JP2001073369A - Press-in erection method for piles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the friction force of a pile peripheral face by cement milk to press piles in by pressing the pile into ground while the cement milk is jetted from the edge part of the pile. SOLUTION: The pile 12 is pressed in ground while the cement milk 1 is jetted from the tip part of the pile 12. Blending of the using cement milk preferably uses the water and cement ratio of 60-150% in the weight ratio of water and cement. Thus, the peripheral ground of the piles is disturbed as well as a conventional water jet by utilizing the flowing time band of the cement milk 1, and the pile 12 can be pressed-in in a state where the friction force of the pile peripheral face is reduced. Since the piles need not be large-sized or it need not deal with the increase of the number of the piles, the piles can be economically pressed in and erected in a single process in pile foundation comparatively large in support force by the comparatively small-sized piles without increasing the construction cost of the pile foundation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piles such as steel pipe piles, concrete piles, concrete sheet piles, steel sheet piles, composite piles of concrete and steel pipes, H-shaped steel members with steel claws (steel continuous wall members) or composite steel sheet piles. Press-fitting construction methods.

[0002]

2. Description of the Related Art Conventionally, in the construction of piles, steel pipe sheet piles and the like (hereinafter referred to as piles or simply piles) in an urban area, an auger screw is inserted into the piles due to noise and vibration problems. Therefore, the inside digging method, in which the soil inside the pile is excavated while being constructed, has been generally used. However, in the middle digging method, the construction machine becomes large-sized, and it becomes impossible to perform the construction in a place where the sky is restricted or under a narrow place, such as under an overpass or under a transmission line. In recent years, as a method of constructing piles in such a place, the number of cases of constructing by a press-fitting method has been increasing.

[0003] In the press-fitting method, the reaction force of the piles to be press-fitted is taken by the peripheral frictional force and the counterweight of the adjacent previously press-fitted piles. It becomes possible.

As a countermeasure, a method has been generally adopted in which a water jet is used as an auxiliary method together with the press-fitting method to reduce the frictional force on the peripheral surface of the pile and facilitate the press-fitting of the piles. The method of using this water jet as an auxiliary method to disturb the ground around the pile and reduce the frictional force around the pile to facilitate the press-fitting of piles makes pile construction easier. Because the surrounding ground is disturbed,
The vertical bearing capacity of the pile will be greatly reduced. For this reason, this press-in method is often used for the construction of piles for revetments and temporary retaining walls where the vertical bearing capacity of the piles is not an issue.

[0005] The application of the method of using a water jet as an auxiliary method to reduce the frictional force on the peripheral surface of a pile to facilitate the press-fitting of piles to a pile foundation requiring a vertical supporting force has been reduced. It is necessary to respond to the frictional force of the pile peripheral surface by increasing the diameter of the pile or increasing the number of piles, and such measures increase the cost of the pile foundation and make the pile foundation extremely uneconomical.

Conventionally, as a countermeasure, a method of injecting a chemical solution for strengthening the surrounding ground is generally known. After the pile is constructed, cement milk or the like is injected near the periphery of the pile using a boring machine or the like. A method of solidifying the ground is used, but this method requires several injections per pile, which requires a long time for injection work, requires new injection equipment, and is expensive. There are disadvantages such as becoming.

[0007]

There are drawbacks in both the press-fitting method combined with water jet, which is the most improved conventional press-fitting method, and the chemical injection method. As described above, in the press-in method, there is a problem that the vertical bearing capacity of the pile is significantly reduced due to the disturbance of the ground by the water jet around the pile.In the press-in method, the chemical injection equipment is installed separately from the pile press-in machine. It becomes necessary, and the construction time is prolonged and the construction cost is increased.

The present inventor has conducted various studies to improve the above-mentioned disadvantages of the conventional press-in method, and as a result, focused on both the liquid fluidity and the time-hardening property of cement milk, and applied this to the jet press-in method. We have found that incorporating them is effective. The present invention belongs to the series of the press-fitting method described above, and effectively utilizes the advantages thereof and solves the disadvantages.

That is, the present invention relates to a steel pipe pile, a concrete pile, a concrete sheet pile, a steel sheet pile, a composite pile of concrete and a steel pipe, and an H-shaped steel with claws shown in FIGS. Or synthetic steel sheet pile (hereinafter collectively referred to as
When simply pressing piles or simply piles) into the ground, replace the water jet of the construction method that had been press-fitted with the conventional water jet to a cement milk jet, and use the time zone of the flowing state of cement milk. The surrounding soil of the piles is disturbed in the same way as a water jet, and the frictional force around the piles is reduced by cement milk to facilitate the injection of the piles. It is an object of the present invention to provide a method of constructing a foundation pile capable of hardening and recovering the ground to a strength equal to or higher than the original ground strength by a hardening action and expressing a peripheral friction force greater than that of a conventional driving pile.

[0010]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is characterized in that the pile is pressed into the ground while the cement milk is injected from the tip of the pile. And

Further, in the method for press-fitting piles according to claim 2, while injecting cement milk from the tip of the pile,
After the pile is pressed into the ground, the cement milk is hardened.

Further, in the method for press-fitting piles according to claim 3, a cement milk jet is jetted from the tip of the pile, and the ground around the pile is disturbed by utilizing the time zone of the flowing state of the cement milk. The pile is pressed into the pile by reducing the peripheral friction force, and after the pile is injected, the hardening effect of cement milk over time allows the ground to harden and recover to the original ground strength or more, and the pile peripheral friction exceeds the driving pile It is characterized by expressing force.

According to a fourth aspect of the present invention, there is provided a method for press-fitting piles according to the first to fourth aspects, wherein the water-to-cement ratio (W / C) of the cement milk is 60% to 150%. And

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. The construction method of the present invention includes a steel pipe pile, a concrete pile, a concrete sheet pile, a steel pipe sheet pile, a composite pile of concrete and a steel pipe, and FIG. 6 (a) or (b).
In either case of the H-shaped steel with claws (steel continuous wall member) 25 or the synthetic steel sheet pile (hereinafter collectively referred to simply as piles or simply piles) shown in FIG. In the following embodiments, an example of construction of a steel pipe sheet pile will be described. FIG. 1 is a diagram showing an example of the construction of a steel sheet pile as an equipment configuration when the present invention is implemented.
And FIG. 3 is a schematic cross-sectional view showing the press-fitting construction process of the piles in the order of processes, FIG. 4 is a diagram showing a range A disturbed by the cement milk jet 11 and a range A where the cement milk is hardened, and FIG. FIG. 3 is a view showing a piping method of a high-pressure hose 8 and a jet nozzle 9 for use. In the drawing, reference numeral 24 denotes a high-pressure hose feeding and winding reel.

First, the equipment configuration used for the cement milk jet combined press-fitting method and its role are as follows. That is, as shown in FIG.
2 having a discharge opening / closing valve (not shown) for kneading the mixture, a cement silo 3 and a cement meter 4 for supplying cement to the mixer 2, and a water tank 5 for supplying water to the mixer 2 The cement milk 1 kneaded by the mixer 2 is supplied to the hopper 6, and is sucked from the suction pipe (suction hose) 18 connected to the outlet thereof to the suction port 7a of the high-pressure pump 7,
High pressure hose 8a for pressure feed from discharge port 7b of high pressure pump 7
Pile 12 such as a steel pipe pile or a steel pipe sheet pile is sent to the cement milk supply high pressure hose 8 via the distribution valve 8b.
A jet nozzle 9 attached to the tip of a vertical pipe 19 for cement milk supply fixed and arranged along the axial outer surface of
Alternatively, a cement milk jet 11 is jetted onto the ground 10 from a jet nozzle 9 attached to the tip of the high pressure hose 8 for supplying cement milk. The jet direction from the jet nozzle 9 is laterally jetted outward from the downward state.

As shown in FIGS. 2 (a) to 2 (c) and FIGS. 3 (a) and 3 (b), a known press-fitting machine 13 is installed at a place where a pile 12 such as a steel pipe pile or a steel pipe sheet pile is constructed. The pile 12 such as the existing steel pipe pile 12a is installed so as to take a reaction force (see FIG. 2A), and the main body of the pile 12 is built into the chuck 14 of the press-fitting machine 13 (see FIG. 2B). The body of the pile 12 is gripped. Next, a high-pressure hose 8 for cement milk supply or a vertical pipe 19 for cement milk supply and a jet nozzle 9 attached to the tip thereof.
Is mounted so that the jet nozzle 9 is located at the pile tip 15. The cement milk supply high-pressure hose 8 and the jet nozzle 9 may be detachably mounted on the pile 12 in advance and built into the press-fitting machine 13.

Next, the press-fitting machine 13 provided with the press-fitting jack 25 is operated to sequentially press-fit the piles 12. When the tip 15 of the pile starts to penetrate into the soil, the cement milk 1 kneaded by the mixer 2 is passed through the high-pressure pump 7 to 2 to 25 N /
mm ² , preferably ^{2 to 5} N / mm ² , and jetted into the soil from a jet nozzle 9 attached to the tip 15 of the pile (see FIG. 2C). While continuing to press-fit the pile 12. Joint pile 1
If 2b is required, the piles are sequentially fixed in series by welding or the like and added together, and the cement milk jet combined press-fitting is continuously performed, and the piles 12 are press-fitted to a predetermined depth.

When the cement milk 1 is injected, the pressure of the high-pressure pump 7 is 2 N / mm ^{2 to} 25 N / m.
It is pumped at a pressure of about m ² and injected at high pressure from the injection nozzle 9 at the tip of the pile. The injection pressure in this case is 2.8 nozzle diameter.
If the injection amount is 60 liters / min or more at a pressure of ² mm to 3.0 mm, the cement milk 1 can be injected at a high pressure from the nozzle 9 at an injection pressure of about ² N to 25 N / mm ² .

Here, the compounding of the cement milk 1 to be used is such that the water-to-cement ratio (W / C) is 60 to 150% by weight of water (W) and cement (C). preferable. For example, when a water-cement ratio (W / C) of 100% is used, the solidification strength of the cement milk 1 itself is 5%.
About N / mm ^{2 is} secured. In addition, water cement ratio (W /
Use of C) of 60% or less is not preferable because the viscosity of the cement milk 1 becomes high and it becomes difficult to pump the cement milk 1 and when the water-cement ratio (W / C) becomes 150% or more, It is not preferable because the strength of the ground is extremely reduced.

The cement amount of the cement milk 1 is preferably 150 kg to 600 kg per 1 m ³ of the hardening range soil amount in the hardening range A shown in FIG. For example, if about 300 kg is injected per 1 m ^{3, the} ground will have an original ground strength (usually a strength of 0.01 to 0.15 N / mm ² ).
Or it can be solidified to a strength of 1 N / mm ² or more, and a strength of the original ground or more can be secured. Since cement content of the cement milk 1 may become impossible to secure to the original ground strength drops below the curing range soil volume 1 m ³ per 150 Kg, undesirably, also the cement milk 1 cement weight curing range soil volume 1 m ³
If it exceeds 600 kg per unit, it is not preferable because the strength of the ground cannot be increased for the injection of the cement amount and the cost increases.

After the piles 12 have reached a predetermined depth (FIG. 3a)
), A high-pressure hose 8 for cement milk supply from a detachable locking tool (not shown) provided at the tip of the pile 12.
Is disengaged, the high-pressure hose 8 for cement milk supply is recovered (see FIG. 3B), and the mixer 2, the high-pressure pump 7, the high-pressure hose 8 for cement milk supply, and the like are washed to complete the pile construction. Complete. The curing time of the cement milk depends on the composition of the cement milk, but is usually fluidized for about 5 to 6 hours by adding a curing retarder moderately (about 3% by weight of cement). So
The work for driving the pile 12 may be completed within this time. The curing range A is, for example, as shown in FIG.
What is necessary is just to harden the range B of about 20 cm around the piles 12 (the steel pipe piles 12a having the diameter D).

As described above, in the present invention, since the cement milk jet 11 is used in the stage of pressing the piles 12 into the soil, both properties of the liquid fluidity and the aging property of the cement milk 1 are effectively combined. The combination of the two properties makes it possible to press the piles into the hard ground in the same manner as the conventional jet water, and also applicable to the construction of large diameter and long piles. When constructing a large-diameter / long pile, a cement milk supply annular pipe base 21 communicating with a lower end of a cement milk supply vertical pipe 19 as shown in FIG.
By using the jet nozzle 9 having a plurality of jet nozzle holes at equal angular intervals, the construction becomes easier. After the construction, the cement component in the cement milk 1, which is the point of the present invention, is hardened, so that a greater frictional force than the driving pile can be exerted, and a large bearing pile can be completed.

The present invention can be applied to any ground as long as piles can be driven by a hydraulic hammer or the like, and can be applied to other grounds. In this case, the hardened portion A shown in FIG. 4 becomes a strong solidified body, and becomes a composite pile 17 closely attached to the outer periphery of the piles. Since the composite pile 17 is a pile having an increased pile diameter, the pile peripheral area becomes large, and a pile having a larger supporting force can be formed.

In the case of the present invention, the area (membrane) of the cement milk 1 is interposed between the peripheral ground 16 and the peripheral surface of the piles while directly spraying the peripheral ground 16 by the cement milk jet 11.
And the disturbed surrounding ground 16
Is mixed with the cement milk 1 so that the cement milk 1 can be relatively uniformly filled in the surrounding ground 16, so that the surroundings of the piles 12 are strengthened to a uniform ground strength or more. Hardened cement milk range A
Can be built. Also, when filling and mixing a cement such as cement milk into the ground in a state where the surrounding ground has been disturbed by a water jet or the like, it is difficult to fill the pile uniformly over substantially the entire length in the longitudinal direction,
In the case of the present invention, the ground 16 around the pile can be more uniformly reinforced than in the conventional case.

In the case of the embodiment shown in FIG.
An annular pipe base 21 for supplying cement milk is arranged near the lower end of the piles 12 so as to fill it, but the present invention is not limited to this. 21 is arranged at the upper end of the pile, and after the lower pile is driven, the annular pipe base 21 is removed, and the upper pile is connected and connected to the lower pile. The annular pipe base 21 may be arranged near the upper end of the pile 12 at the upper end.

When the present invention is applied to a concrete pile 12 such as a concrete pile or a concrete sheet pile, or a composite pile 12 made of concrete and steel, a vertical pipe (pipe) 19 for supplying cement milk is used. The pipe may be buried so as to be buried in the main body, and the cement milk injection nozzle 9 may be buried in the tip portion 15 of the pile 12 similarly. Regarding the gripping mechanism of the existing piles 12a and the gripping mechanism of the new piles to be mounted on the pile press-in machine 13, a known crimping gripping means for pressing and gripping from the outside of the pile or pressing from the inside of the pile. A known pressing and holding means for holding can be appropriately adopted.

In practicing the present invention, the cement milk supply vertical pipe 19 may be provided so as to be fixed to the inner peripheral surface of the pile 12, or embedded in the cross section of the main body of the pile 12. It may be arranged. In addition, the jet nozzle 9 may be similarly disposed so as to be embedded in the cross section of the main body of the pile 12.

[0028]

According to the method for press-fitting piles of the present invention,
The following effects can be obtained by the effective combination of the properties of the liquid fluidity and the aging properties of the cement milk and the jet spraying. According to the invention of claim 1, since the pile is pressed into the ground while the cement milk is injected from the tip of the pile, the surrounding ground of the piles is made the same as the conventional water jet using the flow time of the cement milk. And the pile can be pressed in with the pile peripheral frictional force reduced. In addition, the cement milk that disturbed the ground can harden and harden the ground around the pile via this cement milk, and the large diameter of the piles can be compared to the conventional case where a water jet is used for relatively low-strength ground. It is not necessary to cope with the increase in the number of piles or the number of piles, so a pile foundation with a relatively large bearing capacity using relatively small piles is economical in a single process without increasing the pile foundation construction cost. The piles can be press-fitted into the building.

According to the second aspect of the present invention, the cement milk is hardened after the pile is pressed into the ground while spraying the cement milk from the tip of the pile. After the milk is hardened, the hardened part around the pile becomes a relatively solidified body, and the hardened body is brought into close contact with the outer periphery of the pile to form a synthetic pile in a state in which the peripheral frictional force is recovered. Therefore, the supporting force and rigidity of the pile can be increased.

According to the third aspect of the present invention, a cement milk jet is jetted from the tip of the pile, and the ground around the pile is disturbed by utilizing the time zone of the flowing state of the cement milk.
The pile friction is reduced and the piles are pressed in, and after the pile is injected, the hardening effect of cement milk over time allows the ground to harden and recover to the original ground strength or more, and the pile friction is greater than the driving pile. The cement milk jet uses the flow time of cement milk to disturb the surrounding ground of the piles in the same way as a conventional water jet, and the piles are reduced in a state where the frictional force around the piles is reduced. After the cement milk is hardened, the hardened portion around the pile becomes a relatively hard solidified material that has hardened and recovered to the original ground strength or more. The piles can be made into a composite pile in a state where the piles are in close contact with each other and the peripheral frictional force is higher than that of the original ground, and the piles are recovered, so that the pile supporting force and rigidity can be dramatically increased.

According to the invention of claim 4, according to claim 1,
In the method for press-fitting piles according to any one of 2, 3, or 4, the water-to-cement ratio (W /
Since C) is 60% to 150%, the cement milk in a fluidized state can be easily pumped at a relatively high pressure, and after the cement milk has hardened, the normal ground strength around the pile (0. 1N / mm ² ) or more.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a state in which a steel pipe sheet pile wall is being constructed by using equipment for implementing a construction method according to an embodiment of the present invention.

2 (a) to 2 (c) are schematic cross-sectional construction views showing a press-fitting step of piles in a process order.

3 (a) and 3 (b) are schematic cross-sectional construction views showing a press-fitting step of piles in a process order.

FIG. 4 is a schematic explanatory view showing a range disturbed by a cement milk jet and a range where cement milk is hardened.

FIG. 5 is a schematic explanatory view showing a piping method of a high-pressure hose for supplying cement milk and a jet nozzle.

FIGS. 6A and 6B are a plan view and a perspective view showing a case where a plurality of H-shaped steel members with steel claws (steel continuous wall members) are engaged with each other to form a steel continuous wall.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cement milk 2 Mixer 3 Cement silo 4 Cement weigher 5 Water tank 6 Hopper 7 High pressure pump 8 High pressure hose for cement milk supply 8a High pressure hose for pressure feed 8b Distributing valve 9 Jet nozzle 10 Ground 11 Cement milk jet 12 Piles 12a Steel pipe pile 12b Joint pile 13 Press-fitting machine 14 Chuck 15 Pile tip 16 Pile surrounding ground 17 Synthetic pile 18 Suction pipe (Suction hose) 19 Vertical pipe for cement milk supply 20 Pipe joint of steel pipe sheet pile 21 Ring pipe base for cement milk supply 22 Hard ground ( Support layer) 24 Reel for high-pressure hose feeding and winding 25 H-shaped steel with claws (steel continuous wall member)

Claims (4)

[Claims] 1. A method for press-fitting piles, wherein the pile is press-fitted into the ground while cement milk is injected from the tip of the pile. 2. A method for press-fitting piles, wherein the cement milk is hardened after the pile is pressed into the ground while spraying the cement milk from the tip of the pile. 3. Injecting a cement milk jet from the tip of the pile, disturbing the ground around the piles using the time zone of the flowing state of the cement milk, reducing the frictional force of the pile peripheral surface, and A method of press-fitting piles, wherein the pile is pressed and the cement milk hardens and recovers to a level higher than the original ground strength with the lapse of time after the pile is pressed, and the pile surface frictional force is developed. 4. The water-cement ratio of said cement milk (W
The method for press-fitting piles according to any one of claims 1, 2, and 3, wherein (C) is 60% to 150%.