JP2004011343A - Buried steel-pipe pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a buried steel-pipe pile constituted to maintain perpendicularity and be supported on new soil uncut by a cutting blade. <P>SOLUTION: The buried pile 1 comprises a cylindrical pile body 2 and a cutting blade 3 positioned at the tip of the pile body 2. The cutting blade 3 includes a conical base part 4 having a leading blade 7 at its tip, and a spiral blade 5 welded to the outer peripheral surface of the base part 4. The helical spiral blade 5 is formed to increase in diameter and broaden from its tip to root. The leading blade 7 is positioned to cross the tip of the base part 4 and protrude so that the leading blade 7 leads digging during rotation of the pile body 2 and the ground is excavated using the rotating base part 4 and the spiral blade 5. The cutting blade 3 is supported against uncut new soil to firmly support the buried pile 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steel pipe buried pile used in foundation work, particularly when building a structure on soft ground.
[0002]
[Prior art]
In general, in the case of building a structure on soft ground, a pile is struck to prevent the structure from being supported, and the load is transmitted to a solid underlayer. Pile driving is performed by connecting a plurality of long piles according to the structure and burying them in the ground. As a method of burying a pile in the ground, a pile is hit with a pile driver to press-fit it, or a cylindrical pile is rotated and buried. As the pile, wood, concrete, steel or the like is generally used, but recently, a steel pipe mainly having a light weight and strength has been often used. When burying steel pipes, especially in order to reduce noise and seismic vibration in the environment near the site, spiral steel blades are formed on the outer surface of the steel pipe, and the steel pipe itself supported by construction machinery The method of burying directly in the ground while rotating is adopted. This steel pipe is generally called a steel pipe buried pile. In this case, a lid was attached to the tip of the steel pipe buried pile so that the excavated soil did not enter the inside.
[0003]
Conventionally, as shown in FIG. 9, a steel pipe buried pile 31 is formed with a plate-shaped excavation blade 34 having a tapered inclined surface on a side surface via a closing lid 33 at a tip of a pipe-shaped pile main body 32. The excavation claws 35 are arranged at two places on the outer peripheral surface of the tip of the pile main body 32, and a spiral propulsion blade 36 is formed along the outer peripheral surface of the tip of the pile main body 32. When the steel pipe buried pile 31 is rotated, the pile is buried while the ground is excavated diagonally by the propulsion blades 36 while excavating the soil with the excavation claw 35 and the excavation blade 34.
[0004]
As shown in FIG. 10, another steel pipe buried pile 41 is provided on a tip outer peripheral surface of a pile main body 42 with a pair of propulsion blades 43, 43 that are spirally arranged, and each propulsion blade 43 protruding from the pile main body 42. , 43 are provided with digging blades 45, 44 fixed to digging blades 44, 44.
[0005]
[Problems to be solved by the invention]
However, buried steel pipe piles must accurately maintain the verticality of all piles to be buried.To do so, the steel pipe buried piles to be buried must be firmly supported in the ground. did not become. In particular, when rotating and burying, it is easy to cause misalignment due to a slight obstacle, so it is necessary to pay particular attention to maintaining verticality during construction. Furthermore, in order to be firmly supported in the ground, it was necessary that soil excavated at the tip of the steel pipe buried pile be closely adhered to the steel pipe buried pile without being disturbed. In other words, it is necessary that the soil around the excavation blade be supported by the unsoiled ground with the rotation of the excavation blade stopped, in order to have a strong support base for steel pipe buried piles. Had become.
[0006]
In the conventional steel pipe buried pile, in the former case, although two excavating claws 35 are arranged at positions opposing the axis of the pile, the propulsion blade 36 is formed in a single line, so that the pile main body 42 is formed. When the pile starts to rotate, the pile core is excavated while being shifted by the inertia force, or the pile is eccentric when it interferes with an obstacle during the excavation, so that misalignment is easily caused. Therefore, the verticality is reduced. Further, since the excavation blade 34 is formed in a single plate shape, when it is rotated, a cylindrical hole is formed. After the excavation is completed, the excavation blade 34 itself is supported by the soil. Not done. Further, although the propulsion blades 36 are formed in a spiral shape, since the outer diameters are all formed to the same diameter, a portion of the blade at the upper position of the propulsion blade, that is, a portion of the blade to be excavated late. Then, since the soil is unraveled by the lower part of the blade to be excavated in advance, at the time of completion of the excavation, the upper part of the propulsion blade 36 is not supported by the soil as it is. Therefore, in the conventional steel pipe buried pile 31 shown in FIG. 9, the soil around the excavation blade 34 or the propulsion blade 36 is loosened and softened, and is not supported by the new soil as it is. Thus, it is difficult to obtain strong support for the steel pipe buried pile 31.
[0007]
Further, in the latter case, although the accuracy of the verticality can be improved, since the soil around the excavation blade 45 at the lower end of the steel pipe buried pile 41 is released by the rotation of the excavation blade 45, the soil is in a soft state, When the excavation was stopped, it was difficult to obtain solid support without being supported by new soil.
[0008]
The present invention has been made to solve the above-described problem, and maintains the accuracy of verticality, and at the time of excavation stoppage, the excavation blade and the propulsion blade are supported by a new undissolved soil, whereby An object of the present invention is to provide a steel pipe buried pile that can be firmly supported inside.
[0009]
[Means for Solving the Problems]
The steel pipe buried pile according to the present invention is configured as follows in order to solve the above-mentioned problems. That is,
A pile body which is formed in a cylindrical shape and has both ends opened, and a digging blade for digging soil at a tip of the pile body, a steel pipe buried pile buried in the ground having:
The excavating blade is configured to include a tapered conical base provided with a trigger blade at a tip thereof, and a spiral blade disposed along an outer peripheral surface of the conical base. It is characterized by the following.
[0010]
In addition, it is sufficient that the spiral blade portion is formed in a rectangular cross section.
[0011]
Further, the trigger blades protrude from the tip of the conical base along the inclined surface of the base and are arranged in a two-cross configuration, and the tips of the triggers protrude from the cross. It is sufficient if they are arranged.
[0012]
Further, the spiral blade portion is formed so as to gradually increase in diameter from the tip side to the base portion side of the conical base portion, and the width of the blade portion is equal to the conical base portion. It is even more preferable that the opening is formed so as to gradually spread from the tip end side toward the base part side.
[0013]
Further, the conical support portion may be formed to have a hollow portion, and a nozzle connected from the hollow portion may be formed to protrude from the conical support portion.
[0014]
【The invention's effect】
According to the steel pipe buried pile of the present invention, in the invention according to claim 1, when the pile main body is rotated, the trigger blade of the conical base portion formed at the tip starts the excavation and starts excavation. With the conical base portion and the spiral blades arranged along the outer peripheral surface of the conical base portion, the excavated soil is carried upward, and further the blade portion is formed in a spiral shape. Push the pile body deep inside the ground.
[0015]
At this time, since the spiral blade portion is sequentially enlarged in diameter from the tip side to the base portion side, the soil excavated by the blade portion at a certain point always comes in contact with new soil that has not been unraveled. Will be. Therefore, at the time when the rotation of the blade portion is stopped, the soil that adheres to the lower surface of the blade portion is a new material that has not been unraveled by the reduced diameter blade that was previously excavated. Is supported by the hard soil around the excavation blade at the lower end, and a strong support is obtained. Moreover, since the conical base is formed in a conical shape, the soil around the conical base supports the conical base evenly, so that the verticality of the steel pipe buried pile is reduced. Can be held. In addition, because the cone-shaped base is conical, the drilling blade itself is closed, so that excavated soil does not enter the drilling blade and the pile body, and smooth drilling work is performed. can do.
[0016]
According to the second aspect of the present invention, if the spiral blade has a rectangular cross-section, the excavation can be easily performed in a short time because the soil is easily excavated and propelled. be able to.
[0017]
Further, according to the third aspect of the invention, the trigger for excavation is performed by the trigger blades arranged in two crosses. The trigger blade protrudes from the tip of the conical base along the inclined surface of the conical base, so that new soil is excavated in a diagonal direction with a small excavation area, for example, Even if stones are mixed in the soil, it can be easily triggered by excluding the stones without affecting the excavation.
[0018]
According to the fourth aspect of the present invention, excavation is performed by gradually increasing the width of the spiral blade portion from the reduced diameter portion on the front end side to the enlarged diameter portion on the base portion side. The piled soil can easily pass through the blades, and the pile body can be easily propelled. In addition, as the width gradually increases, the area of the new soil that comes into contact with the blades increases, and the steel pipe embedded pile can be supported more firmly.
[0019]
Further, according to the invention of claim 5, since the cement milk can be injected from the injection nozzle by flowing the cement milk after the steel pipe burying pile is buried in the ground, the soil of soft ground can be used. Can provide solid support, and even if the ground is hard, the unraveled soil can be restored to the original ground, and the solid support of the steel pipe buried pile can be obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0021]
As shown in FIG. 1, a steel pipe buried pile (hereinafter referred to as a buried pile) 1 of the embodiment includes a cylindrical pile body 2 having both ends opened, and a digging blade 3 arranged at a tip end of the pile body 2. It is composed of The excavating blade 3 includes a conical base portion (hereinafter, referred to as a base portion) 4 and a spiral blade 5 formed in close contact with the outer peripheral surface of the base portion 4. In the following description, the tip side of the buried pile 1 to be excavated, that is, the lower part in FIG. 1 is referred to as a tip part, and the side mounted on a rotating machine (not shown), that is, the upper part in FIG. .
[0022]
In the pile main body 2, an engagement protrusion 6 that engages with a rotating machine (not shown) for rotating the buried pile 1 is arranged on the base (upper side in FIG. 1) side of the pile main body 2. The base 4 is fixed to the opened tip.
[0023]
The base portion 4 is formed in a tapered shape tapering toward the distal end side to form a conical shape, and a pair of trigger blades 7, 7 arranged on the distal end surface along the tapered surface of the base portion 4. Is attached. In the embodiment, as the cone angle of the base 4, it is desirable that the angle α of the inclined surface of the base 4 with respect to the mounting surface 3 a on the pile body 2 side is approximately α = 50 °. It can be changed as appropriate depending on the soil and soil quality. For example, in the case of soft ground, the angle may be increased to increase the vertical load. In the case of hard ground, the angle may be reduced to facilitate excavation.
[0024]
The trigger blades 7 are formed in a long rod shape having a rectangular cross section, and are arranged crosswise at portions protruding from the base portion 4. Further, the tip of each of the trigger blades 7, 7 further projects from the crossed portion, is arranged in an X shape in a front view, and is fixed to the base 4 by welding.
[0025]
As shown in FIG. 2, the pile main body 2 and the base portion 4 are fixed by welding after the lid member 4a is attached to the upper end portion of the base portion 4, that is, the largest diameter portion, or as shown in FIG. As shown in (1), screw portions 2a and 4b are formed and screwed and fixed.
[0026]
As shown in FIG. 4, a wide plate member formed in a spiral shape is wound around the outer peripheral surface of the base portion 4 so as to be in close contact with the outer peripheral surface of the base portion 4 to form a spiral blade 5. Stick. The spiral blade 5 is formed so as to gradually decrease in diameter from the base side toward the tip end, and the maximum diameter enlarged section on the base side is formed so as to protrude outward from the maximum diameter of the base 4. Is done. The cross-sectional shape is desirably formed in a rectangular shape that is wide in the lateral width direction (direction orthogonal to the axis). The spiral blade 5 is manufactured by, for example, cutting a material of an iron plate or a cast steel structure into a plate shape, and gradually reducing the diameter of the distal end side in accordance with the conical shape of the base 4. The sheet is bent and stretched while being closely attached to the outer peripheral surface of the base portion 4 and wound. After the winding, it is fixed by welding. Therefore, when the spiral blade 5 is fixed to the base 4, the spiral blade 5 is fixed in a spiral shape as shown in FIG.
[0027]
When the buried pile 1 configured as described above is rotated by the rotating machine to excavate the soil, the trigger blades 7 of the rotating base 4 first create a trigger for excavating the soil. Then, the spiral blade 5 interferes with the soil and gradually penetrates into the ground from the small diameter portion at the tip to excavate while expanding the hole. The excavated soil moves upward on the spiral blade 5 while being guided along the spiral blade 5.
[0028]
At this time, the hole excavated in the buried pile 1 is always formed in a conical shape at the lower end by the conical shape of the base 4, and the excavated soil is moved upward by the spiral blade 5, and The upper part of the hole is excavated in a columnar shape with approximately the outer diameter of the largest diameter portion of the spiral blade 5 by the propulsion of the spiral blade 5 into the column, and the pile body 2 is gradually buried in the ground. Will be invaded. Although the excavated soil is moved along the spiral blade 5, since the conical base 4 is formed as a wall, it may not enter the base 4 or the pile main body 2. Absent.
[0029]
When the excavation blade 3 stops rotating, at the lower end portion of the buried pile 1 where the excavation blade 3 is disposed, the softened soil released by the rotation of the spiral blade 5 is carried upward by the spiral blade 5, The unsolved new soil is attached around the lower surface of the spiral blade 5 and around the base 4 to support the buried pile 1. In other words, since the spiral blades are gradually reduced in diameter toward the tip end, at a position where the spiral blades 5 are located, the soil is not excavated by the spiral blades 5 immediately below, so that the soil is not unraveled and new soil is formed. It will be left. Therefore, the buried pile 1 is always supported by the new soil, so that a strong support can be obtained.
[0030]
Next, a procedure for burying the buried pile 1 in the ground will be described with reference to FIG. In the pile driving construction of the present embodiment, a plurality of piles to be buried are connected to form one buried pile. Of course, it can be buried with one long buried pile.
[0031]
First, the carried buried pile 1 is set on a construction machine (not shown), and as shown in FIG. 6A, the buried pile 1 is suspended and set in accordance with the core of the pile. After the erection is performed, the buried pile 1 is fixed to the construction machine as shown in FIG. This fixing is performed by attaching the steady rest device 9 attached to the construction machine to the pile main body 2.
[0032]
Next, as shown in FIG. 6C, the burial pile 1 is rotated and buried. Before rotating the buried pile 1, the verticality of the buried pile 1 is checked and the center position of the pair of excavating blades 3 is checked. One end of the buried pile 1 on the base side is attached to a speed reducer motor 8 of the construction machine, and driven by the speed reducer motor 8, the buried pile 1 is rotated forward and buried in the ground. At this time, the pair of trigger blades 7 and 7 form a trigger for excavation in the soil, the base portion 4 enters the ground, and the buried pile 1 is propelled deep into the ground by the spiral shape of the spiral blade 5. And invade.
[0033]
If the base end face of the first buried pile 1 is buried to a position slightly above the ground surface, as shown in FIG. 6D, the second buried pile 1A is set on the reduction gear motor. Welding is performed on the first buried pile 1 to add it. The excavation blade 3 is not formed on the second buried pile 1A, and welding is performed in a state where the lower surface of the second pile main body 2A is in contact with the upper end surface of the first pile main body 2. .
[0034]
At this time, welding work is performed while checking the verticality of the second pipe burying pile 1A. Then, the buried pile 1 is rotated and buried further deeply in the same manner as described above. When a plurality of buried piles 1 are added and buried to a predetermined depth, as shown in FIG. 6 (e), the reduction gear motor 8 is reversed so that the engaging projections 6 (see FIG. 1) of the buried pile 1 are formed. After the engagement is released, the reduction gear motor 8 is removed from the buried pile 1 to complete the burying. The buried pile 1 that has been buried is supported by the new soil at the site of the excavation blade 3 at the lower end as described above.
[0035]
As described above, the rotation of the pile body 1 causes the trigger blade 7 of the base 4 formed at the tip to start the excavation by triggering the excavation, and the base 4 and the spiral blade 5 The excavated soil is carried upward, and the spiral blade 5 is formed in a spiral shape, so that the pile main body 2 is propelled deep in the ground.
[0036]
At this time, since the tip of the spiral blade 5 is reduced in diameter, at the time when the rotation of the spiral blade 5 stops, the soil that is in close contact with the outer peripheral surface of the base portion 4 and the lower surface of the spiral blade 5 is released. The buried pile 1 is supported by the hard soil around the excavation blade 3 at the lower end, so that a strong support can be obtained. Moreover, since the base portion 4 is formed in a conical shape, the soil around the base portion supports the base portion 4 evenly, so that the verticality of the buried pile 1 can be maintained. In addition, the conical wall of the base 4 prevents the soil from penetrating into the machine base 4 or the pile main body 2, whereby the excavation work can be smoothly promoted.
[0037]
In addition, since the cross-sectional shape of the spiral blade is formed in a rectangular shape, the soil is easily excavated and propelled, so that the excavation work can be easily performed in a short time.
[0038]
Furthermore, since the trigger for excavation is performed by the two trigger blades 7 arranged in a cross shape, the trigger blade 7 protruding from the tip of the base 4 along the inclined surface of the base 4. Is to excavate new soil diagonally from a diagonal direction with a small excavation area.For example, even if stones are mixed in the soil, it is easy to excavate without excluding stones and excavating without affecting the excavation Can be formed.
[0039]
In addition, by gradually increasing the width of the spiral blade 5 from the reduced diameter portion on the distal end side to the enlarged diameter portion on the base portion side, excavated soil can easily pass through the spiral blade 5. The pile body 2 can be easily propelled. Moreover, as the width gradually increases, the area of the new soil contacting the lower surface of the spiral blade 5 increases, and the buried pile can be supported more firmly.
[0040]
The steel pipe buried pile according to the present invention is not limited to the above-described embodiment.
[0041]
For example, as shown in FIG. 7, in an excavating blade 13 arranged below the pile main body 12, a buried pile formed of two pairs of spiral blades 15 </ b> A and 15 </ b> B arranged symmetrically with respect to the base 14. 11 may be configured. Also in this buried pile 11, at the tip of the base portion 14, triggering blades 17, 17 similar to those of the above-described mobile phone are arranged crosswise. Thereby, the accuracy of the verticality is further improved by improving the rotational balance and preventing the misalignment.
[0042]
Further, the width of the spiral blade 5 may be the same from the leading end to the base.
[0043]
Further, when the buried pile 1B is buried in the soft ground, cement milk or a solidifying agent may be poured to firmly support the buried pile 1B for firm support.
[0044]
In this case, a base 20 on which the injection nozzles 21 are arranged as shown in FIG. 8 is used. The base portion 20 is formed in a conical shape with a hollow inside, and injection nozzles 21 protruding from the outer peripheral surface of the base portion 20 are arranged at a plurality of positions of the body portion. A spiral blade 25 is welded and fixed to the outer peripheral surface of the base portion 20 so as to avoid the injection nozzle 21, and a pipe member 24 connected to a supply pipe 23 inserted through the pile main body 22 into the injection nozzle 21 is attached. It is configured such that cement milk or solidifying agent can be supplied by a pressure pump not shown.
[0045]
In the buried pile 1B having this configuration, cement milk or a solidifying agent is injected and injected from the injection nozzle 21 1-2 m before the buried pile 1B reaches the buried position, and the buried pile 1B is moved up and down or forward and reverse. The ground around the base portion 20 is made into a soil shape while burying the buried pile 1B. As a result, the buried pile 1B can be solidified, and a strong support can be obtained.
[Brief description of the drawings]
FIG. 1 is a front view showing a steel pipe buried pile according to one embodiment of the present invention.
FIG. 2 is a cross-sectional view showing one embodiment of a configuration for connecting a pile main body and a base.
FIG. 3 is a cross-sectional view showing another embodiment of a configuration for connecting a pile main body and a base.
FIG. 4 is a perspective view showing a spiral blade.
FIG. 5 is a view taken in the direction of arrow A in FIG. 1;
FIG. 6 is an operation diagram showing a procedure for burying a buried pile.
FIG. 7 is a front view showing another form of the excavation blade.
FIG. 8 is a partial sectional view showing an embedded pile for soil cement.
9 is a partial front view showing a conventional buried pile. FIG. 10 is a front view showing another conventional buried pile.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 buried pile 2 pile body 3 excavating blade 4 base 5 spiral blade 7 trigger blade 1A buried pile 20 base 21 injection nozzle 23 supply pipe

Claims (5)

A pile body which is formed in a cylindrical shape and has both ends opened, and a digging blade for digging soil at a tip of the pile body, a steel pipe buried pile buried in the ground having:
The excavating blade is configured to include a tapered conical base having a trigger blade at a tip thereof, and a spiral blade disposed along an outer peripheral surface of the conical base. A steel pipe buried pile. The steel pipe buried pile according to claim 1, wherein the spiral blade part is formed in a rectangular cross section. The trigger blades protrude from the tip of the conical base along the inclined surface of the conical base and are arranged in two crosses, and the tips of the respective trigger blades protrude from the cross. The steel pipe buried pile according to claim 1, wherein the pile is disposed. The spiral blade portion is formed so as to gradually increase in diameter from the distal end side of the conical base portion toward the base portion, and the width of the blade portion is equal to the distal end of the conical base portion. The steel pipe buried pile according to claim 1, wherein the pile is formed so as to gradually widen from a side toward a base portion side. The said conical base part is formed so that it may have a hollow part, The nozzle connected from the said hollow part may be formed so that it may protrude from the outer peripheral surface of the said conical base part. , 2, 3 or 4.

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