JP2005282063A - Composite site construction pile, its construction method, and composite field construction pile construction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: There is no weak point of the boundary surface between the completed pile and the ground in the composite site constructed pile, the stress release does not occur in the surrounding ground and the supporting ground, and the construction structure or civil engineering structure of one pile is not Provide a pile that can be used as a foundation pile. Moreover, the construction method and the apparatus for the construction of the composite site construction pile are provided.
SOLUTION: The composite site-built pile has a soil cement solidified layer 3 on an outer peripheral portion of a portion excluding at least a lowermost end portion of a cement milk solidified layer 2 into which a core material 4 is inserted.
This composite site-built pile is constructed with a column of soil cement 3a having a predetermined diameter and length in the ground, and the soil cement 3a is not yet solidified, but at the center of the column of soil cement 3a. The portion of the soil cement 3a having a diameter smaller than the diameter of the columnar body is replaced with a columnar body composed of the cement milk layer 2a, and the core material 4 is inserted into the cement milk that is not yet solidified, so Build as.
[Selection] Figure 1

Description

  The present invention relates to a foundation pile of a building structure or a civil engineering structure, a construction method of the foundation pile, and an apparatus for the construction.

It has been known that a soil cement columnar body into which a core material is inserted is used as a foundation pile of a building structure or a civil engineering structure (see, for example, Patent Document 1).
Moreover, although it is not a foundation pile, it was also known to use the soil-cement pillar row | line | column which inserted the core material as a mountain retaining or earth retaining (for example, refer patent document 2, patent document 3, patent document 4).
On the other hand, a synthetic pile in which soil cement and a steel pipe are integrally combined is also known (see, for example, Patent Document 5).
Excavation and soil removal using earth drilling method or reverse circulation drill excavator, in which concrete is placed after excavating with a rotating bucket and inserting a reinforcing bar into the excavation hole as a foundation for foundation piles instead of soil cement After inserting the reinforcing bar into the drilling hole, drilling using the reverse method of placing concrete or a rotary boring machine, raising the remaining slime with air, inserting the reinforcing bar into the concrete A BH method for placing a slab is known (for example, see Non-Patent Document 1).

JP-A-4-179730 (first page right column-second page upper left column, Fig. 1) Japanese Patent No. 2793968 (Claims, Fig. 2) Japanese Examined Patent Publication No. 57-7247 (Claims, Fig. 9) Japanese Patent Laid-Open No. 9-279579 (summary) Japanese Patent Laid-Open No. 4-185813 (Claims, FIGS. 1a-1f) Nakamura Jun and Naito Shinji, “New Construction Series Vol. 2 Basics Rooted in the Earth”, Sankaido Co., Ltd., January 31, 1994, pages 106-107, pages 110-111, 118 Page-Page 119

  In-situ piles with core materials such as steel bars and H-shaped steel inserted into the soil cement columnar body may cause unloading action associated with excavation like cast-in-place piles when the soil cement columnar body is built. Since there is no looseness of the tip ground and surrounding ground, the ground exhibits a large peripheral friction force and tip support force.

However, the uniaxial compressive strength of the soil cement is affected by the soil quality of the raw ground, and the value is about 1 to 3 N / mm ² at most, which is very small compared to concrete.
As a result, like a ready-made concrete pile or cast-in-place pile, one soil cement columnar body could not be used as a pile bearing a shearing force or bending moment generated by a horizontal force during an earthquake.
Therefore, if it is forcibly used as a foundation pile of a building structure or civil engineering structure, the soil cement columnar body overlaps if a site-built pile with a core material such as steel bar or H-shaped steel inserted into the soil cement columnar body is used. There was a risk that it would be economically expensive because it had to be constructed and used as a large mass.
In addition, when the soil cement column array with the core material inserted is used as a mountain retaining or earth retaining, it is regarded as a soil cement column array for the purpose of waterproofing, and it is a foundation pile for building structures and civil engineering structures. It is not used as. The prior art in which the soil cement column array with the core material inserted in this way is used as a mountain retaining or earth retaining is the foundation pile of the building structure or civil engineering structure with the soil cement columnar body with the core material inserted in one pile. It does not suggest to use as.

  On the other hand, in-situ piles using the earth drill method, reverse method, BH method, etc., all the excavated soil is discharged during drilling, so there is a large amount of generated residual soil, which may cause pollution problems. Also, because bentonite mud is used for the purpose of preventing the collapse of the hole wall until the concrete is placed, the boundary surface between the completed pile and the ground may become a weak point and the peripheral frictional force may be reduced. When the slime remains, the initial subsidence is large and the vertical bearing capacity deteriorates.When the earth and sand are removed during drilling, the surrounding ground and the supporting ground release stress and the ground loosens. There was a risk of falling.

  On the other hand, a composite pile that is a composite of soil cement and steel pipe can be made to have a high vertical bearing capacity, and can make the steel pipe bear the shearing force and bending moment generated by the horizontal force during an earthquake. Because it can, it can be used as a foundation pile for building structures and civil engineering structures with a single pile.

  However, an expensive steel pipe that can withstand such high shearing force and bending moment has to be prepared in advance. As described above, the composite pile in which the soil cement and the steel pipe are integrally combined is a combination pile of the ready-made pile and the soil cement, and cannot be said to be a field-built pile.

  In view of these points, the present invention is a site-built pile, in which no weakness of the boundary surface between the completed pile and the ground occurs, stress release does not occur in the surrounding ground and support ground, and the building structure is constructed with a single pile. It aims at providing the pile which can be used as a foundation pile of a thing or a civil engineering structure, Furthermore, it aims at providing the construction method and the apparatus for the construction.

The composite field-built pile of the present invention has a soil cement solidified layer on the outer peripheral portion of at least the lowermost portion of the cement milk solidified layer into which the core material is inserted as described in claim 1. And
The cement milk solidified layer into which the core material of this composite site-built pile is inserted does not necessarily have to be inserted up to the cement milk solidified layer at the lowest end, but the portion where the core material is inserted is at least In order to insert a higher tip support force, it is preferable that the solid cement layer is formed deeper than the lowermost end of the soil cement solidified layer in the outer peripheral portion and is formed in the support layer.
In addition, since the soil cement solidified layer in the outer peripheral portion is higher in strength than the surrounding ground in the soft ground portion, the composite site constructed pile of the present invention has a larger peripheral frictional force, but the soil cement solidified in the outer peripheral portion. If the layer is made too thick, it will have a thick soil cement solidified layer outside the cement milk solidified layer where the core material is inserted, and the bearing capacity of the pile as a whole will be in proportion to the thick soil cement solidified layer provided. If the soil cement solidified layer is too thin without improving, the protection of the hole wall by providing the soil cement solidified layer is weakened, and the degree of improvement in the peripheral frictional force by providing the soil cement solidified layer tends to decrease There is. Therefore, the thickness of the soil cement solidified layer in the outer peripheral portion is particularly preferably 5 cm to 30 cm, and most preferably 5 cm to 20 cm.
Further, the diameter of the columnar cement milk solidified layer is set to a diameter corresponding to the support force expected from the upper structure or the like.
Core material that can support vertical force and horizontal force acting from the upper structure in a solidified cement milk solidified layer in addition to reinforcing bar, H-shaped steel, various shaped steel, steel pipe, etc. If it is. Further, when the pile length is longer than the single core material length, the core material may be connected and used by a lap joint or welding.

As described in claim 2, in the method for constructing the composite site-built pile of the present invention, a soil cement columnar body having a predetermined diameter and a predetermined length is built in the ground, and the soil cement is not yet solidified. Replace the central part of this soil cement pillar with a diameter smaller than the diameter of the soil cement pillar with a pillar composed of a cement milk layer, and insert the core material while the cement milk is not yet solidified. This is characterized in that it is a cast-in-place pile having a soil cement solidified layer on the outer periphery of the cement milk solidified layer excluding at least the lowermost end.
In this way, a composite on-site formation in which the cement milk solidified layer in which the core material is inserted is formed at least deeper than the lowermost end of the soil cement solidified layer at the outer peripheral portion and is also formed into the support layer. You can build a pile.
When the core material does not settle down to a predetermined depth, a known core material insertion method may be used, such as inserting the core material to a predetermined depth by applying vibration to the core material using a vibro hammer or the like. For example, when inserting a reinforcing bar rod, as shown in, for example, Japanese Patent No. 2793968 cited as publicly known document 2, an insertion jig is attached to the reinforcing rod rod, and the jig is vibrated by a vibrator or the like. Then, the reinforcing bar rod as a core material can be set by a known method in which the bottom portion of the reinforcing bar rod is laid down at a predetermined position by pressing downward, and then the jig is removed.

  A particularly preferred method for constructing a composite on-site construction pile according to the present invention comprises, as described in claim 3, at least one spiral blade having an excavation portion at the tip, and a stirring blade above the spiral blade. A drilling and stirring device comprising at least a drilling rod, comprising a discharge port at a lower side surface of the drilling rod and above a lowermost surface of the spiral blade, and the outer diameter of the spiral blade is Using a device smaller than the outer diameter, the excavated soil and the solidified material liquid are stirred and mixed in the ground while rotating the excavating rod and discharging the solidified material liquid from the discharge port. If the soil cement columnar body is built and the tip of the drilling rod reaches a predetermined depth, the drilling rod is rotated while the cementing rod is discharged, and then pulled up. Therefore, the central portion of the soil cement columnar body and a portion having a diameter smaller than the diameter of the soil cement columnar body is replaced with a columnar body composed of a cement milk layer, and the core material is inserted while the cement milk is not yet solidified. This is characterized in that it is a cast-in-place pile having a soil cement solidified layer on the outer periphery of the cement milk solidified layer excluding at least the lowermost end.

  In this case, it is most preferable that the stirring blades are provided in multiple stages to stir and mix more excavated soil and solidified material liquid. However, it is desirable that only the stirring blade closer to the spiral blade has a drilling claw at least in a portion larger than the diameter of the spiral blade, and this stirring blade may be used as the drilling blade. By comprising in this way, this stirring blade can exhibit the function as an excavation blade and the function as a stirring blade. Thus, since the function as a stirring blade can also be exhibited, this is also expressed as a stirring blade in the present invention.

  According to the construction method described above, there is a drilling and stirring device comprising a drilling rod having at least a spiral blade having a drilling portion at a tip portion and a stirring blade above the tip, and a lower side surface of the drilling rod, Using a device that has a discharge port above the lowermost surface and whose outer diameter of the spiral blade is smaller than the outer diameter of the stirring blade, the solidified material liquid is discharged from the discharge port while rotating the excavating rod in the ground. While excavating, the discharged solidified material liquid and excavated soil are first agitated with a spiral blade while the discharged solidified material liquid and excavated soil are agitated and mixed, and then further with the excavated blade the solidified material liquid and The excavated soil is further stirred and mixed, and a soil cement columnar body having the same diameter as the stirring blade diameter is built to a predetermined length.

  And when the tip of the excavator stirring device reaches the desired depth in the support layer, a soil cement columnar body having the same diameter as the stirring blade diameter is built above the stirring blade closer to the spiral blade. At the same time, soil cement corresponding to the spiral blade diameter is built in the spiral blade portion. Compared with the soil cement of this spiral blade, the soil cement columnar body with the same diameter as the stirring blade on the upper side of the stirring blade closer to the spiral blade has a more uniform solidification material in that the number of stirring by the stirring blade is large. Since the liquid and excavated soil are agitated and mixed, it is a soil cement that can exhibit higher strength.

  In addition, it digs, rotating a rod in the direction in which a spiral wing part is screwed in at the time of digging. In this invention, rotating the rod in the direction in which the spiral wing portion is screwed is called forward rotation of the rod.

  As described above, by excavating the ground while rotating the excavating rod and discharging the solidified material liquid from the discharge port, the excavated soil and the solidified material liquid are stirred and mixed to form a soil cement columnar shape with a predetermined diameter and length. When the body is built and the tip of the excavation rod reaches a predetermined depth, the excavation rod is pulled up while rotating the excavation rod while discharging cement milk from the discharge port. If the rotation direction of the rod in this case is positive, the soil cement is lifted upward by the spiral blade by pulling up. At the same time, since the cement milk is discharged from the discharge port below the soil cement is lifted upward, the range of the same diameter as the diameter of the spiral blade is replaced from the soil cement to the cement milk layer.

In this way, the soil cement layer is left on the outer periphery, and the cement milk layer is built inside. This cement milk layer is formed at least deeper than the lowermost end of the soil cement layer at the outer peripheral portion, and is also formed into the support layer.
The core material is inserted while the cement milk is not yet solidified. It is preferable that the lower end of the core material reaches the support layer. Of course, the portion of soil cement to be replaced is finally discharged to the ground. The soil cement layer becomes a soil cement solidified layer by solidifying, and the cement milk layer becomes a cement milk solidified layer by solidifying.
Thus, it is set as the structure which has a soil cement solidified layer in the outer peripheral part of the part except at least the lowest end part of the cement milk solidified layer in which the core material was inserted. Since this soil cement part is formed at the time of excavation, the boundary surface with the ground does not become a weak point. At the same time, the soil cement part and the cement milk part are integrated into the structure, and since it is built from the bottom end of the digging state, it is supported without generating any weak points on the boundary surface with the ground. It is built up in layers.

Due to such a construction method, it is possible to construct a composite site-constructed pile without releasing stress on the surrounding ground and supporting ground. Further, the cement milk layer replaced with the soil cement layer in this way exhibits a high strength of about 20 N / mm ² after solidification without having a core material.
Therefore, the cement milk solidified layer in which the core material is inserted can provide a composite pile that can exhibit high tip support and calculate the frictional force of the peripheral surface. It can be used as a foundation pile for things.
Also, leave the soil cement part on the outside and form a cement milk layer in it, but if the thickness of the soil cement layer to be left is 5 cm or more, collapse of sandy soil etc. when constructing the cement milk layer There is no risk of collapse of the hole wall even in highly natural ground.

The composite field building pile building device of the present invention is a drilling and stirring device comprising a drilling rod having at least a spiral blade having a drilling portion at a tip portion and a stirring blade above the spiral blade as described in claim 4. The discharge blade has a discharge port at a lower side of the excavation rod and above the lowermost surface of the spiral blade, and the outer diameter of the spiral blade is smaller than the outer diameter of the stirring blade.
In this case, it is preferable that the discharge port is provided at a position where the cement milk discharged on the back surface side of the spiral blade is agitated so that the cement milk is not discharged to the upper surface side of the spiral blade.
By using the apparatus for constructing the composite site creation pile of the present invention, the above-described construction method of the present invention can be implemented, and a high-end support force can be exhibited, and a composite pile capable of calculating the frictional force of the peripheral surface can be obtained. It is possible to obtain a composite site-built pile that can be used as a foundation pile for building structures and civil engineering structures with a single pile.

In addition, the length from the lower end of the lowermost stirring blade (that is, the stirring blade having the excavating claw) to the lower end portion of the spiral blade having the excavating portion at the tip is a cement milk solidified layer in which no soil cement solidified layer exists outside The length (height) of the spiral wing with the excavation part at the tip is occupied by the spiral wing with the excavation part at the tip. It is particularly preferable that the length is not more than three times the outer diameter of the spiral blade, and more preferably, the spiral blade has a length of one turn or more and twice the outer diameter of the spiral blade.
If the spiral wing is formed into one or more spirals, particularly a spiral exceeding one, it becomes easy to move the soil cement upward when the apparatus is pulled up, and the replacement with cement milk becomes more reliable.
In addition, when the length (height) of the spiral blade having the excavation part at the tip becomes long, the length (height) of the cement milk solidified layer in which the soil cement solidified layer does not exist on the outside becomes long. The outer diameter of the blade is 3 times or less, more preferably 2 times or less of the spiral blade.
Note that the length of one turn of the spiral blade generally does not exceed the length of one time the outer diameter of the spiral blade. Therefore, the spiral blade has one or more turns, but the length (height) of the spiral blade with the excavation part at the tip should be at least 1 times the outer diameter of the spiral blade. It is particularly preferable to make the length (height) of the cement milk solidified layer not larger than the outer diameter of the spiral blade.

  Moreover, in the spiral wing part, when the angle formed by the wing part with the surface perpendicular to the rod (that is, the spiral angle) is set to a small angle of 10 degrees or more and 35 degrees or less, the soil cement moves upward when it is pulled up. When the soil cement and cement milk are replaced (when replacing soil cement and cement milk), the soil cement to be replaced can be more reliably prevented from falling down, and a cement milk layer free of soil cement can be formed more reliably. I can do it. Therefore, it is more preferable that the angle formed by the outermost edge portion of the spiral wing portion with a plane perpendicular to the rod (that is, the spiral angle) is a small angle of 10 degrees or more and 35 degrees or less. If this angle is smaller than 10 degrees, in order to make the length (height) of the spiral wing part equal to or larger than the outer diameter of the spiral wing, the spiral wing must have a large number of spirals, and it becomes expensive as a device. If the angle exceeds 35 degrees, depending on the ground properties, when the soil cement is moved upward, the soil cement may be removed when the soil cement is moved upward. There is a risk of falling.

Furthermore, in addition to a spiral blade having a drilling portion at the tip of the drilling rod of the drilling and stirring device and a stirring blade (preferably a multistage stirring blade) above it, it prevents co-rotation larger than the diameter of the stirring blade. The blade may be a device attached to the rod so that the blade does not rotate even if the rod rotates, or the upper portion of the stirring blade provided in multiple stages, A spiral blade having a small diameter can be provided, and a stirring rod having a diameter smaller than that of the stirring blade can be provided in multiple stages.
The spiral blade having a small diameter provided on the upper portion may be a continuous spiral blade or a large number of non-continuous (for example, intermittent) spiral blades.

In this way, when a spiral blade with a small diameter is provided on the rod above the uppermost stirring blade of the multi-stage stirring blade, the soil cement is stirred by this spiral blade portion during digging. Since it is also possible to maintain the fluidity of the cement, not only the replacement of the soil cement with cement milk becomes easier, but also the spiral cement can move the soil cement upward when the device is pulled up, It is possible to make the amount of movement of the soil cement upward by the spiral blade at the tip portion smoother, and the replacement of the soil cement with cement milk can be more reliably performed.
When a stirrer rod with a diameter smaller than that of the stirrer blade is provided in multiple stages on the rod above the uppermost stirrer blade of the multistage stirrer blade, the soil cement is stirred by this stirrer rod. Since it is possible to maintain the fluidity of the cement, the replacement of the soil cement with cement milk becomes easier.

Without using the above-mentioned composite on-site pile building apparatus, there is no lower spiral blade, a drilling blade having the same diameter as the stirring blade is provided at the lower end, a rod having a solidified material liquid discharge port and a multistage stirring blade After building the soil cement column using a normal soil cement column building device, such as a device consisting of a screw auger, etc., preferably with the soil cement still hardened and having a diameter smaller than that of the soil cement column The excavator is used to excavate with the soil cement portion remaining on the outer periphery of the soil cement column, penetrate the bottom of the soil cement column, and excavate into the support layer.
The cement milk columnar body that should become a cement milk solidified layer by rotating the screw auger while discharging the cement milk from the discharge port at the lower end of the excavator such as a screw auger while reaching the tip. It may be formed.

In addition, when the bottom of the soil cement pillar is penetrated, cement milk is discharged from the discharge port of the screw auger, and after forming a small diameter soil cement with a screw auger below one end, When forming a cement milk solidified layer by pulling up the screw auger while discharging cement milk from the discharge port at the lower end of a drilling device such as a screw auger, the disturbance of the ground at the boundary with the ground can be reduced, It can be a field composite pile with higher tip support.
Of course, in any of these cases, the position of the discharge port must be provided above the screw end of the screw auger so that the discharged cement milk reaches the screw diameter range. It is necessary to move the cement or the like upward and discharge it to the ground.

  However, in the method using such a soil cement columnar body building apparatus and a cement milk columnar body building apparatus, the process of digging the soil cement columnar body building apparatus and the subsequent lifting process, and the columnar body building apparatus of the cement milk It is necessary to perform the excavation process and the subsequent pulling process twice, that is, the excavation process and the subsequent pulling process, which increases the time required for construction. Therefore, if a device that can form a soil cement columnar body at the time of excavation and form a cement milk columnar body at the time of pulling up is used as in the above-mentioned apparatus, the target complex site can be achieved by one excavation process and subsequent pulling process. This is preferable because it can be a piled pile and the time required for the construction can be shortened.

The composite site-constructed pile according to the present invention has a cement milk solidified layer in which the core milk is inserted, because the cement milk solidified layer can express a high strength of about 20 N / mm ² normally. It forms a composite cross section, and it becomes a pile that can exhibit the same mechanical behavior as reinforced concrete and also bears a horizontal force.
In addition, since it has a solidified layer of soil cement on the outside of the cement milk solidified layer, it is a composite on-site pile with excellent performance that the peripheral frictional force becomes high and the tip support force by the cement milk solidified layer is exhibited. .
Therefore, the composite field construction pile of the present invention is a pile that can be used as a foundation pile of a building structure or a civil engineering structure with a single pile.
In the above-mentioned composite site-built pile of the present invention, when the bottom of the cement milk solidified layer is located in the support layer and the core material also reaches the support layer, the cement milk solidified layer is directly connected to the support layer. Because it comes into contact, it exerts great support.

  According to claim 2 of the present invention, there is provided a method for constructing a composite on-site pile, wherein a soil cement columnar body having a predetermined diameter and a predetermined length is built in the ground, and the soil cement is not yet solidified. By replacing the central portion of the columnar body with a diameter smaller than the diameter of the soil cement columnar body with a columnar body composed of a cement milk layer, and inserting the core material into the cement milk that has not yet solidified, It is characterized by setting it as the in-situ pile which has a soil cement solidified layer in the outer peripheral part of the cement milk solidified layer except the lowest end part. Therefore, the following various effects are exhibited.

(1) Since a soil cement columnar body is constructed and replaced with cement milk immediately after that, there is no unloading action associated with excavation and the ground around the columnar body is not loosened. Therefore, the bearing capacity of the completed pile is great.
(2) The construction method of the present invention does not use the muddy water that is used when constructing a conventional on-site pile, so there is no tip slime problem as in the conventional cast-in-place pile.
(3) Since the soil cement layer is left on the outer peripheral surface of the built pile, and the soil cement layer is stronger than the ground, the peripheral surface frictional force of the completed pile is large.
(4) Since the substituted cement milk solidifies and expresses a high strength of usually about 20 N / mm ² , it forms a composite cross-section with the inserted core material, exhibits the same mechanical behavior as reinforced concrete, and has a horizontal force. Can be used as a pile to bear.
(5) Since the hole wall is protected with soil cement, there is no hole wall collapse even after replacement with cement milk in a highly collapsible ground such as sandy soil.
(6) Since the specification of the core material to be inserted can be determined according to the load acting on the pile, it is economical.
(7) When the bottom of the cement milk solidified layer is located in the support layer and the core material also reaches the support layer, the cement milk solidified layer is in direct contact with the support layer, so that a large supporting force is exhibited. .

  Further, as in the method for constructing a composite on-site construction pile according to claim 3 of the present invention, at least one spiral blade having an excavation part at the tip is provided, and at least a stirring blade is provided above the spiral blade. A drilling and stirring device comprising a drilling rod provided, having a discharge port on a lower side surface of the drilling rod and above a lowermost surface of the spiral blade, and an outer diameter of the spiral blade being outside the stirring blade Using a device smaller than the diameter, the excavated soil and the solidified material liquid are stirred and mixed in the ground while rotating the excavating rod and discharging the solidified material liquid from the discharge port. When the soil cement pillar is built and the tip of the drilling rod reaches a predetermined depth, the drilling rod is pulled up while rotating the drilling rod while discharging the cement milk from the discharge port. By replacing the central portion of the cement rod with a diameter smaller than that of the soil cement column with a column made of cement milk, and inserting the core material into the cement milk that has not yet hardened, According to the composite site-constructed pile construction method according to claim 2 of the present invention described above, according to the construction method of the composite site-constructed pile which is a cast-in-place pile having a soil cement solidified layer on the outer periphery of the cement milk solidified layer excluding the lowermost end In addition to the effects exhibited by the construction method, the following effects can be exhibited.

(8) Since cement milk is discharged and replaced at the same time while rotating the spiral blade at the tip, the soil cement and the cement milk can be reliably replaced within the range of the diameter of the spiral blade.
(9) It is possible to form a cement milk column at the center of the soil cement column in one step of excavating and pulling up the excavating and stirring device having the spiral wing at the tip, which is efficient and economical. .
(10) When using a device in which the length (height range) of the spiral blade portion at the tip is greater than or equal to the outer diameter of the spiral blade, the soil cement of the spiral blade portion can be reliably moved upward, Replacement with cement milk can be performed more reliably.
(11) When a device with a reduced spiral angle of the blade of the spiral wing at the tip is used, it is possible to prevent the soil cement from falling downward during the replacement of the cement milk, and a reliable replacement of the cement milk becomes possible.

  Furthermore, the composite field construction pile construction device according to claim 4 has at least one or more spiral blades having a drilling portion at the tip, and at least a stirring blade above the spiral blades. An excavation stirring device comprising: a discharge port at a position on a lower side surface of the excavation rod and above a lowermost surface of the spiral blade; and the outer diameter of the spiral blade is smaller than the outer diameter of the stirring blade Since it is an apparatus characterized by this, it can be used for the construction method of the composite site construction pile described in claim 3 above. Therefore, in addition to the above effects, the following effects can also be exhibited.

(12) A spiral blade for replacing cement milk is installed at the tip, and the spiral blade has a length of at least one cycle. The cement can be reliably moved upward, and the replacement can be reliably realized in combination with the discharge of cement milk (cement slurry).
(13) When a device in which a spiral blade having a diameter smaller than the rotation radius of the stirring blade is fixed to the drilling rod above the stirring blade mounting position continuously or intermittently (intermittently), When the soil cement is replaced, the soil cement is forced to move upward, so that replacement of the soil cement with the cement milk becomes more reliable.
(14) When a stirring rod having the same radius of rotation is fixed to the drilling rod instead of the small-diameter spiral blade, the soil cement around the drilling rod is always stirred, so the flow of the soil cement in that portion Can be secured. Therefore, an auxiliary effect of replacing the cement milk (cement slurry) with soil cement is exhibited.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIGS. 1 to 3 are a cross-sectional view (a) and a plan view (b) of a composite field-constructed pile showing an embodiment of the present invention. The composite site-built pile 1 has a soil cement solidified layer 3 on the outer peripheral portion of the cement milk solidified layer 2 into which the core material 4 is inserted, excluding at least the lowermost end. The core material 4 can support vertical force and horizontal force acting from the upper structure by integrating it in the cement milk solidified layer 2 in addition to reinforcing bar, H-shaped steel, various shaped steels, steel pipes, etc. If it is. Moreover, when the pile length is longer than the single core material length, the core material may be used by being connected by a lap joint or welding. FIGS. 1A and 1B show the case where the core material 4 is a reinforcing bar, FIGS. 2A and 2B show the case where the core material 4 is an H-shaped steel, and FIGS. The case where the core material 4 is a bladed steel pipe is shown, respectively.

The cement milk solidified layer 2 in which the core material 4 of the composite site-built pile 1 is inserted does not necessarily need to be inserted up to the cement milk solidified layer 2 at the lowest end, but the core material 4 is inserted. The formed portion is formed at least deeper than the lowermost end of the soil cement solidified layer 3 at the outer peripheral portion, and is formed into the support layer G1, in order to insert a higher tip support force. Is preferable. In addition, G shows a soft ground, 1a is the lower end part of the composite field construction pile 1, and is a part of the cement milk solidified layer 2 in which the soil cement solidified layer does not exist outside.
Further, since the soil cement solidified layer 3 in the outer peripheral portion is stronger than the peripheral ground in the soft ground portion, the composite site-built pile 1 of the present invention has a larger peripheral frictional force, but the soil in the outer peripheral portion is increased. If the cement solidified layer 3 is made too thick, it will have the thick soil cement solidified layer 3 outside the cement milk solidified layer 2 in which the core material 4 is inserted, and the supporting force of the pile 1 as a whole is a thick soil cement. If the soil cement solidified layer 3 is too thin without providing the solidified layer 3, the protection of the hole wall due to the provision of the soil cement solidified layer 3 is weakened, and the soil cement solidified layer 3 is provided. There is a tendency that the degree of improvement of the peripheral frictional force is reduced. Therefore, as shown in an enlarged view in FIG. 4, the thickness h of the soil cement solidified layer 3 in the outer peripheral portion is particularly preferably 5 cm to 30 cm, and most preferably 5 cm to 20 cm. In FIG. 4, the core material 4 is omitted from the cement milk solidified material layer 2 in order to clarify the relationship between the diameter of the cement milk solidified layer 2 and the thickness of the surrounding soil cement solidified layer 3. ing.
Moreover, the diameter of the columnar cement milk solidified layer 2 is set to a diameter according to the supporting force expected from the upper structure or the like.

Such a composite on-site construction pile 1 is constructed on site using an excavating and stirring device 10 as shown in FIGS. 5 and 6 (a) to 6 (d).
As shown in FIG. 5, the basic configuration of the excavating and agitating apparatus 10 includes at least one spiral blade 12 having an excavating claw 13 as an excavating portion at the distal end of the excavating rod (hollow rod) 11, At least a stirring blade 14 is provided above the spiral blade 12, and has a discharge port 17 at a position on the lower side surface of the excavating rod 11 and above the lowermost surface of the spiral blade 12. The outer diameter is smaller than the outer diameter of the excavating blade 14. The excavation and stirring device 10 is allowed to be variously modified.
6 (a) to 6 (d) exemplify a modified example of the excavating and agitating device 10, and FIG. 6 (a) is obtained by adding a co-rotation prevention blade 16 to the one shown in FIG. FIG. 6 (b) shows a configuration in which a small-diameter spiral blade 18 is provided intermittently (intermittently) above the co-rotation prevention blade 16 and the uppermost stirring blade 14 in the structure shown in FIG. In FIG. 6 (d), a plurality of stirring rods 19 are provided above the uppermost stirring blade 14 in a protruding manner.

  It is preferable that the stirring blades 14 of the excavating and stirring apparatus 10 are provided in multiple stages because the excavated soil and the solidified material liquid (for example, cement milk) are well stirred and mixed. However, it is desirable that only the stirring blade 14a closer to the spiral blade 12 has the excavation claw 15 at least in a portion larger than the diameter of the spiral blade 12, and the stirring blade 14a may be used as the drilling blade. By comprising in this way, this stirring blade 14a can exhibit the function as an excavation blade and a function as a stirring blade. Thus, since the function as a stirring blade can also be exhibited, this is also expressed as a stirring blade in the present invention.

The co-rotation prevention blade 16 is loosely fitted to the excavation rod 11 so that the diameter of the anti-rotation blade 16 is larger than the diameter of the stirring blade 14 (including 14a) and the excavation rod 11 does not rotate even if it rotates in the ground. Is prevented from co-rotating with the stirring blade 14 and improves the stirring and mixing properties. Therefore, it is preferable that the co-rotation prevention blade 16 is provided because the excavated soil is well stirred and mixed so that the solidified material liquid is well stirred and mixed to form a good soil cement layer.
In addition, if the small-diameter spiral blade 16 is present, this also has an ascending force that raises the soil cement by rotation, so that the rise of the soil cement by the rotation of the spiral blade 12 becomes smoother, and the central portion of the soil cement layer The fluidity of the soil cement is maintained until it is replaced with cement milk. Moreover, when the stirring rod 19 is projected, the fluidity of the soil cement is maintained until the central portion of the soil cement layer is replaced with cement milk.
Further, the discharge port 17 may be opened on the side surface of the excavation rod 11, or a short pipe may be fixed to the excavation rod 11 and protrude from the excavation rod 11. FIG. 5 shows the protruding discharge port 17, and FIGS. 6A to 6D show the case where the side surface of the excavation rod 11 is opened.

Next, a spiral wing 12 having a digging claw 13 at the tip is fixed to the tip of a drilling rod (hollow rod) 11 shown in FIG. 6B, and the diameter of the spiral wing 12 is larger than the spiral wing 12. Excavation and agitation in which a stirring blade 14 having a diameter is projected in a plurality of stages, a co-rotation prevention blade 16 is provided between the stirring blades 14a and 14, and a small-diameter spiral blade 18 is intermittently protruding above the stirring blade 14. The construction procedure when the rod is used as the excavation stirring device 10 will be described with reference to FIG.
An example of the dimensions of the device 10 is that the diameter of the spiral blade 12 at the tip is 800 mm, the length (height) of the spiral blade 12 is 1000 mm, and has a spiral structure of one or more turns. is there. The diameter of the stirring blade 14 is 1000 mm, and the number of the stirring blades 14 is four. The lowermost stirring blade 14 a is provided with an excavation claw 15 in a portion larger than the diameter of the tip spiral blade 12.
The diameter of the co-rotation preventing blade 16 whose diameter is larger than the diameter of the excavating blade 14 is 1200 mm, and this co-rotation preventing blade 16 is attached at an intermediate position between the stirring blade 14 a and the stirring blade 14. The diameter of the upper small-diameter spiral blade 18 is 400 mm.

First, as shown in FIG. 7A, the excavation rod (hollow rod) 11 of the excavation and stirring device 10 is set at the pile center position of the ground.
Next, while discharging the solidified material slurry (cement milk) from the discharge port 17 provided at the tip of the hollow rod 11, the hollow rod 11 is rotated forward to excavate the ground, and the agitation blade 14 is used to solidify the slurry (cement). (Milk) and excavated soil are stirred and mixed to form a soil cement 3a and dig up to a predetermined depth. FIG. 7 (b) shows a state where the excavation is performed halfway through the ground, and FIG. 7 (c) shows a state where the excavation is performed to a predetermined depth. In this example, the tip was dug up to 22 m, which is the depth at which the tip enters the support layer.
At this time, the excavated soil and the solidified material slurry are agitated and mixed by the agitating blade 14 to construct a columnar body of the soil cement 3a having the same diameter as the diameter of the agitating blade 14 of 1000 mm.
When the tip of the rod 11 reaches a predetermined depth in this way, the hollow rod 11 is pulled up while rotating forward while discharging the solidified material slurry as shown in FIG. In the range where the hollow rod 11 is pulled up and only the spiral blade 12 is excavated, the soil cement is pushed upward by the effect of the spiral blade 12 rotating in the forward direction. This lower part becomes a so-called cement milk layer 2a filled with only the discharged solidifying material slurry (cement milk). The diameter is 800 mm, which is the same diameter as the spiral blade 12. In this way, the soil cement is replaced with the cement milk layer 2a.

Further, when the hollow rod 11 is pulled up while rotating in the normal direction, the upper end of the soil cement to be pulled up reaches the stirring blade 14 and is stirred by the stirring blade 14, but the state of the soil cement is maintained. . Further, at the time of this lifting, the soil cement is moved upward by the small-diameter spiral blade 18 above the stirring blade 14. The amount of increase of the soil cement by the small-diameter spiral blade 18 is equal to the amount of increase of the soil cement by the spiral blade 12 with the excavation claw 13 or more than the amount of increase of the soil cement by the spiral blade 12 with the excavation claw 13. It is preferable to adjust the diameter of the small-diameter spiral blade 18 or the length (height) of the portion where the small-diameter spiral blade 18 is provided, the length of one turn (that is, the pitch), or the like. Even when the amount of increase of the soil cement by the small-diameter spiral blade 18 is smaller than the amount of increase of the soil cement by the spiral blade 12 with the excavation claw 13, the soil cement increases the amount of the soil cement by the spiral blade 12 with the excavation claw 13. It rises as much as it matches. However, since there is an ascending force due to the small-diameter spiral blade 18, the soil cement rises more smoothly.
In this way, while discharging the solidified material slurry (cement milk) in an amount substantially corresponding to the volume formed by the projected area of the spiral blade 12 at the tip of the excavation claw 13 and the moving distance, the soil cement is a layer of the solidified material slurry (so-called so-called so-called soy). The cement milk layer 2a) is replaced. FIG. 7E shows a state in which the excavating and stirring device 10 is pulled up and the soil cement in the central portion of the columnar body of the soil cement 3a is completely replaced with the solidified material slurry (cement milk).

  FIG. 8 shows a state in which the soil cement at the center of the columnar body of the soil cement 3a at this time is replaced with the solidifying material slurry (cement milk), and the cement milk layer 2a is formed from below. That is, the soil cement at the position of the spiral blade 12 is lifted upward by the spiral blade 12 and the lower portion thereof is filled with the solidified slurry, and the soil cement of the portion where the small-diameter spiral blade 18 is intermittently present is shown. Shows that the small-diameter spiral blade 18 can easily move upward, and that the soil cement is discharged to the ground by being replaced with the solidified material slurry.

The diameter of the solidified slurry layer (so-called cement milk layer 2a) formed in this way is 800 mm, which is the same as that of the spiral blade 12 at the tip of the excavation claw, and the soil cement 3a having a thickness of 100 mm is left on the outer periphery. ing. That is, in FIG. 4, the diameter of the cement milk layer 2a is 800 mm, and the thickness h of the outer soil cement 3a is 100 mm.
By pulling up the hollow rod 11 to the end, as shown in FIG. 7E, a solidified material slurry layer (so-called cement milk layer 2a) is present at the center, and the soil cement 3a remains on the outer periphery. .
According to such a construction method, the soil cement 3a left on the outer peripheral part also acts as a protective film for the hole wall, so that even in a highly collapsible soil layer such as a sandy soil layer or a gravelly soil layer, The collapse of the wall can be prevented, and the soil cement at the center can be surely replaced with the solidified material slurry (cement milk).
When the replacement of the soil cement 3a at the center with the solidified material slurry (so-called cement milk layer 2a) is completed as shown in FIG. 7 (e), the uncured state is obtained as shown in FIGS. 7 (f) to (g). A reinforcing bar 4 serving as a core material is inserted into the solidified material slurry (so-called cement milk layer 2a). FIG. 7 (f) shows a state where the reinforcing bar 4 is going to be inserted into the cement milk layer 2a, and FIG. 7 (g) shows a state where the reinforcing bar 4 is inserted into the cement milk layer 2a. The solidifying material slurry (cement milk layer 2 a) is solidified to become the cement milk solidified layer 2, and the outer soil cement 3 a is solidified to become the soil cement solidified layer 3.
In inserting the reinforcing bar 4, the reinforcing bar 4 is suspended vertically using a heavy machine such as a crane and then self-sunk in accordance with the substantially central position of the solidified material slurry portion (so-called cement milk layer 2 a). When the core material 4 does not settle down, auxiliary means such as vertical movement and loading are used. A vibro hammer may be used as long as the core material 4 can be vibrated and vibrated like a H-shaped steel. Furthermore, the core material 4 may be connected and used as a long core material.

When the core material 4 is inserted into the solidified material slurry portion (cement milk layer 2a), the hole wall is protected by the effect of the soil cement 3a left on the inner surface of the hole wall, so that the hole wall collapse is extremely small and reliable. It is possible to build cast-in-place piles with core 4 in the middle. In addition, the composite field construction pile 1 constructed in this way is a solidified body 2 of a solidified material slurry (so-called cement milk layer) in which a core material 4 is inserted into a support layer G1 as shown in FIGS. The tip portion 1a is present, and the pile 1 in which the solid body 3 of soil cement is present on the outer periphery is formed on the upper portion of the support layer G1.
Therefore, since the cement milk solidifies due to the presence of the cement milk solidified layer 2 in which the core material 4 is inserted, a high strength of about 20 N / mm ^{2 is} usually exhibited. It becomes a pile that forms a cross section and can exhibit the same mechanical behavior as that of reinforced concrete and bears a horizontal force. On top of that, when the bottom of the cement milk solidified layer 2 is positioned in the support layer G1, and the core material 4 also reaches the support layer G1, the cement milk solidified layer 3 is in direct contact with the support layer G1, Demonstrate great support.
Moreover, since the solidified layer 3 of soil cement is provided outside the cemented milk solidified layer 2, the peripheral surface frictional force is increased, and the composite field construction having excellent performance of exhibiting the tip supporting force by the cemented milk solidified layer 2 is achieved. It becomes pile 1.
Therefore, the composite field construction pile 1 of this invention turns into a pile which can be used as a foundation pile of a building structure or a civil engineering structure with one pile.
In this construction method, the soil cement mixed with the solidified material is finally discharged to the ground as shown in Fig. 8, but the soil cement is self-hardening, so it can be disposed of on site in the construction site after curing. I do.

Moreover, construction of the composite field construction pile 1 was implemented using the excavation stirring apparatus 10 shown in FIG.6 (b) from which the dimension differs from the said apparatus. The dimensions of the device 10 are as follows.
The tip spiral wing 12 has a diameter of 600 mm, and the tip spiral wing 12 has a length (height) of 800 mm and has a spiral structure of one or more turns. The diameter of the stirring blade 14 is 700 mm, and the number of the stirring blades 14 is four. The lowermost stirring blade 14 a is provided with an excavation claw 15 in a portion larger than the diameter of the tip spiral blade 12.
The rod 11 is loosely fitted in the rod 11 so that it does not rotate in the ground even if the rod 11 is larger than the diameter of the stirring blade 14, and the excavated soil is prevented from co-rotating with the stirring blade 14, so that the mixing ability is improved. The diameter of the co-rotation preventing blade 16 for improvement is 900 mm. The co-rotation prevention blade 16 is attached at an intermediate position between the stirring blade 14 a and the stirring blade 14. The diameter of the upper small-diameter spiral blade 18 is 300 mm.

Using this apparatus 10, as shown in FIGS. 7A to 7C, the excavating rod 11 is rotated forward to discharge the solidified material slurry (cement milk) to a predetermined depth where the tip of the rod 11 enters the support layer. Dig up. In this example, the dug was carried out to a depth of 12 m. As a result, the excavated soil and the solidified material slurry are stirred and mixed by the stirring blade 14 to build a columnar body of the soil cement 3a having a diameter of 700 mm.
When the tip of the rod 11 reaches a predetermined depth as described above, the excavation rod (hollow rod) 11 is discharged while discharging the solidified material slurry (cement milk) from the discharge port 17 as shown in FIGS. Pull up while keeping the forward rotation. At this time, the excavation rod (hollow rod) 11 is pulled up, and in the range where only the spiral blade 12 is excavated, the soil cement is pushed upward by the effect of the spiral blade 12 rotating in the forward direction, and the lower part is discharged solidified. This is a so-called cement milk layer 2a filled with only the material slurry. The diameter is 600 mm which is the same as the diameter of the spiral blade 12, and the soil cement 3a having a thickness of 50 mm is left on the outer periphery.

Thereafter, an H-shaped steel having an H-shaped portion of 300 mm × 300 mm and a length of 12 m is inserted as a core material 4 into an uncured solidified material slurry portion (so-called cement milk layer 2a). This is the same as shown in FIGS.
The core material 4 is suspended vertically using a heavy machine such as a crane and then self-sunk in accordance with the substantially central position of the solidified material slurry portion (so-called cement milk layer 2a). When the core material 4 does not settle down, it is gripped with a vibro hammer and inserted with vibration.
When the core material 4 is inserted into the solidified material slurry portion (so-called cement milk layer 2a), the hole wall is protected by the effect of the soil cement left on the inner surface of the hole wall, so that the hole wall collapse is extremely small and reliable. It is possible to build cast-in-place piles with core material. The solidified material slurry portion (so-called cement milk layer 2 a) is solidified to become the cement milk solidified layer 2, and the outer soil cement 3 a is solidified to become the soil cement solidified layer 3.

Thus, the composite site-built pile 1 constructed in this way is the solidified layer 2 of the solidified material slurry (cement milk) in which the core material 4 is inserted into the support layer G1 as shown in FIGS. The tip portion is present, and the pile 1 in which the solid body 3 of the soil cement is present on the outer periphery is formed on the support layer G1.
Therefore, since the cement milk solidifies due to the presence of the cement milk solidified layer 2 in which the core material 4 is inserted, a high strength of about 20 N / mm ^{2 is} usually exhibited. It becomes a pile that forms a cross section and can exhibit the same mechanical behavior as that of reinforced concrete and bears a horizontal force. Further, when the bottom of the cement milk solidified layer 2 is positioned in the support layer G1 and the core material 4 also reaches the support layer G1, the cement milk solidified layer 2 is in direct contact with the support layer G1, Demonstrate great support.
Moreover, since the solidified layer 3 of soil cement is provided outside the cemented milk solidified layer 2, the peripheral surface frictional force is increased, and the composite field construction having excellent performance of exhibiting the tip supporting force by the cemented milk solidified layer 2 is achieved. It becomes a pile.
Therefore, the composite field construction pile of the present invention is a pile that can be used as a foundation pile of a building structure or a civil engineering structure with a single pile.

  The above-described embodiment does not limit the present invention, and various modifications are allowed without departing from the spirit of the present invention.

It is the cross-sectional front view (a) and top view (b) of the composite field construction pile which show embodiment of this invention. It is the cross-sectional front view (a) and top view (b) of the composite field construction pile which show other embodiment of this invention. It is the cross-sectional front view (a) and top view (b) of the composite field construction pile which show other embodiment of this invention. It is an expanded sectional fragmentary view of the pile by which the center part of soil cement was substituted by cement milk. It is a front view which shows an excavation stirring apparatus. It is a front view which illustrates other excavation stirring apparatus (a) (b) (c) (d). It is a front view which shows the construction process of this invention in process order (a) (b) (c) (d) (e) (f) (g). It is explanatory drawing which shows the creation state at the time of construction of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite site construction pile 1a Lower part of composite site construction pile 2 Cement milk solidified layer 2a Cement milk layer 3 Soil cement solidified layer 3a Soil cement 4 Core material 10 Drilling stirrer 11 Drilling rod (hollow rod)
12 Spiral wing 13 Excavation claw (Excavation part)
14, 14a Stirring blade 15 Drilling claw 16 Co-rotation prevention blade 17 Discharge port 18 Small-diameter spiral blade 19 Stirring rod G Ground G1 Support layer

Claims (4)

  A composite site-built pile characterized by having a soil cement solidified layer on an outer peripheral portion of a portion excluding at least a lowermost end portion of a cement milk solidified layer into which a core material is inserted.   A soil cement columnar body with a predetermined diameter and length is built in the ground, and the diameter of the soil cement columnar body is smaller than the diameter of the soil cement columnar body, while the soil cement has not yet solidified. The soil cement solidified layer is formed on the outer periphery of the cement milk solidified layer except at least the lowermost end by inserting the core material into a columnar body composed of a cement milk layer, and the cement milk is not yet solidified. A method for constructing a composite on-site pile, characterized in that it is a cast-in-place pile with a wall.   A drilling and stirring device comprising a drilling rod having at least a spiral blade having a drilling portion at a tip and a stirring blade thereabove, a position on a lower side surface of the drilling rod and above a lowermost surface of the spiral blade By using a device having a discharge port and an outer diameter of the spiral blade smaller than the outer diameter of the stirring blade, digging while discharging the solidified material liquid from the discharge port while rotating the excavation rod in the ground, A soil cement columnar body with a predetermined diameter and length is built by stirring and mixing the excavated soil and the solidified material liquid. When the tip of the drilling rod reaches a predetermined depth, the cement milk is discharged from the discharge port. While rotating the excavating rod, the central portion of the soil cement columnar body, which is smaller than the diameter of the soil cement columnar body, is removed from the cement milk layer. It is replaced with a columnar shape, and by inserting a core material into the cement milk that has not yet solidified, at least a cement cement solidified layer is formed on the outer periphery of the cement milk solidified layer excluding the lowest end. A method of constructing a composite site constructed pile characterized by that. A drilling and stirring device comprising a drilling rod having at least a spiral blade having a drilling portion at a tip and a stirring blade thereabove, a position on a lower side surface of the drilling rod and above a lowermost surface of the spiral blade A composite on-site pile building apparatus, characterized in that it has a discharge port and the outer diameter of the spiral blade is smaller than the outer diameter of the stirring blade.

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