Method of Pile Driving

Abstract

To provide a pile installation method reducing work load to construct an installation machine in a narrow side under a head space restriction.SOLUTION: A pile installation method comprises: a pile hole boring process forming a pile bore 15 by boring the ground as rotating an earth augur 11 with a rotation mechanism part 7 using a boring hole machine 1 provided with a leader 5 and the rotation mechanism part 7 lifting the leader 5; and a core member installation process installing core member units 21 in a bore hole 15 by inserting the core member units 21 attached on the rotation mechanism part 7 of the boring hole machine 1 by lifting motion of the rotation mechanism part 7 as extending the core member units without rotation in the pile hole 15.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a pile driving method.

Background Art

[0002] Conventionally, as a technique in such a field, a pile driving method described in Patent Document 1 below is known. In this method, a pile core material is built into a previously formed excavation hole at a location with a headroom limit, and split core materials shorter than the headroom limit are sequentially connected and suspended into the excavation hole. In this case, ultimately, it is necessary to suspend the entire core material formed by connecting a plurality of split core materials, and a large crane with a corresponding capacity may not be introduced into a narrow site with a headroom limit. Therefore, a dedicated core material building device having the ability to suspend the entire core material is constructed at the site.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, according to the method using the above core material building device, complicated operations such as carrying in capital equipment for constructing the core material building device and assembling it at a narrow site under the headroom limit occur. In view of this problem, an object of the present invention is to provide a pile driving method that reduces the labor of constructing a building device at a narrow site under the headroom limit.

Means for Solving the Problems

[0005] The pile driving method of the present invention includes a hole drilling step of forming a pile hole by drilling the ground while rotating an earth auger with a rotating mechanism unit that moves up and down on a leader using a hole drilling machine including the leader and the rotating mechanism unit, and a core material building step of building the core material into the pile hole by inserting it into the pile hole without rotation while adding a core material part that is attached to the rotating mechanism unit of the hole drilling machine.

[0006] The above core material may be an H-beam. Further, in the core material building step, the upper end portion of the core material is attached to the rotating mechanism unit via a predetermined attachment, and the addition of the core material is performed by connecting the core materials to each other via an attachment plate using bolt holes provided at the ends of the core materials, and the attachment and the upper end portion of the core material are connected by bolting using the bolt holes located at the upper end portion.

[0007] Further, in the core material building step, a core material connecting step of connecting and adding a new core material to the upper end portion of the core material while the core material is temporarily supported in the pile hole, and after the core material connecting step, a rotating mechanism unit is attached to the upper end portion of the core material, the temporary support of the core material is released, and a core material inserting step of inserting the core material into the pile hole by the lifting and lowering operation of the rotating mechanism unit, and a temporary support step of temporarily supporting the core material inserted into the pile hole in the pile hole are repeatedly executed.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a pile driving method that reduces the labor of constructing a driving device at a narrow site under headroom restrictions.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0010] Hereinafter, an embodiment of the pile driving method according to the present invention will be described in detail with reference to the drawings. The same or equivalent components are denoted by the same reference numerals in the drawings, and redundant explanations are omitted. As shown in FIG. 1, the pile driving method of the present embodiment is to drive a pile of about 17 m with an H-shaped steel as a core material by a pre-boring method at a site 101 with a free head limit of about 4 m. This pile driving method includes a pile hole drilling step and a core material building-in step, which will be described below.

[0011] 〔Pile Hole Drilling Step〕 As shown in Fig. 1(a), a self-propelled boring machine 1 and a self-propelled small backhoe 3 are introduced at the construction site 101. The boring machine 1 includes a traveling device 2, a leader 5, and a rotating mechanism unit 7. The traveling device 2 has, for example, crawlers, and the boring machine 1 can travel by itself with the traveling device 2. The leader 5 extends vertically at the front of the vehicle of the boring machine 1, and the rotating mechanism unit 7 is attached to the leader 5 and guided by the leader 5 to move up and down vertically. A rotating shaft portion 9 that rotates around a vertical axis is provided at the lower end portion of the rotating mechanism unit 7, and an earth auger 11 is attached to the rotating shaft portion 9. The rotating mechanism unit 7 incorporates, for example, a power source and a speed reducer, etc., and rotates the rotating shaft portion 9 to rotate the earth auger 11 attached to the rotating shaft portion 9 around the vertical axis. Further, mortar is supplied from the boring machine 1 to the lower end of the earth auger 11 through the rotating shaft portion 9. As such a boring machine 1, for example, a known pile driver for performing the pre-boring method may be used.

[0012] In the pile hole boring process, a mouthpiece pipe 13 with a length of about 1.5 m is buried at a position slightly lower than the ground surface. The earth auger 11 attached to the boring machine 1 ejects mortar from the tip, and is rotated around the vertical axis by the rotating mechanism unit 7 and pushed downward through the mouthpiece pipe 13. Thereby, the ground is excavated and the pile hole 15 extends vertically downward. Here, a long earth auger 11 cannot be used due to headspace restrictions, and every time the excavation of the pile hole 15 progresses, for example, by 1.5 m, an earth auger 11 with a length of, for example, 1.5 m is added. At this time, the added 1.5 m earth auger 11 is moved to the attachment position of the rotating shaft portion 9 using the arm of the backhoe 3. By repeating such addition and excavation of the earth auger 11, a pile hole 15 with a depth of about 17 m is formed. The diameter of the pile hole 15 is, for example, about 80 cm. Although the pile hole 15 is in a state where mortar is filled after the earth auger 11 is removed, the illustration of this mortar is omitted in each drawing.

[0013] 〔Process of inserting the core material〕 In the core material embedding process, the H-beams 19 are embedded in the mortar filled in the pile holes 15, and finally, a core material 29 (see Fig. 5(b)) with a length of about 17 m formed by connecting a plurality of H-beams 19 (core material) is embedded in the pile holes 15. As shown in Fig. 1(b), in the core material embedding process, first, a self-propelled crane 17 is introduced to the site 101. The H-beams 19 are lifted by this crane 17 and lifted into the pile holes 15. The length of the H-beam 19 is, for example, 1.5 to 2 m, and the width of the H-beam 19 is, for example, 450 mm x 450 mm. The H-beams 19 are inserted into the pile holes 15 while being longitudinally connected and extended. A unit composed of a plurality of mutually connected H-beams 19 is hereinafter referred to as a "core material unit 21". When connecting a new H-beam 19 to the core material unit 21, the upper end of the core material unit 21 (core material) is temporarily supported on the mouthpiece pipe 13 via a temporary support 22 (see Fig. 3(a)). The temporary support 22 is composed of, for example, an angle material (not shown) spanned on the upper edge of the mouthpiece pipe 13 and a clamp material (not shown) for fixing the angle material to the core material unit 21.

[0014] In Fig. 1 and the like, the detailed description of the connection part between the H-beams 19 in the core material unit 21 is omitted, but as shown in Fig. 2, connection bolt holes 23 are formed in advance at the upper and lower ends of the H-beam 19. Then, the H-beams 19 are connected to each other via an attachment plate 24 using the bolt holes 23. In Fig. 2, only the attachment plate 24 connecting the webs of the H-beams 19 is shown as an example, and the illustration of the attachment plate connecting the flanges is omitted. Also, in Fig. 2, the illustration of the bolts and nuts used for connection is omitted. Since the connection structure and connection method of the H-beams by such an attachment plate are well-known, further detailed description is omitted.

[0015] After that, when the length of the core material unit 21 reaches, for example, 6 to 7 m, the upper end of the core material unit 21 is temporarily supported on the mouthpiece pipe 13 using the temporary support tool 22, and then, as shown in Fig. 3(a), the boring machine 1 is introduced into the site 101 again. Also, the crane 17 is placed near the boring machine 1 as it is. After this, since the weight of the core material unit 21 exceeds the lifting capacity of the crane 17, the core material erection is continued by the boring machine 1 instead of the crane 17. That is, the boring machine 1 has the ability to support a core material unit 21 with a greater weight compared to the crane 17. Here, an attachment 25 is attached to the rotating shaft portion 9 of the rotating mechanism portion 7 of the boring machine 1 instead of the earth auger 11. The attachment 25 is for connecting the upper end portion of the core material unit 21 to the rotating shaft portion 9, and the upper end portion of the core material unit 21 is bolted to the attachment 25 using the bolt holes 23 (Fig. 2). The detailed structure of the attachment 25 will be described later.

[0016] After that, in the core material erection process taken over from the crane 17 to the boring machine 1, the core material connection process, the core material insertion process, and the temporary support process, which will be described next, are repeatedly executed.

[0017] (Core material connection process) As shown in Fig. 3(a), the core material connection process is executed with the core material unit 21 temporarily supported on the mouthpiece pipe 13 at the upper end of the pile hole 15 by the temporary support tool 22. At this time, the upper end portion of the core material unit 21 is at a position slightly higher than the upper end of the mouthpiece pipe 13. In this state, the crane 17 suspends and moves a new H-beam 19 to a position above the core material unit 21. Then, the H-beam 19 is connected and added to the upper end portion of the core material unit 21. The connection between the upper end portion of the core material unit 21 and the lower end portion of the H-beam 19 at this time is executed by bolting through the attachment plate 24 as described in Fig. 2. As a result, as shown in Fig. 3(b), the core material unit 21 is extended upward by the length of the new H-beam 19.

[0018] (Core material insertion process) After the core material connection step, in the core material insertion step, the rotating mechanism portion 7 of the boring machine 1 is attached to the upper end portion of the core material unit 21. Specifically, as shown in FIG. 4(a), the rotating mechanism portion 7 is lowered until the attachment 25 fits into the upper end portion of the core material unit 21, and the attachment 25 and the upper end portion of the core material unit 21 are bolted together. Although details will be described later, here the attachment 25 and the upper end portion of the core material unit 21 are connected by bolting using the bolt holes 23 (FIG. 2). Thereafter, the temporary support 22 is removed from the core material unit 21, thereby releasing the temporary support of the core material unit 21, and the core material unit 21 is supported by the rotating mechanism portion 7.

[0019] From this state, as shown in FIG. 4(b), the core material unit 21 is inserted downward into the pile hole 15 by the downward movement of the rotating mechanism portion 7 of the boring machine 1. Here, the rotating mechanism portion 7 is lowered to approximately the lower limit position of the vertical movement range, and the upper end portion of the core material unit 21 moves to a position slightly higher than the upper end portion of the mouthpiece pipe 13. Here, if the core material unit 21 being lowered gets caught in the pile hole 15, measures such as once raising the core material unit 21 by the upward movement of the rotating mechanism portion 7 to release the caught state are also possible.

[0020] The boring machine 1 is provided with a vertical drive function for moving the rotating mechanism portion 7 up and down on the leader 5 and a rotation drive function for rotating the rotating shaft portion 9 around the vertical axis by the rotating mechanism portion 7. However, in the core material insertion step, the rotation drive function is not used, and only the vertical drive function is used. Therefore, here, the core material unit 21 descends without rotating around the vertical axis and is inserted into the pile hole 15. Further, in the above-described vertical drive function, since the operation of pushing the rotating mechanism portion 7 downward is possible, the boring machine 1 can apply a downward force to the core material unit 21 and push the core material unit 21 downward into the pile hole 15.

[0021] Incidentally, here, it is also conceivable to use the vertical driving function and the rotational driving function together to insert the core material unit 21 into the pile hole 15 while rotating the core material unit 21. However, if the core material unit 21 is rotated within the pile hole 15 filled with mortar, the core material unit 21 may be deformed due to the viscous resistance of the mortar, or the rotary shaft portion 9 or the attachment 25 may be damaged. Therefore, in the core material insertion step in the present embodiment, the core material unit 21 is inserted into the pile hole 15 without rotating it. Incidentally, in order to release the caught state when the descending core material unit 21 is caught in the pile hole 15, the core material unit 21 may be slightly rotated using the rotational driving function.

[0022] (Temporary support step) After the core material insertion step, in the temporary support step, the core material unit 21 is temporarily supported on the mouthpiece pipe 13 which is the upper end of the pile hole 15. Specifically, a temporary support tool 22 is attached to the upper end portion of the core material unit 21 that has descended in the core material insertion step. As described above, the temporary support tool 22 is composed of, for example, an angle material (not shown) spanned over the upper end edge of the mouthpiece pipe 13 and a clamp material (not shown) for fixing the angle material to the core material unit 21. Then, by hanging the temporary support tool 22 on the upper end edge of the mouthpiece pipe 13, the core material unit 21 is supported by the mouthpiece pipe 13. After that, the bolting between the attachment 25 and the upper end portion of the core material unit 21 is released, and again, as shown in Fig. 3(a), the rotation mechanism portion 7 moves upward and separates from the core material unit 21, and rises to almost the upper limit position of the vertical movement range. After this temporary support step, the above-described core material connection step is executed again.

[0023] By repeatedly executing the core material connection step, the core material insertion step, and the temporary support step as described above, while adding the H-beam 19, the core material unit 21 is inserted into the pile hole 15 without rotation by the lifting and lowering operation of the rotation mechanism portion 7, and the core material unit 21 is built into the pile hole 15, and the final building-in of the core material 29 is completed. After that, when the mortar in the pile hole 15 hardens, the pile including the core material 29 (see Fig. 5(b)) is completed.

[0024] In the above-described core material insertion process, the rotation mechanism unit 7 descends to approximately the lower limit position of the vertical movement range, and the upper end portion of the core material unit 21 is moved to a position slightly higher than the upper end portion of the mouthpiece tube 13. Then, due to the limitation of the vertical movement range of the rotation mechanism unit 7, the core material unit 21 cannot be moved further downward. Therefore, in order to make the upper end of the completed core material unit 21 lower than the upper end of the mouthpiece tube 13, the following process different from the above-described core material insertion process is required in the last core material insertion process.

[0025] (Last core material insertion process) As shown in Fig. 5(a), in the last core material insertion process, an extension shaft portion 27 is attached so as to be interposed between the rotary shaft portion 9 and the attachment 25. The length of the extension shaft portion 27 is, for example, about 50 cm. Since it is the same as the above-described core material insertion process except that this extension shaft portion 27 is used, duplicate explanations are omitted. In such a last core material insertion process, as shown in Fig. 5(b), when the rotation mechanism unit 7 descends to approximately the lower limit position of the vertical movement range, the upper end of the core material unit 21 is pushed into a position lower than the upper end of the mouthpiece tube 13. Thereafter, the bolting between the attachment 25 and the upper end portion of the core material unit 21 is released, and the rotation mechanism unit 7 retracts upward, thereby completing the installation of the core material 29 (core material unit 21).

[0026] Next, the configuration of the attachment 25 used in the core material building-in process described above will be described with reference to FIGS. 6 and 7. FIG. 6 is a perspective view showing the attachment 25 and the upper part of the H-beam 19 (or the core material unit 21) attached to the attachment 25. FIG. 7(a) is a front view of the attachment 25, and FIG. 7(b) is a side view thereof. The attachment 25 in a state of being attached to the rotation mechanism unit 7 (FIG. 3(a)) includes a main body portion 31 having a horizontal flat plate shape, a mounting shaft 33 extending upward from the center of the upper surface of the main body portion 31, and two holding plates 35 extending downward from the central portion of the lower surface of the main body portion 31, as shown in FIGS. 6 and 7. The main body portion 31 forms a rectangle having a vertical and horizontal width substantially equal to the vertical and horizontal width of the H-beam 19 in plan view. The mounting shaft 33 is a portion that is fitted into the rotating shaft portion 9 (see FIG. 3(a)) of the rotation mechanism unit 7. By detachably fitting the mounting shaft 33 into the rotating shaft portion 9, the attachment 25 is detachably attached to the rotation mechanism unit 7. In the last core material insertion step described above, the mounting shaft 33 is fitted into the lower end portion of the extension shaft portion 27.

[0027] The holding plates 35 have a flat plate shape that exists parallel to the web 19w of the H-beam 19. In order to reinforce the holding plates 35, triangular ribs 32 are provided at the corners between the outer surfaces of the respective holding plates 35 and the lower surface of the main body portion 31. The two holding plates 35 are parallel with a gap 37 therebetween, and this gap 37 is slightly wider than the thickness of the web 19w. Four bolt holes 39 arranged in the horizontal and vertical directions are formed in each holding plate 35 so as to penetrate in the thickness direction. The horizontal pitch and the vertical pitch of the four bolt holes 39 are integer multiples of the pitch of the bolt holes 23 for the attachment plate 24 formed in the web 19w. Therefore, when the web 19w is inserted into the gap 37 from below, the web 19w can be fastened to the holding plates 35, 35 with four bolts that sequentially pass through the bolt holes 39 of one holding plate 35, the bolt holes 23 of the web 19w, and the bolt holes 39 of the other holding plate 35. By thus fastening the web 19w to the holding plates 35, 35, the core material unit 21 is attached to the attachment 25 and is attached to the rotation mechanism unit 7 of the drilling machine 1 via the attachment 25.

[0028] Next, the effects of the pile driving method of the present embodiment will be described. According to this pile driving method, the boring machine 1 used in the pile hole boring process can also be commonly used in the core material embedding process. That is, in the pile hole boring process, the earth auger 11 is attached to the rotation mechanism unit 7, and the boring machine 1 forms a pile hole 15 according to its original usage method. Then, in the core material embedding process, the core material unit 21 is attached to the rotation mechanism unit 7 via the attachment 25, and the boring machine 1 inserts the core material unit 21 into the pile hole 15 using the vertical driving function of the rotation mechanism unit 7.

[0029] In a narrow site 101 with a headroom limit, a large crane cannot be used, and with the crane 17 that can be used at the site 101, as described above, it is impossible to embed the core material 29 due to insufficient capacity. Therefore, conventionally, in order to embed the core material 29, it was necessary to construct a core material embedding device as disclosed in Patent Document 1 above at the site 101. In contrast, according to the pile driving method of the present embodiment, the labor for constructing a core material embedding device such as the above in the narrow site 101 is reduced. In this way, by sharing the machines used and reducing the labor for constructing the core material embedding device, the construction period can be shortened and the cost can be reduced.

[0030] The present invention can be implemented in various forms with various changes and improvements based on the knowledge of those skilled in the art, starting from the above-described embodiments. Also, it is possible to configure a modification of the embodiment by utilizing the technical matters described in the above-described embodiments. The configurations of each embodiment etc. may be appropriately combined and used.

[0031] For example, in the above-described embodiment, the core material of the pile is the H-beam 19, but the core material may be other types of steel, for example, a cylindrical steel pipe.

Explanation of Reference Numerals

[0032] 1... Hole-making machine, 5... Reader, 7... Rotating mechanism section, 11... Earth auger, 15... Pile hole, 19... H-beam (core material), 21... Core unit (core material), 23... Bolt hole, 24... Adhesive plate, 25... Attachment, 29... Core material.

Claims

1. A pile hole drilling step of forming a pile hole by drilling the ground while rotating an earth auger with a rotating mechanism unit that moves up and down on a leader using a drilling machine including the leader and the rotating mechanism unit; A pile core building step of building the pile core into the pile hole by inserting it into the pile hole without rotation by the lifting and lowering operation of the rotating mechanism unit while adding a pile core material that forms a part of the pile core and is attached to the rotating mechanism unit of the drilling machine.

2. The pile driving method according to Claim 1, wherein the pile core is an H-beam.

3. In the pile core building step, the upper end portion of the pile core material is attached to the rotating mechanism unit via a predetermined attachment; the addition of the pile core material is performed by connecting the pile core materials to each other via an attachment plate using bolt holes provided at the ends of the pile core materials; The pile driving method according to Claim 1 or 2, wherein the attachment and the upper end portion of the pile core material are connected by bolting using the bolt holes located at the upper end portion.

4. In the pile core building step, a pile core connecting step of connecting and adding a new pile core material to the upper end portion of the pile core material while the pile core material is temporarily supported in the pile hole; after the pile core connecting step, the rotating mechanism unit is attached to the upper end portion of the pile core material, the temporary support of the pile core material is released, and the pile core material is inserted into the pile hole by the lifting and lowering operation of the rotating mechanism unit; a pile core inserting step; A temporary support step of temporarily supporting the pile core material inserted into the pile hole in the pile core inserting step in the pile hole is repeatedly executed. The pile driving method according to any one of Claims 1 to 3.

Images