JP3694824B2 - Threaded steel pipe pile and its construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw-in type steel pipe pile and a construction method thereof, and more specifically, embeds a steel pipe pile in the ground by applying a rotational force to a steel pipe pile having blades attached to at least the tip of the steel pipe or in the vicinity thereof. It is related with the screwed-type steel pipe pile and its construction method.
[0002]
[Prior art]
Many methods have been proposed for embedding steel pipe piles in the ground by applying a rotational force to a steel pipe pile with wing plates attached to the tip and side surfaces of the steel pipe and using a screw installed on the ground. Some of them are intended for small-diameter piles but have been put to practical use. Here, the invention considered to be representative will be described below.
[0003]
The method of burying steel pipe piles described in Japanese Patent Publication No. 2-62648 is that a bottom plate is fixed to the lower end portion of the steel pipe pile main body, a drilling blade is provided on the bottom plate, and the pile main body is provided on the outer peripheral surface of the lower end portion of the pile main body. Pushing the steel pipe pile projecting a spiral wing with a large blade width and an outer diameter almost twice as large as the outer diameter of the pipe into the ground while rotating it so that it is screwed into the soft ground. The excavation blade at the bottom of the pile is used to excavate and soften the soil at the tip of the pile body. Extruded soil and sand are extruded and compressed to the side of the pile, and the pile body is screwed into the ground without any soil removal (Prior Art 1).
[0004]
Further, the screw-in type steel pipe pile described in Japanese Patent Laid-Open No. 9-324419 has a tip portion divided into a plurality of portions in the circumferential direction, and each of the divided portions is attached in a letter shape in the same direction. And a steel plate (wing) having a flat, semi-circular or fan-like shape in which a circular steel plate or an elliptical steel plate having an outer diameter larger than the outer diameter of the steel pipe is divided into a plurality of parts. The steel plate is attached to each of the L-shaped attachments provided at the tip of the steel pipe so as to cover the tip opening of the steel pipe. And that the blade is attached to the tip of the steel pipe, not the outer peripheral surface (Prior Art 2).
[0005]
As described above, the screw-in type steel pipe pile is designed to embed the steel pipe pile in the ground by the screw action of the wing attached at or near the tip by giving rotational force to the steel pipe pile. It can be constructed with low noise and no soil, and has a feature that a large tip support force can be obtained by utilizing a wide wing area.
However, in the above prior art, when the steel pipe diameter is increased, the resistance due to the blades and the resistance due to the outer peripheral surface friction increase, and a very large torque is required for penetration, so that the construction becomes difficult. Therefore, the current situation is that only a pipe diameter of about 600 mm can be used. Although it is conceivable to reduce the torque by making a large hole in the tip portion of the steel pipe pile, it is not preferable to make a large hole in the tip portion because the tip supporting force is reduced.
[0006]
As described above, the tip support force of the screwed steel pipe pile increases due to the increase of the projected area by the wing. For this reason, when using as a foundation pile of an upper structure, compared with the normal steel pipe pile without a wing | blade, the installation number can be reduced or the outer diameter of a steel pipe can be reduced.
However, the drag force against the horizontal force is insufficient due to the reduced number of steel pipe piles, and if the horizontal force is to be guaranteed, the number of installations cannot be reduced, and thus the above effect cannot be expected.
[0007]
On the other hand, when the outer diameter of the steel pipe is reduced, the yield strength of the horizontal force is reduced accordingly, so even if the thickness of the steel pipe pile is increased to cope with this, the increase in the bending strength is increased in spite of the increase in the weight of the steel material. The effect is small. For this reason, when receiving a large horizontal force or bending moment from the superstructure, the thickness of the steel pipe pile must be increased significantly, and the effect of reducing the outer diameter of the steel pipe is reduced.
[0008]
For this reason, in order to economically respond to large horizontal forces and bending moments, the idea of expanding the diameter near the pile head has been proposed in the past. However, it has not been put into practical use in the field of ready-made piles.
[0009]
Next, the prior art regarding the pile which expanded the pile diameter near a pile head (henceforth a head enlarged pile) is demonstrated.
The head expansion foundation pile driving method described in Japanese Patent Laid-Open No. 52-7109 is a steel pipe pile formed by joining a lower pile and a head expansion pile having a diameter larger than that of the lower pile. By hitting the striking surface provided in the joint part with the enlarged part pile and penetrating the pile, by hitting the joint part in the pipe without hitting the upper end of the pile like the conventional hammering method It aims at reducing the stress which acts on a head expansion pile, and reducing the wall thickness (prior art 3).
[0010]
In addition, the head reinforcing pile forming device described in Japanese Patent Publication No. 58-27366 is a method of forming a head-placed concrete cast-in-place concrete pile or a ready-made pile in a casing having a larger upper diameter than the lower portion. It is constructed by inserting an auger for agitation excavation having an upper diameter larger than that of the lower part and rotating it in opposite directions, and inserting it into a soil cement column for embedding a head enlarged pile. Further, in order to reduce penetration resistance due to enlargement of the head at the joint portion between the upper and lower casings, an excavation blade is provided so that earth and sand are taken into the casing (prior art 4).
[0011]
[Problems to be solved by the invention]
The head expansion foundation pile driving method of prior art 3 is such that the joint portion between the lower pile and the head expansion pile is struck in the pipe. Even if it is reduced from the driving method, the penetration resistance generated in the joint does not decrease because the earth and sand hits the lower surface of the joint.
[0012]
In the prior art 4, since the diameter of the auger inserted into the pipe is smaller than the diameter of the lower steel pipe, the penetration resistance generated in the connecting portion is the same as the former technique. On the other hand, the pressure input of the medium excavation method is as small as a fraction of the impact force by driving. For this reason, it is almost impossible to apply the medium excavation method to the enlarged head pile.
[0013]
As described above, it is problematic in terms of construction and cost to apply the common pile driving method to the enlarged head pile.
[0014]
This invention was made in order to solve said subject, and it aimed at obtaining the following screwed-type steel pipe piles which combined the characteristics of the screwed-type steel pipe pile and the head expansion pile, and its construction method. Is.
(1) To expand the application range of screw-type steel pipe piles that can be constructed with low vibration, low noise, no soil removal, and have a large tip support force to large-diameter steel pipe piles.
(2) A large supporting force can be obtained by the blade provided at or near the tip and the blade-shaped joining member provided at the connection portion between the expanded upper steel pipe and the lower steel pipe.
(3) The penetration of the enlarged diameter portion is good and the manufacturing cost of the enlarged diameter portion can be kept low.
[0015]
[Means for Solving the Problems]
(1) The screwed steel pipe pile according to the present invention is Made of steel pipe for steel pipe pile At least at or near the tip Larger than the outer diameter of the steel pipe Lower steel pipe with wings, and larger diameter than the lower steel pipe And shorter than the lower steel pipe An upper steel pipe and a joining member for joining the lower steel pipe and the upper steel pipe are formed, and the joining member is formed in a wing shape having a larger diameter than the upper steel pipe.
[0016]
(2) Moreover, the outer diameter of the upper steel pipe was made larger than the outer diameter of the wing | blade provided in the lower steel pipe.
[0017]
(3) The construction method of the screwed-type steel pipe pile according to the present invention provides a rotational force to the pile head or body part of the screwed-type steel pipe pile according to the above (1) or (2) to place the screwed-type steel pipe pile in the ground. It is intended to be embedded in the ground.
[0018]
(4) Also, an auger is inserted into the screw-type steel pipe pile of (1) or (2) above, and the auger head is protruded from the tip of the screw-type steel pipe pile, and the screw-type steel pipe pile and the auger are rotated. Applying a force to penetrate the screw-type steel pipe pile into the ground, and when the screw-type steel pipe pile reaches a predetermined depth, leave the screw-type steel pipe pile in the ground and pull out the auger. It is a thing.
[0019]
(5) Further, an auger is inserted into the threaded steel pipe pile of the above (1) or (2), the auger head is projected from the tip of the screwed steel pipe pile, and the screwed steel pipe pile and the auger are rotated. The screwed steel pipe pile is penetrated into the ground by applying a force, and a curable fluid is ejected from the auger head to the support layer or a predetermined section while the screwed steel pipe pile is penetrated, and the blade and the auger head are rotated. When the earth and sand and the curable fluid are stirred and mixed to a predetermined depth, the screwed steel pipe pile is left in the ground and the auger is pulled out.
[0020]
(6) Moreover, in the construction method of the screw-type steel pipe pile of said (4), (5), the auger which can expand the outer diameter of an auger head larger than the front-end | tip part outer diameter of a screw-type steel pipe pile was used.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
FIG. 1 is an explanatory diagram of a screw-in type steel pipe pile according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a screwed steel pipe pile (hereinafter simply referred to as a steel pipe pile) having an enlarged head, which is provided at a lower steel pipe 2, an upper steel pipe 3 having a larger diameter than the lower steel pipe 2, and a tip of the lower steel pipe 2. The wing 10 has a diameter larger than that of the lower steel pipe 2 and a wing-shaped joining member 15 having an outer diameter larger than that of the upper steel pipe 3.
[0022]
The lower steel pipe 2 is made of a steel pipe for a normal steel pipe pile (for example, an outer diameter of 600 mm or less). As shown in FIG. 2, the circumferential direction is divided into two by step portions 4a and 4b having a height h at both ends. These slopes are inclined from the lower end of one step 4a to the upper end of the other step 4b, and are inclined from the upper end of the step 4a to the lower end of the step 4b. Mounting portions 5a and 5b of the L-shaped wings 10 are provided in the same direction depending on the surface.
[0023]
As shown in FIG. 3, the wing 10 has an outer diameter D of the lower steel pipe 2. ₁ Larger outer diameter D _Three Are formed by flat steel blades 11a and 11b obtained by dividing a circular steel plate or an elliptical steel plate into two parts from the center. In addition, the size (outer diameter D) of the blade 10 composed of the steel blades 11a and 11b. _Three ) Is generally the outer diameter D of the lower steel pipe 2 ₁ Is preferably about 1.3 to 2.5 times.
[0024]
As shown in FIG. 4, the steel blades 11a and 11b as described above are placed on the mounting portions 5a and 5b so as to cover the tip opening of the lower steel pipe 2, and are inclined in opposite directions by welding or the like. Are attached to form the wing 10. In addition, you may obstruct | occlude the opening part produced by the discrepancy of both steel wing | blades 11a and 11b with a obstruction board, for example. In addition, what is necessary is just to provide the wing | blade 10 in the most advanced pile (lower pile), when the lower steel pipe 2 is comprised with the connection pile which connected the several steel pipe.
[0025]
Outer diameter D of upper steel pipe 3 ₂ Generally, the outer diameter D of the lower steel pipe 2 is different depending on the horizontal force and bending moment from the building provided in the upper part. ₁ 1.15 to 3.0 times as large as the outer diameter D of the blade 10 provided in the lower steel pipe 2 _Three A larger diameter may be used. Also, the length L of the upper steel pipe 3 ₁ Is preferably in the range of about 1 / β to 2 / β. Here, β is a characteristic value determined from the hardness of the upper steel pipe 3 and the ground. Generally, the length L of the upper steel pipe 3 ₁ Is about 4 to 10 m.
[0026]
At the lower end of the upper steel pipe 3, a letter-shaped attachment part having the same structure as the attachment parts 5 a and 5 b provided at the lower end part of the lower steel pipe 2 is provided. The steel blades 16a and 16b having the same configuration as the steel blades 11a and 11b and having a larger diameter are joined by welding to form a blade-shaped joining member 15. The outer diameter D of the joining member 15 _Four Is generally the outer diameter D of the upper steel pipe 3 ₂ Is preferably about 1.1 to 2.5 times as large as.
[0027]
In addition, one step part is provided in the both ends of the lower steel pipe 2, and the lower end part of the upper steel pipe 3, and the L-shaped (spiral) attachment part which goes around from the lower end part of this step part and reaches the upper end part is provided. The continuous spiral blade 10 and the joining member 15 may be configured by providing and attaching the steel blades 11a, 11b, 16a, and 16b to the mounting portion in the same direction.
[0028]
In the lower steel pipe 2 configured as described above, the attachment parts 5a and 5b provided at the upper end of the lower steel pipe 2 are brought into contact with the lower surface of the joining member 15 provided in the upper steel pipe 3, and are joined together by welding. Thus, the steel pipe pile 1 having an enlarged head is configured. In addition, the joining member 15 may be provided in the upper end part of the lower steel pipe 2, and the upper steel pipe 3 may be joined to the upper surface of this joining member 15. Moreover, the opening part produced by the discrepancy of the steel blades 16a and 16b is obstruct | occluded, for example You may obstruct | occlude with a board.
[0029]
For example, as shown in FIG. 5, the steel pipe pile 1 configured as described above has a pile head connected to a motor 23 mounted on a base machine 21, and rotated by the motor 23 to act as a wood screw of the wing 10. Thus, the lower steel pipe 2 is screwed into the ground and penetrated, and further, the upper steel pipe 3 is screwed into the ground by the wood screw action of the wing-like joining member 15 and buried. At this time, when there is an opening in the staggered portion of the steel blades 11a and 11b constituting the blade 10, a small amount of earth and sand enters the lower steel pipe 2 and when the opening is closed, the lower steel pipe Sediment does not enter 2.
[0030]
The screw-type steel pipe pile penetrates into the ground without draining soil by the wood screw action of the wing as described above, and the earth and sand below the wing is excavated and softened by the wing and passes through the gap between the wings. Moved to the outer periphery of the steel pipe pile and compressed. Since the earth and sand moved to the outer periphery of the steel pipe pile are disturbed during the construction, there is little frictional resistance and the steel pipe pile can penetrate smoothly.
However, with the passage of time, the ground strength recovers due to factors such as dissipation of pore water pressure, and a large peripheral frictional force is exhibited when used as a foundation pile.
[0031]
When the wing-like joining member 15 is not provided at the joint between the lower steel pipe 2 and the upper steel pipe 3, the upper part having a diameter smaller than the outer diameter of the wing attached to the tip of the lower steel pipe is used in order to reduce the torque during construction. It is necessary to install a steel pipe.
However, in the present invention, the joint between the lower steel pipe 2 and the upper steel pipe 3 is the outer diameter D of the upper steel pipe 3. ₂ Larger outer diameter D _Four Since the outer earth and sand are excavated and softened and propelled by the joining member 15, the outer diameter D of the blade 10 provided in the lower steel pipe 2 is constructed. _Three Larger outer diameter D ₂ Even if the upper steel pipe 3 is used, it can be easily constructed with a normal torque. Further, the outer diameter D of the blade 10 _Three Smaller outer diameter D ₂ Even when the upper steel pipe 3 is used, the propulsion is improved and the construction efficiency is improved.
Thereby, the peripheral friction force for the outer peripheral surface of the steel pipe pile 1 is increased, and it is possible to realize the rigidity due to the larger outer diameter and the increase in the horizontal resistance force due to the compression of the peripheral ground, A large supporting force can be obtained by the blade 10 and the joining member 15.
[0032]
In addition, as shown in FIG. 6, when there is a hard ground such as an intermediate layer in construction, if the wing-like joining member 15 is positioned on the ground, the wing 10 and the joining member 15 are larger. Support force can be obtained.
Furthermore, as shown in FIG. 7, by placing concrete or the like inside the upper steel pipe 3 after construction, it is possible to resist a larger horizontal force due to the rigidity effect of the steel pipe and concrete. In addition, concrete may be placed on the lower steel pipe 2 so as to cope with the bending moment from the blade 10. In this case, ribs may be provided on the inner walls of the upper steel pipe 3 and the lower steel pipe 2, or a protrusion may be provided by attaching a reinforcing bar, angle steel, or the like by welding or the like. 6, FIG. 7, and the above example can also be implemented in the embodiment described below.
[0033]
FIG. 8 is an explanatory view showing another example of the steel pipe pile 1 according to the present invention. In this example, the lower steel pipe 2 having the blade 10 at the tip is joined to the middle steel pipe 3a having a larger diameter than the middle steel pipe 3a via a wing-like joining member 15a having a larger diameter than the middle steel pipe 3a. This is joined to the upper steel pipe 3 having a larger diameter via a wing-like joining member 15 having a larger diameter than that of the upper steel pipe 3.
Thus, by gradually increasing the diameter of the steel pipe and the joining member as it becomes the upper part, the propulsive force of the steel pipe pile 1 can be increased, and the peripheral frictional force at the pile head increases. Furthermore, these joining members 15 and 15a can also contribute to a supporting force.
[0034]
【Example】
The upper steel pipe 3 having an outer diameter of 1200 mm and a length of 10 m is connected to the upper end of the lower steel pipe 2 having an outer diameter of 508 mm and a length of 30 m, which is attached to the tip portion by crossing steel blades 11a and 11b having an outer diameter of 1016 mm and a plate thickness of 40 mm. A steel pipe pile 1 having a length of 40 m as shown in FIG. 1, which is formed by welding to a joining member 15 that is attached to a lower end portion of the steel blades 16 a and 16 b having an outer diameter of 1800 mm and a plate thickness of 50 mm. When a steel pipe pile with an outer diameter of 508 mm and a length of 40 m with a steel wing with an outer diameter of 1016 mm and a thickness of 40 mm installed at the tip is installed on the same ground, it is confirmed that the construction efficiency is almost unchanged. did.
[0035]
In the above description, the blade 10 provided at the tip of the lower steel pipe 2 and the joining member 15 provided at the lower end of the upper steel pipe 3 are crossed or continuous with the flat steel blades 11a, 11b, 16a, 16b. Although the case where it is configured to be installed in a spiral shape is shown, one L-shaped attachment portion is provided at the tip end portion of the lower steel pipe 2 and the lower end portion of the upper steel pipe 3, and the donut-shaped steel plate 1 is provided in this attachment portion. You may attach the spiral wing | blade which cut | disconnected the place and was bent into the spiral shape.
[0036]
In addition to the above, a flat steel blade obtained by dividing a plurality of donut-shaped steel plates intersects or spirally is attached to the distal end portion of the lower steel pipe 2 in addition to the above, or to the outer peripheral surface in the vicinity thereof, or the above The structure of the wing | blade 10 and the joining member 15 can be selected suitably, such as attaching the helical wing | blade of this. Further, separately from the blade 10 and the joining member 15, a steel blade or a spiral blade as described above may be attached to the outer peripheral surface of the lower steel pipe 2 and / or the upper steel pipe 3 to form a multistage blade structure. In addition, when there is a hole in the center of the blade 10 provided at the tip of the lower steel pipe 2 or when the blade 10 is provided on the outer peripheral surface of the lower steel pipe 2, the hole or the tip opening of the lower steel pipe 2 is a bottom plate or the like. Therefore, it is desirable that the support force be obtained with certainty (the above-described examples of the blade 10 and the joining member 15 can also be implemented in the embodiments described below).
[0037]
As is apparent from the above description, the present invention can obtain an ideal foundation pile by combining the head-expanded pile and the screw-in type steel pipe pile based on certain conditions. In other words, by adopting the screwed pile method while taking advantage of the design advantage of the head-expanded pile, the construction problems of the head-expanded steel pipe pile can be solved, and low vibration, low noise, no soil removal construction By taking advantage of the screw-type steel pipe pile that the tip support force can be obtained, it was possible to overcome the problem in the construction of the ready-made pile with the enlarged head, which has been considered difficult in the past.
[0038]
[Embodiment 2]
FIG. 9 is an explanatory view of a method for constructing a screw-in type steel pipe pile according to Embodiment 2 of the present invention.
In the figure, reference numeral 1 denotes the steel pipe pile described in the first embodiment, but a through hole for rotatably inserting an auger described later is provided at the center of the wing 10 and the wing-like joining member 15. . Further, as shown in FIG. 10, the motor 25 includes an outer shaft 26 and an inner shaft 27 that rotate independently in forward and reverse directions. 31 is an auger inserted in the steel pipe pile 1, and the spiral blade | wing 33 is provided above the auger head 32, and this spiral blade | wing 33 is equipped with the function to push up earth or sand upward or to push down below.
[0039]
Next, the construction method of the present embodiment will be described with reference to FIGS. In FIG. 11 and FIG. 12, the base machine 21 is omitted.
(1) As shown in FIG. 11 (a), an auger 31 slightly longer than the steel pipe pile 1 is inserted into the steel pipe pile 1. When the ground to be constructed is relatively soft, the steel pipe pile 1 may be inserted into the ground, and the auger 31 may be inserted into the steel pipe pile 1 when the pile tip reaches the vicinity of the support layer.
[0040]
(2) As shown in FIG. 10, the pile head of the steel pipe pile 1 is connected to the outer shaft 26 of the motor 25, and the upper end portion of the auger 31 is connected to the inner shaft 27. At this time, as shown in FIG. 11 (a), the distal end portion of the auger 20 (auger head 32) projects from the distal end portion of the steel pipe pile 1, but the projected length is the outer diameter D of the wing 10. _Three Is preferably less than or equal to.
[0041]
(3) For example, the steel pipe pile 1 is rotated in the forward direction by the motor 25 in the reverse direction of the auger 31.
As a result, as shown in FIG. 11 (b), the auger head 31 excavates and softens the ground in the vicinity of the tip preceding the steel pipe pile 1, and the steel pipe pile 1 penetrates into the ground by the action of the wood screw of the wing 10. Is done. At this time, the earth and sand near the tip of the steel pipe pile 1 passes between the steel blades 11a and 11b constituting the wing 10 and moves to the outer peripheral portion of the steel pipe pile 1 above the wing 10, and part of the earth and sand. Is taken into the steel pipe pile 1 by the spiral blade 33 of the auger 31.
[0042]
The amount of earth and sand taken into the steel pipe pile 1 by the auger 31 varies depending on the size of the tip opening of the steel pipe pile 1 and the size and shape of the auger head 32. By adjusting these, the earth and sand overflows from the steel pipe pile 1 Do not. In this case, the torque decreases as the amount of earth and sand taken into the steel pipe pile 1 increases. Moreover, the density of the earth and sand around the steel pipe pile 1 becomes high, so that the quantity of the earth and sand taken in in the steel pipe pile 1 is small, and a large circumferential friction force is exhibited.
[0043]
When the steel pipe pile 1 is penetrated, the auger head 32 causes the ground to be excavated and softened prior to the blade 10, so that the torque required for the rotation of the steel pipe pile 1 is significantly reduced as compared with the case where the auger 31 is not used. Moreover, since the rotation direction of the steel pipe pile 1 and the auger 31 is reverse, the reaction force from the motor 25 acting on the base machine 21 is also a reaction force due to the difference between the torques of the two, so that it is greatly reduced.
[0044]
When the lower steel pipe 2 is penetrated into the ground, as shown in FIG. 12A, the surrounding ground is excavated and softened by the wing-like joining member 15, and the upper steel pipe 3 is continuously penetrated into the ground. At this time, although the upper steel pipe 3 is larger in diameter than the lower steel pipe 2, excavation softening of the ground near the tip by the auger head 32, propulsion by the wood screw action of the wing 10, and excavation of the surrounding ground by the joining member 15 The steel pipe pile 1 is smoothly penetrated into the ground by softening and propulsion.
[0045]
(4) When the leading end of the pile reaches the support layer, the rotation of the steel pipe pile 1 and the auger 31 is stopped as shown in FIG.
Then, as shown in FIG. 12 (b), if the steel pipe pile 1 is removed from the motor 25 and the motor 25 is raised while rotating the auger 31 in the opposite direction with the steel pipe pile 1 left in the ground, the auger 31 is pulled up from the steel pipe pile 1, and the steel pipe pile 1 is buried in the ground, and the construction is completed. In addition, the earth and sand in the steel pipe pile 1 is pushed down by rotating the auger 31 in the opposite direction.
[0046]
In the construction method of the screwed pile according to the present embodiment, the ground near the tip of the pile is advanced by the auger head 32 of the auger 31 inserted into the steel pipe pile 1 and the lower steel pipe 2 and the upper steel pipe 3 are joined. Since the surrounding ground is excavated and softened by the wing-shaped joining member 15 constituting the portion, the torque for rotating the steel pipe pile 1 can be reduced even in the steel pipe pile 1 with the enlarged head. The penetration efficiency of the steel pipe pile 1 is improved, and the auger 31 and the base machine 21 can be downsized. Moreover, since the torsional moment which acts on the steel pipe pile 1 is small, a screwed pile can be applied also to a thin steel pipe pile or a concrete pile weak against torsion.
[0047]
In addition, since the steel pipe pile 1 and the auger 31 can rotate in the opposite directions as described above, the reaction force acting on the base machine 21 from the motor 25 can be reduced because the respective torques cancel each other. Therefore, stability can be ensured even if the base machine 21 is downsized.
[0048]
[Embodiment 3]
FIG. 13 is an explanatory view of a method for constructing a screw-in type steel pipe pile according to Embodiment 3 of the present invention. In the present embodiment, a through hole 34 is provided in the axial direction of the auger 31 for pressure-feeding a curable fluid such as cement milk, which will be described later, or a chemical solution for solidifying the ground, to the tip portion. Is provided with a jet 35 for jetting the curable fluid.
Reference numeral 41 denotes a curable fluid plant such as cement milk or ground solidifying chemical (hereinafter referred to as a “hardening material plant”). The auger 31 is rotatably connected to a through hole 34 provided in the auger 31 by a hose 42. Yes.
[0049]
Next, the construction method of the present embodiment configured as described above will be described with reference to FIGS. 14 and 15, the base machine 21 and the hardener plant 41 are omitted.
14A, the auger 31 is inserted into the steel pipe pile 1, and as shown in FIG. 10, the pile head of the steel pipe pile 1 is placed on the outer shaft 26 of the motor 25 and the head of the auger 31 is placed. Each is connected to the inner shaft 27. Further, the hose 42 of the hardened material plant 41 is connected to the through hole 34 of the auger 31 via a rotatable joint (not shown).
Hereinafter, as in the case of the second embodiment, a rotational force is applied to the steel pipe pile 1 and the auger 31 to penetrate the steel pipe pile 1 into the ground.
[0050]
When the steel pipe pile 1 has penetrated to an appropriate depth, as shown in FIG. 14 (b), the hardener plant 41 is driven, and the curable fluid 43 is pumped to the through hole 34 of the auger 31 via the hose 42. The auger head 32 is spouted from a spout 35 provided at the tip, and is agitated and mixed with earth and sand softened by the rotation of the auger head 32 and the blade 10. At this time, since the rotation directions of the steel pipe pile 1 and the auger 31 are opposite, the curable fluid 43 and the earth and sand are well agitated to form a highly uniform mixture 44.
The ejection section of the curable fluid 43 is determined according to the peripheral surface friction of the steel pipe pile 1 necessary for design, and may be the entire section from the pile head to the pile tip or in the vicinity of the pile tip. Just be fine.
[0051]
When the lower steel pipe 2 penetrates into the ground, as shown in FIG. 15A, the surrounding ground is excavated and softened by the wing-like joining member 15, and the upper steel pipe 3 is continuously penetrated into the ground.
When the pile tip reaches the support layer, as shown in FIG. 15A, the support layer is sufficiently agitated by the blade 10 and the auger head 32, and the earth and sand and the curable fluid 43 are mixed well. Then, the rotation of the steel pipe pile 1 and the auger 31 is stopped.
[0052]
Then, the steel pipe pile 1 and the hose 42 are removed from the motor 25, and the motor 25 can be raised while rotating the auger 31 in the opposite direction with the steel pipe pile 1 left in the ground as shown in FIG. 15 (b). For example, the auger 31 is pulled out from the steel pipe pile 1, and the steel pipe pile 1 is buried in the ground and the construction is completed. And the softened earth and sand solidify with progress of time, and show big tip support force.
[0053]
In the present embodiment, the same effect as in the second embodiment can be obtained. Furthermore, the curable fluid 43 ejected from the tip of the auger 31 and the earth and sand are agitated and mixed, and the disturbed ground is solidified. Therefore, a large tip support force and peripheral friction force can be obtained. Moreover, since the wing | blade 10, the joining member 15, and the auger 31 can rotate in the mutually opposite direction, the sclerosing | hardenable fluid 43 and earth and sand are stirred and mixed uniformly.
[0054]
In addition, if a rib or a reinforcing bar, angle steel, etc. are attached to the inner wall surface or the outer wall surface of the lower steel pipe 2 by welding and a convex part is provided, the adhesion force of the mixture 44 of earth and sand and the hardenable fluid 43 to the lower steel pipe 2 is increased. The tip support force can be further increased. The range where this convex part is provided is from the tip of the lower steel pipe 2 to the outer diameter D of the lower steel pipe 2. ₁ A range of about ½ to 2 times is desirable. Moreover, if a rib etc. are provided in the outer wall surface of the lower steel pipe 2 and the upper steel pipe 3, a surrounding surface friction force can be raised further.
[0055]
[Embodiment 4]
FIG. 16 is a schematic diagram of a main part of the fourth embodiment of the present invention. In this embodiment, in the second and third embodiments, the auger head 32 of the auger 31 inserted into the steel pipe pile 1 can be enlarged by an operation from the ground. In this case, the auger head 32 is enlarged by the outer diameter D of the steel pipe pile 1. ₁ With the above, the outer diameter D of the blade 10 _Three It is desirable that the range be approximately the same or less.
[0056]
The construction method of the present embodiment is almost the same as in the second and third embodiments, but the auger head 32 is expanded from the beginning after the auger 31 is inserted into the steel pipe pile 1 and protruded from the tip of the pile. Alternatively, it may be enlarged when the tip of the auger 31 reaches the vicinity of the support layer. In the third embodiment, by reducing the amount of protrusion of the auger head 32 from the tip of the pile as much as possible, the stirring and mixing efficiency of the curable fluid and the earth and sand can be increased. And when embedding of the steel pipe pile 1 is complete | finished, the auger head 32 is shrunk | reduced and it returns to the original state, the steel pipe pile 1 is left in the ground, and the auger 31 is pulled up.
[0057]
In the present embodiment, the same effects as those of the second and third embodiments can be obtained. However, since the expanded auger head 32 has a wider range for excavating and softening the soil, the steel pipe pile 1 is rotated. Torque can be further reduced.
Moreover, in Embodiment 3, since the earth and sand below the wing | blade 10 disturbed by the wing | blade 10 and the earth and sand above the wing | blade 10 are solidified by a sclerosing | hardenable fluid, fully exhibit the support capability of a support layer. And the tip support force can be further improved.
[0058]
[Embodiment 5]
In the first embodiment, the pile head of the steel pipe pile 1 is connected to the motor 23 mounted on the base machine 21, and in the second to fourth embodiments, the steel pipe pile is connected to the outer shaft 26 of the motor 25 mounted on the base machine 21. In the present embodiment, a motor for rotating the steel pipe pile 1 is used as a leader of the base machine 21. In the present embodiment, the pile head 1 is rotated by connecting the upper end of the auger 31 to the inner shaft 27. This motor is detachably mounted on the lower steel pipe 2 or the upper steel pipe 3 of the steel pipe pile 1 so that the steel pipe pile 1 is rotated.
[0059]
When the auger 31 is inserted into the steel pipe pile 1, a motor suspended from the base machine 21 (see FIG. 5) is disposed at or near the pile head of the steel pipe pile 1 and the upper end of the auger 31. Can be connected.
The operation of the present embodiment is substantially the same as in the first to fourth embodiments, but the weight of the object (motor) arranged at a high position is reduced, so that the stability of the base machine 21 can be increased. it can.
[0060]
In each of the above embodiments, a flat steel blade obtained by dividing a circular steel plate or an elliptical steel plate into two parts is crossed or attached continuously or spirally or a donut-shaped steel plate is bent spirally. Although the case where the wing and the joining member are configured by processing and mounting is shown, the present invention is not limited to this, for example, dividing a polygonal steel plate having a triangle or more or a polygonal steel plate having a hole in the central portion. Alternatively, one having an appropriate shape can be selected, such as forming a blade and / or a joining member by bending a polygonal steel plate having a hole in the center into a spiral shape.
Further, the steel plates of these shapes are not limited to two divisions, and may be divided into two or more divisions.
[0061]
【The invention's effect】
(1) The screwed steel pipe pile according to the present invention is Made of steel pipe for steel pipe pile At least at or near the tip Larger than the outer diameter of the steel pipe Lower steel pipe with wings and larger diameter than lower steel pipe And shorter than the lower steel pipe It consists of an upper steel pipe and a joining member for joining the lower steel pipe and the upper steel pipe. By forming this joining member in a wing shape with a larger diameter than the upper steel pipe, the upper part having a diameter larger than that of the wing provided on the lower steel pipe Since it can be constructed by joining steel pipes, it can cope with the horizontal force and bending moment generated in the pile head, and the amount of horizontal displacement during an earthquake can be suppressed.
[0062]
(2) Moreover, the construction method of the screwed pile which concerns on this invention gives rotational force to the pile head part or trunk | drum part of the screwed steel pipe pile of said (1), and penetrates this screwed steel pipe pile in the ground. Since it embed | buries, while being able to acquire the effect of said (1), it can construct smoothly with a low noise, a low vibration, and no soil removal.
[0063]
(3) Further, an auger is inserted into the threaded steel pipe pile of (1) above, and the auger head is protruded from the tip of the threaded steel pipe pile, and the screwed steel pipe pile and the auger are given a rotational force and screwed. Since the steel pipe pile is inserted into the ground and the screwed steel pipe pile reaches a predetermined depth, the auger is pulled out by leaving the screwed steel pipe pile in the ground. The effect of 2) can be obtained, the torque during construction can be reduced, and the workability of the upper steel pipe can be improved.
[0064]
(4) Also, the auger is inserted into the threaded steel pipe pile of (1) above, the auger head is protruded from the tip of the threaded steel pipe pile, and the screwed steel pipe pile and the auger are given a rotational force and screwed. The steel pipe pile is penetrated into the ground, and the hardened fluid is ejected from the auger head to the support layer or a predetermined section during the penetration of the screwed steel pipe pile. When stirring and mixing to a predetermined depth, the screw-type steel pipe pile is left in the ground and the auger is pulled out, so that the effects (1) to (3) are obtained, The agitated and mixed earth and sand and the curable fluid are solidified over time, and a larger peripheral surface friction force and tip support force can be secured.
[0065]
(5) In the construction method for screwed steel pipe piles in (3) and (4) above, since the auger whose outer diameter of the auger head is larger than the outer diameter of the tip of the screwed steel pipe pile is used, rotation of the steel pipe pile The torque can be further reduced and the tip support force can be further increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a screw-in type steel pipe pile according to a first embodiment of the present invention.
FIG. 2 is a perspective view of the lower steel pipe of FIG.
3 is an explanatory view showing the manufacture of the wing and the joining member of FIG. 1. FIG.
4 is a perspective view of a lower steel pipe and a wing of FIG. 1. FIG.
FIG. 5 is an explanatory diagram of a construction method for the screw-type steel pipe pile of FIG. 1;
6 is an explanatory view of an example of a construction method of the screw-type steel pipe pile of FIG. 1. FIG.
7 is an explanatory view of another example of a method for constructing the screw-in type steel pipe pile of FIG. 1. FIG.
FIG. 8 is an explanatory diagram of another example of the screwed-type steel pipe pile according to the first embodiment.
FIG. 9 is an explanatory diagram of a method for constructing a screw-in type steel pipe pile according to Embodiment 2 of the present invention.
10 is an explanatory view showing an example of the connection of the motor of FIG. 9 with a steel pipe pile and an auger.
FIG. 11 is an explanatory diagram of the construction procedure of FIG. 9;
12 is an explanatory diagram of the construction procedure of FIG. 9;
FIG. 13 is an explanatory diagram of a method for constructing a screw-in type steel pipe pile according to Embodiment 3 of the present invention.
14 is an explanatory diagram of the construction procedure of FIG. 13;
15 is an explanatory diagram of the construction procedure of FIG.
FIG. 16 is an explanatory diagram of Embodiment 4 of the present invention.
[Explanation of symbols]
1 Screwed steel pipe pile (steel pipe pile)
2 Lower steel pipe
3 Upper steel pipe
10 wings
15 Wing-like joining member
11a, 11b, 16a, 16b Steel blades
21 Base machine
23, 25 Motor
31 Auger
32 Auger Head
34 Through hole
35 spout
43 Curable fluid

Claims (6)

A lower steel pipe made of a steel pipe for steel pipe piles and having a blade having a diameter larger than the outer diameter of the steel pipe at least at or near the tip, an upper steel pipe having a diameter larger than the lower steel pipe and shorter than the lower steel pipe, and the lower steel pipe And a joining member for joining the upper steel pipe,
A screwed steel pipe pile characterized in that the joining member has a larger diameter than the upper steel pipe and is formed in a wing shape. The screwed steel pipe pile according to claim 1, wherein an outer diameter of the upper steel pipe is configured to be larger than an outer diameter of a blade provided in the lower steel pipe. A construction method for a screw-type steel pipe pile, characterized in that a rotational force is applied to a pile head or body part of the screw-type steel pipe pile according to claim 1 or 2, and the screw-type steel pipe pile is embedded in the ground. An auger is inserted into the threaded steel pipe pile according to claim 1 or 2, the auger head is protruded from the tip of the threaded steel pipe pile, and a rotational force is applied to the threaded steel pipe pile and the auger to provide the threaded steel pipe. A pile of steel pipe piles, wherein the pile is inserted into the ground, and when the screwed steel pipe pile reaches a predetermined depth, the auger is pulled out while leaving the screwed steel pipe pile in the ground. Construction method. An auger is inserted into the threaded steel pipe pile according to claim 1 or 2, the auger head is protruded from the tip of the threaded steel pipe pile, and a rotational force is applied to the threaded steel pipe pile and the auger to provide the threaded steel pipe. The pile is penetrated into the ground, and the curable fluid is ejected from the auger head to the support layer or a predetermined section during the penetration of the screw-type steel pipe pile. When the mixture is stirred and mixed to a predetermined depth, the screwed steel pipe pile is left in the ground and the auger is pulled out. The construction method of the screwed-type steel pipe pile according to claim 4 or 5, wherein an auger capable of expanding the outer diameter of the auger head to be larger than the outer diameter of the tip part of the screwed-type steel pipe pile.

Images