JPH01315522A - Piling body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an antibody for use as a foundation pile used in civil engineering and construction work, particularly as a friction pile.

(Prior art) Conventionally, for example, as shown in FIGS. 12 and 13,
As shown in Publication No. 123919, a large number of bags 8 are attached to a steel pipe 7 with a horizontal hole 9, and the steel pipe 7 is inserted into an underground hole excavated by a drilling machine.
A method has been proposed in which the hardened material is injected into the bag 8 through the side hole 9, thereby expanding and expanding the bag 8 underground to strengthen the railway ground. However, this method requires a large number of bags 8 along the entire length of the steel pipe 7.
Since this method is a method of attaching and expanding it, the ground 10 to which this method can be applied is limited to relatively uniform and soft ground made of embankment, and the hardening material that can be used is There are disadvantages such as being limited to cement milk with good fluidity, and in order to sufficiently support the upper load, it was necessary to construct a large number of these piles at intervals of about 1 meter pitch.

In other words, in the method described above in which a side hole is made in the wall of a steel pipe and a hardening material is injected into the bag through the hole, if ordinary cement mortar or concrete is used as the hardening material, the bag may not be fully formed, although the cause is unknown. Does not expand. For this reason, it was impossible to use cement mortar or concrete as a pouring material. Further, the above-mentioned method in which a large number of bags are used over almost the entire length of the steel pipe is not suitable for ground where there is a layer such as a gravel layer in which the bags are difficult to expand.

(Problems to be Solved by the Invention) An object of the present invention is to enable the bag to be buried in a cohesive soil layer even if there is a gravel layer or a sand layer underground, and to expand and excavate the cohesive soil layer. At the very least, the bag can expand and expand sufficiently, and cement mortar or concrete can also be used as the injection hardening material, and when a load is applied to the head of the antibody that is formed by hardening the hardening material in the expanded bag. The object of the present invention is to provide an antibody that solves the conventional problem of having a large ultimate load and being able to have great performance as a foundation pile.

(Means for Solving the Problems) The present invention is characterized in that a core member having a cross-sectional area smaller than the hollow cross-sectional area of the steel pipe is attached to the lower end of the steel pipe so as not to block the lower end, and the core member A tip metal fitting with a closed end is attached to the lower part of the core body, and a flexible cylindrical bag is placed on the outside of the core body, and both ends of the bag are fixed to the lower part of the steel pipe and the tip metal fitting. This is an antibody.

The present invention will be explained below with reference to the drawings. The example shown in FIG. 1 and another example shown in FIG. 5 are examples of antibodies of the present invention.

In these figures, a core member 2 having a cross-sectional area smaller than the hollow cross-sectional area of the steel pipe 1 is attached to the lower end of the steel pipe 1 so as not to block the lower end. This core material 2 is a cross-shaped steel material in FIG. 1, and is a cylindrical steel material in FIG. At the same time, a tip metal fitting 4 whose end is closed is attached to the lower part of the core material 2. The end fitting 4 may be closed at the lower surface as shown in FIG. 1, at the upper surface as shown in FIG. 5, or at any other position. In the drawing, a closing plate 6 is used for this closing.

Furthermore, a flexible cylindrical bag 3 is placed over the outside of the core body 2, and its both ends are fixed to the lower part of the steel pipe 1 and the tip fitting 4. As shown in Figures 1 and 5, the method of fixing the bag to the steel pipe and end fitting is as shown in Figures 1 and 5.
．． It is easiest and surest to tighten at 5'. For example, a steel belt may be used as the band, a steel split band may be tightened with bolts, or other means may be used.

The steel pipe used in the present invention generally has a length of 3 to 10 m, and the thickness of the steel pipe may be about 3 to 9III+, which is the thickness generally used for steel pipes. Since the antibody of the invention is filled with cement mortar etc. during construction, it may be thinner than that. Generally, those with a wall thickness of about 3 to 91 uffI are easily available. Further, the outer diameter of the steel pipe is not particularly limited, but since the bag body can be expanded and expanded underground by the hardening material when constructed using the antibody of the present invention, it is generally made to have an outer diameter of about 100 to 200 mm. That's enough.

The core material used in the present invention has a cross-sectional area smaller than the hollow cross-sectional area of the steel pipe 1 so as not to block the lower end of the steel pipe I. In particular, the cross-sectional area of this core material is preferably 10% to 60% of the hollow cross-sectional area of the steel pipe, and optimally about 20 to 30%, especially about 25%. Its shape is, for example, the shape shown in FIG. 111ffl or FIG. A bag can be folded into the space created by the difference in outer diameter between the core material and the steel pipe, as shown in FIG. 3, for example, to protect the bag when the antibody of the invention is deposited underground. obtain. When the bag can be stored in the core material portion in this way, the bag will not twist even when the antibody is deposited by rotation, so construction by rotation and deposition becomes possible. In addition, when using a core material having a hollow part inside, such as a hollow cylinder, the cross-sectional area of the core material should also be calculated by taking the area of the hollow part as the cross-sectional area. However, in this case, in order to prevent the area of the hollow portion from being too large and the area of the actual cross section to be too small, it is preferable to make it at least approximately equal to or larger than the cross-sectional area of the steel pipe.

The preferred material for the core material of the present invention is steel, but other materials may also be used. In addition, in the present invention, the diameter of the core material is the maximum diameter at the part other than the part where it is attached to the steel pipe, etc., and since the cylindrical bag is more easily protected when inserted into the ground, it is generally used for steel pipes. A diameter smaller than the inner diameter or the diameter of the end fitting is preferably used, but the diameter may be the same as the outer diameter of the steel pipe, or the diameter of the attachment attached to the steel pipe may be the same as the diameter of the band.

Furthermore, in order to attach this core material to a steel pipe, etc., as shown in Fig. 1, the diameter of the upper end portion 2' of the core material 2 is enlarged to be approximately equal to the inner diameter of the steel pipe, and it is fixed to the steel pipe 1 by welding or the like. Or, as shown in Figure 5, for cross-shaped installation, use member 2'' to attach steel pipe 1.
If the core material 2 is fixed by welding or the like, the core material can be attached without blocking the lower end of the steel pipe. In order to prevent the lower end of the steel pipe from being blocked by the attachment parts 2' and 2'', the cross-sectional area of this attachment part should also be within the range of the cross-sectional area of the core material.In other words, by applying pressure from the head of the steel pipe, etc. The hardening material to be injected can be injected into the bag while falling through the large gap between the core material (or its attachment part) and the inner wall of the steel pipe.The length of this core material is 200 to 2000 Inffl.
Generally preferred is 500 to 1200 hearing.

The tip fitting used in the present invention is used to protect the bag body at the tip when depositing the antibody of the present invention into a drilling hole, etc., and may be made of the same material as the steel pipe described above. It may be possible to use a spiral auger mechanism or a screw auger mechanism so that the auger mechanism can be directly rotated and deposited without drilling a hole in advance.
As shown in the figure, the structure may be such that a spiral auger 4', a screw auger, etc. can be attached to the end fitting.

In addition, when attaching the tip fitting and the core material, the diameter of the core material at the attachment part may be increased, as in the case of attaching a steel pipe and the core material, or even if a cross-shaped attachment member is used, the tip It may be attached directly to the closed part of the fitting.

Although the outer diameter of the tip fitting may be as thin as the diameter of the core material, it is generally preferable to make it approximately equal to the outer diameter of the steel pipe. Moreover, the length may be long. but,
In general, it is preferable to make the length as short as possible, and from the standpoint of mounting the cylindrical bag, the length is generally about the same as the outer diameter of the tip fitting.

In addition, as mentioned above, this metal tip is blocked at an arbitrary position, but this may cause dirt, etc. to enter the inside of the bag from the ground where it is buried, reducing the strength of the hardened body.
Or, the hardening material to be injected may leak into the ground from the tip.
This is to prevent the bag from being unable to expand and inflate sufficiently.

Further, the bag used in the present invention has a cylindrical shape, and the cylindrical body may have a selvedge formed by sewing or weaving a fabric, but it is also possible to have an selvage formed by sewing or weaving a fabric. It is generally preferable to have a cylindrical shape. The bag is flexible so that it can be expanded by the hardening material filled therein.

The bag may be made of a water-permeable material such as a cloth made of synthetic fibers or a water-impermeable material such as a rubber bag. When a water-permeable bag is used, excess water from the hardening material injected into the bag is dehydrated through the bag, so the expanded bag retains its expanded shape even when the hardening material is stopped being injected. It is preferable because

Further, the outer diameter of the bag may be set to a diameter necessary for expanding and expanding the bag by the hardening material underground.

In relation to the outer diameter of the steel pipe, the maximum diameter is about 100 times, preferably about 5 times, the outer diameter of the steel pipe from the viewpoint of ease of attachment to the steel pipe and insertion into the ground. Generally, when a hardened material is put inside and expanded, the bag becomes larger than its original diameter, but generally, the initial outside diameter of the bag is 300 to 300 mm.
2000 mm+, particularly preferably 500 to 1500 m.

The length of the bag varies depending on the outer diameter of the steel pipe used, but is generally at least 0.5 times, preferably at least 1 time, the outer diameter of the bag. More specifically, the length of a typical bag body is 300 mm.
1 to 3 m, particularly preferably 700ffI11 to 180
It is 0■. In the present invention, the length of the bag means the length of the so-called inflatable and expandable portion of the inside secured by the bag attachment bands at both ends.

Next, a construction method using the antibody of the present invention will be described.

First, as shown in FIG. 9, the antibody of the present invention is deposited in the ground to a predetermined depth. The burying method may be any method such as driving, embedding after pre-auger, or burying by rotation.

As shown in Figure 9, once the antibody has been deposited, a concrete pump, etc. is connected to the top of the steel pipe, and the hardening material is injected into the bag through the inside of the steel pipe, and the bag is expanded and expanded underground until it reaches a predetermined diameter. let As the hardening material to be injected into the antibody of the present invention, any of cement milk, cement mortar, cement concrete, etc. can be used. When the antibody of the present invention is used, the cured material flows smoothly inside the steel pipe and is then smoothly injected into the bag. FIG. 10 shows a state in which the bag is expanded and expanded by the hardening material. By providing a horizontal hole in the wall of the steel pipe in the past, unlike the case where hardening material is injected into the bag, the hardening material does not become injectable before the bag is sufficiently expanded and expanded.

(Function) The function of the steel pipe used in the present invention is to allow the bag to reach the desired layer, and the function of the core material is to increase the cross-sectional area in order to improve the injection of hardening material into the cylindrical bag. The tip metal fitting protects the bag body at the tip when depositing the antibody of the present invention.

Also, since the tubular bag is flexible, it can be expanded and expanded by the hardening material injected into it.

The first example is a steel pipe with a diameter of 165 mm, a length of 4.5 m, and a wall thickness of 4.5 mm, and an outer diameter of 130 cm, a length of 900 mm, and a wall thickness of 12 mm.
A cross-shaped core material as shown in the figure, a tip fitting with a length of 500mm with the end closed using the above-mentioned steel pipe, and an outer diameter of 80mm.
0 mm, length 1.2 m tensile strength is 700 kg/c
The test was carried out using the antibody of the present invention using a water-permeable bag made of nylon 66 fabric with ffl/3 cm.

After drilling an excavation hole with an outer diameter of 150 mm in advance, the antibody was rotary-engineered and buried in soft viscous ground with an average N value of 3 so that the bag was located. A cement mortar containing 60% W/C and 3 times the cement weight of sand was used as the hardening material, and the injection was terminated when the maximum injection pressure reached 5 kg/afl.

Two weeks after injection, a load was applied to the head of the antibody formed underground to measure the ultimate load. The result is 25 tons
showed a large value. Thereafter, the antibody was excavated and investigated, and it was confirmed that an enlarged bulb with an outer diameter of 850 ma+ and a length of 1.2 ym was formed at the tip covered with a pouch. The compressive strength of the cured product is approximately 600 kg/
It showed a high value of ci.

A steel pipe with a comparative exception diameter of 165 mm, a length of 6 m, and a thickness of 4.5 mm was used.In order to install the bag in the same position as in the example, the bag was attached to the wall of the steel pipe at a position with an outer diameter of 30 mm. Twenty horizontal holes were provided at approximately equal intervals. The bag used was the same as in the example.

After digging a hole with an outer diameter of 200 mm in the same ground as in the example using an auger, the antibody of this comparative example was press-fitted using a construction machine.

Thereafter, the same hardening material as in the example was injected from the head of the steel pipe. However, immediately after starting the injection of hardening material, the pressure
After reaching c+il, it became impossible to inject. The ultimate load of this antibody was extremely low at 3 tons. As a result of pulling out the steel pipe and inspecting it, it was found that almost no hardened material had flowed into the bag, and was clogged near the side hole of the steel pipe.

(Effects of the present invention) The antibody of the present invention allows the hardening material to be smoothly injected into the bag from a steel pipe even when cement mortar or concrete is used as the hardening material, and the bag can expand and expand to a desired size. Since it is an antibody, the curing material for construction can be selected from a wide variety of materials, and the material of the bag body is not limited to either water-permeable or water-impermeable materials.

Furthermore, when producing the antibody of the present invention, as conventionally,
It also eliminates the hassle of creating numerous horizontal holes in the steel pipe wall.

Furthermore, since steel pipes are used in the present invention, it is possible to sink the bag to a predetermined depth even if there is a hard sand layer in the middle of the ground. It becomes possible to. Antibodies with large supporting capacity can be created.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of the antibody of the present invention, and FIG.
3 and 4 are a sectional view taken along line AA, line BB, and line C-C in FIG. 1, respectively. FIG. 5 is a sectional view showing another example of the antibody of the present invention, and FIGS. 6, 7, and 8 are sectional views DD and E in FIG. 5, respectively.
-E sectional view and FF sectional view. FIG. 9 is a diagram showing a state in which the antibody of the present invention is submerged to a predetermined depth underground, and FIG. 10 is a diagram showing a state in which a curing material is injected into the antibody in FIG. 9 and the bag at the tip is expanded and expanded. FIG. Further, FIG. 11 is a diagram showing the performance of the antibody shown in FIG. 9 with a spiral auger for rotational settling attached to the tip of the tip fitting. FIG. 12 is a diagram showing a conventional example, and FIG. 13 is a diagram showing a conventional example.
It is an enlarged view of the bag body part of a figure. 1...Steel pipe, 2...Core material, 2゛, 2''
... Core material attachment part, 3 ... Tubular bag body,
4...Tip fitting, 4'...Spiral auger, 5.5'...Bag mounting band, 6...
...Tip closing plate, 7... Steel pipe, 8...
... Bag body, 9 ... Side hole, 10 ... Ground. Patent applicant: Asahi Kasei Industries, Ltd. Figure 1 Figure 5 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13

Claims (1)

[Claims] A core member having a cross-sectional area smaller than the hollow cross-sectional area of the steel pipe is attached to the lower end of the steel pipe so as not to block the lower end, and a tip fitting whose end is closed is attached to the lower part of the core member. A flexible cylindrical bag is placed on the outside of the core, and both ends of the bag are fixed to the lower part of the steel pipe and the tip fitting.