collapse is unlikely to occur, so there will be no or very little dirt clumps in the filled hydraulic solidification material liquid. As a result, the quality of the built replacement column will be good, and the water produced in the mixing plant will It is possible to build a replacement column of the same quality as hard solidified liquid or close to it.

Among them, in particular, the construction method of the hydraulic solidifying material liquid replacement column shown in claim 5 is characterized in that the bottom surface of the rotating body formed by the excavating claw when the excavating auger rotates is a flat horizontal surface.
Examples of the excavating claw include a flat plate shape (FIGS. 2A and 2C), a curved plate shape (FIG. 2D), and a spiral shape (FIG. 2E).
If the bottom surface of the rotating body formed by the excavation claws during rotation is a flat horizontal surface, the verticality during excavation is improved, and it is easy to ensure the verticality even if the excavation speed is increased. Therefore, the construction time per replacement column can be shortened.
Moreover, even if a part of the excavated earth and sand settles down and accumulates on the bottom of the column, it is dispersed on the bottom surface, so that the adverse effect on the tip support force can be reduced, which is preferable.
Further, it is more preferable to make the excavation claw in a curved plate shape or a spiral shape, since it has an effect of lifting the excavated earth and sand loosened by the excavation claw at the deepest part of the excavation hole when the excavation rod is pulled up.

According to a sixth aspect of the present invention, there is provided a method for constructing a hydraulic solidifying liquid replacement column, wherein the hydraulic solidifying liquid is mainly composed of Portland cement, blast furnace cement, fly ash cement, or cement-based solidifying material. The ratio is 50 to 150%.
The hydraulic solidifying material liquid used in the present invention may be mainly composed of cement generally used in construction work in Japan, and the water cement ratio is 50 to 150%, which is a measure of material strength. Is 3 to 10 N / mm ² . If the water-cement ratio is less than 50%, the amount of cement used per unit volume of the replacement column becomes large and uneconomical, and the viscosity is too high to be kneaded in a small mixing plant used in a small construction machine during construction. The load acting on the plant becomes high, which is not preferable. On the other hand, if the water-cement ratio exceeds 150%, the amount of bleeding of the hydraulic solidifying material liquid that occurs after the placement of the replacement column becomes large and the resulting shape is insufficient. It must be added, and the amount added will be extremely large. In addition, the pouring work must be waited until the bleeding is completed, so that the efficiency of the construction is greatly reduced and labor is required, and there is a case where the poured hydraulic solidifying material liquid causes an unacceptable bleeding. is there. In order to take these measures, the construction period is extended, which in turn increases costs. However, considering the load of the mixing plant and the degree of bleeding, the water-cement ratio is preferably 60% to 120% practically.

According to the construction method and construction apparatus of the hydraulic solidifying material liquid replacement column of the present invention, the following effects can be obtained.
(1) The construction method of the hydraulic solidifying material liquid replacement column shown in claim 1 does not stir and mix the hydraulic solidifying material liquid and the original ground (in-situ soil). Therefore, unlike the conventional deep mixing method, It is possible to build a high-quality column that is similar to or close to the hydraulic solidification material liquid produced at the mixing plant without being affected by the soil quality of the ground like organic soil.
The manufacturing method of the hydraulic solidification material liquid replacement column according to claim 1 is characterized in that a core material is disposed in the hydraulic solidification material liquid replacement column. Thereby, it is possible to obtain a hydraulic solidifying material liquid replacement column in which the pulling resistance is greatly improved by inserting (arranging) the core material into the column.
Further, in the construction method of the hydraulic solidifying material liquid replacement column according to the first aspect, since the magnesium carbonate is mixed in the hydraulic solidifying material liquid, the replacement column can be constructed with a small amount of bleeding. Magnesium carbonate is relatively expensive, but it not only has the effect of reducing bleeding as compared with bentonite, but it also terminates in a relatively short time than when using bentonite. Therefore, there is an advantage that a large working time can be taken within the working time of one day.
Magnesium carbonate has a thickening effect on the hydraulic solidifying material liquid. When using it, considering the workability such as pumpability, the water cement ratio of the hydraulic solidifying liquid and mixing of the bleeding reducing material are required. It is necessary to determine the amount.
(2) In the construction method of the hydraulic solidifying material liquid replacement column shown in claim 2, the outer diameter of the excavation auger is set in the range of 100 to 300 mm, so that the penetration resistance is reduced, and the excavation auger in the small construction machine The intrusion was made possible. In addition, since the diameter of the excavation auger is reduced, even when the excavation auger is inserted without soil removal, the influence of ground displacement in the ground is small. Can be prevented. Since the diameter of the excavating auger is 100 mm or more, the continuity of the replacement column is ensured, and the reliability as the support column is improved. In addition, since the construction equipment can be handled with a small size, it can be carried in and constructed even in a narrow area.

(3) Regarding the construction method of the hydraulic solidifying material liquid replacement column shown in claim 3, in the prior art (technique commonly practiced in the industry), the excavation auger is designed to improve its advanceability. A method of reducing the ground resistance acting on the peripheral side surface of the excavation auger by setting the rotation diameter of the excavation claw to be larger than the excavation auger diameter is generally known. Since the excavation performance of the excavation auger decreases as the rotation diameter of the excavation claw decreases, it is preferable that the rotation diameter of the excavation claw be substantially the same as the excavation auger diameter. Also, if the rotation diameter of the excavation claw is larger than the excavation auger diameter, the excavation claw will scrape the earth and sand of the hole wall when the excavation auger is pulled up, so that the cut soil mass remains in the replacement column, and the quality of the replacement column Decreases. The present invention can solve the above problems by preventing the rotation diameter of the excavation claw from protruding beyond the outer diameter of the excavation auger.
(4) The method for constructing the hydraulic solidifying material liquid replacement column according to claim 4 uses a cylindrical excavation rod type drilling auger with a flat peripheral surface at least partly or entirely of the excavation auger. Since there is no mechanism for extruding the earth and sand to the side of the hole wall and discharging the excavated earth and sand to the ground, there is little or no residual soil generated by drilling. In addition, since the hole wall surface is pressed to the side by the flat peripheral side surface of the excavation rod, the hole wall becomes strong and the hole wall does not easily collapse, so that a high-quality replacement column with less dirt mixing can be built. Moreover, since no spiral screw blade is required, the excavation rod type can be manufactured at low cost.
Furthermore, the excavation auger claw at the tip of the excavation auger can be bent or processed into a spiral shape, so that the excavation soil that has been excavated at the tip is held in the excavation claw, and the earth and sand can be lifted to the ground together with the excavation auger As a result, the quality of the tip of the replacement column can be improved. Therefore, the vertical supporting force as the column of the replacement column can be increased.

(5) In the method for building a hydraulic solidifying material liquid replacement column according to claim 5, the bottom surface of the rotating body formed by the excavation claw at the time of rotation is a flat horizontal surface, so that even when the excavation speed is increased, the excavation speed is increased. Therefore, it is easy to ensure the verticality of the structure, so that the construction efficiency is improved and the construction period can be shortened. In addition, if the bottom of the replacement column becomes flat, even if the excavated soil block settles down in the hydraulic solidified material liquid and accumulates on the bottom of the replacement column, it will become a single point as in the case of an inverted conical tip. Since concentration does not occur, it is possible to prevent a decrease in the tip support force, and thus increase the tip support force of the replacement column.
(6) The construction method of the hydraulic solidifying material liquid replacement column shown in claim 6 is such that the hydraulic solidifying material liquid is mainly composed of Portland cement, blast furnace cement, fly ash cement, or cement-based solidifying material, The water-cement ratio is 50% to 150%. When the water-cement ratio is less than 50%, the viscosity of the hydraulic solidifying material liquid becomes high, and in a relatively light mixing plant for a small construction machine, the load due to stirring resistance during kneading increases, and a grout pump Since the pressure-feeding resistance increases, it is difficult to use it in the construction work. Moreover, since the substantial amount of solidifying material used increases, the cost increases. In addition, when the water-cement ratio increases, the hydraulic solidified liquid bleeds after the replacement column is built, but when the amount of bleeding increases and the finished shape cannot satisfy the required length tolerance, the hydraulic solidified material Repair such as additional filling with liquid is required. Of course, if the water-cement ratio exceeds 150%, bleeding that is unacceptable will occur, but the hydraulic solidified liquid portion that is additionally filled also causes bleeding that becomes unacceptable, and therefore requires repair again. There's a problem. In addition, additional filling can be performed only after bleeding is almost completed, so not only will it take time to repair additional filling, but if the repair process must be carried out the next day, the construction period will be delayed and the construction cost will increase significantly. Occurs. The present invention can solve the above problems by setting the water cement ratio of the hydraulic solidifying material liquid to 50% to 150%. However, considering the load of the mixing plant and the degree of bleeding, the water-cement ratio is preferably 60% to 120% practically.

It is a front view which shows the construction apparatus which implements the construction method of the hydraulic solidification material liquid replacement column of this invention. It is a perspective view (a), (b), (c), (d), and (e) which expand and show the tip of a excavation rod type excavation auger which shows an embodiment of the invention from the bottom side. The perspective view (f) which expands and shows the front-end | tip of the other excavation auger of the excavation rod type which shows embodiment of this invention from the bottom face side, and the perspective view (g) which shows the unsuitable form which is not used in this invention. is there. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view (a), (b), (c), (d), (e) which shows the excavation auger which shows embodiment of this invention. It is explanatory drawing which shows the construction procedure of the hydraulic solidification material liquid substitution column construction method of this invention to process order (a), (b), (c), (d). It is explanatory drawing which shows the construction method which arrange | positions a core material, and is explanatory drawing (e) which shows a mode that a core material is arrange | positioned with a machine, and cross-sectional explanatory drawing (f) which shows the state which arrangement | positioning of a core material was completed. It is a front view which shows the excavation auger used in Example 1 of this invention. It is a graph which shows the time-dependent change of the bleeding rate of the hydraulic solidification material liquid (basic magnesium carbonate addition) of the plant collection of Example 1. FIG. It is explanatory drawing which shows the construction specification of Example 1 and Example 2 of this invention. It is a graph which shows the completed shape of the column in case of column length 3m of Example 1. FIG. It is a graph which shows the completed shape of the column in case the column length of Example 1 is 4m. In the graphs (A) and (B) of the supporting force performance of the test column of Example 1, (A) shows a case where the column length is 5.5 m, and (B) shows a case where the column length is 6.5 m. It is a graph which shows the time-dependent change of the bleeding rate of the hydraulic solidification material liquid (basic magnesium carbonate addition) of the plant collection of Example 2. FIG. It is a graph which shows the completed form of the column in case of column length 4m of Example 2. FIG. Graphs (A), (B), and (C) of the bearing capacity performance of the test column of Example 2, where (A) is a column length of 4.2 m, (B) is a column length of 5 m, and (C) is This is a case where the column length is 8 m. It is a graph which shows the relationship between a bentonite addition rate and bleeding amount. It is a graph which shows the relationship between a magnesium carbonate addition rate and bleeding amount. It is a graph which shows a time-dependent change of the bleeding rate of a hydraulic solidification material liquid (plain). It is a graph which shows the time-dependent change of the bleeding rate of the hydraulic solidification material liquid with bentonite addition. It is a graph which shows the time-dependent change of the bleeding rate of the hydraulic solidification material liquid to which basic magnesium carbonate is added.

  Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5. FIG. 1 is a front view showing a construction apparatus for carrying out the construction method of the hydraulic solidifying material liquid replacement column of the present invention, FIGS. 2 (a), (b), (c), (d), (e) and FIG. 3 (f) is a perspective view showing the excavation rod type excavation auger according to the embodiment of the present invention as viewed from the bottom side, and an enlarged view as seen from the bottom side. FIG. 3 (g) is used in the present invention. It is a perspective view which shows the form which is not suitable. FIG. 2 (a) shows a drilling claw with a flat bottom portion of the excavation auger tip when rotated, FIG. 2 (b) shows a drilling claw with a conical shape of the excavation auger tip when rotated, and FIG. A drilling claw with a bottom that is substantially flat when rotating at the tip of the drilling auger, and a drilling claw that has been cut into the drilling auger shaft center position of the drilling claw tip so that the column center alignment is easy during construction. (D) is a curved plate-shaped excavation claw showing a flat horizontal surface at the bottom, (e) is an excavation claw showing a flat horizontal surface with a spiral bottom, and FIG. 3 (f) is FIG. Excavation claw with the rotation diameter of the excavation claw made smaller than the rotation diameter of the excavation rod by deformation of the type, (g) is also the deformation of FIG. It is the perspective view which showed the excavation nail | claw which protruded more. 4 (a), (b), (c), (d), and (e) are front views of the excavation auger showing an embodiment of the present invention. (A) is a spiral auger, (b) is a thick shaft auger, (c) is a cylindrical excavating auger, (d) is a cylindrical excavating auger with a spiral at the tip, and (e) is a short cylindrical excavating. Indicates an auger.

The excavation auger 1 of the present invention is hollow and the inside of the hollow is a hydraulic solidifying material liquid as shown in FIGS. 2 (a), (b), (c), (d), (e) and FIG. 3 (f). Supply passage 5. When the outer diameter of the excavation auger is relatively small, the hollow interior may be used as a direct supply passage. However, when the outer diameter of the excavation auger is relatively large, an inner pipe 5a dedicated to the supply passage is provided as shown in FIG. It is preferable to provide it. This is to prevent the flow of the hydraulic solidifying material liquid from being hindered by the change in the diameter of the hollow portion between the main body portion and the joint portion of the excavating rod, and to facilitate the cleaning work after the completion of construction. is there. The excavation auger 1 includes a discharge port 4 communicating with an excavation claw 2 and a hydraulic solidifying material liquid supply passage 5 at the tip. The discharge port 4 can be provided on the peripheral side surface of the distal end portion of the excavation auger, but is preferably provided on the bottom surface of the distal end portion of the excavation auger. This is because when the excavation auger is pulled up, the hydraulic solidification material liquid is discharged from the discharge port and replaced, so that the suction (suction phenomenon) at the time of lifting the excavation auger is easy and the discharge port is provided on the peripheral side surface. This is because the hole wall may be collapsed by the discharge pressure when discharging the hydraulic solidifying material liquid. And while excavating this excavation auger 1 with the construction apparatus 6 provided with the auger motor 8 as shown in FIG. 1 or excavating to a predetermined depth without excavation, the excavation auger 1 is rotated. Alternatively, the hydraulic solidifying material liquid is supplied from the hydraulic solidifying material liquid supply passage 5 while being pulled up without being rotated, and discharged from the discharge port 4, and a predetermined section of the excavation part is filled with the hydraulic solidifying material liquid. Build a replacement column of hard solidifying liquid.
In addition, the upper part of the excavation auger 1 shown to Fig.4 (a), (b), (c), (d), (e) is shown thinner than the excavation auger outer diameter. This is because the outer diameter of the excavating auger is determined from the column diameter or workability, while the upper part of the excavating auger 1 needs to be connected to the auger motor 8, so that the penetration type auger motor 8 has a diameter that can be chucked. This is for illustration.
The excavation auger will be described in detail with reference to FIG. The pawls of the excavation auger shown in this figure are all bowl-shaped and the rotating body has an inverted conical shape, but are merely examples and have no particular meaning.
FIG. 4A: Normal spiral auger. Excavation auger that has the function of actively discharging excavated soil to the ground by the spiral screw blade soil removal mechanism. The excavation excavation is good, but the amount of soil is the largest. The strength of the hole wall is the weakest.
FIG. 4 (b): Shaft thick spiral auger. By making the shaft relatively large with respect to the outer diameter of the spiral screw blade, the function of pressing the excavated earth and sand against the hole wall side is enhanced while maintaining the excavability of the spiral screw blade. The amount of soil discharged is smaller than that in FIG. 4A and larger than that in FIG. The strength of the hole wall is intermediate between FIG. 4 (a) and FIG. 4 (c).
FIG. 4C: Cylindrical excavation auger. A drilling auger with the function of strengthening the hole wall and having no soil removal by completely removing the spiral screw blades and pressing almost all of the earth and sand excavated by the drilling claws to the hole wall side. Since the excavation ability is only the function of the excavation claw, it is inferior to that of FIGS. 4 (a) and 4 (b), but the amount of soil removal is the smallest and the strength of the hole wall is the strongest.
FIG. 4D: Cylindrical excavation auger with a spiral at the tip. FIG. 4 (c) improves the excavation ability by arranging a spiral screw blade at the tip. Therefore, the tip has the function of FIG. 4A, and the other parts have the function of FIG. 4C. The amount of soil discharged is larger than that in FIG. 4C, but smaller than that in FIGS. 4A and 4B. The strength of the hole wall is relatively weak in the spiral screw blade portion at the tip, but strong in the cylindrical portion. Therefore, a strong part and a weak part are mixed.
FIG. 4 (e): A short cylindrical excavation auger. The cylindrical part of FIG.4 (c) was shortened, and the small diameter rod which can be connected to an auger motor was connected to it via the reducer above it. A cylindrical part with a large diameter is made the minimum necessary length, making it easy to handle during construction. Since there is no soil removal function like FIG.4 (c), there is little soil removal amount. The strength of the hole wall is stronger than when the spiral screw blade shown in FIGS. 4 (a) and 4 (b) is used, but when the cylindrical excavation auger shown in FIG. 4 (c) and FIG. 4 (d) is used. Is stronger.

  An example of the construction apparatus 6 will be described with reference to FIG. The construction device 6 includes a leader 7 that can be raised and lowered. A slide plate 10 is slidably provided along the leader 7 on the leader 7, and an auger motor 8 is fixed to the slide plate 10. A swivel 9 is connected to the upper end of the excavating auger 1 connected to the digging auger 1. A feeding device (not shown) is connected to the slide plate 10 so that it can move forward and backward along the reader 7. The excavation auger 1 is connected to and attached to an auger motor 8. Therefore, the excavation auger 1 can be rotated by driving the auger motor 8, and since the auger motor 8 is fixed to the slide plate 10, the slide plate 10 is driven by a feeding device (not shown). The excavation auger 1 can be advanced and retracted together with the auger motor 8 by being advanced and retracted along 7. As the feeding device, a chain or a cylinder that is suspended and driven by sprockets provided at the upper end or the lower end of the leader 7 can be exemplified. By connecting the rod of the chain or cylinder to the slide plate 10, the slide plate 10 You can move forward and backward. When the predetermined depth is not reached in one feeding operation, the chuck part of the excavation auger is re-grown or the excavation auger is added.

Thus, the excavation auger 1 can dig while rotating into the ground by moving the slide plate 10 downward along the leader 7. After excavating to a predetermined depth, the excavation auger 1 moves the slide plate 10 along the leader 7. Thus, the hydraulic solidified liquid can be supplied to the supply passage 5 of the excavating auger 1 through the swivel 9.
The excavation auger 1 can be rotated or stopped by driving or stopping the auger motor 8, so that the excavation auger 1 is excavated or pulled up while rotating the excavation auger 1 or is not rotated. Or it can construct by selecting suitably raising.

  Thus, according to the construction apparatus 6, after the excavation auger 1 is attached to the auger motor 8 and excavated to a predetermined depth, the hydraulic aggregating agent liquid supply passage is rotated while the excavation auger 1 is rotated or not rotated. Hydraulic solidifying material liquid mixed with magnesium carbonate is supplied from 5, discharged from the discharge port 4, and a hydraulic solidifying material liquid replacement column for filling a predetermined section of the excavation part with the hydraulic solidifying material liquid mixed with magnesium carbonate. It becomes possible to implement the building method.

Next, an embodiment of the excavation auger will be described with reference to FIGS.
The excavation auger 1 of the embodiment shown in FIGS. 2 (a), (b), (c), (d), (e) and FIG. 3 (f) is hollow, and the inside of the hollow is a hydraulic solidifying material liquid. Supply passage 5. When the outer diameter of the excavating auger is relatively large, an inner pipe 5a is separately provided as a supply passage as shown in FIG. At the tip of the excavation auger 1, a discharge port 4 communicating with the excavation claw 2 and the hydraulic solidifying material liquid supply passage 5 is provided. For example, as shown in FIG. 2A, the discharge port 4 is closed by two semicircular synthetic rubber sheets 14 and 14 each having a circular arc side fixed to the bottom of the tip of the excavating auger 1, and the two sheets are combined. The rubber sheets 14 and 14 are joined at the center 14a, and can be opened and closed by deformation due to the flexibility of the synthetic rubber sheets 14 and 14. Therefore, during excavation auger excavation, the discharge port 4 is closed by the synthetic rubber sheets 14 and 14, but when the hydraulic solidifying material liquid is supplied from the supply passage 5 and pressurized, the synthetic rubber sheets 14 and 14 open. Thus, the hydraulic solidifying material liquid is discharged. As a result, the hydraulic solidifying material liquid can be discharged from the discharge port 4, but it is possible to prevent the excavated soil from entering the discharge port 4 during excavation. In order to enhance the effect of preventing the intrusion of earth and sand during excavation, it is preferable to increase the rigidity by applying a batten 14b with a steel material at the joint portion of the semicircular synthetic rubber sheets 14, 14.

This excavation auger 1 can also be implemented by a spiral screw type excavation auger as shown in FIG. 4 (a). However, when a spiral screw type auger is used as the excavation auger, the excavation earth and sand are removed in the forward rotation. Due to the structure's aggressive discharge to the ground, residual soil is generated, and the amount is almost the same as the volume of the replacement column. In addition, since the excavated earth and sand are discharged to the ground, the force for pressing the hole wall to the side is weak, and therefore, the hole wall is not strengthened and is liable to collapse compared to other excavation augers. There is a method of using a spiral screw type auger to excavate the ground while suppressing the earth removal and reinforcing the hole wall while rotating the hole wall sideways with the spiral screw type auger in the reverse rotation. After excavating to a predetermined depth, the hydraulic solidification liquid is discharged from the discharge port, and the excavation auger is pulled up with or without rotation, and the predetermined section of the excavation part is filled with the hydraulic solidification liquid. Thus, it is preferable to construct a hydraulic solidifying material liquid replacement column because the excavated earth and sand are not dropped into the replaced hydraulic solidifying material liquid.
By this method, it is possible to prevent the perforated wall soil from falling into the filled hydraulic solidified liquid, and as a result, it is possible to build a replacement column of almost the same quality as the hydraulic solidified liquid produced in the mixing plant, and good quality Column.

Further, the excavation auger 1 preferably has an outer diameter of 100 mm to 300 mm. When the excavation auger 1 having an outer diameter of 100 mm to 300 mm is used to construct a hydraulic solidifying material liquid replacement column, the replacement column to be constructed has an outer diameter of 100 mm to 300 mm which is substantially equal to the outer diameter of the excavation auger 1. However, as shown in FIGS. 4 (c), (d), and (e), when a drilling auger having a small excavating property is used, especially in a viscous ground, the drilling hole returns elastically, and the diameter of the drilling hole is increased. There is a phenomenon that becomes smaller than the outer diameter of the rotating diameter of the excavating auger.
When the outer diameter of the excavating auger 1 is less than 100 mm, the outer diameter and the cross-sectional area of the replacement column to be built are small, so that the reliability of the continuity of the replacement column as a column becomes low when the elastic return of the excavation hole is taken into consideration. . In addition, since the replacement column without inserting the core material is an unmuscle, the smaller the outer diameter, the larger the length-to-length ratio and the lower the reliability as the column. Moreover, when an outer diameter is less than 100 mm, in order to support the same structure, it is necessary to drive a relatively large number of replacement columns, which takes time for construction.
When the outer diameter of the excavation auger 1 exceeds 300 mm, the excavation resistance increases, so that it becomes difficult to perform excavation without using a excavation auger having a flat peripheral side surface by a small construction machine. Moreover, even if non-excavated excavation becomes possible, a large amount of earth and sand is pressed to the side, so that the surrounding ground may be displaced and surrounding structures such as retaining walls may be deformed.
As mentioned above, as the excavation auger 1 used for the construction method of the hydraulic solidification material liquid substitution column of this invention, it is preferable that an outer diameter is 100 mm-300 mm.

Further, examples of the excavation claw provided at the tip of the excavation auger 1 include a hook shape, a flat plate shape, a curved plate shape, and a spiral shape. If the excavation claw has a bowl shape, the shape of the rotating body becomes a conical shape. The tip claw shape of the present invention may be bowl-shaped as shown in FIG. 2 (b), but when excavated earth or the like remains in the replacement column and settles, it accumulates at the tip portion and easily accumulates at the bottom end portion of the cone shape. . In this case, the tip end portion is liable to have poor quality, and the tip support force as a replacement column may be reduced. It is preferable to make the shape of the rotary claw at the tip of the excavation claw flat and horizontal when rotating, because it is possible to prevent the remaining and mixed excavated earth and sand from being concentrated on one point at the lower end of the column. Further, it is preferable to process the excavation claw into a curved plate shape or a spiral shape because excavation earth and sand at the lowest depth can be held on the excavation claw and the excavation earth and sand can be easily discharged to the ground.
FIG. 2A shows a flat excavation claw 2. The bottom surface of the excavation hole formed by the rotation of the lowermost end 2a of the excavation claw 2 forms a flat horizontal plane, and the rotation diameter of the excavation claw 2 is equal to or less than the rotation diameter of the excavation auger 1. The structure does not protrude beyond the diameter. As shown in FIG. 3 (g), when the excavating claw 2 has a larger diameter portion 3 than the excavating auger 1 and protrudes from the outer diameter of the excavating auger 1, the effect of pressing the peripheral surface of the excavating auger against the hole wall decreases during excavation. It disappears and the hole wall is not strengthened. Further, when the excavation auger is pulled up, the excavation claw scrapes off the hole wall and remains in the hydraulic solidification material liquid filled with the earth and sand that has been scraped off, so that the quality of the replacement column is deteriorated. On the other hand, when the rotation diameter of the excavation claw 2 is made smaller than the rotation diameter of the excavation auger 1, the excavation performance is deteriorated. Therefore, it is more preferable that the end in the circumferential direction of the excavation claw 2 is arranged so as to substantially coincide with the peripheral surface of the main body of the excavation auger 1 from the viewpoint of ensuring excavation performance.

The excavation auger 1 shown in FIGS. 2 (d) and 2 (e) is a case where the excavation claw 2 provided at the tip has a curved plate shape and a spiral shape, respectively. 2b constitutes a flat horizontal plane.
When the excavation claw 2 has a curved plate shape or spiral shape as in this example, the excavation soil loosened at the tip is held in the excavation claw, and the excavation soil is pulled up to the ground together with the excavation auger. It is possible to prevent dirt from being mixed at the tip of the slab and improve the quality. Therefore, there is an advantage that the vertical supporting force as the column of the replacement column can be improved, which is preferable.

Next, the construction procedure of the hydraulic solidifying material liquid replacement column construction method of the present invention will be described with reference to FIG.
First, as shown in FIG. 5 (a), the excavation auger 1 is attached to the auger motor 8 of the construction device 6, the excavation auger 1 is set vertically along the leader 7, and the excavation claw center and the drilling position (column) of the excavation auger 1 are arranged. Set them so that their hearts match.
Next, as shown in FIG. 5B, the excavation auger 1 is excavated while rotating (forward rotation or reverse rotation). This is performed by rotating the auger motor 8 and moving the slide plate 10 (see FIG. 1) downward along the reader 7. As shown in FIG. 5B, when the excavation reaches a predetermined depth, or from the vicinity of the predetermined depth, discharge of the hydraulic solidifying material liquid from the discharge port 4 is started. When the excavating auger 1 reaches a predetermined depth, the vertical movement of the excavating auger 1 is stopped and the rotation continues until it is confirmed that the hydraulic solidification liquid is discharged from the discharge port 4. It is desirable to ensure wall reinforcement and tip replacement.

  Next, after starting the discharge, as shown in FIG. 5C, the excavation auger 1 is discharged while discharging the hydraulic solidified material liquid while rotating (forward or reverse) the excavation auger 1 or without rotating. When 1 is pulled up and the hydraulic solidification material liquid filling in the predetermined section is completed, the excavation auger 1 is further pulled up to complete the construction of the hydraulic solidification liquid replacement column. The predetermined section here is the replacement column length to be constructed, but may be a filling section of the hydraulic solidifying material liquid in consideration of the bleeding amount of the hydraulic solidifying material liquid. The excavation auger 1 is pulled up by moving the slide plate 10 upward along the leader 7 so that the auger motor 8 is pulled up together. At this time, the pulling speed is such that the discharge amount (volume) of the hydraulic solidifying material liquid is 1.0 to 1.5 times the hole volume generated under the excavating claw 2 by pulling the excavating auger 1 per unit time. Adjust. This is because the hydraulic solidification material liquid is always filled with the excavation auger 1 so that no gap is generated under the excavation claw 2 by pulling up the excavation auger 1. If the discharge amount of hydraulic solidifying material liquid is small, suction is induced, and when suction occurs, hole wall collapse is induced in order to eliminate the suction, and not only soil blocks are mixed in the replacement column, but in some cases, The required column shape may not be secured, which is not preferable because the quality of the replacement column is lowered.

  When the excavation auger 1 is pulled up and the hydraulic solidification material liquid is discharged to fill the hydraulic solidification material liquid in a predetermined section, the discharge of the hydraulic solidification material liquid is stopped, and the excavation auger 1 is further pulled up to the ground. FIG. 5D shows a state where the construction is completed. In FIGS. 5C and 5D, reference numeral 12 denotes a portion of the hydraulic solidifying material liquid filled in the excavation hole. The filled hydraulic solidifying material liquid is solidified to form a replacement column.

Further, when the core material is arranged on the replacement column, it can be constructed manually or by a machine. An example of the embodiment will be described with reference to FIGS. FIG. 6E is an explanatory diagram illustrating a state in which the core material is disposed by a machine, and FIG. 6F is a cross-sectional explanatory diagram illustrating a state in which the core material has been disposed.
After the predetermined section of the excavation part is filled with the hydraulic solidifying material liquid 12 by the construction method shown in FIGS. 5A to 5D, the replacement column of the hydraulic solidifying material liquid 12 is uncured. 6 (e), the construction material 6 is used to insert the core material 11 into the replacement column (uncured hydraulic solidifying material liquid 12). Thereby, as shown in FIG.6 (f), the replacement column which has arrange | positioned the core material 11 can be built.

  After construction, the position of the replacement column head after the hydraulic solidification liquid is discharged or bleeding and the hydraulic solidification liquid is solidified becomes lower than the predetermined depth (position) or lower. In this case, the excavation hole is additionally filled with a hydraulic solidifying material liquid. When the hydraulic solidifying material liquid is additionally filled, it may be carried out by a construction machine, but may be filled manually by using a separate bucket or the like.

  If the hydraulic solidifying liquid causes bleeding or water loss, it needs to be repaired later, which is troublesome. In addition, if the time until the bleeding is completed is long, the repair work may have to be postponed from the next day, which delays the construction period and increases costs, and is annoying in subsequent processes such as foundation slab placement. Will be applied. In order to avoid such a situation, a bleeding reducing material may be mixed with the hydraulic solidifying material liquid. In this example, magnesium carbonate (basic magnesium carbonate) is used as a bleeding reducing material. Bentonite is also known, but bentonite is readily available on the market and is relatively inexpensive depending on the variety, but requires a relatively large amount of blending, and as the amount blended increases, the compressive strength after curing decreases. . In addition, there is a feature that the bleeding reduction effect is lowered by the order of introduction into the mixer. On the other hand, compared to bentonite, magnesium carbonate (basic magnesium carbonate) exerts the same effect with a relatively small amount of mixing, so that the workability for producing a hydraulic solidifying material liquid with reduced bleeding amount is improved. . Moreover, since the bleeding end time of the hydraulic solidifying material liquid mixed with magnesium carbonate (basic magnesium carbonate) is shorter than that of bentonite, workability is good.

  Next, the present invention will be described in more detail with reference to examples.

1. Ground G3:
In the ground G3, 1 m of topsoil is embankment made of cohesive soil, clay of N value 1-4 is deposited at a layer thickness of about 3 m below it, and sand of N value 2-3 is about 2 m below it. Deposited in layer thickness.
2. Drilling auger:
As the excavation auger, the cylindrical excavation auger shown in FIG. 7 and Table 1 was used. The diameter of the cylindrical part of this auger was 216.3 mm, and a tip-shaped excavation claw was attached.

３．水硬性固化材液
（ａ）使用材料
使用材料は、早強ポルトランドセメント（Ｃ）及び塩基性炭酸マグネシウム（Ｍ）とした。塩基性炭酸マグネシウムは、施工後の水硬性固化材液（スラリー）のブリーディングによる硬化体上面の沈降を防ぐ目的で混和している。
（ｂ）配合
水硬性固化材液の配合は、表２に示すように、Ｗ／Ｃは８０％、Ｍ／Ｃは２％とした。なお、Ｗは水を指す。

3. Hydraulic Solidifying Material Liquid (a) Material Used The materials used were early strong Portland cement (C) and basic magnesium carbonate (M). Basic magnesium carbonate is mixed for the purpose of preventing sedimentation of the upper surface of the cured body due to bleeding of the hydraulic solidifying material liquid (slurry) after construction.
(B) Blending As shown in Table 2, the blending of the hydraulic solidifying material liquid was 80% for W / C and 2% for M / C. W represents water.

(C) Bleeding amount The bleeding amount of the hydraulic solidifying material liquid (slurry) collected from the plant was 0% after 20 hours from kneading as shown in FIG. When no anti-bleeding material is added, about 20% of bleeding occurs in the cement slurry with W / C = 80%, indicating that the basic magnesium carbonate sufficiently functions as a anti-bleeding material.
(D) compressive strength at the age of 28 days compressive strength hydraulic solidifying material liquid (slurry), as shown in Table 3, in the plant harvested 13.5 N / mm ^2, the test column taken at 12.5 N / mm ² Yes, both showed almost the same strength. This value was higher in strength than when bentonite was used as a bleeding reducing material although there was a difference in W / C.

4). Test Column Construction Details As shown in Table 4, six test columns were constructed, with two column lengths of 3 m and 4 m each and one column length of 5.5 m and 6.5 m each.
For columns with column lengths of 3.0 m and 4.0 m, immediately after building the column, a steel rod with a bearing plate that is slightly longer than the entire length of the column as the core (bearing plate diameter 150 mm, bearing plate thickness 6 mm, steel rod diameter 35 mm) ) Was manually inserted to the bottom of the column.

5. Construction specifications As shown in FIG. 9, the test column construction is carried out at a digging speed of 2.0 m / min while rotating in the forward direction, and when reaching a predetermined depth, the hydraulic solidification liquid is discharged and stopped at the forward rotation for 30 seconds. After that, it was pulled up while discharging the hydraulic solidifying material liquid at a pulling speed of 1.2 m / min while rotating forward. The discharge amount of the hydraulic solidifying material was 45 to 50 l / min. This is a discharge amount of 1.0 to 1.1 times the pore volume. The excavation auger was pulled up to the ground and completed.

6). Fig. 10 and Fig. 11 show the results of the test column. As the result of the column, the built column was pulled out, the diameter was measured, and compared for each column length. In order to pull out the column and investigate the finished shape, a deformed bar was inserted to the end of the column immediately after construction.
In all the columns, the diameter tends to be slightly larger at the surface (upper end), but the depth variation is small beyond that, and the “finished diameter / construction diameter” is close to 1.0. A stable column can be built.

7). Pull-out load Table 5 shows the pull-out load when pulling out the test column. In the case of column lengths of 3 m and 4 m, the extraction load was about 60 to 70 kN.

8). Supporting force performance The results of the indentation test conducted for the column lengths of 5.5 m and 6.5 m in Table 4 for grasping the supporting force performance of the test column are shown in FIGS. If the maximum load until the displacement of the column head reaches 10% (20 mm) of the column diameter (about 200 mm) is the ultimate support force, the ultimate support force is 174.1 kN when the column length is 5.5 m, and the column length is 6 In the case of 0.5 m, it was 225.0 kN.

1. Ground G4:
In the ground G4, a loam layer having an N value of 3 to 6 is deposited with a layer thickness of about 5 m, and a sand layer having an N value of 3 to 4 continues below the loam layer.
2. Drilling auger:
The same cylindrical excavation auger as in Example 1 was used as the excavation auger. The diameter of the cylindrical part of this auger was 216.3 mm, and a tip-shaped excavation claw was attached.
3. Hydraulic Solidifying Material Liquid (a) Material Used The materials used were early strong Portland cement (C) and basic magnesium carbonate (M) as in Example 1. Basic magnesium carbonate is mixed for the purpose of preventing sedimentation of the upper surface of the cured body due to bleeding of the hydraulic solidifying material liquid (slurry) after construction.
(B) Blending As shown in Table 6, the blending of the hydraulic solidifying material liquid was 80% for W / C and 1% for M / C. W represents water.

(C) Bleeding amount As shown in FIG. 13, the bleeding amount of the hydraulic solidifying material liquid (slurry) collected from the plant was almost 0% after 20 hours from kneading. When no anti-bleeding material is added, about 20% of bleeding occurs in the cement slurry with W / C = 80%, indicating that the basic magnesium carbonate sufficiently functions as a anti-bleeding material.
(D) compressive strength at the age of 28 days compressive strength hydraulic solidifying material liquid (slurry), as shown in Table 7, the plant collected 14.14N / mm ^2, the test column taken at 14.08N / mm ² Yes, both showed almost the same strength as in the example. This value was higher than that in the case of using bentonite as a bleeding reducing material as in Example 1.

4). Test Column Construction Details As shown in Table 8, the test column was constructed with two column lengths of 4 m, a column length of 4.2 m, a column length of 5 m, and a column length of 8 m.
For columns with a column length of 4 m, immediately after the column is built, a steel rod with a bearing plate (bearing plate diameter 150 mm, bearing plate thickness 6 mm, steel rod diameter 35 mm) slightly longer than the entire length of the column as a core is manually Inserted with.

5. Construction specifications As shown in FIG. 9, the test column construction is carried out at a digging speed of 2.0 m / min while rotating in the forward direction, as shown in FIG. The rotation was stopped for 30 seconds in the normal direction, and then the cylinder was pulled up while discharging the hydraulic solidifying material liquid at a pulling speed of 1.2 m / min while rotating in the normal direction. The discharge amount of the hydraulic solidifying material was 45 to 50 l / min. The excavation auger was pulled up to the ground and completed.

6). Fig. 14 shows the result of the test column. As the result of the column, the built column was pulled out, the diameter was measured, and compared for each column length. In order to pull out the column and investigate the finished shape, a deformed bar was inserted to the end of the column immediately after construction.
In all the columns, the diameter tends to be slightly larger at the surface (upper end), but the depth variation is small beyond that, and the “finished diameter / construction diameter” is close to 1.0. A stable column can be built.

7). Pull-out load The pull-out load of the test column was 70.65 kN and 83.75 kN with a column length of 4 m.

8). Bearing force performance The results of indentation tests conducted on columns with a column length of 4.2 m, 5 m, and 8 m for grasping the bearing force performance of the test column are shown in FIGS. 15 (A), (B), and (C). Assuming that the maximum load until the displacement of the column head reaches 10% (20 mm) of the column diameter (about 200 mm) is the ultimate support force, the ultimate support force is 135.4 kN when the column length is 4.2 m, and the column length is 5 m. In the case of 190.3 kN, the column length was 8.0 m and 245.5 kN.

  In order to examine the performance of the bleeding reducing material (agent) with respect to the hydraulic solidifying material liquid, the test was carried out by changing the bleeding reducing material (agent) type, the water cement ratio (W / C), the addition amount, and the like. The bleeding reduction grades are basic magnesium carbonate and bentonite as a comparative example. Water cement ratio (W / C) is 4 levels from 60% to 120% in increments of 20%, and the addition rate is changed depending on the breeding reducing agent (agent) type, but 3 levels each except for the plain with no additive It was. Table 9 shows the factors and levels of the bleeding test.

  Table 10 shows the final bleeding rate and the time required to reach 90% as a result of the bleeding test.

The bleeding rate of plain without adding a bleeding reducing material is 11.0% when W / C = 60%, and 44.9% when W / C = 120%. As the W / C increases, the bleeding rate increases. Yes. If a hydraulic solidification liquid without adding bleeding reducing material is used for the replacement column according to the present invention, subsidence of the column head surface that cannot be ignored after construction occurs, so additional supplementation of the hydraulic solidification liquid is necessary. , Useless work and cost increase.
When bentonite is used as a bleeding reducing material, the bleeding rate is W / C = 60%, B / C = 5% is 4.1%, B / C = 20% is 0.0%, and W / C = 120%, B / C = 5%, 25.0%, B / C = 20%, 3.7%. The bleeding ratio increases as W / C increases, but its absolute value. Is significantly lower than the plain. FIG. 16 shows the relationship between the bentonite addition rate and the bleeding rate.
The bleeding rate when using basic magnesium carbonate as a bleeding reducing material is W / C = 60%, M / C = 1% is 2.2%, M / C = 4% is 0.0%, Although W / C = 120%, M / C = 1% 22.8%, M / C = 4% 4.1%, the bleeding rate increases as W / C increases. Its absolute value is significantly lower than that of the plane. FIG. 17 shows the relationship between the addition rate of basic magnesium carbonate and the bleeding rate. Bentonite and basic magnesium carbonate have an addition ratio of 5: 1, but the bleeding reduction effect is almost the same. In other words, basic magnesium carbonate exhibits the same bleeding reduction effect with an addition amount of 1/5 of bentonite.

About the result of having investigated the time-dependent change of the bleeding rate of a hydraulic solidification material liquid, FIG. 18 shows a plain, FIG. 19 shows the case of adding bentonite, and FIG. 20 shows the case of adding basic magnesium carbonate.
As shown in FIG. 18, the plain increases linearly after kneading the hydraulic solidifying material liquid at any W / C from 60% to 120%, and the breathing ends in about 3 hours. ing.
As shown in FIG. 19, the addition of bentonite increases after kneading the hydraulic solidifying material liquid in any W / C and B / C except for the addition rate of 20% where the W / C is 60% and 80%. It will end in approximately two and a half hours to three hours. Although the end time of breathing is slightly shorter than in the case of the plane, the end time cannot be shortened much. Bleeding did not occur when the W / C was 60% and the addition rate was 20% and 20%.
As shown in FIG. 20, the addition of basic magnesium carbonate has a relatively large W / C (100 to 120%), and a small addition rate (1 to 2%) completes bleeding in 30 minutes to less than 1 hour. . Bleeding does not occur at other W / C and addition rates, or even if it occurs, the breathing rate is a small value of about 0.05 (5%) or less.
When no bleeding reducing material is added to the hydraulic solidifying material liquid, the bleeding rate increases with W / C, and the value is 0.1 (10%) to 0.45 (45%), causing a very large bleeding. To do. Therefore, since the solidified surface of the hydraulic solidifying material liquid is lowered by bleeding after the replacement column is cast, additional replenishment of the hydraulic solidifying material liquid is required, which increases labor. Further, since it takes about 3 hours to finish bleeding, the replenishment work must be performed on the next day, and the construction period is extended, resulting in problems such as increased construction costs. Further, in the case of a hydraulic solidifying material liquid having a high bleeding rate, there is a problem that the replenished hydraulic solidifying material liquid itself causes bleeding again.
When bentonite is used as a bleeding reducing material, if W / C is relatively small and the addition rate is 10 to 20%, it is possible to suppress the bleeding rate that does not require additional replenishment of the hydraulic solidifying material liquid. Become. Since the amount of addition is larger than that of basic magnesium carbonate, there is a problem that it takes time to handle at the construction site. In addition, bentonite has a variation in the bleeding reduction effect due to the mixing order with cement in the mixing plant, and because the bleeding termination time is long, the replacement column constructed just before the end of the day's work causes a large amount of bleeding on the next day. There is also the problem of having to replenish it.
When using basic magnesium carbonate as a bleeding reducing material, if W / C is relatively small and the addition rate is 1 to 2%, it should be suppressed to a bleeding rate that does not require additional replenishment of the hydraulic solidifying material liquid. Is possible. Compared with bentonite, since the addition amount is small, there is an advantage that handling at the construction site is easy. In addition, since the ending time of bleeding is short, there is an advantage that various problems described with bentonite do not occur.

  In the present invention, there is no dirt in the replacement column, it is not affected by the properties of the target ground, a stable replacement column can be built, and the hydraulic property has a uniform diameter from the tip to the end of the replacement column. Since the solidifying material liquid replacement column can be built, it is useful as the foundation of the structure.

DESCRIPTION OF SYMBOLS 1 Excavation auger 2 Excavation claw 3 Protrusion 4 Discharge port 5 Supply passage 5a Inner pipe 6 Construction apparatus 7 Leader 8 Auger motor 9 Swivel 10 Slide plate 11 Core material 12 Filled hydraulic solidification material liquid 14 Rubber sheet

Claims (6)

  At least the excavation claw and the discharge port of the hydraulic solidification material liquid are provided at the tip of the excavation auger having a hydraulic solidification material liquid supply passage inside, and the excavation auger is rotated by a construction device equipped with an auger motor (forward rotation). (Or reverse rotation) while digging to a predetermined depth, and then discharging the hydraulic solidified material mixed with magnesium carbonate from the discharge port, rotating the excavation auger (forward rotation or reverse rotation) or not rotating To build a hydraulic solidifying material liquid replacement column by filling a predetermined section of the excavation part with the hydraulic solidifying material liquid mixed with magnesium carbonate, and to arrange the core material in the hydraulic solidifying material liquid replacement column Construction method of hydraulic solidifying material liquid replacement column characterized by   The construction method of a hydraulic solidifying material liquid replacement column according to claim 1, wherein the outer diameter of the excavation auger is 100 mm to 300 mm.   3. The hydraulic solidifying material liquid replacement column according to claim 1, wherein a rotation diameter of the excavation claw is equal to or less than a rotation diameter of the excavation auger and does not protrude from an outer diameter of the excavation auger. Building method.   The construction method of a hydraulic solidifying material liquid replacement column according to any one of claims 1 to 3, wherein the excavation auger has a cylindrical shape in which at least a part or all of the peripheral side surface thereof is a flat cylindrical shape.   The method for building a hydraulic solidifying material liquid replacement column according to any one of claims 1 to 4, wherein the bottom surface of the rotating body formed by the excavation claws during rotation is a flat horizontal surface.   The hydraulic solidifying material liquid is mainly composed of Portland cement, blast furnace cement, fly ash cement, or cement-based solidified material, and the water-cement ratio is 50 to 150%. 5. A method for building a hydraulic solidifying material liquid replacement column according to any one of 5 above.

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