JP4228943B2 - Ready-made pile construction method and holding leader - Google Patents

Description

  The present invention relates to a method for constructing a ready-made pile, and relates to a method for burying a ready-made pile using both an auger and a full swirler and a holding leader for an auger.

There are several methods for constructing ready-made piles, such as the digging pile method, the pre-boring method, and the rotary pile method. The medium digging method and the pre-boring method are usually constructed by excavation with an auger using a three-point pile driver.
Moreover, as a construction method of the ready-made pile which used an auger and all the turning machines together, there exist the method described in patent document 1 and patent document 2, for example.

  In the construction method described in Patent Document 1, the tip (excavation head) of an auger rod for excavating soil is attached to the lower end of the pile in a state of protruding from the pile, and the pile is rotationally press-fitted using an all-swivel machine. This is a construction method in which the auger rod is rotated along with the auger rod. According to this construction method, since the auger rod rotates and the excavation is performed in accordance with the rotation of the pile, the rotation driving unit (electric motor and speed reducer) installed at the upper end of the pile to rotate the auger rod is provided. It becomes unnecessary. As a result, the efficiency and simplification of the work can be achieved, the pile burying work can be facilitated in a low or narrow space in the sky, and the construction machine can be downsized.

In addition, the construction method described in Patent Document 2 sets the upper limit position of the earth and sand blockage above the tip of the steel pipe pile when the steel pipe pile (rotating pile) provided with blades at the tip is rotationally press-fitted with a full swirler. It is described that the increase in penetration resistance due to the clogging of the tip of the pile with the earth and sand is avoided by disturbing and removing the earth and sand in the pile rising to the upper side with an auger.
An example of a holding leader that guides the rotation driving unit of the auger in the vertical direction and receives a reaction force during rotation from the rotation driving unit is a holding reader provided in a three-point pile driver. This holding leader supports the rotation drive unit in a cantilevered state and guides it up and down with respect to a rail that is supported by the base machine and projects outward from a support column with its axis directed upward and downward. .
JP-A-6-341143 JP 2002-220830 A

  The method of Patent Document 1 does not require an electric motor or speed reducer for rotating the auger rod, so that the construction machine can be miniaturized, but the torque for rotary press-fitting of the pile and the torque for excavation by the auger Both of these need to be borne by all swirlers, and accordingly, the rotational torque for press-fitting the piles is reduced. Also, the auger rod can only move downward as the pile descends. In other words, it is not possible to improve the excavation performance by moving the auger rod up and down flexibly according to the hardness of the ground, so it is necessary to discharge a large amount of water from the auger tip in order to perform excavation efficiently. , Muddy water treatment becomes a problem.

  Moreover, since the method of patent document 2 is constructed so as not to block the soil in the steel pipe pile, it is possible to reduce excavation resistance, but it is necessary to apply a special machine to disturb and remove sediment, There is a problem that the cost for preparing the special machine is high. That is, in order to drive all the swirlers and the rotation drive of the auger at the same time, it is necessary to install them so that they do not interfere with each other. . In addition, when construction is performed so that the steel pipe pile is not blocked by earth and sand, it is difficult to judge whether the surrounding ground is disturbed due to the occurrence of boiling or how much excavation can be performed efficiently. Not right.

Here, when constructing a ready-made pile, it is practically difficult to construct a pile with a large diameter of about 1500 mm using a three-point pile driver. For this reason, large-diameter piles are constructed using all swirlers, but as the pile diameter increases, the rotational torque required for construction increases, resulting in limited mechanical capacity and applicable pile diameters that are restricted. .
This invention is made paying attention to such a point, and makes it a subject to be able to construct a ready-made pile efficiently even if it is a large-diameter pile and the ground is hard and soft.

In order to solve the above-mentioned problem, the invention described in claim 1 of the present invention is a holding leader used when pre-boring a pile burying position by an auger, and is capable of loosely inserting a rotation driving part of the auger. And a cylinder used with its axis facing up and down, and formed so as to extend vertically with respect to the wall of the cylinder, guiding the rotation drive unit in the vertical direction and rotating from the rotation drive unit The present invention provides a holding reader comprising a reaction force receiving portion that receives a reaction force during driving.

Next, the invention described in claim 2, a part or all of the piles embedded position after drilling by auger, a method of constructing the prefabricated pile rotating pressed prefabricated pile by the total turning machine, in claim 1 The holding leader described above is arranged and fixed with the shaft up and down, and after inserting the rotation driving part of the auger into the holding leader and performing excavation by the auger, and removing the auger and the holding leader, the ready-made pile method of constructing prefabricated pile you characterized in that the rotating press-fitted and provides a.
Next, the invention described in claim 3 is characterized in that, with respect to the configuration described in claim 2 , the holding reader is fixed by the all-swivel machine.
Next, the invention described in claim 4 provides the structure described in claim 2 or claim 3 with an ejection hole capable of ejecting a fluid at the tip of the auger, and water, air, It is characterized in that a curable fluid can be ejected.

Next, the invention described in claim 5 uses an auger having a diameter-enlarged portion at the tip as the auger, with respect to the configuration described in any one of claims 2 to 4. Auger is expanded at the bottom of the excavation by an auger, and a curable fluid is injected to form a rooted bulb, and the tip of the ready-made pile is embedded in the rooted bulb by the whole swirler Is.
Here, the ready-made pile used as the object of this application is not limited to hollow piles, such as a steel pipe pile and a ready-made concrete pile, A tip obstruction | occlusion and a solid pile may be sufficient. Further, the pile may not be a rotating pile (a pile having a blade at the tip).

According to the present invention, it is possible to suppress the interference between the auger and the entire turning machine, and it is not necessary to use a special machine, and even if the pile has a large diameter and the ground is hard and soft, the ready-made pile can be efficiently used. Can be constructed.
In the holding reader of the present invention , the rotational reaction force from the rotation driving unit is received inside the cylinder, but the rotation driving unit and the cylinder are in a substantially coaxial state, so the holding reader of the three-point pile driver As compared with the above, the rotational reaction force can be absorbed by the cylinder more efficiently. That is, the reaction force receiving portion projecting outwardly from the reader body is held reader 3-point pile driver, but the subject to rotational reaction force in a cantilevered state, the present invention, rotational reaction Since the force can be transmitted to the cylinder as a rotation torque about the substantially center of the cylinder, the rotation torque can be received more effectively. For this reason, the apparatus for fixing and supporting the holding reader can also fix and support the holding reader without having a portion protruding outward.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a holding reader 1 used in the present embodiment. In FIG. 1, a state in which the holding reader 1 is fixed to all the revolving machines 6 is shown. The holding leader 1 has a tubular body 4 having a diameter that allows the rotational drive unit 3 of the auger 2 to be loosely inserted, and projects from the side surface of the rotational drive unit 3 to the inner wall of the tubular body 4. A reaction force receiving portion 5 that receives a reaction force from the overhang portion 3a is provided.

  The overhang portions 3a are formed in two axially symmetric portions, and the reaction force receiving portions 5 are also provided in two axially symmetric portions corresponding to the pair of overhang portions 3a. As shown in FIGS. 2 and 3, each reaction force receiving portion 5 is composed of two stopper rails 5a and 5b extending vertically in the axial direction of the cylindrical body 4, and between the two stopper rails 5a and 5b. By inserting the overhanging portion 3a of the rotation drive unit 3 into the recess formed in the above, the rotation drive unit 3 is guided by the reaction force receiving unit 5, that is, in a state where the circumferential swing is small. It can move up and down. One of the two stopper rails 5a, 5b is formed to be relatively long. Reference numeral 5c is a rib for reinforcing the stopper rails 5a and 5b.

In the above description, the stopper rails 5a and 5b constituting the reaction force receiving portion 5 are two, but may be one. In the case of one line, the rotation of the rotation drive unit 3 in the circumferential direction increases, but it can be guided in the vertical direction. Even in the case of one line, the reaction force receiving unit 5a applies a reaction force. It is possible to rotationally drive the auger screw.
Further, the reaction force receiving portion 5 may be provided at only one place in the circumferential direction, but the reaction force input from the rotation driving portion 3 becomes a rotational torque (couple) about the substantially central axis of the cylindrical body 4. Thus, it is preferable to provide two or three or more locations. For example, the torque transmitted to the cylinder 4 becomes a rotational torque about the central axis by providing it at positions at equal intervals along the circumferential direction, and even if the rigidity of the cylinder 4 is reduced accordingly. I do not care.
And in this embodiment, after performing a pre-boring by the auger 2 using the above-mentioned holding | maintenance leader 1, it is the construction method which carries out the rotary press-in of the pile with the all-swivel machine 6, and embeds the pile to a support layer.

Next, an example of a pile construction method according to the present embodiment will be described with reference to FIGS.
First, as shown to Fig.4 (a), all the turning machines 6 are installed in the position which embeds a pile. This all-swivel machine 6 is fixed by a weight or the like (not shown). Note that the all-swivel machine 6 generally has a function of gripping and holding the side surface of the pile, a function of moving up and down by a predetermined stroke in the held state, and a rotational force applied to the pile by rotating while holding the pile. It has the function to provide.
Then, the lower end portion of the cylindrical holding reader 1 is inserted into the center of the all-swivel machine 6, and the lower end portion outer surface of the holding reader 1 is held and fixed by the all-swivel machine 6.

Next, the rotation drive unit 3 of the auger 2 is lifted by a crane or the like 10 and the auger rod 9 and the rotation drive unit 3 are inserted into the holding reader 1 from above. Here, the auger rod 9 is composed of an auger screw 7 and an excavation head 8 attached to the tip of the auger screw 7.
At this time, as shown in FIG. 4 (b), the rotation drive unit 3 is inserted to a depth where it hits one stopper rail of one reaction force receiving unit 5, and the entire swivel machine 6 is rotated to rotate the rotation drive unit 3. The overhanging portion 3 a is hit against the stopper rail and positioned at the position of the reaction force receiving portion 5. Positioning is automatically performed by the protruding portion 3a coming into contact with one of the stopper rails.
When the positioning is performed, as shown in FIG. 4C, the auger 2 is lowered and the overhang portions 3a are inserted into the stopper rails 5a and 5b of the two overhang portions. Thereby, the rotation drive unit 3 is guided by the reaction force receiving unit 5 and can move up and down.

Next, as shown in FIG. 4 (d), the rotation drive unit 3 is driven to rotate the auger screw 7, that is, excavation is started, the auger 2 is guided to the reaction force receiving unit 5 and the reaction force is taken. While descending, excavate to a predetermined depth.
Next, as shown in FIG. 5A, the lifting / lowering cylinder device of all the revolving machines 6 is driven to displace the chuck portion 6a for gripping the cylinder 4 upward (at this time, the holding reader 1 is also upward). The rotation drive unit 3 and the auger screw 7 are separated, and only the rotation drive unit 3 is lifted and removed from the holding reader 1.

  Here, in the present embodiment, an example is shown in which the joint portion between the rotary drive unit 3 and the auger screw 7 is disconnected and connected at a lower space position where the chuck portion 6a that holds the cylindrical body 4 is raised. However, it is not limited to this. For example, a work opening may be provided on the side surface of the cylindrical body 4 above the position held by all the swirlers 6, and the disconnection and connection work may be performed through the opening. . The opening may or may not have a lid. You may make it observe the descending condition of the auger screw 7 through this opening.

Next, a new auger screw 7 (without the excavation head 8) is attached to the rotation drive unit 3, and again inserted into the holding leader 1 as shown in FIG. The auger screw 7 is connected by connecting the auger screws 7 and the auger screws 7 are added.
Here, when the auger screw 7 is added, the lower auger screw 7 is buried and fixed in the ground, and the upper auger screw 7 has a pair of anti-rotation drive units 3 opposite to each other. Since the position with respect to the cylindrical body 4 is regulated by the force receiving portion 5, the new auger screw 7 and the lower auger screw 7 are almost coaxial with each other simply by lowering the new auger screw 7.
Then, as shown in FIG.5 (c), after lowering | hanging the chuck | zipper part 6a holding the cylinder 4 to an original position, the rotation drive part 3 is driven and further excavation by an auger is performed.

In this way, excavation by the auger 2 is performed while the auger screw 7 is sequentially added, and the excavation is performed up to the target support layer as shown in FIG.
When excavation is completed, the auger 2 is pulled up and removed while rotating in reverse. At this time, contrary to the time of excavation, the auger screw 7 is pulled up while being sequentially separated. When the tip of the auger 2 (excavation head 8) appears on the ground, the rotary drive unit 3 is pulled out from the holding reader 1. Note that a new auger screw 7 is attached to the rotation drive unit 3 by using an unillustrated extension stand that is separately prepared.
Subsequently, the holding by the all-swivel machine 6 is loosened, and the holding leader 1 is removed from the all-swivel machine 6.

Next, as shown in FIG. 6, the pile 11 is inserted into the central portion of the all-swivel machine 6, the pile 11 is rotationally press-fitted by the all-swivel machine 6, and the pile 11 is moved along the excavation hole 12 excavated in advance. It will be buried. At this time, since the excavation and the pile 11 are buried using the same all-swivel machine 6, the excavation hole 12 and the pile 11 are coaxial or substantially coaxial. Further, the piles 11 are sequentially added by a known method.
Since the burying position of the pile 11 is pre-bored, a large rotational torque is not necessary and it can be embedded easily. Therefore, construction can be performed at a speed that is twice or more that of embedding the pile 11 without pre-boring. Moreover, since the penetration resistance at the time of embedding is small, it can be applied not only to the small-diameter pile 11 but also to the large-diameter pile 11.
Here, the said pile 11 is not limited to the rotary pile 11 provided with the blade | wing on the front-end | tip part outer periphery, Even if it is the normal pile 11 without a blade | wing, it can fully rotationally press fit.

  Further, when excavating with the auger 2, the excavation may be performed while injecting water or air from an ejection hole provided at the distal end portion of the auger 2 as necessary by looking at the ground condition (hardness and softness). In this case, it is possible to excavate efficiently even on hard ground or the like. Moreover, if a curable fluid such as cement milk is injected from the tip of the auger 2, a large peripheral friction force and tip support force can be obtained after the pile 11 is constructed. In addition, cement milk can be injected at an arbitrary position, for example, where the surface friction cannot be expected. However, the present invention can be applied even if the tip of the auger 2 has no ejection hole.

  Further, as the excavation head 8 attached to the tip of the auger screw 7, an excavation head 8 having an enlarged diameter portion 8a as shown in FIG. While a curable fluid is ejected, stirring is performed with an enlarged wing to form a root-clamping bulb portion 14 as shown in FIG. 8, and the tip of the pile 11 is press-fitted into the root-clamped bulb portion with all swirler 6. And bury it. At this time. You may make it join the tip part of the pile 11 and the root compaction bulb | ball part 14 which rotationally press-fitted by providing the protrusion 15 of the screw shape (shape extended helically) in the outer periphery of the front-end | tip part of the pile 11 more firmly. In this way, a large tip support force can be expected by forming the rooted bulb 14 in the support layer portion.

In addition, when constructing a pile 11 that does not use cement milk or the like, if the support layer portion is softened by excavation, there is a risk of adversely affecting the tip support force. It is desirable to embed the pile by the propulsion force of the pile 11. That is, excavation by the auger 2 may be performed up to a position shallower than the burial depth of the pile 11.
Further, in the case of the rotating pile 11 at the open end, it is desirable to perform excavation with an auger up to the front of the support layer and to close the tip when the support layer is buried in order to promote the end blockage.

  In this construction method, since preboring is performed by an auger, a large rotational torque or pushing force is not required to penetrate the pile 11. For this reason, all the turning machines 6 can be downsized or used with a small capacity, and the construction cost can be greatly reduced. Moreover, since the torsional moment which acts on the pile 11 is also small, it can be applied to thin steel pipe piles and concrete piles.

Furthermore, since the height can be suppressed lower than that of a three-point pile driving machine and the length of the holding leader 1 can be changed as appropriate, the present invention can also be applied to a low-flying site constructed under a viaduct.
Here, in the above-described embodiment, the case where the holding reader 1 is held and fixed by the all-swivel machine 6 is illustrated, but the holding reader 1 may be fixed and held by another holding machine. For example, the holding leader 1 of the present invention may be attached to a conventional three-point pile driver. However, as described above, the holding by the all-swivel machine 6 can be held and fixed in a small area and the construction itself is simplified.
Moreover, although the case where the cross section was circular was illustrated as the cylinder 4 of the holding | maintenance reader 1 in the said embodiment, the cylinder 4 which carried out cross-sectional polygonal shape, such as a cross-sectional rectangle, may be sufficient.

A normal steel pipe pile 11 having a pile diameter of 1500 mm, a plate thickness of 19 mm, and a length of 40 m was constructed. The ground is a relatively soft clay-sand double layer ground up to around 31m, there is an intermediate sand layer with an N value of 50 to 31 to 34m, and a hard silt layer with an N value of 20 to 30 at 34 to 37m. The depth below is a gravel layer that becomes a support layer having an N value of more than 50. A rotating pile 11 having a pile diameter of 1500 mm, a plate thickness of 25 mm, and a length of 40 m was also constructed on the same ground for comparison (in the comparative example, only rotary press-fitting with a swivel machine). In the construction according to the present invention using pre-boring and full turning, the pile 11 penetrated without any problem in the intermediate sand layer, and the support layer could be constructed quickly. On the other hand, in the rotation pile 11 which does not implement pre-boring, it took twice or more time than the construction of this patent invention. Moreover, in the comparative example, in order to endure rotational torque, the board thickness required for construction had to be considerably increased. When a rotary pile is applied to the construction method of this patented invention, construction with a plate thickness of 19 mm similar to the embodiment is possible.
Thus, in this patent invention, since a general purpose thing can be used without using a special machine as the rotation drive part 3, it can procure anywhere and can reduce cost.

It is a figure explaining the apparatus which concerns on embodiment based on this invention. It is a figure which shows the reaction force receiving part which concerns on embodiment based on this invention. It is a top view which shows the reaction force receiving part which concerns on embodiment based on this invention. It is a figure which shows the construction procedure which concerns on embodiment based on this invention. It is a figure which shows the construction procedure which concerns on embodiment based on this invention. It is a figure which shows the construction procedure which concerns on embodiment based on this invention. It is a figure which shows the example of the excavation head which concerns on embodiment based on this invention. It is a figure which shows the relationship between the consolidation bulb | ball part which concerns on embodiment based on this invention, and a pile.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Holding leader 2 Auger 3 Rotation drive part 3a Overhang | projection part 4 Cylindrical body 5 Reaction force receiving part 5a, 5b Stopper rail 6 Whole turning machine 6a Chuck part 7 Auger screw 8 Excavation head 9 Auger rod 11 Pile 12 Excavation hole 13 Ejection hole 14 Root consolidation bulb

Claims (5)

A holding leader used when pre-boring the pile burying position by an auger,
A cylindrical body that is large enough to allow loose insertion of the rotation drive portion of the auger and that is used with its axis directed up and down, and formed so as to extend up and down with respect to the wall of the cylinder body. A holding reader, comprising: a reaction force receiving portion that guides and receives a reaction force during rotation driving from the rotation driving portion. After excavating a part or all of the pile burying position with an auger, it is a construction method of a ready-made pile that rotationally press-fits the ready-made pile with a full swirler,
The holding reader according to claim 1 is arranged and fixed with its shaft up and down, and the auger rotation drive unit is inserted into the holding reader to perform excavation by the auger, and the auger and the holding reader are removed. later, the construction method previously made piles you characterized in that the rotating press-ready piles. The method for constructing a ready-made pile according to claim 2 , wherein the holding leader is fixed by the all-swivel machine. The ready-made product according to claim 2 or 3, wherein a jet hole capable of jetting fluid is provided at a tip of the auger, and water, air, curable fluid, etc. can be jetted from the jet hole. Pile construction method. An auger with an enlarged diameter portion at the tip is used as the auger, and the auger performs enlarged excavation at the bottom of the excavation and injects a curable fluid to form a rooted bulb, which is ready-made by an all-swivel machine. The method for constructing a ready-made pile according to any one of claims 2 to 4 , wherein a tip end portion of the pile is embedded in the root-fixed bulb portion.

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