JP2005200865A - Work execution method for foundation pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To work execute a foundation pile having a steel frame reinforced enlarged part larger than a pile diameter at a prescribed position of the pile with excellent workability. <P>SOLUTION: In a work execution method for the foundation pile providing the steel frame reinforced enlarged part larger than the pile diameter at the prescribed position of the pile, a steel frame reinforced body 10 having a structure enlarged by compression force acting in a vertical direction at the prescribed position of an existing pile. The steel frame reinforced body 10 in a prescribed depth is enlarged to widen a pile hole so as to be enlarged, and after enlarging the pile hole, the steel frame reinforced body is a reinforced material of the enlarged part as it is. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a foundation pile construction method in which an enlarged portion larger than the pile diameter is provided at a predetermined position of the pile.

  2. Description of the Related Art Conventionally, as a means for increasing the supporting force and pulling resistance of a pile, a widened pile having a widened portion at the lower end of the pile is widely known. In this case, there are two types of bottom-pile piles: one that has a bottom-up portion at the lower end of the cast-in-place pile, and one that has a bottom-up portion at the lower end of the ready-made pile, both of which have a diameter larger than the pile diameter at the bottom of the pile hole After excavating the hole bottom widened portion, cement milk or concrete or the like is placed in the hole bottom widened portion to provide the widened bottom portion.

  As an apparatus for excavating the hole bottom expanding portion, a device having a mechanism that opens the expansion blade by utilizing the resistance of the ground by reverse rotation and closes the blade by normal rotation (for example, see Patent Document 1), One having a structure that is enlarged by raising and lowering (for example, see Patent Document 2) is known.

  In the above-mentioned expanded bottom pile, if the concrete expanded portion provided at the lower end of the pile is simply expanded beyond the diameter of the pile in the state of non-reinforcing bars, it cannot cope with the limit bearing capacity of the pile, and the pull-out resistance is also reduced. There is a problem of not being able to respond sufficiently. Therefore, conventionally, the reinforcement material that replaces the reinforcing bar or the reinforcing bar in the hole bottom widened part is expanded to be larger than the pile diameter, and then cement milk or concrete is placed and reinforced by the reinforcing material such as the reinforcing bar. Means have been proposed for providing an enlarged bottom portion larger than the pile diameter.

  As a means of expanding the above-mentioned reinforcing material to be larger than the pile diameter in the hole bottom expanding part, the reinforcing material provided at the lower end of the pile is expanded by rotating the ready-made pile inserted in the hole in the hole. There are known a method of opening (for example, see Patent Document 3), a method of expanding a reinforcing material by pushing down a reinforcing bar or an already-made pile or a rod (for example, see Patent Documents 4 to 7), and the like.

  In addition, when constructing a structure such as a building on a site with poor ground conditions, such as soft ground or embankment landfill, in order to increase the bearing capacity due to the peripheral frictional force, in the pile axis direction, that is, in the depth direction There is a method of embedding pre-made piles with protrusions (node piles, etc.) provided with a plurality of enlarged diameter portions at required intervals.

JP 9-25579 A Japanese Patent Laid-Open No. 11-6382 Japanese Patent Laid-Open No. 11-61811 JP-A-5-339941 JP-A-7-3783 JP-A-8-246445 JP-A-8-246446

  However, the excavation apparatus described in Patent Document 1 requires a certain amount of frictional force with a hole wall or excavated soil in order to close the blade by normal rotation, and may not be able to close the blade on loose ground. In addition, since the blade expansion mechanism is complicated, there are cases where the blade cannot be completely closed due to clogging or co-rotation of clay at the base of the blade expansion mechanism.

  Moreover, although the excavation apparatus described in Patent Document 2 performs the lifting / lowering timing by movement of the clutch, in actuality, there is a case in which the clutch is not moved due to co-rotation.

  The conventional excavator as described above is collected and used repeatedly after excavation, but it cannot be recovered if the expansion blade (expansion bit) cannot be closed. In the worst case, the excavator is separated from the rod. There have been problems such as cases where it must be left in the soil.

  On the other hand, in any method of expanding the reinforcing material described in Patent Documents 3 to 7, the reinforcing material is configured to be rotatable via a mechanical hinge structure (pin joint). It is necessary to provide a large number of hinge structures every time, and there is a problem that the manufacturing cost is high because the structure is complicated and a large number of parts are used.

  In addition, the above-mentioned ready-made piles with protrusions are made of concrete using a knurled formwork, which requires a large capital investment such as making the formwork. In addition, since the steel pipe pile joint pile could not be manufactured in the past, the steel pipe pile joint pile is not currently constructed.

  The present invention has been made in order to solve the above-described problems. Particularly in soft ground such as a beet layer and clay ground (in a broad sense, viscous ground), etc., a steel-reinforced type that is larger than the pile diameter at a predetermined position of the pile. It aims at making it possible to construct a foundation pile having an enlarged portion of the above with good workability.

The present invention, which has been made to achieve the above object,
A construction method of a foundation pile in which an enlarged portion of a steel reinforced type larger than the pile diameter is provided at a predetermined position of the pile,
A steel reinforcement body having a structure that is expanded by a compressive force acting in the vertical direction is provided at a predetermined position of the ready-made pile, and the steel reinforcement body is expanded at a predetermined depth to expand the pile hole, thereby expanding the pile hole. After that, the steel frame reinforcing body is used as a reinforcing material for the enlarged portion.
The steel frame reinforcing body has a structure in which a pair of upper and lower annular members are connected by a plurality of rod-like members, and includes a connecting portion between the annular member and the rod-like member and a plurality of small rigid portions on the rod-like member. The structure is characterized in that the structure is expanded by bending the part by a compressive force acting in the vertical direction.

  In the present invention, as a method of applying a vertical compressive force to the steel frame reinforcing body, for example, (1) a pushing force of a pre-made pile, (2) a pulling force that lifts the tip of the steel reinforcing body, and (3) the pushing force And (4) a compression force that directly acts on the steel frame reinforcement, and the like can be applied.

  In the present invention, a steel reinforcement body having a structure expanded by a compressive force acting in the vertical direction is used as a pile hole enlargement device, and after the pile hole has been enlarged, this steel reinforcement body is used as a reinforcement for the enlarged portion as it is. As the foundation pile is constructed, the method of expanding the steel frame reinforcement is simple, and there is no need to close and collect the excavator after the excavation of the enlarged part as in the conventional case, and the simple structure and simple With a simple procedure, a foundation pile having an enlarged portion of a steel-reinforced type larger than the outer diameter of the pile can be constructed at a predetermined position of the pile (for example, the head portion, intermediate portion, and bottom portion of the foundation pile).

Moreover, this invention exhibits a great effect especially as a construction method of the foundation pile in a viscous ground. That is, in the conventional excavation apparatus, there are many cases in which the expansion blade, which is considered to be caused by clogging of clay or the like, frequently occurs in the expansion excavation of the viscous ground, which is a problem. On the other hand, in soft ground such as the beet layer and viscous ground, compared to gravel and sand gravel layers, the steel frame reinforcement can be easily expanded and the pile hole can be expanded. Can be expanded.
In addition, as a steel reinforcing body, it has a structure in which a pair of upper and lower annular members are connected by a plurality of rod-shaped members, and includes a connecting portion between the annular member and the rod-shaped member and a plurality of small rigid portions on the rod-shaped member, By using a structure having a structure that is expanded when the part is bent by a compressive force acting in the vertical direction, the manufacturing cost of the steel frame reinforcement can be reduced, and the formation of a desired expansion portion and the extremely simple structure can be achieved. Reinforcement can be performed.

  Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments, and can be appropriately modified within the scope of the gist of the present invention.

(First embodiment)
This example relates to a construction method of a foundation pile structure in which an enlarged portion (an enlarged bottom portion) of a steel frame reinforcement type larger than the pile diameter is provided at the bottom of the pile.

  The steel frame reinforcement according to this example is shown in FIG. FIG. 1 shows a state after the steel frame reinforcement has been expanded, in which (a) is a top view and (b) is a side view. In the figure, 10 is a steel frame reinforcement, 11a and 11b are annular members, 12 is a rod-shaped member, and 13a to 13d are small rigid portions.

  As shown in FIG. 2, the steel frame reinforcing body 10 of the present example is formed by integrally forming a steel plate processed into a predetermined shape with a cutter or the like by overlapping AA ′ on both sides and rounding it into a cylindrical shape. . In addition, 14 is a notch line and 15 is a notch part (opening part).

  This steel frame reinforcing body 10 has a structure in which a pair of upper and lower annular members 11a and 11b are connected by a plurality of rod-like members 12, and a connecting portion between the annular members 11a and 11b and the rod-like member 12 and a predetermined portion of the rod-like member 12 are provided. The portions are provided with small rigid portions 13a to 13d.

  The small rigid portions 13a to 13d are portions designed to have a bent portion with a smaller rigidity than the other portions. In short, the portions are prone to plastic deformation. Regardless of a mechanical hinge structure (pin joint), the steel reinforcement body is expanded by a plastic deformation caused by a compressive force acting in the vertical direction on the steel reinforcement body. Specifically, this small rigidity part is formed thinner (or thinner) than other parts by notching or the like, bent in a predetermined shape in advance, or bent in a predetermined direction. It can be formed, for example.

  The steel frame reinforcement 10 is integrally fixed near the lower end of the ready-made pile 100 as shown in FIG. At this time, as shown in FIG. 4, it is preferable that the mountain fold (or valley fold) is slightly performed in advance in the small rigid portions 13 a to 13 d. Thereby, it can be surely expanded by applying a compressive force in the vertical direction.

  As a method of fixing the steel frame reinforcing body 10 to the ready-made pile 100, it is easy to wrap the upper annular member 11a around the lower end outer periphery of the ready-made pile 100 and fasten and fix it with a fastening band or the like. It is also possible to use a fastening band or the like together with an adhesive, or to process the upper annular member 11a itself into a fastening band shape. The lower annular member 11b is preferably formed into a complete ring shape by welding or the like, unlike the upper annular member 11a attached to the ready-made pile 100.

  The ready-made pile 100 for fixing the steel frame reinforcing body 10 is not particularly limited, and may be a concrete pile (so-called PHC pile, PRC pile or the like), a steel pipe pile, an SC pile, or the like.

  Next, the concrete construction method of the foundation pile in this embodiment is demonstrated using FIG.

  The present embodiment is based on the digging method. First, as shown in FIG. 5 (a), the spiral auger 101 is inserted into the hollow portion of the ready-made pile 100 to which the steel reinforcing body 10 is mounted, and the leading end of the pile is advanced. While digging, the ready-made pile 100 is stowed to a predetermined depth by press-fitting. After reaching a predetermined depth, cement milk, cement mortar, etc. are filled from the tip of the spiral auger.

  Next, after raising the spiral auger 101 to the ground, a vertical pushing force is applied to the ready-made pile 100. As a result, when the steel frame reinforcing body 10 is subjected to a large vertical compressive stress on the small rigid portions 13a to 13d, the rod-like member 12 is bent outward at the portions 13a to 13d, for example, soft ground such as a beat layer. Or in a cohesive land, you can easily expand the pile hole to the desired size by expanding the pile hole.

  Eventually, the expansion of the steel reinforcing body 10 stops when the lower end of the ready-made pile 100 reaches the lower end of the steel reinforcing body 10. Therefore, by adjusting the fixing position of the steel reinforcement body 10 to the ready-made pile 100, that is, by adjusting the L1 and L2 dimensions in FIG. It can be adjusted and a desired widened portion can be formed.

  Then, after the predetermined widened portion 102 as shown in FIG. 5 (b) is formed, by placing cement milk or cement mortar as necessary, for example, when a space remains in the pile hole A foundation pile structure having an expanded bottom portion reinforced with the steel frame reinforcing body 10 is formed.

  As described above, according to the present embodiment, the steel reinforcing body 10 having a structure that is expanded by the compressive force acting in the vertical direction is used as an expansion device for a pile hole, and this steel reinforcing body is used as it is as a reinforcing material for the expanded bottom portion. Since the foundation pile is constructed, it is possible to provide a steel-reinforced type bottom-up portion larger than the pile diameter at the lower end of the pile by an extremely simple procedure.

  Further, the steel frame reinforcing body 10 has a very simple structure in which a pair of upper and lower annular members 11a and 11b are connected by a plurality of rod-like members 12, and is low in cost as compared with a structure having a large number of conventional hinge structures (pin joints). Can be manufactured.

  In the above example, the basic pile structure in which the lower end of the steel frame reinforcing body 10 is completely in contact with the bottom of the hole has been described. However, after the bottomed portion 102 has been formed, the entire pile is lifted slightly and floated from the bottom of the hole. In some cases. By lifting the entire pile from the bottom of the hole in this way, the hardener (filler such as cement milk and cement mortar) will sufficiently wrap around the bottom of the steel frame reinforcement 10 to expand the load applied to the pile more effectively. While being able to transmit to a hole bottom via a part, the phenomenon (punching) which the ready-made pile 100 bites into a hole bottom can be prevented effectively.

  If it is necessary to prevent the steel reinforcing body from opening before reaching the predetermined depth, for example, a ring-shaped member such as a steel pipe is set outside the steel reinforcing body and the ring is reached after reaching the predetermined depth. The steel member can be removed from the hollow ready-made pile and then used after being pushed into the hollow ready-made pile after reaching the predetermined depth.

(Second Embodiment)
The present example relates to a construction method of a foundation pile structure in which an enlarged portion (node portion) of a steel reinforced type larger than the pile diameter is provided at an intermediate portion of the pile.

  First, as shown to Fig.6 (a), a spiral auger (not shown) is inserted in the hollow part of the ready-made pile 200 to which the steel frame reinforcement body 10 was mounted | worn, and it is ready-made to the predetermined depth by press-fitting while carrying out a prior digging of the pile front end. The pile 200 is stood up and the pile hole is filled with cement milk, cement mortar or the like. The steel reinforcing body 10 is the same as the steel reinforcing body 10 of the first embodiment, but only the lower annular member 11b is fixed to the ready-made pile 200, and the upper annular member 11a is not fixed.

  Next, for example, the upper annular member 11a that is not fixed to the ready-made pile 200 is pushed downward by an outer pipe (not shown) that passes through the outside of the ready-made pile 200, and a compressive force is directly applied to the steel reinforcing body 10. Then, the steel frame reinforcement body 10 expands radially outward from the ready-made pile 200 when a large compressive stress in the vertical direction acts on a small rigid portion. Thereby, for example, in soft ground such as a beet layer or viscous ground, the pile hole can be pushed and widened to easily expand the pile hole to a desired size.

  And after the predetermined enlarged part 202 as shown in FIG.6 (b) is formed, when space remains in a pile hole etc., by placing cement milk or cement mortar etc. as needed, The foundation pile structure which has the expansion part (node part) reinforced with the steel frame reinforcement 10 is formed.

  As described above, according to this embodiment, there is no need for capital investment such as production of a formwork, and an enlarged portion (node portion) reinforced accurately through a steel frame in a middle portion of a steel pipe pile as well as a concrete pile. The foundation pile structure which has can be constructed with good workability.

  Moreover, when providing an expansion part (node part) in the intermediate part of a pile like this example, multiple expansion parts (node part) can be provided in an appropriate place.

  In the above description, the upper annular member 11a of the steel frame reinforcing body 10 is made free, but conversely, the lower annular member 11b may be made free. In this case, the steel reinforcing body 10 can be expanded by using a force that hooks a plurality of hooks or the like on the annular member 11b and pulls a wire connected thereto.

(Third embodiment)
This example relates to a construction method of a foundation pile structure in which an enlarged portion (node portion) of a steel reinforced type larger than a pile diameter is provided at a connection portion between an upper pile (steel pipe pile) and a lower pile (steel pipe pile).

  FIG. 7 is a side view showing the lower end portion of the upper pile, and the upper pile 300 is provided with a plurality of bolt holes 301 in the vicinity of the lower end portion.

  FIG. 8 is a perspective view showing a connecting pipe for connecting the upper pile and the lower pile. A plurality of sets of moving grooves 311 including two through holes 311a and 311b having a predetermined interval in the vertical direction (dimension L3 in the drawing) and a communication groove 311c for communicating these are provided on the upper portion of the connection pipe 310. ing. The connection pipe 310 can be a short steel pipe or the like, but is not particularly limited as long as it has the necessary bending rigidity.

  The construction method of the foundation pile structure in this embodiment is demonstrated using FIG.

  First, as shown to Fig.9 (a), it connects using the said connecting pipe 310 so that the space | interval (dimension L4 in a figure) of the lower pile 320 and the upper pile 300 may become equal to the said dimension L3, for example. The lower pile 320 and the connecting pipe 310 are fixed by bolting or welding. The upper pile 300 and the connecting pipe 310 are connected by a bolt 312 through the upper through hole 311a of the connecting pipe 310 and the bolt hole 301 of the upper pile 300. The bolt 312 can move up and down the movement groove 311. It has become. That is, the upper pile 300 can be moved downward by the dimension L3 (= L4) from the state of FIG.

  Next, as shown in FIG. 9B, the steel frame reinforcing body 10 is fixed to the upper pile 300 and the lower pile 320 across the connecting pipe 310. The steel frame reinforcing body 10 is the same as the steel frame reinforcing body 10 of the first embodiment. However, the space between the upper annular member of the steel frame reinforcing body 10 and the upper end portion of the connection pipe 310 is secured at least the dimension L3. .

  Next, a spiral auger (not shown) is inserted into the hollow portion of the connecting pile equipped with the steel reinforcing body 10, and the connecting pile is stowed to a predetermined depth by press-fitting while leading the pile tip, and cemented in the pile hole. Fill with milk, cement mortar, etc.

  Next, the upper pile 300 is pushed into the connecting pipe 310 by applying a vertical pushing force to the upper pile 300. Then, the steel frame reinforcement body 10 expands to a predetermined shape by a large vertical compressive stress acting on a small rigid portion. Thereby, for example, in soft ground such as a beet layer or viscous ground, the pile hole can be pushed and widened to easily expand the pile hole to a desired size.

  Finally, as shown in FIG. 9C, the bolt 312 is positioned in the lower through hole 311b of the connecting pipe 310, and the steel pile reinforcing body 10 is in a state where the upper pile and the lower pile are in contact with each other. The expansion stops. Therefore, by adjusting the L3 dimension in FIG. 8 (or the L4 dimension in FIG. 9A), the diameter of the final steel reinforcing body 10 after the expansion can be easily adjusted, and a desired value can be obtained. An enlarged portion can be formed.

  After the enlarged portion is formed, when the space remains in the pile hole, etc., it is reinforced by the steel reinforcing body 10 at the connecting portion of the pile by placing cement milk or cement mortar as necessary. A foundation pile structure having an enlarged portion (node portion) is formed.

  As described above, according to the present embodiment, it is possible to easily connect the piles using the connection pipe having a simple cylindrical shape, and not only in the concrete piles but also in the steel pipe piles without the need for capital investment such as formwork production. In addition, it is possible to construct a foundation pile structure having an enlarged portion (node portion) reinforced accurately through a steel frame at the pile connecting portion with good workability.

(Other embodiment examples)
In the example of the previous embodiment, the case where the steel-reinforced type enlarged portion is provided at the bottom or intermediate portion of the foundation pile has been described. However, in the construction method of the present invention, the steel-reinforced type enlarged portion (head enlarged) is provided at the pile head. You can also. When providing a steel-reinforced type enlarged portion (head expansion) on the pile head, appropriate reinforcement is placed on the enlarged portion (head expansion) for further reinforcement of the head expansion and joining with the foundation (footing, etc.) It is preferable.

  Moreover, the construction method of the present invention provides a plurality of steel reinforcement type enlarged portions at desired positions of the head, middle, and bottom of the foundation pile by appropriately combining the embodiments described above. You can also.

  In addition, in the previous embodiment example, it was described as being based on the medium digging method, but the pre-boring method (pre-boring method) that is performed by inserting a pile equipped with a steel reinforcement body into a pile hole excavated to a predetermined depth in advance with an auger ). Also in this pre-digging method, as in the previous embodiment, the steel reinforcing body is expanded at a predetermined depth to expand the pile hole, and after expanding the pile hole, the steel reinforcing body is directly used as a reinforcing material for the enlarged portion. To do. Moreover, in soft ground, the steel frame reinforcement can be used as a drilling device for pile holes.

  Moreover, the steel frame reinforcement used for this invention is not limited to what was illustrated in FIG. 1 etc., The thing of the very simple structure which processed the steel pipe or the steel pipe pile itself may be sufficient. An example of the steel frame reinforcement which processed the steel pipe is shown in FIG.10 and FIG.11. 10A and 10B show a state after the steel frame reinforcing body 10A is expanded, where FIG. 10A is a top view and FIG. 10B is a side view. FIG. 11 is a development view of the steel frame reinforcing body 10A. In these drawings, the same members as those in the steel reinforcing body 10 in FIG.

  Thus, the steel frame reinforcing body used in the present invention has a structure that is expanded by a compressive force acting in the vertical direction, and can expand a pile hole by the expansion, and an expansion formed thereby. Any material may be used as long as it can serve as a reinforcing material for the part. For example, an iron plate, a reinforcing bar, a steel pipe, a steel frame, or the like may be appropriately combined and assembled by welding or the like.

It is a figure which shows the state after the expansion of the steel frame reinforcement which concerns on the 1st Example of this invention. It is an expanded view which shows the processing shape of the steel frame reinforcement which concerns on the 1st Example of this invention. It is a figure which shows the state which fixed the steel frame reinforcement which concerns on the 1st Example of this invention to the ready-made pile. It is a figure which shows the state which expanded the steel frame reinforcement which concerns on the 1st Example of this invention slightly. It is a figure for demonstrating the construction method of the foundation pile in the 1st Example of this invention. It is a figure for demonstrating the construction method of the foundation pile in the example of the 2nd Embodiment of this invention. It is a side view which shows the structure of the lower end part of the upper pile in the example of 3rd Embodiment of this invention. It is a perspective view which shows the connection pipe for connecting the upper pile and the lower pile in the example of 3rd Embodiment of this invention. It is a figure for demonstrating the construction method of the foundation pile in the example of 3rd Embodiment of this invention. It is a figure which shows the state after the expansion of the steel frame reinforcement which concerns on the other embodiment example of this invention. It is an expanded view which shows the processing shape of the steel frame reinforcement which concerns on the other embodiment example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A Steel frame reinforcement body 11a, 11b Annular member 12 Rod-like member 13a-13d Small rigidity part 14 Cut line 15 Notch part (opening part)
100, 200 Ready-made pile 101 Spiral auger 102 Expanded bottom portion 202 Expanded portion 300 Upper pile 301 Bolt hole 310 Connection pipe 311 Movement groove 311a, 311b Through hole 311c Communication groove 312 Bolt 320 Lower pile

Claims (2)

A construction method of a foundation pile in which an enlarged portion of a steel reinforced type larger than the pile diameter is provided at a predetermined position of the pile,
A steel reinforcement body having a structure that is expanded by a compressive force acting in the vertical direction is provided at a predetermined position of the ready-made pile, and the steel reinforcement body is expanded at a predetermined depth to expand the pile hole, thereby expanding the pile hole. After the construction, a method for constructing a foundation pile, wherein the steel frame reinforcement is used as a reinforcing material for the enlarged portion.   The steel reinforcing body has a structure in which a pair of upper and lower annular members are connected by a plurality of rod-like members, and includes a connecting portion between the annular member and the rod-like member and a plurality of small rigid portions on the rod-like member, The construction method for a foundation pile according to claim 1, wherein the foundation pile has a structure that is expanded by being bent by a compressive force acting in a direction.

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