JPH0678615B2 - Pile driving method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a so-called medium excavation method such as construction of a foundation pile to be cast in situ, construction of an underground continuum and a method of press-fitting a foundation pile.

<Prior art> Conventionally, in the method of “casting in-situ” by driving a pile locally, the part that contacts the support layer at the bottom of the pile, the excavation hole for driving the pile, and the void created around the pile are solidified with concrete or the like. However, since the hardening time of this concrete is as short as 3.5 to 5 hours, it is necessary to piling in a short time in which the concrete does not harden.

One of the construction methods for in-place piles is the earth drill method using an earth auger excavator. This method involves excavating the screw by rotating it with a drive device. When it invades, the amount of earth and sand is discharged through the screw. Therefore, it is necessary to add a new screw to the screw pressed into the soil after the operation for a suitable time. It takes about 20 minutes to add one screw, for example, about 1 m for excavating about 40 m.
With this 5m screw, this screw connection alone would take about two and a half hours. In addition, since the earth and sand generated by excavation is taken to the ground as waste soil, it takes a lot of time and money to dispose of this earth and sand, and it becomes an industrial waste in the society, causing pollution problems. .

There is the Benoto method as another method. This is to excavate the excavated earth and sand while rocking the casing and holding it with the grab and lifting it to the ground and disposing of it, which requires a great amount of power to drive the grab and has to treat a large amount of waste soil. There is a problem of not becoming.

In addition, there is a reverse method, which is a sludge in which a large amount of water is injected at the time of excavation to mix excavated soil and water, and this is pumped to perform excavation. Although, unlike the screw type, it does not take a long time to connect the screw, but as described above, a large amount of sludge must be discarded, so equipment for that is also necessary, which requires time and money, and socially. Becomes industrial waste and causes pollution problems.

For this reason, it is necessary to be able to drive piles in the shortest possible time before concrete or the like has hardened, and there is a demand for a pile driving method that does not cause problems such as waste soil and sludge.

In addition, after pile driving, it is necessary to measure the bearing capacity of the pile in order to confirm that the pile is sufficiently supported with respect to the structure to be installed. Conventionally, weight loading tests have been performed after pile driving. . It would be even more advantageous if there was a method capable of measuring the supporting force of a pile with a pile driver or the like at the final stage of pile driving without performing this loading test.

<Object of the Invention> An object of the present invention is to solve the above problems in the conventional pile driving method. That is, the present invention saves the trouble of adding screws during excavation, can strike a pile with a large bearing capacity in a short time, does not cause pollution problems due to waste soil from the excavation hole, and corresponds to a narrow construction required area It is intended to provide a pile driving method capable of simultaneously measuring the pile supporting force.

<Concrete Configuration of the Invention> The present invention for achieving such an object is a base machine, a leader supported by a stay on the base machine, and a drive device that is slidably mounted in the longitudinal direction of the leader. And a rod driven to rotate by this drive device and inserted into the drive device, and a pile driving machine having a drilling head and a hollow pile pushing tool detachably attached to the tip of the rod to form a field driving pile. A method of driving a pile, wherein the excavating head is rotationally driven to excavate a soil layer, and at the same time, concrete milk and air are supplied to the excavating head through the rod, and the concrete milk and air are provided to the excavating head. While ejecting from the hole into the excavation hole, the rotation of the excavation head causes the concrete milk, air and the excavation head to A step of stirring and mixing the excavated earth and sand to form a fluidized product, and substituting the excavation head with the fluidization to sequentially excavate; and, after the excavation head reaches a support layer, the excavation from inside the rod. A step of injecting concrete milk having a high concrete concentration into the upper part of the supporting layer through the hole of the head to form a supporting part of the pile, and inserting a hollow pile in the drilling hole, and a hollow pile lower end from the hollow part of the hollow pile. A circulation in which a stirring pump is inserted into the hollow pile, and the stirring pump is inserted into the hollow pile to suck the fluidized product below the lower end of the hollow pile and the rear end of the stirring pump to discharge the fluidized liquid into the hollow pile. Thereby, a step of sinking the hollow pile to reach the supporting layer gradually by placing only the lower end of the hollow pile in a depressurized state, and the lower end of the hollow pile reaches the supporting layer and A method for providing a pile, characterized in that the method includes a step of fixing a hollow pile by hydraulic pressure of the push-in tool and measuring a push-in pressure by a hydraulic pressure gauge of the push-in tool to measure a pile supporting force. is there.

First, a pile driver used in the conventional and the pile driving methods of the present invention will be described.

In the earth auger using the conventional earth drill method,
As shown in FIG. 9, the drive device 12 is mounted on a base machine 13 such as a crane so as to be vertically movable along a guide 40 of the leader 1 supported by the stay 2. The upper end of the torque tube 42 having the screw 5 is fixed to the lower end of the drive unit 12. The earth auger has a drive device 12 for a torque tube 42, and while the torque tube drive device 12 rotates the torque tube 42, the earth auger is screwed vertically to perform excavation. The earth and sand generated by the excavation rises on the screw 5 due to the rotational descent of the torque tube 42, and by adding the screw 5, the earth and sand is discarded and the excavation proceeds.

The pile driving machine used in the present invention is, as shown in FIG. 1, a base machine 13, a leader 1 supported by the base machine 13 via a stay 2, and a guide 40 mounted in the longitudinal direction of the leader 1. Drive unit 12 slidably mounted on
And a rod 3 which is inserted into the drive device 12, and an excavation head 4 which is detachably attached to the tip of the rod 3.

A known excavating machine such as a crane is used as the base machine 13.

As shown in FIG. 4, the drive device 12 has a motor 25 and a reduction gear train having at least a high speed side speed reducer 26 and a low speed side speed reducer 27. In addition, as shown in FIG. 5, the driving device 12 is rotated by the rotational driving force that is generated by reducing the rotational movement of the motor 25 by the high-speed side speed reducer 26 and the low-speed side speed reducer 27, and rotates. There is provided a member 47 having a through hole through which the through hole can be inserted. This may be a gear 47 as shown in FIG. Further, the driving device 12 is a chuck for gripping the rod 3 inserted into the member 47 having the through hole.
Having 24.

As shown in FIG. 5, the motor 25 is driven by a high speed reducer.
It is transmitted to the gear 45 via 26, the rotation direction is changed by the gear 46, and further reduced by the gear 47. Since the gear 47 is attached with the rod 3 as the through shaft, the driving force of the motor is decelerated and transmitted to the gear 47 to rotate the rod 3.
The rotation of the rod 3 causes the excavation head 4 to rotate. The number of revolutions of the excavation head 4 is appropriately determined according to various conditions such as hardness of the ground.

The chuck 24 at the lower end of the earth auger 12 acts to hold the rod 3 tightly. Therefore, it has a first wedge 39 and a second wedge 41, which are rotatable by a bearing 55. A hydraulic device having a cylinder rod 48 and a cylinder 50 on the outer side of the rod tightens the rod by a wedge action. When the cylinder 50 is moved upward by the cylinder rod 48 as seen in FIG. 5, the second wedge 41 slides relatively on the first wedge 39 to move the wedge 39 inward, that is, to the rod 3. The rod 3 can be chucked by pressing it toward. When releasing the rod 3, it suffices to perform an action opposite to the above.

As shown in FIGS. 4 to 6, the rod 3 is provided so as to penetrate the drive device 12 and can be connected to the required length of the entire drill hole.

The rod 3 may have various sectional shapes such as a square shape and a round shape. However, it is usually preferable to use a square rod as shown in FIGS. 2 and 6. Because the member
This is for accurately transmitting the rotary motion transmitted from the motor 25 via the gears 45, 46, 47 by the 47 to the rod 3. If necessary, a stirring claw 56 capable of mixing the excavated earth and sand can be provided at the lower end of the rod 3.

As shown in FIG. 2, the rod 3 has a through hole 7 for feeding concrete milk supplied from a concrete supply source through a connector 44 (see FIG. 1) such as Suibiru, and a connector 44 from a compressed air supply source. It has a through hole 6 for feeding the supplied compressed air. Through the through holes 6 and 7, concrete milk and compressed air can be sent to the excavating head during excavation at a desired flow rate. Various arrangements and shapes of the through holes 6 and 7 in the rod are possible, and one example thereof is shown in FIG.

The lower end of the rod 3 has a through hole 29 to which the excavating head 4 is detachably attached.

As shown in FIG. 3, the drilling head 4 can be fixed to the rod 3 by penetrating the pin 31 through the through hole 29 of the rod and the through hole 30 of the drilling head. The drilling head needs to be removable, and as long as it is mounted, mounting methods other than the above are possible.

The shape of the excavation head 4 is usually a rotating body, and has supply ports 7a and 6a for ejecting the concrete milk and the compressed air sent from the rod 3. Further, the excavation head 4 has a claw 9 as a means necessary for excavating and stirring the soil layer. In the case shown in FIG. 3, the tip has an acute-angled shape, but it may be another type, for example, a screw-shaped shape. The claws and the like are preferably made of a material such as a superalloy because they can withstand excavation of the hard layer. First
As shown in Fig. 14, after the excavation is completed, the stirring pump 11
Is inserted into the lower end of the hollow portion of the hollow pile 51.

The stirring pump 11 may be attached to the tip of the rod 3 from which the excavation head 4 has been removed by the same method as described above, or may be hung separately with a wire or the like. As shown in FIG. 7, the stirring pump 11 has one or more multi-stage motors 17, 17 therein, a suction port 15 at the lower end, and a discharge port 16 at the upper end. The tip of the stirring pump 11 is a rotating body with a sharp shape, and a blade
Have 14. The blade 14 may be a blade, a claw, a stirring blade, or a screw as long as it can efficiently stir a mixture of concrete milk, air, water, and sand (hereinafter referred to as “fluid”). Stirring pump
The tip of 11 is rotationally driven to stir the earth and sand. The rotation drive may be performed by the motor 17, or the rod 3 may be driven by the above-mentioned drive device.
It may be rotated by 12, and the entire stirring pump 11 may be driven to rotate.

The agitation pump 11 sucks the fluid through the suction port 15 and discharges the fluid 16
It is a mechanism that circulates so that it is discharged more.

As shown in FIG. 8, the jack 10 is for fixing the stake 51, the cylinder 22 on the substrate 53, the hold chuck 19 at the center of the substrate 53, the plurality of anchor bolts 52 on the lower surface of the substrate 53, and the drive. The portion 54 has a piston 21 inserted into the cylinder 22 and a press-fit chuck 18 at the center of the drive portion 54.

The jack (10) is firmly fixed to the ground by the base machine (13) and the anchor bolts (52) so that it does not rise when the pile is pushed in.

Hold chuck 19 and rotary press-fit chuck 18 are
It has a mechanism that can be gripped at any outer peripheral position and tightened or loosened.

The piston 21 moves up and down in the cylinder 22 by hydraulic pressure.

Such a jack 10 has a hydraulic pressure gauge 20. The oil pressure gauge 20 measures and displays the oil pressure in the cylinder 22, and can measure the supporting force of the pile.

The pile driving method of the present invention is performed as follows using the pile driving machine described above.

As shown in FIG. 1, the driving device 12 of the pile driver is operated to rotate the rod 3 and the excavation head 4 attached to the tip of the rod 3 to excavate. The excavation head 4 descends as the excavation is carried out by the driving device 12 and the rod 3 due to the weight of the excavation head 4 while excavating the soil by the rotary motion. The rotation speed of the excavation head 4 may be appropriately determined according to various conditions such as hardness of the ground.

At this time, as shown in FIG. 2 and FIG.
While excavating the earth and sand by this rotary descending motion, concrete milk, air, and other necessary solids, liquids, and gases are moved from the openings 6a, 7a of the excavation head 4 to the excavation holes by the through holes 6, 7 in the rod 3. Gush out. The excavated soil is mixed with concrete milk and air to form a fluid, and the so-called N value of the soil layer becomes close to zero. Since this fluid is subjected to the rotating action of the excavation head 4 and various other pressures, it permeates into the soil from the side wall of the excavation hole. Then, the surroundings of the drill hole hardened over time, and as shown in Fig. 11, a layer of concrete milk and soil soaked in 3
It will be 2,33, and the ground around the pile will be strengthened, and the pile will be firmly supported and fixed. Depending on the soil to be excavated, fluid such as soil and concrete milk may or may not be easily absorbed. As shown in FIG. 11, in the excavated hole, there are a water layer 35, layers 36 and 37 filled with fluid such as earth and sand and concrete milk, and layers with many bubbles.

As shown in FIG. 11, since the excavated earth and sand are mixed with concrete milk and absorbed from the side wall of the excavation hole, it is substantially unnecessary to carry it out as waste soil or sludge. If the mixed water of soil and concrete milk is discharged from the drilling hole when the hollow pile is driven later, a pump provided separately will pump up this mixed water of soil and concrete milk and store it in the tank. , It can be used when excavating the next pile hole, and the water can be effectively used as a whole.

As the excavation progresses as shown in FIG.
When it reaches the upper part of, the through-hole 7 in the rod 3 injects a high concentration of concrete milk, forming a hard concrete support part 34 in the lower part of the drill hole, a so-called consolidation part.

When the drill hole is completed as shown in Fig. 13,
Hollow stake 51 fixed by jack 10 by raising rod 3 by base machine 13 and raising excavation head 4 to the ground.
Is installed on the top of the drill hole. As the hollow pile 51, a steel pipe, a concrete pile, or the like can be used as needed.

As shown in FIG. 14, normally, the excavation head 4 at the tip of the rod 3 is removed, the stirring pump 11 is attached instead, and this is inserted into the hollow portion of the pile to the lower end of the pile. The agitation pump 11 can be attached by another method such as hanging one end with a wire wound around a winch.

As shown in FIG. 7 and FIG. 14, this stirring pump 11
While stirring the fluid filled in the excavation hole with the blade 14 and sucking it through the suction port 15 as shown by the arrow, and discharging the discharge port 16
Eject more. At this time, since the tip of the agitation pump 11 is in a depressurized state, the hollow pile 51 descends in the excavation hole by this depressurized state and its own weight.

The operation of the stirring pump 11 can be appropriately performed according to the lowered state of the pile 51. At this time, when dirty water is discharged from the upper part of the excavation hole as the pile descends, it is also possible to pump up with a separately provided pump. Furthermore, this wastewater can be stored in a tank and used again for excavation.

The pile 51 has an appropriate diameter and length according to the purpose of driving. However, it is usually used by connecting a plurality of lines.

The method of connecting the piles is as shown in FIG. 8, in which the piles that are already in the ground are fixed with the hold chuck 19 of the jack 10, and the piles that are to be inserted into the ground are fixed with the rotary press-fitting chuck 18, The pile joint portion 57 is joined by welding or the like.

The jack 10 is firmly fixed to the ground by the anchor bolts 52 and the base machine so as not to float when the pile is press-fitted.

As shown in FIG. 15, the pile 51 gradually becomes difficult to descend due to an increase in frictional force received on the pile surface and an increase in buoyancy received from the fluid filled in the drill hole and the hollow portion of the pile. . Therefore, in that case, as shown in FIG.
The 10 can be used to press down a pile into a drill hole.

That is, as shown in FIG.
Raise the piston 21 of 10 to the top and pile it with the press-fit chuck 18.
Hold 51. At this time, holdcha 19 is loose. Then, the rotary press-fitting chuck 18 grips the pile, and the piston 21 is lowered to press the pile downward. After the piston 21 reaches the top and stops, hold the pile by the hold chuck 19 and loosen the press-fit chuck 18,
Raise the piston 21 to the top again. Such steps are sequentially repeated, and press-fitting is performed until the lower end of the pile reaches the support layer 38.

At this time, since the jack 10 has the oil pressure gauge 20, the pressure of press fitting can be measured. When the lower end of the pile 51 reaches the support layer 38, the press-fitting pressure of the pile rises, and the pressure at this time is the hydraulic pressure gauge 20.
Shown in. Thus, the pressure at which the pile is fixed to the support layer is measured. By doing so, the final pile bearing capacity can be measured. Therefore, after pile driving, it is not necessary to measure the pile supporting force by a load test or the like as in the conventional case.

<Effects of the Invention> The present invention is capable of pouring concrete milk or the like into an excavation hole and agitating it with the earth and sand excavated while rotating the excavation head to excavate the land. Can be immersed in the soil from the inner wall of the excavation hole, so that the inner and outer walls of the excavation hole can be solidified, and excavation can be performed deep with a uniform diameter.

Further, it is not necessary to substantially carry out the excavated earth and sand to the outside of the excavation hole as waste soil or sludge, excavation can be performed efficiently at low cost, and pollution problems do not occur. Unlike the screw construction method, it is not necessary to replace the screw that is clogged with waste soil during excavation, so it can be excavated in a very short time, and the piled concrete is fully completed before the solidification of the concrete is completed. be able to.

Moreover, after the drilling hole reaches the support layer, it can be used as the support part of the pile by driving in concrete with a high concentration, and the water in the drilling hole is sucked by the suction pump to reduce the pressure of the drilling hole and drive the pile. As the pile is inserted, the pile can be driven smoothly and easily.

In addition, unlike the on-site pile construction method, since it is a cast-in-place construction method, standard concrete piles can be used, and the driven piles do not have the strength mixed with earth and sand, and the shape is uneven. There is no chance of becoming.

Further, since a means for press-fitting the pile with a jack is also provided, even if it is difficult to drive the pile by the usual method, the pile can be easily driven. Since the pressure during press-fitting is displayed by a hydraulic gauge, it is no longer necessary to measure the pile supporting force after pile driving by a load test, etc. as in the conventional case, and avoiding such complicated labor and cost for pile driving. Savings can be achieved.

As described above, the piles are piled using standard piles manufactured in the factory without constructing the piles on the site, the amount of waste soil is very small, and there is no need to replace screws, etc. Pile driving can be performed even in a narrower area than the driving method.

[Brief description of drawings]

FIG. 1 is a side view showing the appearance of a pile driver used in the pile driving method of the present invention. FIG. 2 is a sectional view of a rod of a pile driver used in the pile driving method of the present invention. FIG. 3 is a sectional view of an excavating head of a pile driver used in the pile driving method of the present invention. FIG. 4 is a side view of a drive unit used in the pile driving method of the present invention. FIG. 5 is a cross-sectional view showing a low-speed side reducer and a chuck of a drive unit used in the pile driving method of the present invention. FIG. 6 is a cross-sectional view showing the relationship between the low-speed side speed reducer and the rod of the drive unit used in the pile driving method of the present invention. FIG. 7 is a side view of the stirring pump used in the pile driving method of the present invention. FIG. 8 is a side view of the jack used in the pile driving method of the present invention. FIG. 9 is a side view showing the appearance of a conventional pile driver. FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15 and FIG. 15 are schematic diagrams showing a pile driving method according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Leader, 2 ... Stay, 3 ... Rod, 4 ... Drilling head, 5 ... Screw, 6,7 ... Through hole, 6a, 7a ... Opening, 8 ... Chuck, 9 ... Claw, 10 ... Jack, 11 … Agitation pump, 12… Drive device, 13… Base machine, 14… Blade, 15… Suction port, 16… Discharge port, 17… Motor, 18… Press chuck, 19… Hold chuck, 20… Hydraulic gauge, 21… Piston , 22,23 ... Cylinder, 24 ... Chuck, 25 ... Motor, 26 ... High speed side reducer, 27 ... Low speed side reducer, 28 ... Drive device, 29 ... Rod through hole, 30 ... Head through hole, 31 ... Pin, 32… Soil layer, 33… Concrete milk soaked soil layer, 34… Support portion, 35… Water, 36,37… Soil / water / air / concrete milk mixture, 38… Support layer, 39… No. 1 wedge, 40 ... Guide, 41 ... 2nd wedge, 42 ... Torque tube, 43 ... Lot guide, 44 ... Nectar, 45, 46, 47 ... Gear, 48 ... Cylinder rod, 50 ... Cylinder, 51 ... Hollow pile, 52 ... Anchor bolt, 53 ... Substrate, 54 ... Drive part, 55 ... Bearing, 56 ... Stirring claw, 57 ... Joining Department

Claims (1)

[Claims] 1. A base machine, a leader supported by a stay on the base machine, a drive unit slidably mounted in the longitudinal direction of the leader, and a rotary drive by the drive unit, and the drive unit. A method for forming a pile in the field using a rod to be inserted, a drilling head detachably attached to the tip of this rod, and a pile driver having a hollow pile pushing tool, which comprises rotating the drilling head. At the same time as excavating the soil layer by driving, concrete milk and air are supplied to the excavating head through the rod, and the concrete milk and air are ejected from the hole provided in the excavating head into the excavating hole. Along with the rotation of the excavation head, concrete milk and air and the sand excavated by the excavation head are stirred and mixed into a fluidized product, A step of sinking the excavating head with fluidization to perform excavation in sequence, and after the excavating head reaches the support layer, concrete milk with high concrete concentration through the holes of the excavating head from inside the rod. To form a support portion of the pile by injecting into the upper portion of the support layer, a hollow pile is put in the excavation hole, a stirring pump is inserted from the hollow portion of the hollow pile to the lower end of the hollow pile, and this stirring pump is used. Only the lower end of the hollow pile is decompressed by the circulation of sucking the fluidized product below the lower end of the hollow pile at the tip and discharging the fluidized liquid from the rear end of the stirring pump into the inside of the hollow pile. And a step of sinking the hollow pile so as to gradually reach the support layer as a state, and the hollow pile lower end portion reaches the support layer and press-fixes the hollow pile by hydraulic pressure of the pushing tool, Pile construction method, characterized in that a step of hydraulically meter closet tool to measure the closet pressure measuring a pile bearing capacity.