JP3932173B2 - Steel pipe pile construction member and steel pipe pile construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for constructing a steel pipe pile used for preventing uneven settlement of a house or the like in soft ground, and a steel pipe pile construction member for constructing the steel pipe pile .
[0002]
[Prior art]
As is well known, as a method for preventing the uneven settlement of a house or the like in soft ground and a method for transmitting an upper load to the ground, there is, for example, a rotary penetration method of a steel pipe pile that is free from problems such as noise and vibration.
[0003]
In this rotary penetration method, as shown in FIG. 11 and FIG. 12, the bottom plate in which the spiral blade 2 is spirally projected on the outer periphery in the vicinity of the tip 3a, for example, a triangular plate-shaped excavation piece 4 is projected on the one surface side 5a. In many cases, a steel pipe pile 51 made of a steel pipe shaft pipe 3 having the other surface side 5b fixed to the tip 3a is used. At the time of construction, it is common to rotate the steel pipe pile 51 while pressing or supporting the head 51b of the steel pipe pile 51 into the ground. After the rotation penetration, the ground reaction force (tip support force) received by the tip 51a of the steel pipe pile 51 including the spiral blade 2 and the friction force (circumferential friction force) generated between the steel pipe pile 51 and the ground It has a structure that provides support.
[0004]
[Problems to be solved by the invention]
However, in the conventional steel pipe pile 51 as described above, when the penetration amount per rotation of the steel pipe pile 51 is smaller than the circumferential pitch P of the spiral blade 2 at the time of rotational penetration into the ground, the spiral blade 2 is disturbed in the ground. The part that remains is generated. Further, a portion that remains disturbed by the excavation piece 4 also occurs. Therefore, if a load acts on the steel pipe pile 51, there is a possibility that harmful settlement occurs when supporting a house or the like, and there is a problem that the tip supporting force with respect to the ground is not so large.
[0005]
This invention is made in view of the above problems, and provides the construction method of the steel pipe pile which can improve the tip supporting force with respect to the ground, and the member for steel pipe pile construction for constructing the steel pipe pile. With the goal.
[0006]
[Means for Solving the Problems]
Steel pipe pile construction member according to claim 1 for achieving the above object, a steel pipe pile at least one helical blade is made of helically projecting steel pipe made of shaft tube on the outer periphery near the tip, the shaft tube Made of a steel pipe whose outer diameter is slightly smaller than the inner diameter of the base plate, the other surface side of the bottom plate protruding at least one excavation piece on one side is fixed to the tip, and the excavation piece is directed to the tip end side of the shaft pipe in the shaft pipe And an inserted inner tube.
[0007]
Construction method for steel pipe pile according to claim 2, there is provided a method of constructing the steel pipe pile provided in the steel pipe pile construction member according to claim 1, wherein the cuttings in a state of protruding from the distal end of the shaft tube After rotating and penetrating the steel pipe pile construction member to a predetermined depth in the ground, the steel pipe pile construction member is moved up and down while rotating, and the ground near the tip of the steel pipe pile construction member is provided to provide a crushed portion The tip of the shaft tube is hardened by press-fitting mortar into the crushed portion with the tip of the shaft tube located at a predetermined height in the crushed portion and with the inner tube pulled out from the shaft tube. An improved soil section will be provided.
[0008]
In the construction method of the steel pipe pile of Claim 3, the height from the bottom face of the said crushing part at the time of the press injection of the said mortar to the front-end | tip of the said axial pipe is more than the outer diameter of the said spiral blade.
[0009]
The construction method of the steel pipe pile of Claim 4 makes it harden | cure in the state with which this mortar was filled in the inside of the front-end | tip of the said axial pipe while pressing the said mortar in the said crushing part.
[0010]
The construction method of the steel pipe pile of Claim 5 press-fits the said mortar in the said crushed part by the free fall of the monken inserted in the said axial pipe.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same structure as a prior art.
[0012]
As shown in FIGS. 1 to 3, steel pipe pile construction member 1 according to this embodiment, steel pipe pile in which the helical blade 2 is made of a shaft tube 3 made of steel pipe which protrudes in a spiral manner around the circumference near the tip 3a The outer surface 5b of the bottom plate 5 is made of a steel pipe whose outer diameter is slightly smaller than the inner diameter of the shaft tube 3 and protrudes from the one surface 5a. The other surface 5b of the bottom plate 5 is fixed to the tip 6a. Is provided with an inner tube 6 inserted toward the tip 3a side of the shaft tube 3.
[0013]
The shaft tube 3 is made of, for example, a tubular steel tube having an outer diameter of about 10 to several tens of centimeters and a thickness of several millimeters, and is formed in a length of several meters to several tens of meters.
[0014]
The spiral blade 2 is made of, for example, a steel plate, and is projected in a spiral shape by welding or the like on the outer periphery in the vicinity of the tip 3a of the shaft tube 3. In this embodiment, the circuit circulates only once, but the present invention is not limited to this. Further, the number of spiral blades 2 is not limited to one, and a plurality of spiral blades 2 may project along the length direction of the shaft tube 3.
[0015]
The inner tube 6 is made of a tubular steel pipe similar to the shaft tube 3, but has an outer diameter slightly smaller than the inner diameter of the shaft tube 3, and the excavation piece 4 is inserted into the shaft tube 3 at the tip of the shaft tube 3. It is inserted in the direction of 3a so that it can be inserted and removed freely. The length of the inner tube 6 may be substantially the same as that of the shaft tube 3, but is not particularly limited. In a state where the excavation piece 4 protrudes from the tip 3 a of the shaft tube 3 during the rotation penetration into the ground 7. Any length may be used as long as the inner tube 6 and the shaft tube 3 can be rotated simultaneously by a heavy machine or the like.
[0016]
The bottom plate 5 is made of, for example, a disk-shaped steel plate, and the excavation piece 4 protrudes from one surface side 5a by welding or the like, and the other surface side 5b is fixed to the tip 6a of the inner tube 6 by welding or the like. . The excavation piece 4 is made of, for example, a triangular plate-shaped steel plate, but the shape, size, number, projecting position, projecting angle, etc. of the excavation piece 4 are not particularly limited, and can be appropriately changed as necessary. is there.
[0017]
Next, the construction method of the steel pipe pile with which the member 1 for steel pipe pile construction comprised as mentioned above was equipped is demonstrated .
In the construction of the steel pipe pile provided in the steel pipe pile construction member 1, first, as shown in FIG. 4, the steel pipe pile construction member 1 is grounded with the excavation piece 4 protruding from the tip 3a of the shaft pipe 3. Rotate to a predetermined depth of 7. In this case, the shaft tube 3 and the inner tube 6 may be simultaneously rotated in the same direction by a heavy machine or the like. Alternatively, the shaft tube 3 and the inner tube 6 may be rotated while being fixed by a conventionally known fixing means.
[0018]
And as shown in FIG. 5, the steel pipe pile construction member 1 is moved up and down by rotating with a heavy machine etc., and the ground 7 near the front-end | tip 1a of the steel pipe pile construction member 1 is crushed, and the crushed part 8 is provided. In this case, the rotation and movement of the steel pipe pile construction member 1 may be performed in an appropriate direction, and a predetermined range of the ground 7 may be crushed by the spiral blade 2 to form the crushed soil portion 8.
[0019]
Further, as shown in FIGS. 6 and 7, for example, the steel pipe pile construction member 1 is moved upward so that the tip 3 a of the axial pipe 3 is positioned at a predetermined height in the crushed portion 8, and then the axial pipe 3 The inner tube 6 is pulled out from. The timing at which the inner tube 6 is pulled out from the shaft tube 3 is not particularly limited. The shaft tube 3 may be pulled out after moving only the shaft tube 3 upward, or after the inner tube 6 is pulled out. May be moved upward.
[0020]
Next, as shown in FIGS. 8 and 9, after the mortar 9 is put into the crushed soil part 8 through the shaft tube 3, the monken inserted into the shaft tube 3 via a wire rope 10 or the like so as to be freely dropped and pulled up. The mortar 9 is press-fitted into the crushed portion 8 by 11 or the like. In press-fitting, as in this embodiment, the periphery of the crushed portion 8 may be compressed outward to expand the crushed portion 8. In addition, although the mortar 9 can also be press-fit into the crushed soil part 8 with compressed air or the like, the free fall of the monken 11 as in this embodiment has an advantage that it can be easily press-fitted with a large load.
[0021]
If the mortar 9 is hardened by allowing it to stand for a predetermined period after the press-fitting, the improved soil portion 12 is formed at the tip 3a of the shaft tube 3 as shown in FIG. The head 3b of the shaft tube 3 may be cut by a predetermined length as necessary, and then the upper plate 13 made of a disk-shaped steel plate may be fixed by welding or the like. The foundation such as the cloth foundation 14 may be constructed above the shaft tube 3 by a conventionally known method. Here, if the height from the bottom surface 8d of the crushed portion 8 to the tip 3a of the shaft tube 3 when the mortar 9 is press-fitted is equal to or larger than the outer diameter of the spiral blade 2, the improved soil portion 12 having a sufficient height can be formed. In addition, there is an advantage that the mortar 9 can be easily press-fitted. Further, when the mortar 9 is press-fitted into the crushed portion 8 and the mortar 9 is hardened in a state where it is filled in the tip 3 a of the shaft tube 3, the tip 3 a of the shaft tube 3 is securely attached to the improved soil portion 12. Therefore, there is an advantage that the shaft tube 3 and the improved soil portion 12 are not likely to be displaced.
[0022]
If the improved soil portion 12 is provided at the tip 3a of the shaft tube 3 in this manner, the tip support force with respect to the ground 7 is increased, so that the amount of settlement can be kept small even when a load is applied to the shaft tube 3. There are advantages.
[0023]
【The invention's effect】
As described above, according to the first aspect of the present invention, the steel pipe pile including the shaft pipe made of steel pipe in which at least one spiral blade spirally projects on the outer periphery near the tip, and the inner pipe is provided. Therefore, it can be suitably used as a steel pipe pile construction member for providing an improved soil portion at the tip of the shaft pipe.
[0024]
According to the invention of claim 2, since the improved soil portion is provided at the tip of the shaft tube as described above, the tip support force with respect to the ground is increased, and therefore the amount of settlement is reduced even when a load is applied to the shaft tube. Can be suppressed.
[0025]
According to the invention of claim 3, since the height from the bottom surface of the crushed portion to the tip of the shaft tube at the time of press-fitting mortar is equal to or larger than the outer diameter of the spiral blade, a sufficiently high improved soil portion can be formed. Easy to press-fit mortar.
[0026]
According to the invention of claim 4, since the mortar is press-fitted into the crushed portion and hardened in a state where the mortar is filled in the tip of the shaft tube, the tip of the shaft tube is securely embedded in the improved soil portion. There is no risk that the shaft tube and the improved soil portion will be displaced.
[0027]
According to the invention of claim 5, since the mortar is press-fitted into the crushed portion by free fall of monken, it can be easily press-fitted with a large load.
[Brief description of the drawings]
FIG. 1 is a partially omitted front view of a steel pipe pile construction member according to an embodiment.
FIG. 2 is a bottom view of a steel pipe pile construction member .
FIG. 3 is a partially omitted front view of the inner pipe.
FIG. 4 is a partially omitted cross-sectional view showing a state after a steel pipe pile construction member has been rotated and penetrated to a predetermined depth of the ground.
FIG. 5 is a partially omitted cross-sectional view showing a state after providing a crushed soil part.
FIG. 6 is a partially omitted cross-sectional view showing a state after the steel pipe pile construction member is moved upward.
FIG. 7 is a partially omitted cross-sectional view showing a state where the inner tube is pulled out from the shaft tube.
FIG. 8 is a partially omitted cross-sectional view showing a state in which mortar is thrown into the crushed soil part.
FIG. 9 is a partially omitted cross-sectional view showing a state in which mortar is pressed into a crushed soil part.
FIG. 10 is a partially omitted cross-sectional view showing a state after an improved soil portion is provided at the tip of the shaft tube.
FIG. 11 is a partially omitted front view of a conventional example.
FIG. 12 is a bottom view of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steel pipe pile construction member 1a Tip 2 Spiral wing 3 Shaft tube 3a Tip 4 Excavated piece 5 Bottom plate 5a One side 5b Other side 6 Inner pipe 6a Tip 7 Ground 8 Crushed part 8d Bottom 9 Mortar 11 Monken 12 Improved soil part

Claims (5)

At least one steel pipe piles consisting of helically projecting the shaft tube made of steel to the outer periphery of the spiral blade near the tip, a little small steel pipe outer diameter than the inner diameter of the shaft tube, at least one cuttings For steel pipe pile construction characterized in that the other side of the bottom plate protruding on one side is fixed to the tip, and the inner pipe is inserted into the shaft pipe with the excavation piece facing the tip side of the shaft pipe Member . A steel pipe pile construction method provided in the steel pipe pile construction member according to claim 1,
The steel pipe pile construction member is rotated and penetrated to a predetermined depth of the ground with the excavation piece protruding from the tip of the shaft pipe, and then the steel pipe pile construction member is moved up and down while rotating, A crushed portion is provided by crushing the ground near the tip of the construction member, and the tip of the shaft tube is located at a predetermined height in the crushed portion, and the inner tube is pulled out from the shaft tube, and the inside of the crushed portion by curing by press-fitting the mortar, construction of the steel pipe pile you characterized by providing a modified soil portion to the distal end of the shaft tube method. The construction method of the steel pipe pile of Claim 2 whose height from the bottom face of the said crushing part at the time of the press injection of the said mortar is more than the outer diameter of the said spiral blade. The construction method of a steel pipe pile according to claim 2 or 3, wherein the mortar is pressed into the crushed portion and hardened in a state where the mortar is filled inside the tip of the shaft pipe. The construction method of the steel pipe pile of any one of Claim 2 thru | or 4 which press-fits the said mortar in the said crushed soil part by the free fall of the monken inserted in the said axial pipe.

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