JP2009174232A - Foundation pile construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a foundation pile construction method which is excellent in workability and positively obtains support force even if a long pile body is employed. <P>SOLUTION: The foundation pile construction method is carried out by using an auger having an excavating blade, and a rotary pressing pile device 1 having an excavating blade 16 larger than the pile body 2 on a distal end 3 of the pile body 2 and pressed for excavation by axial rotation. According to the method, the ground is preliminarily excavated by the auger to form an excavated hole 61, and a foot protection liquid is injected to a lower portion of the excavated hole 61 to form a foot protection portion 62 formed of a mixture consisting of the foot protection liquid and soil, followed by drawing up the auger 51. After back filling discharged soil into the excavated hole 61, the rotary pressing pile device 1 is axially rotated to pressing the pile body 2 into the excavated hole 61. By virtue of the preliminary excavation of the auger 51, even a long pile is easily built in, and by virtue of the foot protection portion 62 formed by the auger 51, predetermined support force is obtained. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for constructing a foundation pile for reinforcing a ground portion which is a foundation of a building or a civil engineering structure.

  Conventionally, a pre-boring method has been known as a construction method for this type of foundation pile. Cement milk is poured into a drill hole drilled in advance by an auger, and the cement milk and earth and sand are mixed together. Fill with cement, pull up the auger, rotate and press the pile body into the excavation hole, and fix it at a predetermined depth.

  However, this pre-boring method discharges muddy water residual soil corresponding to the volume of the foundation pile, and this residual soil is an industrial waste containing cement-based solidified material, and there is a problem that the treatment cost is high.

  On the other hand, a tip member made of a short pipe having a connecting portion to which a torque transmission device is connected and having a blade attached to the tip or outer periphery, and the tip is rotatable to the short pipe of the tip member. And a steel pipe fitted or connected to the screw, and a torque transmission device is connected to the connecting portion so that torque transmission is possible and detachable. There exists a steel pipe pile and its construction method (for example, patent documents 1).

  However, in the screwed steel pipe pile with wings, the frictional drag generated from the unexcavated earth and sand on the side surface of the steel pipe pile body, the entire side surface of the steel pipe pile body, and the entire spiral surface of the wing increases in proportion to the depth of excavation. In addition, since there is no mechanism for compacting earth and sand corresponding to the volume of the steel pipe pile main body with rotational force, the construction requires a large pressing force and a strong torque and their power energy to rotate the steel pipe pile. There was a drawback. For this reason, construction on hard ground having a high N value (one of the indices indicating the strength of the ground) has become difficult, leading to an increase in construction costs.

  As a solution to such a problem, a steel pipe pile having a drilling blade at the tip and drilled and penetrated by rotating the shaft, a flange-shaped bottom expansion plate is formed on the outer periphery of the lower end of the steel pipe pile, and the bottom expansion With the outer peripheral point of the steel pipe pile where two radial lines having a predetermined included angle intersect at one or more places on the plate as the rotation axis, the two radial lines are respectively set in the reverse direction of the steel pipe pile. An escape opening is formed by notching between the line segments rotated by an angle, and an upper blade extending upward in the reverse rotation direction at a predetermined inclination angle is attached to the edge of the escape opening on the forward rotation direction side. In addition, a lower blade extending downward in the forward rotation direction at a predetermined inclination angle is attached to an edge portion on the reverse rotation direction side of the relief opening, and the excavation blade is radially extended from the center by one or more blade bodies There exists a rotation penetration steel pipe pile (for example, patent documents 2).

In this rotary penetrating steel pipe pile, the earth and sand excavated by the shaft rotation of the steel pipe pile is positively and forcedly discharged to the outer peripheral side of the steel pipe pile to be consolidated, so that the driving energy of the smaller shaft rotation can be reduced. Not only is it possible to ensure efficient penetration into the ground with a high N value, but it also realizes no discharge soil, low vibration, and low noise, which are the characteristics of conventional steel pipe piles that are buried under rotation.
JP-A-11-303069 JP 2003-27475 A

  However, in the above-mentioned Patent Document 2, since the steel pipe pile provided with the excavating blade is press-fitted while rotating, a large frictional force is generated between the steel pipe pile and the earth and sand of the excavation hole, and the steel pipe pile is elongated. If it becomes, there exists a problem that workability falls.

  Then, this invention intends to solve such a problem, and provides the construction method of the foundation pile which is excellent in workability even if it uses a long pile main body, and can obtain a supporting force reliably. For the purpose.

  The invention of claim 1 uses an auger having excavation blades and a rotary press-fitting pile device having a excavation blade larger than the pile main body at the tip end portion of the pile main body, and excavating and press-fitting by axial rotation. To form a drilling hole, injecting root-setting liquid into the lower part of the drilling hole to form a root-solidifying part made of a mixture of the root-setting liquid and earth and sand, pulling up the auger, and discharging the earth and sand In this construction method, the pile body is press-fitted into the excavation hole by rotating the rotary press-fitting pile device after being backfilled in the excavation hole.

  The invention according to claim 2 is a construction method in which a diameter of the excavation blade is larger than a diameter of the excavation blade.

  According to a third aspect of the present invention, the auger is provided with a tip bit, and after the injection of the root-setting liquid, the auger reciprocates a plurality of times in the injection section to mix the root-setting liquid and the earth and sand. is there.

  Further, the invention of claim 4 is the construction method in which, in the excavation hole, the rooting portion having a length equal to or larger than the diameter of the pile main body is left below the tip portion.

  The invention of claim 5 is the construction method in which the root hardening liquid has an expansion function.

  In the present invention, preferably, the auger is used for preliminary excavation with a diameter substantially the same as the diameter of the pile main body, and a root consolidation portion composed of a mixture of a root consolidation liquid and earth and sand is formed at the tip of the pile, and the reverse rotation is performed. However, since the auger is pulled up, there is little discharge of excavated soil, and the earth and sand in the excavation hole can be softened by preliminary excavation, and after raising, the earth and sand are returned to the excavation hole. And, by applying rotary press-fitting while giving rotation in the excavation direction to the rotary press-fitting pile device, the earth and sand can be moved to the side and built up to a predetermined depth while being compacted, and the discharged soil is construction residual soil, processing Is easy.

  In this way, preliminary excavation improves the workability of long piles and enables reliable formation of root consolidation, and because it is non-draining, it becomes a construction method that considers pollution and the environment. The amount of settlement can be suppressed by the formation, and the support force can be increased. The friction force can be increased by using cement milk or the like having an expansion function as a root-setting liquid and extending the injection section.

  According to the configuration of claim 1, by performing preliminary excavation with an auger, it becomes easy to build even a long pile, and a predetermined supporting force is obtained by a root-fixing portion formed by an auger. The pre-excavated excavation hole can be consolidated by a rotary press-fitting pile device having an excavation blade larger than the main body.

  Moreover, according to the structure of Claim 2, it becomes the thing excellent in the consolidation effect of the excavation hole.

  Moreover, according to the structure of Claim 3, a root hardening liquid and earth and sand are mixed well, a root hardening part and the circumference | surroundings can be integrated and the stable support force is obtained.

  Moreover, according to the structure of Claim 4, the support force by a root hardening part becomes stable.

  Moreover, according to the structure of Claim 5, the support force by a root hardening part can be improved.

  Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all the configurations described below are not necessarily essential requirements of the present invention. In each Example, the foundation pile construction method which is not in the past is obtained by adopting the foundation pile construction method different from the conventional one, and the foundation pile construction method is described respectively.

  Hereinafter, Example 1 of the construction method of the foundation pile of this invention is demonstrated with reference to FIGS. As shown in FIG. 5 to FIG. 12, the rotary press-fitting pile device 1 is a pile main body 2 made of a hollow pile or a steel pipe, a tip portion 3 provided at the tip of the pile main body 2, and the tip portion 3 is rotated. And a rotary press-fitting drive means 4 for press-fitting. The pile body 2 and the tip portion 3 constitute a pile. The tip portion 3 includes a tip body 5 that connects the pile body 2, a rotation transmission body 6 is detachably coupled to the tip body 5, and a blade body 7 is provided at the tip of the tip portion 3. . And the said front-end | tip part 3 and the rotation transmission body 6 are steel. Similarly, the blade body 7 is made of steel, or is made of a hard material having higher strength. The rotation transmitting body 6 is provided at the tip of the rotating rod 8. A passage 6A is formed in the rotation transmitting body 6, and the passage 6A communicates with the passage 8A of the rotating rod 8.

  In this example, the rotation direction at the time of the rotation penetration of the tip portion 3 will be described as a plane clockwise direction indicated by an arrow in FIG.

  The tip body 5 includes a connecting portion 11 that is rotatably fitted to the tip of the pile body 2, and the connecting portion 11 is a tubular body such as a steel short pipe, and a flange-like shape is formed at the tip of the connecting portion 11. The bottom expansion plate 12 is welded. The outer diameter of the bottom plate 12 is larger than the outer diameter of the pile body 2, and for example, the outer diameter of the bottom plate 12 is about 1.5 to 2.0 times the outer diameter of the pile body 2. A pair of openings 13 and 13 are formed in the bottom plate 12 at a target position around the axis of the tip portion 3.

  As shown in FIGS. 7 and 8, the opening 13 is positioned closer to the rotational direction side with respect to a diametrical line segment that is parallel to the opening 13 and passes through the center of the tip portion 3.

The edge 13A on the rotational direction side of the opening 13 is provided with an upper blade 14 extending in the reverse rotational direction at an inclination angle θA that is an angle with respect to the bottom expansion plate 12, and the edge 13B on the reverse rotational direction side of the opening 13 is provided. Is provided with a lower blade 15 that extends downward in the rotational direction at an inclination angle θB that is an angle with respect to the expanded base plate 12. And the excavating blade 16 larger in diameter than the pile main body 2 is constituted by the bottom expanded plate 12, the upper blade 14 and the lower blade 15. The diameter D ₀ of the excavation blade 16 is substantially equal to the diameter of the bottom expansion plate 12.

  The inclination angle θB is set to about 40 to 80 degrees. If the inclination angle θB is increased, the digging performance is improved, but the required torque required for rotational driving is increased, so that the soft soil is large and the hard soil is small. As a result of the experiment, it was found that 50 to 70 degrees (50 degrees or more and 70 degrees or less) is preferable.

  A connecting opening 21 is formed in the center of the bottom plate 12. On the distal end side of the connection opening portion 21, arc-shaped engagement members 22, 22 projecting inward are provided at the edge of a circle centering on the axial center of the distal end portion 3. The inner edge 22A has an arc shape centered on the axis. In addition, a front end cylinder part 23 is fixed to the bottom expansion plate 12 so as to close the connection opening 21, and the front end of the front end cylinder part 23 is closed by a cover plate 24, and the pair of blade bodies on the cover plate 24 7,7 are provided.

  The distal end side of the rotation transmission body 6 is inserted and connected to the connection opening 21 and the distal end cylinder portion 23 so as to be detachable, and the distal end of the rotation transmission body 6 projects from the distal end surface of the bottom expansion plate 12 in the connected state. It is inserted into the cylinder part 23. A tip end side of the rotation transmission body 6 has a substantially cylindrical shape, and a pair of insertion groove portions 31 and 31 into which the pair of engagement members 22 and 22 can be inserted from the axial direction are formed on the outer periphery of the tip end. The distal end side of this has an arc shape in a flat cross section, and an engagement groove portion 32 that is wide on one side in the arc direction (the counter-rotating direction of the rotating rod 8) is formed continuously from the insertion groove portion 31 on the proximal end side of the insertion groove portion 31. The engagement member 22 is movable along the engagement groove 32.

  The base end portion 6K of the rotation transmitting portion 6 is formed to be narrower than the tip end side, and the tip of the rotating rod 8 of the rotary press-fitting drive means 4 is inserted and fixed. The rotary rod 8 is a rotation transmission shaft that transmits the rotation of the rotary press-fitting drive means 4 to the rotation transmission body 6.

  Therefore, the insertion grooves 32 and 32 are aligned with the engaging members 22 and 22, the distal end of the rotation transmission body 6 is inserted into the connection opening 21, and the distal end surface of the rotation transmission body 6 comes into contact with the lid body 24 to rotate. By rotating the rod 8 in the excavation direction, the engaging members 22 and 22 are engaged with the engaging groove portions 32 and 32, and the rotation of the rotating rod 8 is transmitted to the distal end portion 3 in the retaining state. Is rotated in the anti-excavation direction, and the engagement members 22 and 22 are aligned with the insertion grooves 32 and 32, whereby the rotation transmission body 6 can be pulled out from the tip portion 3.

  As shown in FIG. 7 and the like, the blade bodies 7 and 7 are respectively provided at target positions with respect to the axis, and the blade bodies 7 and 7 are parallel to a diameter line segment passing through the axis of the rotation transmission body 6. And it is located in the rotation direction side and provided in parallel with an interval 41. Then, as shown in FIG. 10, the tips of the blade bodies 7, 7 are on the center side of the tip portion 3, and the tip edge 71 intersects with the shaft core, and continues to the tip edge 71 toward the outer peripheral side. An inclined edge 72 that is lowered is formed. Thus, the effect which pushes excavation earth and sand to an outer peripheral direction increases by providing the space | interval 41 between the blade bodies 7 and 7 and providing two sheets. In addition, an opening 25 is formed in the center of the lid 24, and cement milk, compressed air, compressed water, or the like can be sprayed from the opening 25 toward the tip side. At the time of rotation penetration, both or one of compressed air and compressed water can be injected from the opening 25 through the passage 8 </ b> A in the rotating rod 8 through the rotation transmission body 6 connected to the rotating rod 8.

  Further, a packing 81 which is a water stop material is fitted into the tip of the passage 6A of the rotation transmission body 6, and the packing 81 has a cylindrical shape, and the packing 81 comes into contact with the lid body 24, whereby the passage 8A. Compressed air, compressed water, etc. are prevented from leaking into the pile body 2.

  And the front-end | tip of the hollow pile main body 2 is inserted in the connection part 11 of the front-end | tip part 3, and the rotation transmission body 6 and the rotation rod 8 are inserted in the pile main body 2. FIG.

  As shown in FIGS. 1 and 3, an auger 51 that performs preliminary excavation has a spiral excavation blade 53 at the tip of a stirring rod 52, and a plurality of bits 54 are provided at the tip of the excavation blade 53. . The stirring rod 52 is provided with a plurality of stirring blades 55 at intervals, and these stirring blades 55 are provided radially. Specifically, in the same place, a pair of stirring blades 55, 55 are provided at positions that are 180 degrees from each other, and the stirring blades 55, 55 adjacent to each other in the length direction of the stirring rod 52 have an angle of approximately 90 degrees with each other. It is arranged at the position to make. Further, each stirring blade 55 is attached obliquely in the same direction as the inclination direction of the excavation blade 53. The diameter of the excavation blade 53 of the auger 51 is equal to the diameter of the pile body 2.

  Further, a liquid feeding path 56 is provided in the stirring rod 52, and a rooting liquid such as drilling liquid or cement milk having an expansion function is injected into the drilling hole 61 from a discharge port 57 at the tip. In addition, water is illustrated as a drilling liquid. In this case, on the ground, an injection driving device 58 is connected to the rotating rod 8, and the rooting liquid is discharged from the discharge port 57 through the rotating rod 8. The injection drive device 58 is a compressor if it is compressed air, and a pump if it is compressed water.

  In such a rotary press-fit pile device 1, as described above, the distal end side of the rotation transmission body 6 is inserted into the connection opening 21 and rotated by a predetermined angle to connect the rotation transmission body 6 and the distal end body 5. Then, the rotary rod 8 is rotated and press-fitted by the ground rotary press-fitting drive means 4. In this case, it is preferable to push in so that the pile main body 2 may self-sink. That is, the pile body 2 sinks due to its own weight. When the rotating rod 8 rotates, only the tip portion 3 rotates, and the pile body 2 made of a hollow pile is pushed in without rotating. Due to the rotation of the tip portion 3, earth and sand is excavated by the lower blade 15. The excavated earth and sand moves to the base end side (upper surface in the figure) of the bottom expansion plate 12 through the opening 13, and is close to undisposed soil. The pile body 2 is pushed in the state. In this case, since the lower blade 15 is positioned in the rotational direction, the force of the arrow G is received from the earth by rotation, and this force is a force in the direction intersecting the rotational side surface of the lower blade 15, so that the rotating lower blade 15 generates a force to push the earth and sand in the outer circumferential direction, and similarly, the side surface in the rotational direction of the upper blade 14 and the side face in the rotational direction of the blade body 7B also push the earth and sand in the outer circumferential direction. Can be consolidated. And since the circumference | surroundings of the pile main body 2 are compacted in this way, while reducing waste soil, it can be set as a waste soil, and the supporting force by the consolidated part around the pile main body 2 also rises.

  Therefore, since the earth and sand of the excavation part is pushed to the periphery and the tip side of the excavation hole, the ground strength is improved by the consolidation effect. In addition, the support force can be increased by increasing the bottom plate 12 of the tip portion 3. Furthermore, the rotational torque during construction can be reduced due to the configuration of the tip portion, and no specially large construction machine is required.

  Then, when the pile main body 2 is self-sunk to a predetermined depth and stopped as described above, the rod 4A is slightly rotated in the reverse rotation direction, and the insertion groove portion 31 of the rotation transmission body 6 is aligned with the position of the engagement member 22, The rotation transmitting body 6 is pulled out from the connection opening 21 and collected together with the rotating rod 8 on the ground. Therefore, the bottom plate 12 that compensates the supporting force of the pile body 2 is left in the ground, and the rotation transmission body 6 can be used repeatedly.

  Next, the construction method of the foundation pile using the auger 51 and the rotary press-fit pile device 1 will be described.

  First, a preliminary excavation is performed by the auger 51. In this preliminary excavation, as shown in FIG. 1A, the auger 51 is aligned with the pile core position of the foundation pile, and the auger 51 is moved in the excavation direction by the rotary press-fitting drive means 4. As shown in FIGS. 1B and 1C, the excavation hole 61 is formed by excavating to the excavation lower end position having a predetermined depth. In this case, water that is the drilling fluid can be injected from the discharge port 57 until the lower end position is reached. When the tip of the auger 51 reaches the lower end position, as shown in FIG. 1D, a rooting liquid such as cement milk is injected from the discharge port 57, and the auger 51 is moved up and down by a predetermined height. (D) to (F), the auger 51 is reciprocated twice in the range of the height H while rotating in the excavating direction. During this up and down movement, it is preferable to inject a root hardening material. As a result, a root consolidation portion 62 made of a mixture of earth and sand and the root consolidation material in the excavation hole 61 is formed, and this root consolidation portion is formed from the lower end of the excavation to the height H. 1 (G) (H) in FIG. 1 while rotating the auger 51 in the direction opposite to the excavation direction from the position shown in FIG. As described above, after slowly pulling up and then pulling up, a small amount of excavated soil (not shown) discharged to the ground surface is filled back into the excavation hole 61. The height H is preferably 3 to 6 times, preferably 4.5 times the diameter of the pile body 2.

  After completing the preliminary excavation in this way, as shown in FIG. 2, the pile is built by the rotary press-fitting pile device 1.

As shown in FIG. 2 (I), the center of the tip portion 3 is aligned with the excavation hole 61, the axis of the pile body 2 is aligned with the excavation hole 61, and only the tip portion 3 is rotated by the rotation of the rotating rod 8. Then, the pile body 2 made of a hollow pile is pushed into the excavation hole 61. In this case, the diameter D ₀ of the excavating blade 16 at the tip portion 3 is larger than the diameter D of the excavating blade 53, and in this case, is 1.5 times or more of the previous diameter D, so that the excavating blade 16 is rotated. By press-fitting, the pile can be press-fitted to a predetermined depth while moving the earth and sand to the side and compacting. Incidentally, the tip body 5 of the pile is inserted to the position of a height H ₀ from the excavation bottom. The height H ₀ is 1.5 times or more the diameter D of the root hardening portion 62. In this example, the height H ₀ is 1.5D. As shown in FIG. 2 (K), the excavation is finished at the position where the root fixing portion 62 having the height H ₀ is located below the pile, and the rotating rod 8 is slightly rotated in the reverse rotation direction. The insertion groove 31 of the rotation transmission body 6 is aligned with the position, the rotation transmission body 6 is pulled out from the connection opening 21, and is collected together with the rotation rod 8 on the ground as shown in (L) to (N) of FIG. Therefore, the bottom plate 12 that compensates the supporting force of the pile body 2 is left in the ground, and the rotation transmission body 6 can be used repeatedly. Then, as shown in FIG. 2L, the rotating rod 8 is pulled up while injecting the filling material 63 into the pile body 2. In this case, cement milk is used for the filling material 63 in the same manner as the root hardening liquid. Further, the injection height H _N of the filling material 63 is set to be not less than three times the diameter D of the excavation blade 53. The diameter of the pile body 2 is substantially equal to the diameter D _S of the excavation hole 61 and the diameter D of the excavation blade 53.

  In this way, the auger 51 performs preliminary excavation with a diameter substantially the same as the diameter of the pile body 2 to form a root consolidation portion 62 composed of a mixture of root consolidation liquid and earth and sand at the tip of the pile, Since the auger 51 is pulled up, there is little discharge of excavated soil, and the earth and sand in the excavation hole 61 can be softened by preliminary excavation. After the pull-up, a small amount of discharged earth and sand is returned to the excavation hole 61. And by giving the rotary press-fitting pile device 1 the rotation in the excavation direction, the rotary press-fitting allows the earth and sand to move to the side and can be built to a predetermined depth while being compacted, and the discharged soil is slight, The discharged soil is construction surplus soil and is easy to treat.

  Thus, preliminary excavation improves the workability of long piles and enables reliable formation of the root-solidified part 62, and since it is non-draining, it becomes a construction method that considers pollution and the environment. By forming 62, the amount of subsidence can be suppressed and the support force can be increased. The friction force can be increased by using cement milk or the like having an expansion function as a root-setting liquid and extending the injection section.

  Thus, in this embodiment, the auger 51 having the excavation blades 53, the rotary press-fitting pile device 1 having the excavation blade 16 larger than the pile main body 2 at the tip portion 3 of the pile main body 2, and being excavated by axial rotation, The excavation hole 61 is formed by performing preliminary excavation with the auger 51, and the root consolidation liquid is injected into the lower portion of the excavation hole 61, and has a function of expansion. 62 is formed, the auger 51 is pulled up by reverse rotation, and the discharged earth and sand is backfilled in the excavation hole 61, and then the rotary press-fitting pile device 1 is axially rotated to press-fit the pile body 2 into the excavation hole 61. Preliminary excavation by the auger 61 facilitates the construction of a long pile, and a predetermined support force can be obtained by the rooting portion 62 formed by the auger 61. Pre-excavated excavation hole by rotary press-fit pile device 1 having 16 61 can be consolidated.

As described above, in this embodiment, the diameter D ₀ of the excavation blade 16 is 1.5 times or more the diameter D of the excavation blade 53, and therefore, the consolidation effect of the excavation hole 61 is excellent.

  Further, in this embodiment, the auger 51 is provided with the tip bit 54, and after injecting the root-setting liquid, the auger 51 moves up and down twice in this injection section to mix the root-setting liquid and the earth and sand. The liquid and the earth and sand are well mixed, and the root fixing part 62 and the surroundings can be integrated, and a stable supporting force can be obtained.

  In this way, in this embodiment, in the excavation hole 61, the root consolidation part 62 having a length equal to or greater than the diameter of the pile body 2 is left in the lower part of the tip part 3, so that the support force by the root consolidation part 62 is stable. Will be.

  In this way, in this embodiment, since the cement milk that is the root hardening liquid has an expansion function, the support force by the root hardening part 62 can be improved.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, although a hollow pile was shown as a pile main body in the Example, various things, such as a steel pipe pile, can be used.

It is process drawing of preliminary excavation showing Example 1 of the present invention. It is a process drawing of the erection work of a pile by a rotary press-fit pile apparatus same as the above. It is a sectional view of an auger same as the above. It is sectional drawing of a rotary press-fit pile apparatus same as the above. It is sectional drawing of the front end side of a rotary press-fit pile apparatus same as the above. It is a side view of the front-end | tip part of a rotary press-fit pile apparatus same as the above. It is a bottom view of the front-end | tip part of a rotary press-fit pile apparatus same as the above. It is a top view of the front-end | tip part of a rotary press-fit pile apparatus same as the above. It is sectional drawing of the principal part of the front-end | tip part of a rotary press-fit pile apparatus same as the above. It is a side view of the wing | blade of the front-end | tip part of a rotary press-fit pile apparatus same as the above. It is a side view of the rotation transmission body of a rotary press-fit pile apparatus same as the above. It is a bottom view of the rotation transmission body of a rotary press-fit pile apparatus same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotation press-fit pile apparatus 2 Pile main body 3 Tip part 4 Rotation press-fit drive means 5 Tip body 6 Rotation transmission body 7 Blade body 8 Rotation rod
16 Drilling blade
51 Auger
52 Stir rod
53 Drilling blade
54 Tip bit
61 Drilling hole
62 Root consolidation part D Drilling blade diameter Ds Preliminary drilling hole diameter D ₀ Drilling blade diameter

Claims (5)

Using an auger having excavation blades and a rotary press-fitting pile device that has a excavation blade larger than the pile main body at the tip of the pile main body and is excavated by axial rotation.
Preliminary excavation is performed by the auger to form a drilling hole, a rooting liquid is poured into the lower part of the drilling hole to form a rooting part composed of a mixture of the rooting liquid and earth and sand, and the auger is pulled up, A foundation pile construction method, wherein after the discharged earth and sand are backfilled in the excavation hole, the rotary press-fitting pile device is axially rotated to press-fit the pile main body into the excavation hole. The foundation pile construction method according to claim 1, wherein a diameter of the excavation blade is larger than a diameter of the excavation blade. The auger includes a tip bit, and after injecting the root-setting liquid, the auger reciprocates a plurality of times in the injection section to mix the root-setting liquid and earth and sand. Construction method of foundation pile. The foundation pile construction method according to claim 3, wherein in the excavation hole, the root consolidation portion having a length equal to or greater than the diameter of the pile main body is left below the tip portion. The foundation pile construction method according to claim 1, wherein the root hardening liquid has an expansion function.

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