JP6634251B2 - Pile foundation structure, ready-made pile burying device, method of constructing pile foundation structure using said ready-made pile burying device - Google Patents

Description

  The present invention relates to a pile foundation structure in which a pile having a hollow inside is buried in a pile hole filled with a mixture of a pile periphery fixing liquid and excavated earth and sand, and a prefabricated pile used for constructing the pile foundation structure. The present invention relates to a burying device and a method for constructing the pile foundation structure using the ready-made pile burying device.

  There is a pre-boring method as one of the construction methods for constructing a pile foundation structure with a ready-made pile with a hollow inside the pile diameter. This method involves excavating the ground with an earth auger or the like to form a pile hole, and then using a soil consolidation solution, a pile circumference fixing solution, or a soil cement-like material obtained by stirring and mixing these with the excavated earth and sand. The prefabricated pile is buried in the pile hole filled with the filler.

  When burying the ready-made pile, the pile head and the driving part of the pile driver are connected via a rotating cap, and the rotating cap is used to push the ready-made pile into the pile hole filled with the filler while rotating the ready-made pile. It is done.

  The rotating cap is hollow and has a cylindrical shape with an open bottom surface. A notch which can be engaged with a projection provided on the outer peripheral surface of the pile head for suspending and holding the pile on the outer peripheral side surface of the cylinder. Those having a portion are generally used.

  Some of them are equipped with various fixtures depending on the purpose, such as those equipped with a pile head fixing jig so that pre-made piles can be accurately buried, and those that have a pile head treatment function so that pile head processing can be performed reliably. There is also. Patent Document 1 is an example of the former.

  Patent Document 1 discloses that “the inner diameter of the hollow portion of the foundation pile is increased from the upper end closed portion of the cylindrical foundation pile cap body fitted on the outer periphery of the pile head toward the lower end side of the foundation pile cap body. A pile head fixing jig having a corresponding outer diameter and made of a rod-shaped elastic body shorter than the axial length of the cylindrical foundation pile cap body is vertically provided so as to be coaxial with the foundation pile cap body. Foundation pile cap ".

  Patent Document 2 is an example of the latter. Patent Document 2 discloses that “a hollow shaft portion for connecting to a pile driver is provided at an upper portion, a pile grip portion for gripping a pile head of a ready-made pile is provided at a lower portion, and a lower end of the hollow shaft portion. A rotary cap with a pile head processing function, in which a nozzle capable of discharging a diluting liquid into the hollow portion of the ready-made pile is mounted in the base of the rotary cap so as to communicate with the portion.

  On the other hand, when a PHC pile or the like is used as a ready-made pile, concrete is cast inside the pile diameter of the pile head of the upper pile in order to strengthen the connection with the pile head and the footing in the upper pile. Is being done.

  FIG. 6 shows this, as shown in FIG. 6A, after burying a ready-made pile in a pile hole 3 filled with a filling 6 of a mixture of a pile circumference fixing liquid and excavated earth and sand using a rotating cap 23. After the filling material 6 has hardened, the filling material 6 filling the pile diameter inside 14 of the pile head of the upper pile is removed with a double scoop 28 or the like as shown in FIG. Thereafter, as shown in (c), concrete 29 is poured into the pile diameter inside 14 from which the filler 6 has been removed. In addition, if necessary, before placing the concrete 29, a reinforcing bar cage in which reinforcing bars and connecting bars to the footing are arranged is installed. (Not shown)

  Various measures have been taken to reinforce the pile head of the upper pile. Patent Literature 3 is an example of this. In this example, an outer pipe (steel pipe) is arranged around the outer periphery of a pile head of a ready-made pile, and the pile head is reinforced with a double pipe structure.

JP 2009-263881A JP 2001-336147 A JP 2001-107356 A

  When trying to seismic reinforcement of the upper pile by the ready-made pile, in the method of casting concrete inside the pile diameter of the pile head in the upper pile as described above, although the pile head becomes strong, it can be seismic reinforcement, Since the filler shown in (b) is hardened, it is difficult to remove it, and the concrete casting shown in (c) also requires labor and cost.

  In the method of reinforcing a pile head using an outer pipe (steel pipe) as disclosed in Patent Document 3, the construction is complicated, and the labor and cost are increased by the outer pipe (steel pipe) and the amount of the work.

  The present invention provides a pile foundation in which at least an upper pile or a pile head of the upper pile is subjected to seismic reinforcement in a pile foundation in which a ready-made pile having a hollow inside the pile diameter is buried in consideration of the above-described problem. It is another object of the present invention to provide a pile foundation structure construction method capable of easily constructing the pile foundation structure without greatly changing the construction method of the conventional pile foundation structure or increasing the number of construction steps.

  The present inventors have conducted intensive studies to achieve the above object, and as a result, if at least the purpose is to provide seismic reinforcement to the upper pile or the pile head of the upper pile, fill the inside of the pile diameter of the upper pile or the like. It is sufficient to use cement milk instead of concrete.If a rotating cap used to bury ready-made piles is provided with a function to discharge cement milk, the upper pile and upper pile can be used without greatly changing the conventional pile foundation structure construction method. The present inventors have found that seismic reinforcement can be applied to a pile head or the like of a pile and completed the present invention.

One invention of the present application, the Kuiana the mixture of pile circumferential fixative and drilling soil is filled, a pile foundation structure pile radially inner portion formed by burying a hollow concrete prefabricated piles are embedded The pile diameter inside the ready-made pile is at least between the upper end position of the upper pile and a position 20 m below the upper end position and a cement milk layer of cement milk filled in a range of a predetermined depth from the upper end position. A pile foundation comprising a layer below and a layer of a mixture of a pile periphery fixing liquid and excavated earth and sand , wherein the unconfined compressive strength of the hardened cement milk is 5 to 65 N / mm ^2. Structure.

  The pile foundation structure of the present invention is a pile foundation structure made of ready-made piles constructed in the ground as a foundation for an upper structure such as a building or a footing.

  The pile hole in which the ready-made pile is buried is formed by a conventional method using an excavator such as an earth auger. The shape and dimensions of the pile hole are not particularly limited. For example, those having a straight shape, those having an enlarged diameter portion, and the like are available.

  As before, the pile hole is filled with a mixture of a pile periphery fixing liquid and excavated earth and sand, and a ready-made pile having a hollow inside of the pile diameter is buried before the mixture does not harden. Instead of the mixture, the bottom of the pile hole may be filled with a root compaction liquid or a mixture of the root compaction liquid and excavated earth and sand, and those filled are also included in the scope of the present invention. The pile circumference fixing liquid and the root compaction liquid may be those conventionally used, and these types are not particularly limited.

Pile-diameter portion which is embedded in the pile hole type hollow concrete prefabricated pile is not particularly limited. For example, concrete piles such as PC piles, PHC piles, and PRC piles; composite piles such as RC piles; SC piles; In many cases, the pile of the pile foundation in the present invention is formed by connecting a plurality of piles such as an upper pile and a lower pile, an upper pile, a middle pile, and a lower pile by a joint or the like. In some cases, a joint is not provided and used as a single pile. The upper pile also includes this single pile.

The pile foundation structure of the present invention is obtained by embedding a ready-made pile having a hollow inside of a pile diameter in a pile hole filled with a mixture of a pile periphery fixing liquid and excavated earth and sand. The mixture is filled into the space between the peripheral wall of the pile and the outer surface of the buried pile (upper pile, middle pile, lower pile, etc.) and inside the pile diameter of the ready-made pile as the middle pile or lower pile, and the mixture is hardened. The pile diameter of the ready-made pile within a range of a predetermined depth from the upper end of (within) 20 m or less (within) from the upper end of the upper pile of the buried ready-made pile has a structure in which cement milk is filled and hardened. I have. With such a structure, seismic reinforcement of the upper pile or the pile head of the upper pile, which is the object of the present invention, can be achieved.

The reason that the filling range of the cement milk is a range of a predetermined depth from the upper end of 20 m or less (within) from the upper end of the upper pile of the buried ready-made pile is that the main bending moment acting on the pile at the time of the earthquake And the range of shear force. Since the filling range of the cement milk is within the pile diameter of the ready-made pile within a predetermined range from the upper end of the buried ready-made pile within 20 m or less (within) from the upper end of the upper pile, the upper pile is not necessarily required. It is not limited to the part, depending on the pile length of the upper pile, the filling range may extend to the inside diameter of the middle pile or the lower pile, and such a pile foundation structure is also within the scope of the present invention. included.

  The above-mentioned cement milk is obtained by kneading any one of various cements such as Portland cement such as ordinary Portland cement and Portland cement with high strength, mixed cement such as blast furnace cement, and eco-cement with kneading water having a water cement ratio of 50 to 150%. It is.

  If necessary, a chemical admixture such as a bleeding inhibitor, a retarder, a dispersant, a water reducing agent and the like, and a cement admixture such as activated silica powder and an expanding agent may be added. In addition, the cement milk may be mixed with excavated earth and sand or a pile periphery fixing liquid during the filling work, so that the cement milk includes those containing these contaminants.

The cured product of the cement milk preferably has a uniaxial compressive strength of 5 to 65 N / mm ² . By setting the strength within this range, the adhesive strength between the concrete in the pile body and the cement milk filled inside the pile diameter in the hollow ready-made pile is improved, so that the pile body and cement milk behave integrally against external forces such as shaking And sufficient seismic performance can be secured. If the strength exceeds 65 N / mm ² , the strength is excessive, and if it is desired to obtain the strength, the strength is good, but the construction may be difficult or the cost may be high.

  In order to achieve the uniaxial compressive strength in the above range, for example, a cement milk in an amount required to fill a predetermined filling range or more is poured into the filling range, and a mixture of a pile circumference fixing liquid and excavated earth and sand is mixed. May be replaced as much as possible with cement milk, or cement milk may be injected into the filling area after a pretreatment for removing the mixture present in the predetermined filling area with washing water.

  The pile foundation structure of the present invention can be obtained in a conventional pile foundation construction process. For example, as shown in FIG. 4, when excavating a pile hole with an earth auger, cement milk is discharged from a discharge port provided in a drilling head or a drilling rod, and a root consolidation liquid or a pile periphery is formed below the pile hole. A pile hole filled with a mixture of the fixing liquid and the excavated earth and sand and filled with cement milk is formed in the upper portion, and the pile foundation structure of the present invention can be obtained by burying a ready-made pile in the pile hole.

  Alternatively, as shown in FIG. 5, the ready-made pile is buried in a pile hole filled with a mixture of a consolidation liquid or a pile periphery fixing solution and excavated earth and sand, and then the buried ready-made pile is buried. The above pile foundation structure of the present invention can be obtained by injecting cement milk and filling the inside of the pile diameter by excavating the inside of the pile diameter of the upper pile with a small diameter drilling rod while removing the filled mixture.

  Alternatively, the above-described pile foundation structure of the present invention can also be obtained at the stage of burying a pile by using a special ready-made pile burying device (rotary cap) of the present invention as in the construction method of the present invention described later.

This ready-made pile embedding device as a rotating cap which is another one of the present invention is provided with a rotating cap body for holding and embedding the ready-made pile, and detachably detachable downward from the center of the rotating cap body. And a discharge liquid supply rod provided with a discharge port for discharging liquid.

  The structure and shape of the rotating cap body are not limited as long as the rotating cap body has a function of holding and burying the ready-made pile, and may be the same as the conventional one. For example, as described above, it is a hollow cylindrical shape having an open bottom surface, and engages with a projection provided on an outer peripheral surface of a pile head to suspend and hold a pile on an outer peripheral side surface of the cylinder. One having a notch to be obtained can be used.

  A discharge liquid supply rod provided with a discharge port for discharge liquid is detachably attached to the center (central shaft portion) of the rotary cap main body through a joint portion toward the lower side of the rotary cap main body.

  The discharge liquid supply rod is similar to a rod used in an excavator such as an earth auger, and a discharge port (a discharge port) through which a discharge liquid such as cement milk, washing water or the like can be discharged (sprayed) at a tip of the rod or a side surface of the rod. Including a nozzle). The discharge port is not particularly limited as long as it has a diameter and a shape that allows the discharge liquid to be jetted at a low pressure to a high pressure. The same discharge port as the conventional discharge port provided on the rod of the earth auger may be used.

  It is preferable that the discharge port is a nozzle, and the tip of the nozzle has a structure that can discharge the liquid in various directions at the same time or at the same time, since the above-mentioned cement milk can be efficiently filled.

  The inside of the discharge liquid supply rod is hollow, and a supply pipe for supplying the discharge liquid to the discharge port is arranged. This supply pipe may be the same as the conventional supply pipe provided on the rod of the earth auger.

  When the pile diameter of the pile to be buried is small, the diameter (inner diameter) inside the pile diameter becomes small, so that a simple injection pipe having the above-mentioned discharge port is preferable instead of the rod. In the present invention, the liquid supply rod including the injection pipe is also referred to as a discharge liquid supply rod.

  The length of the discharge liquid supply rod is preferably 1 to 20 m. Within this range, the cap, rod and head can be easily attached to the standard length leader of the pile driver, the head and rod can be easily inserted into the pile diameter, and the vertical stirring and discharge liquid Injection into the pile diameter is also easy. As described above, since the length of the filling range of the cement milk may be longer than the pile length of the upper pile, in such a case, the length of the discharge liquid supply rod is longer than the pile length of the upper pile to fill. Is also good. As described above, in the pile foundation structure of the present invention, since the cement milk is filled inside the pile diameter of the ready-made pile no more than 20 m from the upper end of the upper pile of the ready-made pile, the length of the discharge liquid supply rod is Need not be longer than 20 m.

  It is preferable that a plurality of stirring blades are provided on the outer surface of the discharge liquid supply rod (excluding the injection pipe). If there is a stirring blade, the mixture inside the pile diameter can be eliminated, or the mixture remaining in the pile diameter and the cement milk can be easily stirred, and the quality of the filled cement milk and the strength and workability can be ensured. Variation can be reduced.

  The stirring blade is of a blade shape or a screw type (spiral type). The dimensions are desirably the same as or less than the diameter of the excavating head described below.The installation position of the stirring blade is not particularly limited, and a plurality of blades may be located at any position. Is desirable.

  Further, it is preferable that a drilling head is provided at a tip of the discharge liquid supply rod (excluding the injection pipe). By rotating the excavating head, a mixture of the uncured pile circumference fixing liquid and the excavated earth and sand filled in the inside of the pile diameter can be dug up and pushed upward, so that the mixture can be easily removed.

  This excavation head is similar to the one attached to the tip of the earth auger. For example, there is an excavation claw at the tip, and a plate on a spiral of half a turn or more is attached.

  As one of the above-described methods of constructing the pile foundation structure of the present invention, there is a method of constructing using the above-described ready-made pile burying device of the present invention.

That is, a method for constructing a pile foundation structure, which is another one of the present invention, is the method for constructing a pile foundation structure described above, and holds the ready-made pile when burying the ready-made pile as an upper pile. A rotary cap body for embedding and using a ready-built pile embedding device as a rotary cap having a discharge liquid supply rod equipped with a discharge port for discharge liquid, which is mounted downward from the center of the rotary cap body, Holding the ready-made pile to be buried by the rotating cap body in a form in which the discharge liquid supply rod is inserted inside the pile diameter of the ready-made pile, self-sinking the ready-made pile, burying it by rotation, and installing an upper pile, After the completion of the upper pile installation, the rotating cap body is reversely rotated to remove the rotating cap body from the ready-made pile as the upper pile, and the cement milk is discharged from the discharge port while pulling up the ready-made pile burying device, The pile-diameter portion of the prefabricated pile as the pile is method for constructing a pile foundation structure characterized in that filling with cement milk.

  As described above, the use of the ready-built pile burying device of the present invention makes it possible to efficiently use the present invention in the conventional method of constructing a pile foundation (forming a pile hole, filling a soil cement-like material, and burying a ready-made pile). Pile foundation structure can be constructed.

  The pile foundation structure of the present invention to be constructed and the pre-built pile burying device of the present invention used for construction are as described above.

  In the construction method of the present invention, first, a pile hole filled with a mixture of a pile circumference fixing liquid and excavated earth and sand is formed by a conventional method using an excavator such as an earth auger. Next, before the mixture is hardened, ready-made piles other than the upper pile are buried in the pile holes by a conventional method. When burying, a conventional ready-built pile burying device (rotating cap) may be used, but the above-mentioned ready-made pile burying device of the present invention may be used.

  When burying and installing at least the upper pile, the above-mentioned prefabricated pile burying device of the present invention is used. A ready-made pile is gripped and lifted by the rotating cap body portion of the ready-made pile embedding device of the present invention in which a discharge liquid supply rod is attached to the rotating cap body downward from the main body, and the ready-made pile is embedded by self-sedimentation rotation. I do. When a ready-made pile is gripped and lifted, the discharge liquid supply rod is inserted into a pile diameter of the ready-made pile.

  When the installation to the upper pile is completed, the rotating cap body is rotated in the reverse direction to remove the rotating cap body from the ready-made pile as the upper pile, and the discharge port of the discharge liquid supply rod is pulled up while pulling up the ready-made pile burying device. Cement milk is discharged from the inside diameter of the ready-made pile as the upper pile, or the inside diameter of the pile from the upper pile to the middle pile, or the predetermined range of the inner diameter of the pile from the upper pile to the lower pile with cement milk. Fill.

  The filling of the cement milk may be performed by raising or lowering the ready-built pile burying device (the discharge liquid supply rod) once or plural times, and in the process, and such a filling method is also within the scope of the present invention. include.

  Further, the discharge of the cement milk from the discharge port of the discharge liquid supply rod (filling the inside of the pile diameter of the hollow pre-made pile) is performed when the rotary cap body is removed from the upper pile and the pre-made pile burying device is pulled up. Instead, it may be performed after pre-processing the inside of the pile diameter of the ready-made pile.

  For example, as the discharge liquid supply rod, a rod equipped with the excavating head and the stirring blade is used, and a pretreatment is performed such that the mixture filled in the pile diameter is discharged to the ground before discharging the cement milk. Thereafter, a filling operation of the cement milk may be performed.

  Alternatively, when removing the rotating cap body from the upper pile and pulling up the ready-built pile burying device, perform a pretreatment such as squirting high-pressure washing water to wash the inside of a predetermined range of pile diameters to be filled with cement milk, A filling operation of cement milk may be performed. Patterns for performing such preprocessing are also included in the scope of the present invention.

  The discharge port for the discharge liquid such as cement milk or the like is provided at any one of the end, the side, and both the end and the side of the discharge liquid supply rod. When the excavation head is attached to the tip of the rod, a discharge port may be provided only in the excavation head.

  The discharge of the discharge liquid such as cement milk, washing water or the like is performed by jetting at an appropriate low pressure to high pressure as necessary. Here, the low pressure is a pressure of about 2 MPa, and the high pressure is a pressure of about 18 MPa. Usually, the discharge pressure (injection pressure) is about 2 MPa when the cement milk is discharged from the head or rod of the earth auger when the pile hole is formed. If the pressure is too low, the filling efficiency of the cement milk will be poor, and the mixture of the mixture will be increased, resulting in poor quality of the filled cement milk. If the pressure is too high, the inner surface of the ready-made pile may be damaged.

  If the pile foundation formed below the building or footing is the pile foundation structure of the present invention, reinforcement is applied to the upper pile or the pile head where at least a large bending moment or shear force acts at the time of an earthquake Therefore, it becomes an earthquake-resistant pile foundation. Further, according to the method of constructing a pile foundation structure of the present invention using the ready-built pile burying device of the present invention, the pile structure can be easily prepared without greatly changing the conventional method of constructing a pile foundation or increasing the number of construction steps. Since the foundation structure can be constructed, the pile foundation using ready-made piles can be made earthquake-resistant without complicating the construction and significantly increasing the construction cost.

It is a figure showing an example of the pile foundation structure of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the ready-made pile embedding apparatus of this invention, and the state which attached it to the upper pile. (A) is an example using a drilling head and a stirring blade as a discharge liquid supply rod, (b) is an example using a supply pipe as a discharge liquid supply rod, and (c) is an AA of a rotary cap body. It is an example of the plane in FIG. It is a figure showing an example of the construction method of the pile foundation structure of the present invention. (A) is a diagram showing a state immediately before embedding a middle pile and a lower pile in a pile hole using a conventional rotating cap, and (b) is embedding an upper pile in a pile hole using the ready-made pile embedding device of the present invention. (C) is a diagram showing the state immediately before the pile is buried and the ready-built pile burying device is removed from the upper pile, and (d) and (e) are diagrams while the cement milk is injected into the pile diameter of the upper pile. A diagram showing a state in which the pile diameter of the upper pile is filled with cement milk by raising and lowering the ready-made pile burying device, and (f) shows a state in which the filling of the cement milk is completed and the pile foundation structure of the present invention is completed. FIG. It is a figure which shows an example of the method of constructing the pile foundation structure of this invention, without using the ready-made pile burying apparatus of this invention. (A)-(e) is a diagram showing the formation of a pile hole by an earth auger, and (f)-(g) is the embedding of a pile consisting of a lower pile, a middle pile, and an upper pile into a pile hole by a conventional rotating cap. (H) is a diagram showing a state in which the burial of the pile is completed and the pile foundation structure of the present invention is completed. It is a figure which shows an example of the method of constructing the pile foundation structure of this invention, without using the ready-made pile burying apparatus of this invention. (A)-(b) is a view showing the burial of a pile consisting of a lower pile, a middle pile, and an upper pile by a conventional rotating cap in a pile hole, and (c)-(d) are diagrams of the upper pile using a small diameter drilling rod. The figure which mainly shows excavating the mixture of the pile circumference fixation liquid and the excavated earth and sand filled inside the pile diameter, and discharging it to the ground, and FIG. (F) is a diagram showing a state in which the filling of the cement milk is completed and the pile foundation structure of the present invention is completed. It is a figure showing an example of the conventional pile head reinforcement method. (A) is a diagram showing a ready-built pile buried in a pile hole filled with a mixture of a pile circumference fixative and a mixture of excavated earth and sand using a rotating cap, and (b) is a diagram showing a pile head of an upper pile using a double scoop. FIG. 3C is a view showing a pile foundation in which pile heads are reinforced by placing concrete inside the pile diameter from which the filler has been removed, and FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments described below.

  Drawing 1 is a figure showing an example of pile foundation structure 1 of the present invention. In this example, a pile hole 3 is provided in the ground 2, and a pile made of ready-made piles (SC pile, PRC pile, PHC pile, etc.) including an upper pile 4 and a lower pile 5 is buried in the pile hole 3. .

  The bottom of the pile hole at the bottom of the pile is filled with a root compaction liquid 7 made of cement milk. The soil between the pile hole peripheral wall above the bottom of the pile hole and the outer surface of the pile, and part of the inside of the pile diameter of the lower pile 5 and the inside of the pile diameter of the upper pile 4 are made of a soil 6 composed of a mixture 6 of a pile periphery fixing liquid and excavated earth and sand. Cement is filled.

The pile circumference fixing liquid is cement milk, and the mixing ratio between the pile circumference fixing liquid and the excavated soil is 1: 9 to 9: 1. It is preferable to adjust the type and composition of the pile circumference fixing liquid so that the hardened uniaxial compressive strength of the mixture 6 of the pile circumference fixing liquid and the excavated earth and sand is about 0.1 to 3.0 N / mm ² . Cement milk is a cement slurry in which a cement admixture such as slag, a viscosity adjusting agent such as bentonite, a flow adjusting agent, and a chemical admixing agent such as a strength enhancer are added to cement.

Cement milk 8 is filled inside the pile diameter at the pile head of the upper pile 4. In this example, only the pile head of the upper pile 4 is used, but the entire pile inside the upper pile 4 or the upper pile 4 and the lower pile 5 may be filled. The cured product obtained by curing the cement milk 8 preferably has a uniaxial compressive strength of 5 to 65 N / mm ² . Within this range, the seismic reinforcement effect can be obtained without greatly impairing the workability and without significantly increasing the cost.

  The filling range of the cement milk 8 is within the pile diameter of the ready-made pile 20 m or less from the upper end of the upper pile 4 of the buried ready-made pile. The reason for setting the length to 20 m or less is that this range is the range of the main bending moment and shear force acting on the pile during an earthquake.

  If the pile foundation constructed under the building or the footing is the pile foundation structure 1 of the present invention as described above, the pile top which is susceptible to damage such as buckling due to a large earthquake becomes strong, so that the earthquake-resistant pile is formed. The basis is obtained.

  FIG. 2 is a diagram showing a ready-built pile burying device 11 of the present invention and a state where it is attached to an upper pile 13. (A) is an example using a drilling head 16 and a stirring blade 17 as a liquid supply rod 10, (b) is an example using a supply pipe 20 as a liquid supply rod, and (c) is a rotary cap body. 9 is an example of a plane at AA.

  The prefabricated pile burying device 11 of the present invention includes a rotating cap body 9 and a liquid supply rod 10. The rotating cap body 9 is the same as the conventional one, and the upper surface can be connected to the Yatsuko rod 18 via the joint 15.

  FIG. 1 (a) shows a cylindrical shape having a hollow and open bottom surface, and a projection provided on an outer peripheral surface of a pile head for hanging and holding a pile on an outer peripheral side surface of the cylinder. Has a notch 12 that can be engaged with the notch.

  As shown in (c) of the figure, an opening 22 is provided on the upper surface of the rotating cap main body 9 so that the filler 6 inside the pile diameter inside 14 can be discharged to the ground as needed. Therefore, it is preferable that the opening area of the opening 22 is large.

  The ready-built pile burying device 11 of the present invention includes a discharge liquid supply rod 10. The upper end of the liquid supply rod 10 is attached to the upper bottom surface of the rotary cap body 9.

  The discharge liquid supply rod 10 is attached downward from the center of the rotating cap body 9 as shown in the figure. The attachment is detachable from the rotary cap main body 9 via the joint 15, and the length of the rod can be changed by providing a plurality of joints 15.

  The discharge liquid supply rod 10 shown in FIG. 1A includes a digging head 16 and a stirring blade 17. The excavating head 16 has an excavating claw at the tip and a spiral plate of half or more turns, and the stirring blade 17 is a blade-shaped or screw type (spiral type).

  A discharge port 19 for discharging (ejecting) a discharge liquid such as cement milk is provided in the vicinity of these. In the example of FIG. 2A, the discharge port 19 is provided only near the tip of the excavation head 16. However, if necessary, the discharge port 19 may be provided near the stirring blade 17 or the outer surface of the discharge liquid supply rod 10. Good. The discharge port 19 is a nozzle, a discharge valve, or the like. When the discharge liquid is ejected at a high pressure, a nozzle is used.

  The provision of the excavating head 16 and the stirring blade 17 facilitates discharge of the filler (a mixture of the perimeter fixing liquid and the excavated earth and sand) filled into the pile diameter to the ground through the opening 22, By providing the discharge port 19 as described above, it is possible to efficiently and effectively fill the pile diameter inside 14 with the cement milk.

  The discharge liquid supply rod 10 has a double pipe structure in which an inner pipe serving as a discharge liquid transport pipe is installed inside, so that a discharge liquid such as cement milk can be sent to the discharge port 19.

  The discharge liquid supply rod shown in FIG. The injection pipe 20 is provided with a discharge port 19 having an opening / closing lid 21 at least at the end, and a valve for preventing backflow from the discharge port 19 is provided at the back of the discharge port 19. When the pile diameter of the pile to be buried is small, the diameter (inner diameter) of the inside 14 of the pile diameter becomes small. Therefore, a simple injection pipe 20 having a discharge port 19 at the tip or the like is preferable instead of the discharge liquid supply rod 10.

  The inside of the injection pipe 20 also has a double pipe structure capable of pumping a discharge liquid such as cement milk or the like, so that the discharge liquid such as cement milk can be supplied to the discharge port 19 at the tip. The opening / closing lid 21 is operated by a discharge pressure from the inside, and is closed except when discharging the discharge liquid. In this example, the discharge port 19 is provided only at the tip of the injection pipe 20, but a plurality of discharge ports 19 may be provided on the side of the injection pipe 20 as needed.

  FIGS. 2A and 2B are views showing a state where the ready-made pile burying device 11 of the present invention is attached to the upper pile 13. As shown in the figure, the ready pile burying device 11 grips the upper end of the upper pile 13 (hollow ready pile) with the rotating cap body 9 and inserts the discharge liquid supply rod 10 into the inside 14 of the pile diameter. Attached to.

  In this example, a protrusion (not shown) that fits into the notch 12 of the rotating cap body 9 is provided on the side surface of the pile head of the upper pile 13, and the protrusion and the notch 12 fit together. By doing so, the ready-made pile burying device 11 can hold (grasp and lift) the upper pile 13. The method of holding the upper pile 13 by the ready-built pile burying device 11 is not limited to this, and other conventional methods may be used as long as the configuration of the ready-built pile burying device 11 of the present invention is not changed.

  FIG. 3 is a diagram illustrating an example of a method for constructing a pile foundation structure according to the present invention. (A) is a diagram showing a state immediately before the lower pile 5 is buried in the pile hole 3 using the conventional rotating cap 23, and (b) is a diagram showing the upper pile 4 using the ready-built pile burying device 11 of the present invention. 3 shows a state immediately before the pile is buried, (c) is a diagram in which the burying of the pile is completed, and the ready-made pile burying device 11 is removed from the upper pile 4, and (d) and (e) show that the cement milk 8 is removed from the upper pile 4. A diagram showing a state in which the ready-built pile burying device 11 is moved up and down while pouring the cement milk 8 into the inside of the pile diameter 14, and the cement milk 8 is filled in the pile diameter inside 14 of the upper pile 4. FIG. It is a figure which shows the state which was completed and the pile foundation structure 1 of this invention was completed.

  In this example, the pile buried in the pile hole 3 includes an upper pile 4, a middle pile 24, and a lower pile 5. The pile may be composed of the upper pile 4 and the lower pile 5 and is not limited to these.

  The pile hole 3 is filled with a mixture 6 of a pile periphery fixing liquid and excavated earth and sand, which were formed at the time of forming the pile hole, as shown in FIG. A conventional rotating cap 23 is attached to the upper end of the lower pile 5, and the lower pile 5 is buried in a predetermined position of the pile hole 3 while being held by the conventional rotating cap 23 and self-rotating by a conventional method. . The middle pile 24 is also buried in the pile hole 3 while being self-sinking and rotating by the conventional method using the conventional rotating cap 23 so as to be connected to the lower pile 5 (not shown). In this example, the conventional rotary cap 23 was used when burying the middle pile 24 and the lower pile 5. However, the present invention is not limited to this. May be used.

  When burying at least the upper pile 4, the existing pile burying device 11 of the present invention is used instead of the conventional rotary cap 23. A drilling head and a stirring blade are provided at the tip of the liquid supply rod 10 in the ready-built pile burying device 11.

  As shown in FIG. 2B, the upper end of the upper pile 4 is gripped by the rotating cap body 9 so that the discharge liquid supply rod 10 of the ready pile burying device 11 is inserted into the inside of the upper pile 4 pile diameter. The burying device 11 is attached to the upper end of the upper pile 4. Thereafter, by rotating the rotating cap body 9 forward, the upper pile 4 is buried in the pile hole 3 while rotating by itself.

  When the pile is buried, the rotating cap body 9 of the ready-built pile burying device 11 is removed from the pile by rotating in the reverse direction as shown in FIG. By rotating forward, the mixture 6 of the pile periphery fixing liquid and the excavated earth and sand filled in the pile diameter inside 14 of the upper pile 4 via the excavation head and the blades of the stirring blades is pushed upward, and The mixture 6 with the excavated earth and sand is discharged to the ground. At this time, the inside of the pile diameter 14 in the filling range may be cleaned by discharging (spraying) high-pressure washing water or cement milk from the discharge port 19. The step (c) is performed after the pile is buried and before the mixture 6 of the pile periphery fixing liquid and the excavated earth and sand starts to harden.

  Thereafter, as shown in (d) to (e) of the drawing, the ready-built pile embedding device 11 is moved up and down while discharging the cement milk 8 having a predetermined composition and a predetermined density from the discharge port 19 of the discharge liquid supply rod 10. While further discharging the mixture 6 of the peripheral fixation liquid and the excavated earth and sand to the ground, the cement milk 8 is filled in a predetermined filling range as shown in the figure.

  When the filling is completed, as shown in (f) of the figure, the ready-built pile burying device 11 of the present invention is taken out from the pile hole 3, and the mixture 6 of the cement milk 8, the pile circumference fixing solution, and the excavated soil is sufficiently hardened. The pile foundation structure 1 of the present invention is completed.

  As described above, the use of the ready-built pile burying device of the present invention makes it possible to easily obtain the foundation pile structure 1 of the present invention in which the pile head of the foundation pile is made earthquake-resistant, without substantially changing the conventional construction process.

  FIG. 4 is a diagram showing an example of a method of constructing the pile foundation structure 1 of the present invention without using the above-described pile burying device of the present invention. (A)-(e) is a figure which shows formation of the pile hole 3 by the earth auger 25, (f)-(g) The pile which consists of the lower pile 5, the middle pile 24, and the upper pile 4 by the conventional rotating cap 23. (H) is a diagram showing a state in which the embedding of the pile is completed and the pile foundation structure 1 of the present invention is completed.

  The pile foundation structure 1 of the present invention can be constructed in the conventional pile foundation construction as in the example shown in FIG. 4 without using the method using the ready-made pile burying device of the present invention as described above. .

  As shown in the figures (a) to (c), first, a target pile hole 3 is formed by an excavator such as an earth auger 25 or the like. Then, as shown in (d) of the figure, at the time of excavation or when the excavator such as the earth auger 25 is lifted, the pile hole 3 is filled with the mixture 6 of the pile periphery fixing liquid and the excavated earth and sand. In most cases, the bottom of the pile hole 3 is filled with the root compaction liquid 7.

  In the upper part of the pile hole 13, the excavated earth and sand is discharged to the ground as much as possible, and then the cement milk 8 is filled by discharging cement milk from a discharge port provided in the excavator such as the earth auger 25. Therefore, as shown in (e) of the figure, the pile hole 3 has a structure in which the lower part is filled with the mixture 6 of the pile circumference fixing liquid and the excavated earth and sand, and the upper part is filled with the cement milk 8. I have.

  Thereafter, as shown in (f) to (g) of the figure, before the mixture 6 of the pile circumference fixing liquid and the excavated earth and sand and the cement milk 8 are hardened, the pile is buried by the conventional method using the rotating cap 23. I do. Then, as shown in (h) of the figure, the pile foundation structure 1 of the present invention can be constructed in the conventional pile foundation construction.

  As described above, it is not always necessary to use the ready-made pile burying device 11 of the present invention to construct the pile foundation structure 1 of the present invention. However, according to this method, the cement milk moves when the pile is inserted. In order to reliably fill the filling range, there is a possibility that a problem that the filling range needs to be longer than the filling range may occur. Therefore, the above-described construction method using the ready-built pile burying device of the present invention is used. Is more preferred.

  As a method of constructing the pile foundation structure of the present invention without using the ready-made pile burying device of the present invention, there is also the following method.

  FIG. 5 is also a diagram showing an example of a method of constructing the pile foundation structure 1 of the present invention without using the above-described pile burying device of the present invention. (A)-(b) is a figure which shows the embedding of the pile which consists of the lower pile 5, the middle pile 24, and the upper pile 4 in the pile hole 3 by the conventional rotating cap 23, (c)-(d) is small diameter excavation. FIG. 6E is a view mainly showing excavation of a mixture 6 of a pile periphery fixing liquid and excavated earth and sand filled in the pile diameter inside 14 of the upper pile 4 with the rod 26 and discharging the mixture 6 to the ground, and FIG. FIG. 3F is a diagram showing the filling operation of the cement milk 8 into the inner diameter 14, and FIG. 4F is a diagram showing a state in which the filling of the cement milk 8 is completed and the pile foundation structure 1 of the present invention is completed.

  The pile foundation structure 1 of the present invention can be constructed without using the ready-made pile burying device of the present invention other than the method shown in FIG.

  In the method shown in FIG. 5, first, a pile hole 3 filled with a mixture 6 of a pile periphery fixing liquid and excavated earth and sand is formed by a conventional method using an earth auger or the like (not shown), and (a) to () of the drawings. As shown in b), the pile is buried in a conventional manner using the rotating cap 23. Thereafter, as shown in (c) to (e) of the drawing, the pile circumference fixed liquid filled in the pile diameter inside 14 using the small diameter drilling rod 26 insertable into the pile diameter inside 14 of the upper pile 4 and excavation. While removing the mixture 6 with the earth and sand, the removed portion is filled with cement milk 8. The operations (c) to (e) are preferably performed before the mixture 6 of the pile periphery fixing liquid and the excavated earth and sand is hardened. After the curing, the removal operation becomes difficult.

  When the filling is completed, the small diameter drilling rod 26 is removed from the pile hole 3 and the mixture 6 of the cement milk 8, the pile circumference fixing liquid, and the excavated earth and sand is sufficiently hardened, as shown in FIG. Is completed.

  Even with such a method, the pile foundation structure 1 of the present invention can be constructed without using the ready-made pile burying device of the present invention. However, according to this method, (1) when the burial position of the upper pile is deep, small-diameter excavation When the rod is inserted inside the pile diameter, it may contact the pile and push the pile. (2) There is a problem that the muddy water remaining at the top of the pile hole is pushed into the pile diameter when the small diameter drilling rod is inserted Because of the possibility, the construction method using the above-mentioned ready-built pile burying device of the present invention is also preferable.

  DESCRIPTION OF SYMBOLS 1 ... Pile foundation structure, 2 ... Ground, 3 ... Pile hole, 4 ... Upper pile, 5 ... Lower pile, 6 ... Mixture of pile circumference fixing liquid and excavated earth and sand, 7 ... Root compaction liquid, 8 ... Cement milk, 9 ... Rotating cap body, 10 ... Discharge liquid supply rod, 11 ... Prefabricated pile burying device, 12 ... Notch, 13 ... Upper pile (hollow prefabricated pile), 14 ... Pile diameter inside, 15 ... Joint part, 16 ... Drilling head, 17: stirring blade, 18: Yatsuko rod, 19: discharge port, 20: injection pipe (discharge liquid supply rod), 21: opening / closing lid, 22: opening, 23: conventional rotating cap, 24: middle pile, 25 ... Earth Auger, 26 ... Small Drilling Rod, 27 ... Auger Drive, 28 ... Double Scoop, 29 ... Concrete, 30 ... Bucket

Claims (7)

The Kuiana the mixture of excavated soil and the pile circumferential fixative is filled, a pile foundation structure pile radially inner portion formed by burying a hollow concrete prefabricated pile, pile diameter inner portion of the buried the prefabricated pile A cement milk layer filled with cement milk at least between the upper end position of the upper pile and a position 20 m below the upper end position and a predetermined depth from the upper end position, and a pile peripheral fixing liquid thereunder. And a layer made of a mixture of excavated earth and sand, the pile foundation structure having a uniaxial compressive strength of 5 to 65 N / mm ² , wherein the cured product of the cement milk is 5 to 65 N / mm ² . It is a ready-built pile burying device as a rotating cap used when constructing the pile foundation structure according to claim 1, wherein the ready-made pile burying device is a rotating cap body for holding and burying the ready-made pile. And a discharge liquid supply rod, which is detachably mounted downward from the center of the rotary cap body and has a discharge liquid discharge port. 3. The ready-built pile burying device according to claim 2 , wherein a plurality of stirring blades are provided on an outer surface of the discharge liquid supply rod. 4. Wherein the tip of the ejection liquid supply rod, ready-made pile embedded device according to claim 2 or 3, characterized in that are equipped with drilling head. The method for constructing a pile foundation structure according to claim 1, wherein, when burying the ready-made pile as an upper pile, a rotary cap body for holding and burying the ready-made pile, and Using a ready-built pile burying device as a rotating cap having a discharge liquid supply rod provided with a discharge liquid discharge port, which is mounted downward from the center, and the discharge liquid supply rod is inserted into the pile diameter of the ready-made pile. The ready-made pile to be embedded by the rotating cap body is held in a form to be buried, the ready-made pile is buried by self-sinking rotation, and the upper pile is installed. Remove the cap body from the ready-made pile as an upper pile, discharge cement milk from the discharge port while pulling up the pre-made pile burying device, and cement milk inside the pile diameter of the ready-made pile as the upper pile. Method for constructing a pile foundation structure, characterized in that the filling. The method according to claim 5 , wherein a plurality of stirring blades are provided on an outer surface of the discharge liquid supply rod. Wherein the tip of the ejection liquid supply rod, method for constructing a pile foundation structure according to claim 5 or 6, characterized in that are equipped with drilling head.

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