JP3449246B2 - Construction method of embedded pile using expanded steel pipe pile and expanded steel pipe pile - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried pile which is frequently used for pile foundation work in urban areas and the like, and a method for constructing a buried pile using a bottom expanded steel pipe pile having a diameter increased at the tip and a bottom expanded steel pipe for the buried pile. It concerns the structure of the pile.

[0002]

2. Description of the Related Art Pile construction methods are roughly divided into
There are impact method, cast-in-place concrete pile method, embedded pile method, etc., but the embedded pile method is applied as a method that can be constructed in a narrow space with low vibration and noise in urban areas.
If you do not give the Ru Seza often.

The buried pile construction method further includes a pre-digging construction method, a mid-digging construction method, and a rotary press-fitting construction method. In the pre-digging method, holes for building prefabricated piles are pre-digged with a drilling device such as a spiral auger or a drilling rod with a drilling head at the tip, and a solidifying material such as cement milk is usually injected from the drilling head part. However, the precast piles are to be sunk into the holes where soil and cement milk have been positively replaced or the holes filled with soil cement that has been stirred and mixed with earth and sand.
By solidifying soil cement, etc., the existing pile is fixed in the excavation hole to obtain the bearing capacity.

At the lower end, in order to increase the supporting force at the tip of the support layer, the diameter of the auger or the excavation head of the excavation rod is expanded and enlarged, and the cement pile or mortar containing a rich mixture is filled to form the existing pile. In many cases, it is built and a root consolidation part is formed.

Further, the hollow digging method uses hollow precast piles such as steel pipe piles, hollow concrete piles, and steel-concrete composite piles, while excavating the auger through the hollow portion or rotating the drilling head at the tip of the drilling rod. , Hollow prefabricated piles will be built.

An excavating head attached to an excavating rod is usually provided with an excavating bit, an expandable / contractible stirring blade, a co-rotation preventing blade, etc., and excavates while pouring a drilling liquid such as water or a solidifying material such as cement milk. , Can be stirred and mixed.

Also in the case of the intermediate digging method, the tip root consolidation portion can be formed to enhance the tip supporting force, if necessary.
Further, the rotary press-fitting method is a method of screwing into the ground while rotating a pile having a spiral wing or a rotary wing at the tip or the general part of the pile.

In order to reduce the amount of discharged soil and the amount of residual soil to be treated, even in the case of the digging method or the rotary press-fitting method, hollow piles with open ends such as steel pipe piles are used as precast piles for embedded piles. As an embedded pile using a steel pipe pile and a construction method thereof, there are those described in, for example, JP-A-63-97711 and JP-A-64-75715.

The one described in Japanese Patent Laid-Open No. 63-97711 discloses that when a steel pipe pile is built in a soil cement column formed by a digging method, the steel pipe pile has almost the entire outer peripheral surface and the tip of the steel pipe pile. The protrusions are provided on the inner surface of the portion and the head to increase the adhesive force with the soil cement, to achieve the effect of closing the tip of the pile, the effect of increasing the horizontal resistance, and the improvement of the friction resistance.

Further, the one disclosed in Japanese Patent Laid-Open No. 64-75715 discloses a steel pipe pile or a hollow concrete pile as an embedded pile while pouring, stirring and mixing a solidifying material such as cement milk by a digging method. When building,
By switching the solidified material to a solidified material that can obtain higher compressive strength in front of the tip part, increasing the tip support force at the tip root consolidation part, and by installing spiral wings on the outer peripheral surface of the built-up pile to be built, soil It is designed to facilitate the rotational press-fitting of existing piles into cement.

[0011]

In the case of a hollow prefabricated pile whose tip is open, the excavated soil remains in the hollow portion of the precast pile, which is advantageous in that the amount of discharged soil and the amount of excavated soil remaining are reduced. In particular, in the case of steel pipe piles, since the pipe thickness is smaller than the pile diameter, it is possible to perform construction close to no soil discharge.

On the other hand, since the area of the tip of the steel pipe pile itself is small, in order to increase the support force at the tip, an enlarged diameter portion having a diameter larger than that of the general portion of the pile is formed at the tip of the steel pipe pile, or cement is provided at that portion. It is desirable to inject a solidifying material such as milk to form the tip root fixing portion.

From the above, the applicant of the present application previously comprises a sufficiently long base steel pipe, a tip steel pipe having a diameter larger than this steel pipe, and a connecting member for connecting the base steel pipe and the tip steel pipe. It has developed a拡底steel pipe pile (Japanese Patent Application No. 9 -26
No. 0285).

By the way, in the construction of an embedded pile using such a bottom steel pipe pile, when forming the tip root consolidation part, there is a step between the general pile part made of a normal steel pipe pile and the large diameter tip steel pipe. In some cases, sticky earth and sand such as cohesive soil, earth and sand that is improperly mixed with solidifying material such as slime-like earth and cement milk (hereinafter referred to as inappropriate material) adheres to the inside of the corner of the step position. However, there is a possibility that the expected tip support force may not be obtained.

The present invention is intended to solve the above-mentioned problems, and even if there is a step between the general portion and the expanded diameter portion of the expanded steel pipe pile, it is inappropriate for the inside of the corner. It is an object of the present invention to provide a method for constructing an embedded pile and a structure for a bottomed steel pipe pile that can prevent a decrease in tip supporting force due to material adhesion.

[0016]

[Means for Solving the Problems] A method of constructing an embedded pile using a bottomed steel pipe pile according to claim 1 of the present application is a pile general part made of a long steel pipe and a general pile part formed at the tip. A method for constructing an embedded pile using a bottom-expanded steel pipe pile having a large-diameter expanded portion, the tip of the pile general portion, and a disc-shaped connecting portion that connects the expanded portion, and can be expanded and contracted at the lower end. Pass a drilling device with a drilling head through the hollow part of the expanded steel pipe pile, expand the diameter of the drilling head, excavate the ground and sunk the expanded steel pipe pile by the medium excavation method, and solidify or expand the expanded part. When fixing to the root-hardening part filled with a mixture of material and earth and sand, the adhesion-preventing blade expanded to a diameter substantially equal to the inner diameter of the diameter- increasing part provided at the rear part of the excavating head.
Is located inside the corner between the connecting part and the expanded part.
Allowed, by the rotation of the anti-adhesion blade, it is characterized in that to prevent the adhesion of inappropriately material from entering the inside of 該隅 corner.

Regarding the expanded steel pipe pile to which the present invention is applied, the applicant previously described in Japanese Patent Application No. 9-260285 that a sufficiently long base steel pipe (pile general portion) and a tip steel pipe having a diameter larger than this steel pipe. It proposes a steel pipe pile including a (diameter expanded portion) and a connecting member that connects the base steel pipe and the tip steel pipe.

Further, regarding the connecting portion composed of the connecting member, this is used as a perforated disc and is joined to the base steel pipe and the tip steel pipe by welding, respectively, and the tip steel pipe portion and the connecting member are manufactured as an integral casting, and the base portion is manufactured. Proposals are for welding to steel pipes.

The excavating rod or auger used in the medium excavation method is usually provided with an excavating bit, a stirring blade, a spiral blade or the like at the excavation head portion, and the stirring blade or the like can be expanded or contracted by earth pressure or the like. There are many.

Also in the present invention, the same type of excavator itself can be used, and the rear part of the excavating head is provided with an adhesion preventing blade capable of expanding its diameter to a diameter substantially equal to the inner diameter of the expanded diameter portion. Therefore, when the anti-adhesion blades rotate, the solidified material such as cohesive soil or slime-like sand and cement milk that penetrates into the corners between the joints and expanded diameters of the expanded bottom steel pipe pile is insufficient. Prevents adhesion of inappropriate materials such as natural earth and sand.

According to claim 2 of the present application, a method of constructing an embedded pile using a bottomed steel pipe pile is a pile general part made of a long steel pipe, and an expanded part having a diameter larger than the general part of the pile formed at the tip part. And a method of constructing an embedded pile using a bottomed steel pipe pile having a tip of the pile general portion and a disc-shaped connecting portion connecting the expanded diameter portion, in a drilling hole by a digging method or a digging method. When fixing the expanded diameter portion to the root-hardening portion filled with the solidifying material or the mixture of the solidified material and earth and sand, the entire inner circumference of the corner between the connecting portion and the expanded diameter portion. , The partition and the filler are attached in advance so as to form an inner surface that gradually expands from the pile general part to the expanded part side or an inner surface that has the same inner diameter as the pile general part, so that the connecting part and the expansion part expand in diameter. It is also characterized in that it prevents the adhesion of inappropriate materials that enter the inside of the corner between the It is.

In the construction method according to claim 1, unsuitable materials are forcibly removed by the adhesion preventing blade, whereas in the construction method according to claim 2, the connection portion and the expanded diameter portion of the expanded bottom steel pipe pile are connected. By installing partitions or fillers in the corners between the embedded piles, the embedded piles are constructed so that inappropriate materials do not easily adhere to the embedded piles when they are built.

As a material for the partition, for example, a skirt-processed steel plate, synthetic resin plate, synthetic resin sheet or the like that forms a smooth surface is preferable. There is no particular limitation as long as it forms an inner surface that gradually expands to the side or an inner surface that has the same inner diameter as the general pile portion, and has the strength required to obtain a supporting force because an inappropriate material hardly adheres.

Further, instead of the partition, by filling a filling material that gives a predetermined inner surface shape to the corner,
Adhesion of inappropriate materials can be prevented by the inner surface shape. The filler is a material to which an unsuitable material is difficult to adhere, and is not particularly limited as long as it has strength or hardness equal to or higher than that of the solidifying material such as cement milk or soil cement at the tip, hardness, and durability. Resin materials, metal materials, etc. are desirable.

As a result, when the expanded steel pipe pile is built to a predetermined depth and the tip reaches the root consolidation part, solidification materials such as mortar and cement milk, or cement milk and earth and sand are stirred and mixed in the corners. Soil cement etc. that have been removed are spread, and it is possible to obtain the tip supporting force according to the design.

In the case of the construction method according to claim 2, it is also possible to pierce the hollow portion of the expanded bottom steel pipe pile with an excavating device to dig it by the intermediate excavation method and build the expanded bottom steel pipe pile. It is also possible to build an expanded bottom steel pipe pile after forming an uncured soil cement column etc. by the construction method.

A bottom expanded steel pipe pile for an embedded pile according to claim 3 of the present application is a pile general portion made of a long steel pipe, an enlarged diameter portion formed at a tip end portion having a diameter larger than that of the general pile portion, and the pile. A bottom expanded steel pipe pile having a tip of a general portion and a disc-shaped connecting portion connecting the expanded portion, wherein the pile general portion is provided on the entire inner circumference of a corner between the connecting portion and the expanded portion. A partition or packing made of a material that satisfies the strength required to obtain supporting force is provided so that the inner surface that gradually expands from the It is characterized by that.

A third aspect of the present invention is to provide a bottomed steel pipe pile for use in the construction method of the second aspect, and the partition, filler, etc. are as described above.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a construction procedure in an embodiment of a construction method according to claim 1 of the present application.
The bottomed steel pipe pile 1 having the expanded diameter portion 1b at the tip of the steel pipe 1a is used, and construction as an embedded pile is performed by the medium excavation method. Hereinafter, the construction procedure will be described.

(1) When excavating a general part (see FIG. 1 (a)) The excavating rod 2 having the excavating head 3 attached to the tip thereof is inserted into the hollow portion of the expanded steel pipe pile 1 to constitute the excavating head 3. 3a, the upper and lower stirring blades 3b and 3c, the co-rotation preventing blade 3d, etc. are expanded, and the excavating rod 2 is rotated to build the steel pipe pile 1 while excavating the ground.

In this example, the excavation water a is injected from the tip of the excavation rod 2 into the ground for excavation, and the cement milk b as a solidifying material is provided on the upper surface of the tip of the upper stirring blade 3c. The cement milk b is prevented from directly entering into the steel pipe pile 1 by discharging it upward from (not shown). However, the hollow excavation method to which the present invention is applied is not limited to that of the present embodiment, and a method in which cement milk or the like enters the steel pipe pile 1 may be used.

Further, above the upper stirring blade 3c, there is provided an adhesion preventing blade 4 capable of expanding the diameter to a diameter substantially equal to the inner diameter of the expanded diameter portion 1b of the steel pipe pile 1, and the steel pipe constituting the general portion of the pile. The excavated soil and the like adhere to the corner portion of the portion connecting the 1a and the enlarged diameter portion 1b, so that the formation of the tip root consolidation portion A later will not be hindered.

That is, in the viscous soil or slime-like soil, or in the vicinity of the root consolidation portion, an inappropriate material such as soil mixed with cement milk or the like is clogged in the corner portion of the expanded steel pipe pile 1 The adhesion preventing blade 4 prevents the rooting function from being insufficiently exhibited.

In this embodiment, the steel pipe pile 1 provided with the stirring blades 6 is built while rotating in the direction opposite to the direction of the excavation rod 2, but as described above, the steel pipe pile 1
May be rotated in the same direction as the excavation rod 2, or the steel pipe pile 1 itself may be built without rotating.

Also, in the figure, 5 is for this kind of construction,
It is a stabilizer that has been used conventionally. (2) When excavating the support layer (see Fig. 1 (b)) When the lower end of the expanded steel pipe pile 1 reaches the support ground surface N, the excavation water a and, if necessary, the cement milk b are changed to cement milk c with high solidification strength. Replace and excavate the root consolidation part. In this example, the diameter of the excavation hole is the same in the pile general portion and the pile tip portion, but there is also a case where the tip excavation portion A is enlarged and excavated.

(3) At the end of construction (see FIG. 1 (c)) When the excavation is completed and the tip of the expanded steel pipe pile 1 reaches a predetermined depth below the support ground surface N, the excavation head 3 is subjected to earth pressure or the like. It is used to reduce the diameter in the radial direction and gradually pulled up while rotating from the hollow portion of the steel pipe pile 1.

As a method for reducing the diameter of the excavating head 3 in the radial direction, a method of reducing the diameter by rotating the hinge portion or the like by utilizing contact with the steel pipe pile 1 or a hydraulic mechanism or other mechanical reducing mechanism is used. There is also a way to reduce it.

[0038] Figure 2, an embodiment of a construction method and拡底steel pipe pile according to claim 2 of the present application illustrates schematically. FIG. 2 (a) shows that a partition 11 made of steel plate or resin sheet is provided at the corner formed between the expanded diameter portion 1b of the expanded bottom steel pipe pile 1, the connecting portion 1c, and the steel pipe 1a which is the general portion of the pile. By forming a tapered inclined surface at this corner by the partition 11, when the expanded steel pipe pile 1 is built in the excavated earth or soil cement 13,
It is possible to prevent inappropriate materials from adhering to the corners.

In FIG. 2 (b), a corner 12 is similarly filled with a filling material 12 made of a curable resin material or the like to form an inclined surface. FIG. 3 schematically shows an embodiment of the root consolidation portion of the embedded pile by the construction method according to claim 2 of the present application.

As for the root consolidation portion A, the enlarged and excavated portion is filled with mortar or high-strength soil cement 14 and the tip portion of the expanded steel pipe pile 1 is fixed so that a large tip supporting force can be obtained. Further, as shown in FIG. 2 (a), since the partition 11 is provided at the corner portion, improper material does not enter this portion, and the embedded pile has high reliability.

Although the connecting portion 1c of the expanded steel pipe pile 1 is horizontal in FIGS. 1 and 2, it may be slightly inclined as shown in FIG. Moreover, when this inclination is large, it is not always necessary to apply the construction method or structure of the present invention.

With respect to the general pile portion, a bearing force due to circumferential friction is obtained between the excavated earth and sand or the soil cement 13 having a relatively low strength.

[0043]

EFFECTS OF THE INVENTION According to the construction method of claim 1 of the present application, the solidified material such as cohesive soil or slime-like earth and sand, cement milk, etc., which tends to stay inside the corner of the expanded steel pipe pile is not sufficiently mixed. By removing unsuitable materials such as natural earth and sand by the adhesion prevention blades, a high tip support force is guaranteed for the embedded piles with the bottom-expanded steel pipe piles whose roots are solidified after the completion of construction. Further, since the adhesion preventing blades forcefully remove the inappropriate material, the effect is certain.

According to the construction method according to claim 2 and the expanded bottom steel pipe pile according to claim 3 of the present application, the partition or filler provided at the corner portion prevents adhesion of an inappropriate material. Similar to the invention according to, the high tip supporting force is guaranteed for the embedded pile made of the expanded steel pipe pile. Also, since it is a simple structure that only attaches partitions or packing,
Almost no increase in construction cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a construction procedure in an embodiment of a construction method according to claim 1 of the present application.

2 (a) and 2 (b) are vertical cross-sectional views schematically showing an embodiment of a construction method and a bottomed steel pipe pile according to claims 2 and 3 of the present application, respectively.

FIG. 3 is a vertical cross-sectional view schematically showing an embodiment of a root consolidation portion of an embedded pile by the construction method according to claim 2 of the present application.

[Explanation of Codes] N ... Supporting ground surface, A ... Tip consolidation part a ... Drilling water, b ... Cement milk, c ... Cement milk (rich mixture) 1 ... Expanded steel pipe pile, 1a ... Steel pipe, 1b ... Expanded part 1c ... Connection part, 2 ... Drilling rod, 3 ... Drilling head, 3a ... Drilling bit, 3b ... Stirring blade (lower side), 3c ... Stirring blade (upper side),
3d ... co-rotation prevention blade, 4 ... adhesion prevention blade, 5 ... stabilizer, 6 ... stirring blade (steel pipe pile side), 7 ... soil cement (low strength), 8 ... soil cement (high strength), 9 ... earth and sand (not yet) (Improved soil) 11 ... Partition, 12 ... Filling material, 13 ... Excavated sand or low strength soil cement, 14 ... Mortar or high strength soil cement

Front page continuation (72) Inventor Yukinori Yoshizawa 4-5-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd. (72) Hiroyuki Tanaka 4-53-3 Kitahama, Chuo-ku, Osaka City, Osaka Prefecture Sumitomo Metal Industries, Ltd. (56) Reference JP-A-59-92741 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 5/44 E02D 5/48

Claims (3)

(57) [Claims] 1. A general pile portion made of a long steel pipe, a diameter-increasing portion formed at a tip end portion having a diameter larger than that of the general pile portion portion, a disk shape connecting the tip end of the general pile portion and the diameter-increasing portion. A method for constructing an embedded pile using a bottom-expanded steel pipe pile having a connecting part of, wherein a drilling device having a drilling head that can be expanded and contracted at the lower end is passed through the hollow part of the bottom-expanded steel pipe pile to expand the diameter of the drilling head. When excavating the ground and digging the bottom expanded steel pipe pile by the medium excavation method and fixing the expanded diameter part to the root consolidation part filled with the solidifying material or the mixture of the solidifying material and earth and sand, at the rear part of the drilling head. The adhesion preventing blade expanded to a diameter substantially equal to the inner diameter of the expanded diameter portion provided is formed between the connecting portion and the expanded diameter portion.
Is located inside the corner between, by the rotation of the anti-adhesion wing, the buried piles using拡底steel pipe, characterized in that to prevent the adhesion of inappropriately material from entering the inside of 該隅 corner Construction method. 2. A pile general portion made of a long steel pipe, a diameter-increased portion having a diameter larger than that of the pile general portion formed at a tip portion, and a disk shape connecting the tip of the pile general portion and the diameter-increased portion. Is a method of constructing an embedded pile using a bottom-expanded steel pipe pile having a connecting part of, wherein the diameter-expanded portion is built into the excavation hole by a digging method or a medium-digging method, and the expanded diameter portion is a solidified material or a mixture of solidified material and earth and sand. When fixing to the root consolidation part filled with, the inner surface or pile that gradually expands from the general pile part to the expanded part side along the entire inner circumference of the corner between the connecting part and the expanded part. By attaching a partition or filler in advance so as to form an inner surface having the same inner diameter as that of the general portion, adhesion of an inappropriate material penetrating inside the corner between the connecting portion and the expanded diameter portion A method for constructing an embedded pile using a bottomed steel pipe pile, which is characterized by preventing 3. A pile general part made of a long steel pipe, a diameter-increased part formed at the tip part having a diameter larger than that of the pile general part, and a disk shape connecting the tip of the pile general part and the diameter-increased part. A bottom expanded steel pipe pile having a connecting part of, and an inner surface or a pile that gradually expands from the general pile part to the expanded part side on the entire inner circumference of the corner between the connecting part and the expanded part. A bottomed steel pipe pile for an embedded pile , characterized in that a partition or filler is provided so as to form an inner surface having the same inner diameter as the general portion.