JP3900486B2 - Steel pipe pile for embedded pile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steel pipe pile for an embedded pile method (such as a pre-boring method, a digging method, a rotary burying method, a soil cement method) used for a foundation pile such as a bridge foundation pile and a building foundation pile.
[0002]
[Prior art]
JP, 2000-45274, A JP, 2000-220139, etc. exist as a steel pipe pile which expanded and deformed the peripheral surface of the steel pipe tip part. A steel pipe pile in which a protrusion is formed on the outer peripheral surface of the distal end portion of the steel pipe pile is described as a fixing structure to the distal end anchoring portion as a support pile and a distal end detent of the steel pipe pile for the digging method. However, in any steel pipe pile 1 of any conventional example, there is only a description of providing one or more protruding portions 2. Japanese Patent Application Laid-Open No. 2000-45274 states that “the height of the protrusion is preferably 5% or more of the outer diameter even in the case of a steel pipe support pile” paragraph [0018], “ -It is preferable that the height of this time part is suppressed to about 35% of the outer diameter of the support pile at the maximum. "Japanese Patent Laid-Open No. 2000-220139 states that" the protrusion width L of the protrusion is In order to avoid sudden deformation and load drop due to local buckling of the steel pipe pile, it is necessary to take a larger than the local buckling wavelength S of the steel pipe pile. " There is only a diameter expansion specification for the shape of.
[0003]
[Patent Document 1]
JP 2000-45274 A [Patent Document 2]
Japanese Patent Laid-Open No. 2000-220139
[Problems to be solved by the invention]
The axial proof stress and anti-slip characteristics of steel pipe piles with two or more tiers with deformed protrusions increase the anti-slip proof strength in the case of multiple tiers, and when the axial force increases, a single diameter expansion specification Then, there is a possibility that local buckling may occur even in a shape that does not normally buckle, and in the case of multiple stages, the ratio of the detent force varies depending on the number of stages and the stage position. As a result, if the shape of the protrusion is a single standard, it is not possible to effectively exhibit the anti-slipping function, and there is a possibility that local buckling that occurs due to the uneven sharing of anti-slipping proof stress may not be suppressed. .
[0005]
An object of this invention is to provide the steel pipe pile for embedded piles which eliminated the trouble which such a prior art has.
[0006]
[Means for solving problems]
According to the first aspect of the present invention, in a steel pipe pile for embedded piles, there are two protrusions that are formed by projecting a steel pipe into a convex shape by expanding the diameter of the steel pipe in advance on the outer peripheral surface of the tip of the steel pipe pile that is embedded in the ground by the embedded pile method. provided stage above, the two-stage or more projections, so as to improve axial strength from pile tip side to the pile head side, and stopped deviation toward the pile head side pile tip side It is characterized by having different shapes to improve the proof stress .
[0007]
The second aspect of the present invention is the steel pipe pile for embedded piles of the first aspect of the present invention, in which the condition that the shape of the two or more protrusions formed by expanding and deforming the outer peripheral surface of the tip end of the steel pipe pile is a different shape, The height of the protrusion (expanded height), the radius of the protrusion (expanded radius), the length of the protrusion (expanded length), or a combination thereof.
[0008]
The third invention relates to a steel pipe pile for embedded piles according to the first or second invention, wherein in the shape of two or more different protrusions formed by expanding and deforming the outer peripheral surface of the tip of the steel pipe pile, the steel pipe pile Whether the shape of the protrusion on the pile head side is smaller than the shape of the protrusion on the lower side, the expanded diameter is large, the expanded diameter is large, or the expanded diameter is large, Moreover, it is the combination.
[0009]
The fourth aspect of the present invention is the steel pipe pile for embedded piles according to any one of the first to third aspects of the present invention, wherein two or more protrusions formed by expanding and deforming the outer peripheral surface of the tip end of the steel pipe pile are It is embedded in the root-fixed bulb part or is stopped near the tip root-fixed bulb part, and the steel pipe is filled with cement milk or the like.
[0010]
According to the fifth aspect of the present invention, in the steel pipe pile for embedded piles, there are provided two protruding portions that are formed by projecting the steel pipe into a convex shape by expanding the diameter of the steel pipe in advance on the outer peripheral surface of the steel pipe pile pile head to be embedded in the ground by the embedded pile method. Provided with two or more steps, the two or more protrusions of the pile are shifted from the pile head side to the pile tip side, and the pile displacement from the pile tip side to the pile head side is improved. It is characterized by having different shapes so as to improve the holding strength .
[0011]
The sixth aspect of the present invention is the steel pipe pile for embedded piles of the fifth aspect of the present invention, wherein the two or more protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile pile head have different conditions. The height of the protrusion (expanded height), the radius of the protrusion (expanded radius), the length of the protrusion (expanded length), or a combination thereof.
[0012]
According to a seventh aspect of the present invention, there is provided a steel pipe pile for embedded piles according to the fifth or sixth aspect of the present invention, in the shape of two or more different protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile pile head. Whether the shape of the protrusion on the pile tip side is smaller than the shape of the protrusion on the upper side, the expanded diameter is large, the expanded diameter is large, or the expanded length is large. It is a combination.
[0013]
The eighth invention is a steel pipe pile for embedded piles according to any one of the fifth to eighth inventions, wherein two or more protrusions formed by expanding and deforming on the outer peripheral surface of the steel pipe pile pile head Is embedded in the upper footing concrete or directly below the footing concrete, and the steel pipe pile is filled with concrete.
[0014]
The ninth invention is a steel pipe pile for embedded piles, wherein the embedded steel pipe pile according to any one of claims 1 to 4 and the embedded steel pipe pile according to any one of claims 5 to 8 are combined. It is characterized by that.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. Here, the height of the protrusion (expanded height) means the length in the direction perpendicular to the tube axis from the inner surface of the mother pipe to the inner surface of the largest expanded portion at each of the protrusions that have undergone diameter expansion. The radius of the projection (expansion radius) means the radius of curvature in the tube axis direction of the expanded diameter of each projection portion that has been expanded and deformed, but a long projection portion is formed in the tube axis direction by continuous expansion. When it does, it means the radius of curvature of the rising part of the protrusion in the tube axis direction. Further, the length of the projection (expanded length) means the length in the tube axis direction of the portion of the projected portion that has been expanded and deformed, the diameter of which is expanded on the outer surface of the mother pipe.
[0016]
In FIG. 1, the shape of a plurality of protrusions 2 formed on the outer peripheral surface of the tip end of the steel pipe pile 1 is the same as the protrusion radius (expansion radius), and the height of the protrusion (expansion height). The height of the protrusion of the protrusion 2 on the pile tip side is increased, and the height of the protrusion is lowered as it goes upward, and the length of the protrusion (expansion length) is set to the length of the protrusion of the protrusion 2 on the pile tip side. An example is shown in which the length of the projection 2 is made longer and shorter as it goes upward.
[0017]
In FIG. 2, the shape of the plurality of protrusions 2 formed on the outer peripheral surface of the tip of the steel pipe pile 1 is the same as the protrusion length (expansion length) and the protrusion radius (expansion radius). Reduce the radius of the protrusion of the protrusion 2 on the pile tip side, increase it as you go upward, and increase the height of the protrusion (expanded height) of the protrusion 2 on the pile tip side In this example, the shape of the protrusion 2 is made lower as it goes upward.
[0018]
In FIG. 3, the shape of the plurality of protrusions 2 formed on the outer peripheral surface of the tip end portion of the steel pipe pile 1 is the same as the protrusion height (expanded height) while the protrusion height (expanded height) is constant. ) Shorten the projection length of the projection 2 on the pile tip side and increase it as it goes upward, and decrease the radius of the projection (expansion radius) of the projection 2 on the pile tip side In this example, the shape of the protrusion 2 is made different as it goes upward.
[0019]
The protrusion 2 formed by expanding and deforming on the outer peripheral surface of the steel pipe pile 1 may be formed not only on the tip end of the pile but also on the pile head. In this case, the projection 2 is formed in a shape that is the reverse of FIGS.
[0020]
FIG. 5 shows the formation of the projection 2 at the tip of the pile by embedding the tip of the pile in which the projections 2 of the plurality of steps are formed in the tip consolidation bulb 3 formed of a tip consolidation solution such as cement milk. An example in which cement milk or the like is filled up to the top of the position is shown.
[0021]
FIG. 6 shows that the pile tip portion on which the multi-step protrusions 2 are formed is positioned in the vicinity of the top of the tip rooting bulb portion 3 formed with the tip rooting liquid such as cement milk. This shows an example in which cement milk or the like is filled up to above the formation position.
[0022]
FIG. 7 shows an example in which a pile head having a plurality of projections 2 formed therein is embedded in a footing 4 made of concrete, and the inside is filled with concrete up to the formation position of the projections 2 of the pile head. Is shown.
[0023]
FIG. 8 shows that the pile head having a plurality of protruding portions 2 formed is positioned directly below the bottom surface of the footing 4 formed of concrete, and the concrete is filled up to the position below the protruding portion 2 of the pile head. An example is shown.
[0024]
The effect | action by the structure of this invention is demonstrated.
By the experiment conducted by the present inventors, as a factor that affects the displacement prevention function by the protrusion provided in the steel pipe part,
1) Axial strength (buckling)
2) Shear failure of concrete filled in protrusions 3) There are three types of failure: climbing concrete loaded in protrusions of steel pipes.
For each influential factor, if the diameter and thickness of the steel pipe pile are constant,
1) Regarding the axial proof stress, the diameter expansion height is inversely proportional and the diameter expansion radius is proportional.
2) Regarding the concrete shear strength, the expanded diameter is proportional.
3) Regarding the ride strength, the diameter expansion height and the diameter expansion length are proportional.
It turned out that there was a tendency.
[0025]
In addition, when the multi-stage protrusion is provided, with respect to the anti-slip performance, the sharing is different, there is a tendency for the sharing to increase sequentially from the loading direction, the multi-stage and the anti-slipping strength at the pile tip or pile head improves, It has been found that when the axial force increases, the protrusion in the loading direction that requires axial proof stress may buckle.
[0026]
Therefore, in the present invention, in the steel pipe pile for embedded piles, when providing multi-stage projections on the pile tip side and pile head side, the projection height, projection radius, and projection length, which are projection influencing factors, are changed. By doing so, the sharing of the anti-slipping proof stress is smoothed, and the axial proof stress of the protrusion near the loading direction is improved.
[0027]
The specific examples shown in FIGS. 1 to 3 show changes in the influence factors when the influence factors are fixed. In the case shown in FIG. 1, when the diameter of expansion is constant, the height of diameter expansion is sequentially increased from the upper stage toward the lower stage, and the length of the diameter expansion is lengthened, thereby sequentially preventing the displacement from the upper stage. Is large and the axial proof stress is small. In addition, what is shown in FIG. 2 is that when the diameter of expansion is constant, the diameter of expansion is decreased from the upper stage toward the lower stage, and the height of expansion is increased from the upper stage toward the lower stage. Starting from the top, the anti-displacement strength increases and the axial strength decreases. In the case shown in FIG. 3, when the height of the diameter expansion is constant, by decreasing the diameter expansion radius from the upper stage toward the lower stage, the axial proof stress is sequentially reduced from the upper stage. to become shorter towards the lower from also becomes successively smaller displacement-preventing strength, poor efficiency in smoothing the shift prevention function. In such a case, as shown in FIG. 4, by increasing the diameter expansion length from the upper stage toward the lower stage by continuous diameter expansion deformation, the anti-slipping proof stress sequentially increases, and the efficiency can be improved. As shown in FIG. 5, the pile tip portion formed with multi-stage protrusions is installed in the root-setting bulb portion 3 formed of a tip-setting solution such as cement milk, so that the steel pipe outer side can be prevented along with the anti-slipping function. Due to the influence of the bearing pressure of the projection portion, the integration with the tip root bulb is achieved and a bottom expansion effect is produced. FIG. 6 shows that the pile tip portion in which the multi-stage protrusions 2 are formed is positioned in the vicinity immediately above the tip root bulb portion 3 formed of a tip rooting solution such as cement milk. By filling cement milk or the like up to the position where the protrusions 2 are formed, the function of preventing displacement from the end-filled concrete is exhibited. By applying the application examples shown in FIGS. 1 to 6 upside down and replacing the tip root bulb with a footing, it can be applied to a pile head.
[0028]
【The invention's effect】
According to the present invention, in a steel pipe pile for embedded piles, a protrusion formed by expanding and deforming a steel pipe in advance on the tip outer peripheral surface or pile head outer peripheral surface of the steel pipe pile to be embedded in the ground by the embedded pile method. By providing two or more parts and forming the protrusions of two or more stages with different shapes so that the axial strength is improved, the anti-slipping function can be efficiently demonstrated and the anti-slip strength is shared. The local buckling which arises from the bias | inclination of this can be suppressed, and the advantage with respect to the conventional structure by the displacement prevention function, friction cutter function, and supporting force improvement function which an enlarged-diameter steel pipe pile originally has can be exhibited effectively.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of the present invention. FIG. 2 is a diagram illustrating an embodiment of the present invention. FIG. 3 is a diagram illustrating a reference example. FIG. 4 is a diagram illustrating an embodiment of the present invention. 5 is a diagram illustrating an embodiment of the present invention. FIG. 6 is a diagram illustrating an embodiment of the present invention. FIG. 7 is a diagram illustrating an embodiment of the present invention. FIG. 8 is a diagram illustrating an embodiment of the present invention. FIG. 9 is a diagram showing a prior art. FIG. 10 is a diagram showing a prior art.

Claims (9)

The distal end portion outer peripheral surface of the steel pipe pile burying construction in the ground by burying Pile, provided with a projection portion which is protruding in a convex shape with enlarged deformed in advance steel pipe 2 or more stages, the two stages or more projections, It has a different shape so that the axial yield strength improves from the pile tip side to the pile head side, and the anti-displacement strength improves from the pile head side to the pile tip side . A steel pipe pile for embedded piles.   The conditions for making the shape of the two or more protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile tip different are the height of the protrusion (expansion height), the radius of the protrusion (expansion radius). ), The length of the protrusion (expanded length), or a combination thereof, The steel pipe pile for embedded piles according to claim 1.   In the shape of two or more different protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile tip, the shape of the protrusion on the steel pipe pile pile head side is more than the shape of the lower protrusion. The embedded pile according to claim 1 or 2, wherein the expanded height is small, the expanded radius is large, or the expanded diameter is large, or a combination thereof. Steel pipe pile.   Two or more protrusions formed by expanding and deforming on the outer peripheral surface of the steel pipe pile front end are embedded in the front end rooting bulb, or are stopped near the top of the front end rooting bulb, The steel pipe pile for embedded piles according to any one of claims 1 to 3, which is filled with cement milk or the like. Steel pipe Kuikui head peripheral surface of burying construction in the ground by burying Pile, provided with a projection portion which is protruding in a convex shape with enlarged deformed in advance steel pipe 2 or more stages, the two stages or more projections, It has a different shape so that the axial strength is improved from the pile head side to the pile tip side , and the anti-displacement strength is improved from the pile tip side to the pile head side . A steel pipe pile for embedded piles.   The condition that the shape of the two or more protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile pile head is different is the height of the protrusion (expanded height), the radius of the protrusion (expanded diameter). The steel pipe pile for embedded piles according to claim 5, which is any one of a radius, a length of a protrusion (expanded length), or a combination thereof.   In the shape of two or more different protrusions formed by expanding and deforming the outer peripheral surface of the steel pipe pile pile head, the shape of the protrusion on the steel pipe pile tip end side is larger than the shape of the upper protrusion. The steel pipe pile for embedded piles according to claim 5 or 6, wherein the diameter height is small, the expansion radius is small, the expansion length is large, or a combination thereof. .   The protrusions of two or more steps formed by expanding and deforming on the outer peripheral surface of the steel pipe pile pile head are embedded in the upper footing concrete or directly below the footing concrete, and the steel pipe pile is filled with concrete The steel pipe pile for embedded piles of any one of Claims 5-7 characterized by the above-mentioned.   An embedded steel pipe pile, wherein the embedded steel pipe pile according to any one of claims 1 to 4 and the embedded steel pipe pile according to any one of claims 5 to 8 are combined. Steel pipe pile.

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