JP2006063526A - Expanded rooting method using friction piles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a node in which a ground loosened during excavation to which an expansion pressure of a cylindrical bag body provided at an outer peripheral tip portion of a friction pile is transmitted is provided at an outer peripheral intermediate portion above the cylindrical bag body. It is an object of the present invention to provide an enlarged rooting method using a friction pile that can be firmly compacted by high expansion pressure acting on the ground by being received by the part.
SOLUTION: After forming an excavation hole 4 in the ground 3 and an enlarged excavation hole 4b at the tip thereof, a cylindrical bag body 9 for forming a bulb is provided at the outer peripheral tip part, and an upper part of the tubular bag body 9 is provided. The friction pile 5 provided with the node portion 7 having an outer diameter larger than the outer diameter of the pile body 5 a at the outer peripheral intermediate portion is set in the excavation hole 4, and the cement hardened body slurry is placed in the cylindrical bag body 9. By injecting, the ground 3 in the excavation hole 4 extending from the cylindrical bag 9 to the node portion 7 is compacted in the process of expanding the cylindrical bag 9 in the enlarged excavation hole 4 b at the tip of the excavation hole 4. It is characterized by comprising.
[Selection] Figure 2

Description

  The present invention relates to an enlarged rooting method using friction piles.

  Conventionally, various construction methods for ready-made piles have been developed, but low-pollution construction methods are required in urban areas. There is a pre-boring method as a low-pollution method for such ready-made piles.

  As a conventional pre-boring method, an enlarged-diameter hole is formed by widening the hole diameter at the tip of a drilling hole drilled with a predetermined diameter, and a cylindrical bag body is provided at the outer peripheral tip in the drilling hole. After laying the ready-made pile, injecting slurry for cement hardened body such as cement milk into the cylindrical bag body and expanding the cylindrical bag body at the enlarged diameter hole to push the surrounding ground loosened during excavation, There is one in which an enlarged root bulb portion is formed (for example, see Patent Documents 1 and 2).

  On the other hand, a friction pile (for example, refer to Patent Document 3) provided with a node having an outer diameter larger than the outer diameter of the pile main body at the outer peripheral middle portion of the pile main body, or a large diameter portion provided at the lower end of the pile main body. There is also a friction pile in which an annular ridge is provided on the outer wall of the upper part and the intermediate part of the pile body (for example, see Patent Document 4).

Japanese Patent No. 2589672 Japanese Examined Patent Publication No. 04-059409 JP 2004-176466 A Japanese Patent Laid-Open No. 05-230832

  However, in the above-described conventional example, in the techniques of Patent Documents 1 and 2, the ground loosened during excavation is expanded and compacted at the side surface portion of the cylindrical bag body in the diameter-enlarged hole due to the expansion of the cylindrical bag body. Even if it can, the expansion pressure of the cylindrical bag body is gently transmitted to the ground in the excavation hole and released on the ground surface above the enlarged diameter hole portion, so that a larger supporting force and resistance force can be obtained. I couldn't.

  Moreover, in the technique of patent documents 3 and 4, although the support force and resistance force of a pile can be obtained by the node part which has an outer diameter larger than the outer diameter of a pile main body, like the technique of patent documents 1 and 2, Since the ground loosened at the time of excavation could not be expanded by the expansion of the cylindrical bag provided at the outer peripheral tip of the pile, it was not possible to obtain a larger support force and resistance force.

  The present invention solves the above-mentioned problems, and an object of the present invention is to provide the cylindrical bag with the ground loosened during excavation to which the expansion pressure of the cylindrical bag body provided at the outer peripheral tip of the friction pile is transmitted. It is intended to provide an expanded rooting method using friction piles that can be firmly compacted by receiving high expansion pressure on the ground by being received by a joint provided at the outer peripheral middle part above the body. .

  In order to achieve the above object, the method of expanding the root using the friction pile according to the present invention includes forming a drilling hole in the ground and an expanding drilling hole at the tip thereof, and then forming a cylindrical bag for bulb formation at the tip of the outer periphery. A friction pile provided with a body and having a node having an outer diameter larger than the outer diameter of the pile main body at the outer peripheral intermediate portion above the cylindrical bag body is set in the excavation hole; In the excavation hole from the cylindrical bag to the node in the process of expanding the cylindrical bag in the enlarged excavation hole at the tip of the excavation hole by injecting the slurry for the hardened cement body into the excavation bag It is characterized by compacting the ground.

  According to the enlarged consolidation method using the friction pile according to the present invention, the ground loosened at the time of excavation to which the expansion pressure of the cylindrical bag body provided at the outer peripheral front end portion of the friction pile is transmitted from the cylindrical bag body. In addition, by receiving it by a node provided at the upper outer peripheral intermediate portion, a high expansion pressure acts on the ground and can be firmly tightened, and a larger support force and resistance force can be obtained.

  An embodiment of the enlarged rooting method using the friction pile according to the present invention will be specifically described with reference to the drawings. FIG.1 and FIG.2 is a figure explaining the expansion rooting method using the friction pile which concerns on this invention.

  FIG. 1 is a view showing a state in which the tip of the excavation hole 4 in which the friction pile 5 shown in FIG. 2 is embedded is enlarged and excavated by using the enlargement excavation bit 2. First, the tip of the excavation rod 1 is placed at the pile core position. As shown in FIG. 1 (a), the shaft of the enlarged excavation bit 2 provided is aligned and the auger motor (not shown) is driven to rotate to rotate the excavating rod 1 while the enlarged excavating blade 6 is housed. 3 is dug down to form a small-diameter excavation hole 4a corresponding to the outer diameter of the spiral blade 1a.

  At this time, the drilling fluid is supplied from the mortar plant installed on the ground to the piping provided inside the drilling rod 1, and the drilling fluid is supplied from a discharge port (not shown) provided in the enlarged drilling bit 2 connected to the piping. Excavation is carried out while pouring, and the ground 3 is dug down to a predetermined depth as shown in FIG. As such drilling fluid, ground improvement fluid such as bentonite mud is used in addition to water and mud.

  After excavating the ground 3 to a predetermined depth, the excavating rod 1 is reversed and the expanded excavating blade 6 is expanded to excavate, and the excavating rod 1 is predetermined as shown in FIGS. The section is pulled up to form the enlarged excavation hole 4b. Further, as shown in FIG. 1D, the excavation rod 1 is repeated up and down to muddy the inside of the enlarged excavation hole 4b, and the construction of the enlarged excavation hole 4b is confirmed.

  The enlarged drilling hole 4b is excavated while repeating the excavating rod 1 up and down, and the rooting liquid is supplied from the mortar plant installed on the ground to the pipe provided inside the excavating rod 1 and connected to the pipe. After injecting the root-setting liquid from a discharge port (not shown) provided in the excavation bit 2, the rotation of the auger motor is returned to the normal rotation, and the enlarged excavation blade 6 is accommodated as shown in FIG.

  Then, the root hardening liquid is switched to the pile circumference fixing liquid, the pile circumference fixing liquid is injected from a discharge port (not shown) provided in the enlarged excavation bit 2, and the inside of the excavation hole 4 is muddy, as shown in FIG. 1 (e). Thus, the excavation rod 1 is pulled up. As a result, an enlarged excavation hole 4 b is formed at the tip of the excavation hole 4 excavated in the ground 3.

  As described above, instead of the enlarged excavating blade 6 that opens and closes by changing the rotation direction of the excavating rod 1, the tip of the excavation hole 4 excavated in the ground 3 by a configuration in which the enlarged excavating blade 6 is opened and closed by a hydraulic mechanism. An enlarged excavation hole 4b may be formed in the portion.

  FIG. 2 is a view showing a state in which the friction pile 5 is buried after the excavation hole 4 and the enlarged excavation hole 4b are formed at the tip portion of the ground 3 as shown in FIG. As shown in FIG. 2, the friction pile 5 of the present embodiment is provided with a cylindrical bag body 9 for bulb formation at the outer peripheral tip of the pile main body 5 a, and an outer peripheral intermediate portion above the cylindrical bag body 9. A plurality of annular node portions 7 having an outer diameter larger than the outer diameter of the pile body 5a are provided at a predetermined pitch.

  A plurality of the node portions 7 of the present embodiment are provided at a predetermined pitch over the entire circumference of the pile body 5a, having the same outer diameter as the outer diameter of the spiral blade 1a provided on the outer periphery of the excavating rod 1. However, the outer diameter of the node 7 can be set to various other outer diameters smaller than the outer diameter of the spiral blade 1a and larger than the outer diameter of the pile body 5a. Further, the node portion 7 may have a configuration in which a part of the entire circumference is cut out, or may be a configuration like a spiral blade, in addition to being provided over the entire circumference of the pile body 5a. Alternatively, one node portion 7 may be provided at the outer peripheral intermediate portion above the cylindrical bag body 9.

  As shown in FIG. 2 (a), first, a friction pile 5 provided with a cylindrical bag body 9 for bulb formation at the outer peripheral tip portion and provided with node portions 7 at a predetermined pitch at the outer peripheral intermediate portion is used as an auger motor (not shown). It is suspended and set in the attached rotating cap and set in the excavation hole 4.

  And as shown in FIG.2 (b), the cylindrical bag body 9 of the friction pile 5 sunk by its own weight supports in the state located in the expansion excavation hole 4b, and as shown in FIG.2 (c), At the head of the friction pile 5, an injection jig 10 that is disposed inside the friction pile 5 and connected to the injection pipe 11 that communicates with the inside of the cylindrical bag body 9 is installed. The slurry for the hardened cement body is injected into the cylindrical bag body 9 from the injection jig 10 through the injection pipe 11, and as shown in FIG. It expands in the enlarged excavation hole 4b. At this time, the injection pressure and the injection amount of the cement cement slurry are controlled.

  In the process of expanding the cylindrical bag body 9 in the enlarged excavation hole 4 b at the tip of the excavation hole 4, the tubular bag body 9 is formed into a tubular shape on the ground 3 loosened during excavation in the excavation hole 4 extending from the cylindrical bag body 9 to the node portion 7. The ground 3 loosened at the time of excavation in the excavation hole 4 to which the expansion pressure of the bag body 9 is applied and the expansion pressure of the cylindrical bag body 9 is transmitted is provided at the outer peripheral intermediate portion above the cylindrical bag body 9. By being received by the joint 7, a high expansion pressure acts on the ground 3 and can be firmly compacted, so that the friction pile 5 embedded in the ground 3 has a large supporting force and resistance against the ground 3. You can get power.

  And as shown in FIG.2 (d), the injection jig | tool 10 is removed, the cement hardening body slurry is hardened, and the friction pile 5 is embed | buried.

  According to such a configuration, the vertical support force of the friction pile 5 is increased by the tip support force by the cylindrical bag body 9 provided at the tip portion of the friction pile 5 and the friction force by the node portion 7 provided in the intermediate portion. Also, the pulling strength increases.

  The enlarged bulb portion formed by inflating the cylindrical bag body 9 is preferably about 100 to 200 mm larger in diameter than the outer diameter of the friction pile 5 and about 5 to 10 times the height of the outer diameter of the friction pile 5. . The cylindrical bag body 9 is inserted into the cylindrical bag body 9 having a diameter larger than the outer diameter of the friction pile 5, and both ends of the cylindrical bag body 9 are banded on the outer periphery of the friction pile 5. Attach it with adhesive.

  The friction pile 5 has an inlet through which the slurry for cement hardened body can be injected into the inside of the cylindrical bag body 9 after the friction pile 5 is laid, and the cylindrical bag body 9 is obtained by connecting the injection pipe 11 to the inlet. The slurry for hardened cement body can be poured into the interior from the ground.

  Moreover, as a material of the cylindrical bag body 9, it is preferable to use cloths, such as nylon, vinylon, and polyester.

  The outer diameter of the cylindrical bag body 9 is commensurate with the diameter of the enlarged bulb portion formed by hardening the slurry for cement hardened body, for example, an outer diameter that is about 100 mm to 500 mm larger than the outer diameter of the friction pile 5. Have

Cement milk, cement mortar, or the like can be used as the slurry for a hardened cement body to be injected into the cylindrical bag body 9 after the friction pile 5 is set. Whether or not the cylindrical bag body 9 has sufficiently expanded by injecting the slurry for hardened cement body is determined based on the pressure of the injection pump and the injection amount. Although the injection pressure varies depending on the intensity of the ground ^{3, 0.3N / mm 2 ~0.5N /} mm 2 is preferably about.

  As an application example of the present invention, it can be applied to an enlarged rooting method using friction piles.

It is a figure explaining the expansion rooting method using the friction pile which concerns on this invention. It is a figure explaining the expansion rooting method using the friction pile which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Excavation rod 1a ... Spiral blade 2 ... Expansion excavation bit 3 ... Ground 4 ... Excavation hole 4a ... Small diameter excavation hole 4b ... Expansion excavation hole 5 ... Friction pile 5a ... Pile main body 6 ... Expansion excavation blade 7 ... Node part 9 ... Cylindrical bag
10 ... Injection jig
11 ... Injection piping

Claims (1)

After the excavation hole is formed in the ground and the enlarged excavation hole is formed at the tip thereof, a cylindrical bag body for bulb formation is provided at the outer peripheral tip part, and the outer diameter of the pile body is provided at the outer peripheral middle part above the cylindrical bag body A friction pile having a node having a larger outer diameter is set in the excavation hole, and then the cylindrical bag body is excavated by injecting a slurry for a hardened cement body into the cylindrical bag body. An enlarged rooting method using a friction pile, wherein the ground in the excavation hole from the tubular bag body to the node is compacted in the process of expanding in the enlarged excavation hole at the tip of the hole.

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