JPS62170614A - Construction work of steel pipe pile - Google Patents

Abstract

PURPOSE:To make the penetration of a steel pipe pile easier by a method in which a reinforcing band is fixed to the periphery of the lower end of a steel pipe pile and a projected band is also fixed and a foot-protecting bulb consisting of a filled portion and an expanded spherical portion is formed inside of the lower end of the pile. CONSTITUTION:A reinforcing band 2 is fixed to the periphery of the lower end of a steel pipe pile 1 and a band 3 projected downwards from the pile 1 and the band 2 is also fixed to the periphery of the band 2. The steel pipe pile 4 with the double bands 2 and 3 is penetrated under pressure into the ground until the bearing stratum 6 is reached, and a hardening material is injected into near the lower end of the pile 4 to form a footing-protecting bulb 9 consisting of a filled portion 7 and an expanded bulb portion 8 positioned on the lower part of the pile 4 inside of the lower end of the pile 1. Great load can thus be transmitted from the pile 1 to the bulb portion 8.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention enables construction of steel pipe piles with low noise and low vibration, and also enables construction of long and large diameter steel pipe piles without disturbing the ground around the piles. This invention relates to a method of constructing steel pipe piles that makes it possible to reliably and firmly support the steel pipe piles by spraying a hardening material such as cement milk at high pressure onto the bottom edge of the desk.

[Prior art]

In recent years, when constructing piles, in order to deal with pollution problems such as noise and vibration, the conventional driving methods that utilize striking force such as diesel hammers and hammers are no longer used, and the method of driving piles using the impact force of diesel hammers and hammers is no longer used. Embedded construction methods such as sailing construction methods are the mainstream.

In the medium mb construction method, an auger screw is inserted into the pile, and the pile is press-fitted with a hydraulic jack while excavating the earth and sand at the tip of the pile. When the pile reaches a specified depth, mortar is poured into the bottom edge of the pile. This is a known method of supporting piles.

However, with this method, when the piles are long or when the piles are constructed on hard ground, the frictional force around the pile becomes too strong. There are drawbacks that make it impossible. In addition, when supporting a pile by injecting mortar into the lower end of the pile, if the pile is thick like an existing concrete pile, the pile will simply rest on the bulb made of mortar, which will support the pile. Since the pressure area is large, the bearing capacity is sufficiently exerted, but there is a drawback that the sufficient bearing capacity is not exerted with thin walled piles such as steel pipe piles.

Conventionally, when a steel pipe pile is penetrated into the ground by a large impact force such as a diesel hammer, steel reinforcement is provided around the lower end of the steel pipe pile 1 as shown in Fig. 9 in order to prevent local buckling at one end of the underside of the desk. ,? The throat 2 is fixed by welding, but when this steel pipe pile 10 with a reinforcing band is used for the hollow construction method, the lower edge of the reinforcing band 2 is located above the lower edge of the steel pipe pile 1, so the pile The surrounding earth and sand 11 does not enter the steel pipe pile 1 and is consolidated by the reinforcing band 2, which increases the friction force on the pile circumferential surface and prevents the pile from penetrating. It is inappropriate to use this method for hollow construction of long steel pipe piles.

Furthermore, even if a small-diameter or short-length steel pipe pile 10 with a reinforcing band can be penetrated, as shown in FIG. When the load P from the steel pipe pile acts on the enlarged bulb 8 at 9, the adhesion force between the inner surface 12 of the steel pipe pile 1 and the filling part 7 made of a hardenable material filled in the steel pipe pile is small. Most of the load P is transmitted to the enlarged bulb 8 from the lower end section of the pile. As a result, the shoulder portion of the enlarged bulb 8 is gradually lost due to the bearing force of the cross section of the steel pipe pile, resulting in a disadvantage that the pile lower end bearing capacity is not exerted.

In addition, in order to improve this drawback, steel pipe piles for the hollow construction method [
As shown in FIG.
It is known that the steel pipe pile is designed to guide the steel pipe pile 1 into the steel pipe pile 1, and when this steel pipe pile for hollow digging is used, the pile penetration becomes easy. However, as shown in Figure 12', when a hardening material is injected near the bottom end of the pile to create a hardening bulb 9''f, the wall thickness t of the steel pipe pile 1 is thin, so the expansion is similar to the case in Figure 10. The shoulder of the bulb 8 is missing, and the lower end of the steel pipe pile cannot support it.This problem can be solved by making the wall thickness of the steel pipe pile thicker like the wall thickness of the concrete pile. In order to increase the thickness, it is necessary to increase the wall thickness over the entire length of the steel pipe pile, which is extremely uneconomical.

As a means of increasing the wall thickness at the tip of the steel pipe pile, it is possible to increase the thickness of the reinforcing band 2″f as shown in FIG. P is mainly transmitted through the cross section of the reinforcing band 2, and this bearing force 13 inevitably causes the shoulder of the enlarged bulb 8 to be missing, so the drawback that the pile lower end support force is not exerted cannot be resolved.

Conventionally, as shown in FIG. 14, after the steel pipe pile 10'f with a reinforcing band is deposited on the support skin 6, the lower end of the steel pipe pile 10 with a reinforcing band is lowered while rotating an excavator 5 consisting of an auger screw. The ground below is excavated, and then, as shown in Fig. 15, cement milk is injected near the bottom end of the pile, and the excavator 5 is rotated and gradually ascended, and the excavator 5 is filled with cement milk. The hardening bulbs 14 are created by forcibly stirring and mixing with the ground soil, but in this case, it is difficult to create expanded bulbs that are larger than the pile diameter, and the inner periphery of the lower end of the pile is difficult to create. Since the earth and sand 15 remain, the frictional force between the foot hardening bulb 14 and the inner circumferential surface of the lower end of the pile is not exerted, so there is a problem that a large support force at the lower end of the pile cannot be obtained.

[Purpose and structure of the invention]

This invention advantageously resolves these gaps, facilitates the construction of long or large-diameter steel pipe piles, and the construction of steel pipe piles on hard ground, and provides a large supporting capacity at the lower end of the pile. The purpose of the present invention is to provide a method for constructing a hollow-type steel pipe pile, which enables the construction of a steel pipe pile. A steel pipe pile 4 with a double band is constructed by fixing a steel pipe pile 1 and a protruding nozzle 3 projecting downward from the reinforcing band 2 to the outer periphery of the reinforcing band 2, and is inserted into the steel pipe pile 4 with a double band. The double-banded steel pipe pile 4 is press-fitted into the ground while excavating the ground with the excavator 5, and the lower end of the double-banded steel pipe pile 4 is sunk to the supporting ground 6. A liquid hardenable material such as cement milk is injected into the vicinity of the lower end of the steel pipe pile 1, and the hardenable material and the local soil are stirred and mixed to form the filling part 7 filled inside the lower end of the steel pipe pile 1. This steel pipe pile construction method is characterized in that a hardening bulb 9 consisting of an enlarged bulb 8 located at the lower part of a double banded steel pipe pile 4 is created.

be.

〔Example〕

Next, the present invention will be explained in detail using illustrated examples.

FIG. 7 shows an example of a double-banded steel pipe pile 4 used in the present invention, in which a steel reinforcing band 2 is fitted to the outer periphery of the lower end of the steel pipe pile 1. A steel protrusion/tandem 3 is fitted to the outer periphery, and the lower edge of the reinforcing band 2 is arranged slightly above the lower edge of the steel pipe pile 1.
The steel pipe pile 1, the reinforcing band 2, and the protruding band 3 are fixed to each other by welding.

When carrying out this invention using the double banded steel pipe pile 4 shown in FIG. 7, first, as shown in FIG. An excavator 5 is inserted, and while the excavator 5 excavates the ground f below the steel pipe pile 4 with a double band, the steel pipe pile 4 with a double band is press-fitted. When the excavator 5 excavates inside the double-banded steel pipe pile 4 in this way, the earth and sand 11 around the pile tend to be guided inside the lower end of the steel pipe pile 1. It is possible to reduce the friction force on the pile circumferential surface and to promote soil removal. Therefore, it is possible to easily press-fit long or large-diameter steel pipe piles, which have been difficult to perform in the past, and to press-fit steel pipe piles into hard ground.

As shown in FIG. 2, after the lower end of the double banded steel pipe pile 4 is sunk to the support layer 6,
As shown in FIG. It is placed about 1.5 times the pile diameter below the lower end of the pile 4, and then a liquid hardening material such as cement milk is applied.
A high pressure of about 200 to 240'C9/crn2 is supplied from the upper part of the injection nozzle 16, and the injection is injected horizontally from a nozzle 17 provided on the side of the lower end of the injection nozzle 16. For A Eve 16'! r The hardening material and the ground soil are stirred and mixed by gradually pulling up while rotating, creating an enlarged bulb 8 at the lower end of the pile, and then, while injecting the hardening material from the nozzle 17, By rotating and raising the inside of the steel pipe pile 1 as shown in Fig. 1, the inside of the steel pipe pile 1 is cleaned by the hardenable material sprayed, and the hardenable material and local soil are also washed inside the steel pipe pile 1. By stirring and mixing the
and the steel pipe pile 1 are integrated.

Note that the excavator 5 does not use the injection nozzle 16.
When pulling out, the liquid hardening material may be injected from a nozzle provided at the tip of the hollow shaft of the excavator to create a hardening bulb 9 consisting of the filling part 7 and the enlarged bulb 8. .

When the hardening bulb 9 consisting of the filling part 7 and the enlarged bulb 8 is created as described above, the lower end of the steel pipe pile 1 and the lower end of the reinforcing band 2 are integrated into a large support, as shown in FIG. The enlarged bulb 8 transmits the load P to the enlarged bulb 8 through the pressure area and attempts to eliminate the shoulder part of the enlarged bulb 8 generated by the bearing force of the lower end of the steel pipe pile 1 and the lower end of the reinforcing band 2.
The outwardly moving fully protruding band 3 on the upper part of the steel pipe pile 4 restrains the expanded bulb 8f, and the lower end of the double-banded steel pipe pile 4 brings the expanded bulb 8f into a triaxial consolidation state as shown in FIG.
A large load can be transmitted to the pile, and therefore a large pile bottom end supporting force can be exerted.

FIG. 8 shows another example of the double-banded steel pipe pile 4 used in the present invention, in which the lower edge of the reinforcing band 2 is arranged below the lower edge of the steel pipe pile 1, and the protruding band The lower end portion of the reinforcing band 3 is projected downward from the lower edge of the reinforcing band 2, but the other structure is the same as that shown in FIG.

FIG. 16 shows another example of the shape of the protruding band, in which the protruding band 3 expands in a ratchet shape as it deviates downward from the reinforcing band 2. By expanding the protruding band 3 in a ratcheted manner in this manner, the frictional resistance between the pile and the ground can be reduced, and the ease of press-fitting the pile can be significantly improved.

The reinforcing band 2 in this invention increases the area of use of the pile and also serves as a non-slip member.
Although an appropriate thickness is required, the height of the reinforcing band 2 may be small. Furthermore, regardless of whether the lower end level of the reinforcing band 2 is above or below the lower end level of the steel pipe pile 1,
There is no particular problem since the liquid hardenable material is injected at high pressure, but if the lower end level of the reinforcing band 2 is placed above the lower end level of the steel pipe pile 1, the reinforcing band 2 should be fixed to the steel pipe pile 1. The actual welding range is limited.

Furthermore, the material constituting the protruding band 6 and L7 are as follows:
High strength materials other than steel may also be used.

stomach.

The protruding band 3 serves to guide earth and sand around the pile into the steel pipe pile 1 and to bring the enlarged bulb 8 into a triaxially consolidated state.Moreover, in the case of the hollow excavation method, the pile is statically press-fitted. Therefore, the thickness of the protruding band B may be thin. If the thickness of the protruding band 3 is made thinner, the amount of steel used can be reduced, which is economical.

〔Effect of the invention〕

According to this invention, the reinforcing band 2 is fixed to the outer periphery of the lower end of the steel pipe pile 1, and the protruding band 3 that protrudes below the steel pipe pile 1 and the reinforcing band 2 is fixed to the outer periphery of the reinforcing throat 2. The double-banded steel pipe pile 4 is constructed by using the double-banded steel pipe pile 4, and the double-banded steel pipe pile 4 is press-fitted into the ground while excavating the ground with the excavator 5 inserted into the double-banded steel pipe pile 4. , the protruding band 3 removes the earth and sand around the pile from the steel pipe pile 1.
The soil around the pile 11 can be guided inside the lower end of the pile.
It is possible to prevent consolidation and reduce the friction force on the pile circumference, making it easy to press-in long or large-diameter steel pipe piles and to press-fit steel pipe piles into hard ground.
Furthermore, after lowering the lower end of the double-banded steel pipe pile 4 to the supporting ground 6, a liquid hardening material such as cement milk is injected near the lower end of the double-banded steel pipe pile 4,
The hardenable material and the ground soil are stirred and mixed to form a root consisting of a filling part 7 filled inside the lower end of the steel pipe pile 1 and an enlarged bulb 8 located in a part of the double banded steel pipe pile 4. Since the hardened bulb 9 is created, the lower end of the steel pipe pile 1 and the lower end of the reinforcing band 2 work together to transmit the pile load to the filling part 7 with a large bearing pressure area, and the protruding band 6 is connected to the lower end of the steel pipe pile 1. The relative lateral movement of the lower end of the reinforcing band 2 and the filling part 7 is restrained, and the filling part 7 is triaxially moved between the lower end surfaces of the steel pipe pile 1 and the reinforcing band 2 and the inner surface of the protruding part of the protruding band 3. This makes it possible to transfer a large load from the steel pipe pile 1 to the enlarged bulb 8. Furthermore, since the inner circumferential surface of the steel pipe pile 1 is cleaned by spraying liquid hardenable material, the filling part 7 It is possible to increase the adhesion force between the steel pipe pile 1 and the steel pipe pile 1, and therefore, it is possible to obtain effects such as being able to exhibit a large pile lower end supporting force.

[Brief explanation of drawings]

Figures 1 to 7 show one embodiment of the present invention, in which Figure 1 is a vertical cross-sectional side view showing a double banded steel pipe pile being press-fitted without being dug in the middle, The figure is a vertical side view showing a double banded steel pipe pile that has been sunk in the support layer. Figure 6 shows the injection of hardenable material by inserting an injection molding tube into the double banded steel pipe pile and the ground below it. Fig. 4 is a longitudinal side view showing the condition in which the hardenable material has been injected to the lower end of the steel pipe pile, and Fig. 5 is a longitudinal side view showing the state in which the hardenable material has been injected to the lower end of the steel pipe pile with double bands. Figure 6 is a vertical side view showing a state in which hardened bulbs have been created, Figure 6 is a vertical side view showing an enlarged view of the lower part of Figure 5, and Figure 7 is a vertical side view showing an example of a steel pipe pile with double bands. be. FIG. 8 is a longitudinal sectional side view showing another example of a steel pipe pile with double bands. Figures 9 to 15 show conventional examples, in which Figure 9 is a longitudinal cross-sectional side view showing the flow of earth and sand around the pile when a steel pipe pile with reinforcement bands is press-fitted, and Figure 10 is an Mt with reinforcement bands. Figure 11 is a longitudinal side view showing the condition in which a foot protection bulb is created at the lower end of the pile.
Figures 12 and 13 are longitudinal side views showing a steel pipe pile with a protruding reinforcing band, with a hardening bulb created at the tip, and Figure 14 is a steel pipe pile with a reinforcing band that is dug in the middle using an auger screw. FIG. 15 is a longitudinal side view showing a state in which a hardening material and field soil are stirred and mixed by an auger screw to form a hardened bulb. FIG. 16 shows another double-banded protruding band that can be used when carrying out the method of the present invention, 4 a double-banded steel pipe pile, 5 an excavator, 6 a supporting ground, and 7 a filling. Part 8 is an enlarged bulb,
9 is a root hardening bulb, 16 is a tube for injection, and 17 is a nozzle. Chest 10 Figure 9

Claims (1)

[Claims] A reinforcing band 2 is fixed to the outer periphery of the lower end of the steel pipe pile 1, and a protruding band 3 that protrudes below the steel pipe pile 1 and the reinforcing band 2 is fixed to the outer periphery of the reinforcing band 2, thereby forming a double-banded steel pipe pile 4. The double-banded steel pipe pile 4 is press-fitted into the ground while excavating the ground with the excavator 5 inserted into the double-banded steel pipe pile 4, and the lower end of the double-banded steel pipe pile 4 is supported. After the steel pipe pile has been sunk down to the ground level 6, a liquid hardenable material such as cement milk is injected near the lower end of the double banded steel pipe pile 4, and the hardenable material and the local soil are stirred and mixed to form the steel pipe pile. This steel pipe pile construction method is characterized by creating a foot hardening bulb 9 consisting of a filling part 7 filled inside the lower end of the steel pipe pile 1 and an enlarged bulb 8 located at the lower part of the double banded steel pipe pile 4.