JP4560560B2 - Pile construction method - Google Patents

Description

  The present invention relates to a pile construction method, for example, a pile construction method for constructing a steel pipe pile on hard ground such as underwater rock.

  When constructing underwater structures such as breakwaters, steel pipe piles may be placed on hard underwater ground.

Conventionally, a pile construction method for constructing a pile on hard underwater ground in this way is to attach a bit to the tip of a steel pipe pile and lower it into the ground while rotating the pile to excavate a ring-shaped groove. Meanwhile, there is a method in which a pile is built in the ground (see Patent Document 1).
JP 2000-45276 A

  In the conventional pile construction method as described above, a pile with a bit used for excavation is used as it is as a main pile, so that an expensive bit formed of special steel is also buried in the ground. There was a problem of being wasteful and uneconomical. Moreover, when a hard ground is excavated, a large load is applied to the pile used for excavation. Therefore, there is a problem that a long pile tends to be damaged or deformed. Therefore, there is a demand for a pile construction method that can solve the problem of waste of materials in pile construction and the problem of damage and deformation of the pile. The above is the subject of the present invention.

  The present invention has been made in view of such a problem, and enables reuse of a first tube with a bit for excavation, eliminates waste of materials, and prevents damage and deformation of a pile. It aims at providing the pile construction method which can do.

  The present inventor makes it possible to reuse an expensive bit without burying it by forming a ring groove with a first tube with a bit for excavation and then inserting another main pile into the ring groove. It has been found that the problem of uneconomical and damage and deformation of the pile are eliminated, and based on this, the following new pile construction method has been invented.

  (1) A pile construction method in which a pile is constructed on the ground, and a coupling portion at an upper end portion of a tubular first tube having a drilling bit attached to a lower end portion is attached to and detached from a coupling portion at a lower end portion of a tubular casing. A first step of enabling mounting, and the casing and the first tube are built in an excavator for drilling, and the casing is lowered while being rotated by the excavator to form a ring groove in the ground by the first tube. Two steps, a third step of separating the connecting portions of the casing and the first tube after the casing is pulled up by the pulling means and the first tube is pulled out of the ring groove, and the coupling of the casing Removably attach the connecting portion of the upper end of the tubular main pile to the part, build the casing and the main pile into the excavator, A fifth step of lowering the casing by rotating the excavator and inserting the main pile into the ring groove, and reversely rotating the casing to separate the coupling portions of the casing and the main pile. And a sixth step of lifting only the casing by the lifting means.

  According to the pile construction method described in (1), after attaching a first tube with a bit to the casing and lowering the casing while rotating the casing with an excavator, the ring groove is formed in the ground, and then the first tube is removed from the ring groove. Unplug, replace the first tube, attach the pile to the casing, and insert the pile into the ring groove. As a result, the expensive first tube with a bit can be reused without being buried, the waste of materials can be prevented, and the economy can be improved. Moreover, since this pile only needs to be inserted in the ring groove excavated with the first tube, a large load is not applied at the time of insertion, and damage and deformation of the pile are prevented.

  (2) The pile construction method according to (1), wherein each of the first tube and the main pile is coupled to the coupling portion of the casing by screwing means.

  According to the pile construction method described in (2), since the respective joint portions of the first tube and the main pile can be attached to the joint portion at the lower end of the casing by screwing means, the construction of the joint portion of the casing is simple. At the same time, by rotating the casing and the first tube or the casing and the main pile relative to each other, the first tube or the main pile can be easily attached to and detached from the casing.

  (3) The pile construction method according to (1) or (2), wherein a bit is attached to the tip of the main pile, and the bit is bitten into the ground at the bottom of the ring groove.

  According to the pile construction method described in (3), when the bit attached to the tip of the main pile is bitten into the ground at the bottom of the ring groove and the casing is rotated in the reverse direction, the main pile does not rotate. The casing can be reliably detached from the main pile.

  According to the present invention, it is possible to reuse a first tube with a bit for excavation, and it is possible to prevent waste of materials and damage or deformation of a pile.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 are process diagrams of a pile construction method according to an embodiment of the present invention.

  (1) of FIG. 1 shows the positioning process of a trolley. In the figure, reference numeral 10 denotes a trolley installed at a place where pile driving is performed, and is installed above the sea surface 13 via a support column 12 on the seabed ground 11. A crane 14 is installed on the carriage 10. In addition, a gantry 15 for installing an excavator is provided at the front portion of the carriage 10. The height position of the carrier 10 is determined by the lifting device 17 attached to the carrier 10.

  (2) of FIG. 1 shows the installation process of the excavator 16 for drilling. In the figure, the excavator 16 is suspended from a hook 19 attached to the wire 18 of the crane 14, and installed on the mount 15 by lowering the wire 18.

  (3) of FIG. 1 shows the first tube (excavation member) 21 and casing installation process. As shown in the figure, the first tube 21 is attached to the lower end of a casing 20 made of a steel pipe that is long (a joint type that is spliced together).

  As shown in FIG. 3 (a), the first tube 21 has a connecting portion made of an internal thread 21b formed at the upper end of a main body 21a such as a steel pipe, and a plurality of bits 21c are attached to the lower end edge of the lower end of the main body 21a. The excavation ring 21d is fixed. A thin portion 20a is formed at the lower end portion of the casing 20, and a female screw 21b of the excavation tube 21 is detachably screwed into a coupling portion formed by a male screw 20b formed on the outer periphery of the thin portion 20a.

  In this way, the casing 20 with the first tube 21 attached to the lower end is suspended from the hook 19 of the crane 14 and built into the excavator 16.

  (4) in FIG. 1 shows a drilling process by the excavator 16. As shown in the figure, the bottom 20 is cut by the bit 21c of the first tube 21 by lowering the casing 20 to a predetermined position while rotating the casing 20 by the excavator 16, as shown in (5) of FIG. A ring groove 22 having a predetermined depth is formed.

  (5) in FIG. 2 shows the completion of drilling and the first tube drawing process, and a part of the ring groove is cut out and shown in cross section. As shown in the figure, the first tube 21 is pulled out from the ring groove 22 by hanging the casing 20 on the hook 19 and pulling it up by the crane 14. After the casing 20 is pulled up to a position where the first tube 21 exits from the excavator 16, the coupling portion between the female screw 21 b and the male screw 20 b is separated, and the first tube 21 is removed from the casing 20.

  (6) in FIG. 2 shows the pile building process. As shown in the figure, a steel pipe main pile 23 is coupled to the lower end portion of the casing 20 instead of the first tube 21, and the casing 20 having the main pile 23 coupled to the lower end portion is built in the excavator 16.

  As shown in FIG.3 (b), the attachment structure to the casing 20 of this pile 23 is a screwing structure similar to the first tube 21, Comprising: At the upper end part of main bodies 23a, such as a steel pipe, the coupling | bond part which consists of the internal thread 23b It is a thing of the structure provided with. A thin portion 20a is formed at the lower end portion of the casing 20, and a female screw 23b of the main pile 23 is detachably screwed into a connecting portion formed of a male screw 20b formed on the outer periphery of the thin portion 20a. A main pile bit 24 is attached to the lower end of the main body 23a. The main pile bit 24 is a bit for insertion and rotation prevention of the main pile 23, and is not used for excavation.

  As another example of the structure for attaching the main pile 23 to the casing 20, as shown in FIG. 3C, the main pile 23 is fitted to the thin portion 20a at the lower end of the casing 20 (no screw is provided). The hook-shaped locking groove 26 provided at the lower end of the casing 20 is engaged with the locking protrusion 25 provided at the upper end of the main pile 23, and the casing is rotated to engage with the locking protrusion 25. By engaging the stop groove 26 and rotating the casing 20 in the reverse direction, the engagement between the locking protrusion 25 and the locking groove 26 is released and the casing 20 is detached from the main pile 23.

  (7) of FIG. 2 shows this pile insertion process. As shown in the figure, the excavator 16 lowers the casing 20 while rotating it and inserts it into the ring groove 22, and the main pile bit 24 is thrust against the seabed ground 11 at the bottom of the ring groove 22. Since the main pile 23 only needs to be inserted into the ring groove 22, an excessive load is not applied to the main pile 23, so that the long main pile 23 can be used, and when installing the underwater pedestal The positioning accuracy can be improved.

  (8) of FIG. 2 shows a casing extraction process. The casing 20 is rotated in the direction opposite to that when the casing 20 is lowered to separate the casing 20 from the main pile 23, and then the casing 20 is hung on the hook 19 of the crane 14 and pulled up, thereby leaving the main pile 23 on the seabed ground 11. Only the casing 20 is pulled up. In this way, the construction of the main pile 23 is completed.

  As described above, the pile construction method according to the present invention is such that the first tube 21 with the bit 21c is attached to the casing 20 and the ring groove 22 is formed by lowering the casing 20 while rotating, and then the first tube 21 is replaced. The main pile 23 is attached to the casing 20, and the main pile 23 is inserted into the ring groove 22. Thereby, the first tube 21 and the expensive bit 21c can be reused without being buried, and wasteful use of materials can be prevented. Further, since the main pile 23 only needs to be inserted into the ring groove 22 excavated by the first tube 21, damage and deformation of the main pile 23 can be prevented.

  In the above embodiment, the casing 20 in FIGS. 2 (5) and 2 (8) is pulled up by the crane 14, but the excavator 16 may be used as the casing lifting means. Moreover, in the said embodiment, the same casing 20 was used at the time of excavation in (1) -FIG. 2 (5) of FIG. 1, and at the time of this pile construction in (6)-(8) of FIG. Although an example is shown, it is also possible to use different casings when excavating and when building this pile.

  The pile construction method of the present invention can be suitably used for construction of underwater structures used in harbor construction and marine construction, but can also be applied to other pile construction.

It is process drawing of the pile construction method by embodiment of this invention. It is process drawing following FIG. 1 of the pile construction method by embodiment of this invention. (A) is sectional drawing which shows the attachment or detachment structure of a first tube, (b) and (c) the attachment or detachment structure of this pile.

Explanation of symbols

14 Crane (lifting means)
16 Excavator 20 Casing 20b Male Thread 21 First Tube (Drilling Member)
21b Female thread 21c Bit for excavation 23 piles 24 pile bits

Claims (3)

A pile construction method for constructing a pile on the ground,
A first step of detachably attaching a coupling portion of an upper end portion of a tubular excavation member having a drilling bit attached to a lower end portion to a coupling portion of a lower end portion of a tubular casing;
A second step of building the casing and the excavating member in a drilling machine for drilling, lowering the casing while rotating by the excavator, and forming a ring groove in the ground by the excavating member;
A third step of separating the coupling portion of each of the casing and the excavation member after the casing is pulled up by the lifting means and the excavation member is pulled out of the ring groove;
A coupling portion at the upper end of a tubular main pile is detachably attached to the coupling portion of the casing, the casing and the main pile are built in the excavator, and the casing is lowered while being rotated by the excavator. A fifth step of inserting the main pile into the ring groove;
A pile construction method comprising: a sixth step in which the casing is reversely rotated to separate the coupling portions of the casing and the main pile and only the casing is pulled up by the lifting means; .   The pile construction method according to claim 1, wherein each of the excavation member and the main pile is coupled to the coupling portion of the casing by screwing means.   The pile construction method according to claim 1 or 2, wherein a main pile bit is attached to a lower end of the main pile, and the main pile bit is bitten into the ground at the bottom of the ring groove.

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