JPS59228521A - Landslide preventive pile - Google Patents

Abstract

PURPOSE:To facilitate the construction work of landslide preventive piles by a method in which a landslide preventive pile is formed by providing a tapered portion with a specific slope on the inner surface of its coupler and also providing a tapered portion with the same slope as the coupler on the end outer surface of its pipe. CONSTITUTION:Tapered portions 12 and 12a with a slope of 1/50-1/200 are provided on the inner surface of a coupler 15, and tapered portions 16 and 16a with the same slope as the tapered portions 12 and 12a of the coupler 15 are provided on the end outer surface of a base pipe 11. The length of the coupler 15 is 2.0-3.5 times the outside diameter of the base pipe 11. The base pipes 11 and 11a are inserted into the upper and lower parts of the coupler 15 in such a way as to form a 20-30mm. aperture (l) between ends of the base plates 11 and 11a to form a landslide preventive pile. Since the pile can be simply formed by assembling the base pipes and the coupler, the construction work can be made easier and the construction period can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a landslide prevention pile installed to prevent landslides in a landslide area.

In order to prevent this, groundwater removal work, mechanical restraint work, groundwater inflow prevention work, scouring prevention work, soil improvement work, or a combination of these are generally carried out in soil-covered areas. Recently, ground piles are often installed as part of mechanical restraint construction.

Landslide prevention piles are installed in the opposite slope area, so the construction site is often a steep slope where it is difficult to bring in heavy machinery, etc., and it is impossible to drive υ piles by hammering. Piles are being erected in holes drilled with an auger. Incidentally, the length of landslide prevention piles varies depending on the local situation, but generally reaches 20 m to 30 m in many cases.

On the other hand, the length of the original pipe is limited to about 10 to 15 m, and due to transportation considerations, it is customary to construct the pipe by splicing it on site.

Since this joint work is performed in an unstable environment, quick and reliable work is strongly required. In addition, because it is extremely difficult to predict which surface the landslide pile will collapse on, it is important to note that landslide prevention piles must have a bending strength that exceeds the design bending strength at any part of the pile, including the joints, over the entire length of the pile. It must have uniform cross-sectional properties.

Conventionally, the technologies for on-site joints for piles to prevent ground beams include (1) joints made by butt welding between original pipes, (2) internal type fitting joints, (3) coupling type joints, (4) flange type bolt joints, etc. .

As shown in Figure 1, a butt welded joint is made by butting and welding master pipes 1 and 1a made of steel pipe piles, and if proper design and strict construction management are carried out, the joint part 2 will also be the same as the master pipe 1. Although it is possible to obtain the same joint strength as , 1a,
If current standard size pipes are used, it takes several hours to weld in some places, and there are many places that do not pass inspection, so it is preferable as a joint for piles to prevent foundation piles. do not have.

As shown in FIG. 2, the internal fit-in joint has tapered surfaces 5 on both outer surfaces of a flange 6a provided at the center of the joint 3, and a tapered surface with the same slope as the tapered surface 5 on the inner surface of the end of the original pipe 1. 4, and the original pipes 1 and 1a are connected to the joint 6 as shown in FIG. 6, and the aim is to shorten the construction time, which is the biggest drawback of butt welded joints. However, it is extremely difficult to make this joint have the same strength as the original pipe 1.1a. Furthermore, if the wall thickness of the original tube 1 is larger than the outer diameter (
There are many types of ground prevention stakes like this one).
There are cases where it is completely impossible to implement such a joint, and there are disadvantages such as the weight of the joint 3 becomes large and expensive even when the wall is relatively thin, and the workability is also poor. .

From the viewpoint of bending strength of the joint, it is relatively easy to make the coupling type joint have the same cross-sectional performance as the original pipe. However, in order to have a stress transmission function, it is necessary to either ■ weld the coupling and the original pipe, or ■ use a threaded joint (the fourth
(Fig. 5) or (1) provide a mechanical fitting mechanism.

In the case of welding (2), there are problems similar to those described in the conventional example shown in FIG. In addition, when making the threaded joint (■), as shown in Fig. 4, tapered surfaces 5, 5 are provided on the inner periphery of the joint, and a tapered surface with the same slope is provided on the outer periphery of the end of the original pipe 1. 4, and screws 7 are provided on each of these tapered surfaces 5, 5, and 4 to be screwed together. However, in this case, cutting of the screw 7 also creates a defect on the original tube 1 side, so it is impossible to maintain the original cross-sectional area, and it is possible to use an upset type screw, but it is an expensive and expensive method. However, it is unavoidable that each screw thread will undergo shear failure due to stress concentration. Furthermore, the provision of the fitting mechanism (2) has many drawbacks as a joint for ground pile prevention piles, such as the unavoidable loss of functionality due to the loss of the upper section, which is expensive.

As shown in Fig. 6, the flange type bolt joint has a main pipe 1,
1aK flanges 8 and 8a are provided and connected with bolts and nuts 9, but the wall thickness of the flange part is excessive, and it is necessary to use a torque wrench on site, so the construction must be strictly controlled. Not only that, but also the total construction time.

The disadvantage is that construction costs increase.

The present invention was made in order to solve the above-mentioned conventional problems, and the joint part has the same strength as the original pipe, easy to construct on site, and shortens the construction time. The purpose is to provide low-cost landslide prevention piles.

In order to achieve the above object, the landslide prevention pile according to the present invention includes a joint having a tapered part on the inner circumferential surface, and an original pipe having a tapered part having the same slope as the tapered part on the end outer circumferential surface. In the pile formed by joining the tapered parts, the slope of the taper part is formed to be 1150 to 1/2[1[1] for both the joint and the original pipe, and a non-contact part is provided at the tip of the tapered part. It is characterized by this.

Furthermore, the present invention is characterized in that the above-mentioned foundation pile prevention pile is provided with at least one or more of the following items (1) to (2). ■The length of the joint is 2.0 to 3.5 times the outer diameter of the original tube, ■The surface of each cheek and groove is finished with the JIS finishing symbol W, ■The taper of the joint and the original tube. some of it,
When the upper and lower master tubes are connected to the joint, there is a gap of 20 to 30 mm between the opposing ends of the two master tubes; ■ A reinforcing disk or reinforcing hollow plate or A reinforcing cross lip was installed; ■ A reinforcing disk, a reinforcing hollow plate, or a reinforcing cross rib was installed at the tip of the original tube and the tapered end, respectively.

The present invention will be explained below using the drawings.

FIG. 7 is a front view of an embodiment of the present invention. Reference numeral 11 is a master pipe made of a steel pipe pile, and reference numeral 15 is a joint made of the same material as the master pipe. As shown in FIG. 8, the present invention is characterized in that the original tube 11.11a is inserted into the joint 15 with a predetermined thrust to connect the two. A part of the taper is 16° and 16m, and the original pipe 11
, 11a is also provided with a tapered portion 12.12a having the same slope as the tapered portion 16.16a. These joints 15 and the taper part of the original pipe 11.11m 16°1
6a and 12.12m are finished to have a predetermined roughness (frictional resistance against pulling force) during cutting.

Further, when inserting the original pipe 11.11a into the joint 15, the original pipe 11.11a is connected so as to form a gap in the center as shown in FIG. This gap t is usually 20 to 60 cm, that is, the joint 15
From the central cross section of the original tube at 11°11 at, respectively 1
The length is 0 to 15 m.

The length L1 of the steel pipe used for the joint 15, the outer diameter 'D1, the inner diameter d,
and the wall thickness t is the outer diameter of the original tube 11), the inner diameter d2, and the wall thickness 1
1, the following relationship shall be satisfied, and the slope of the taper shall be 115o~'/200.

L=2. ODffi~3.5 D2nt>a,
> a.

t, ≧ or (section modulus of the central part of the joint) ≧ (section modulus of the original pipe) Furthermore, the end portions of the tapered portions 16, 16a, 12.12a in the final connected state of the joint 15 and the original pipe 11. The surfaces that come into contact with the counterpart are cut out to form non-contact parts 17 and 13, respectively, as shown in FIG.

The landslide prevention pile constructed as described above is first shipped at a factory by inserting the original pipe corresponding to the lower pile into one side of the joint with a predetermined thrust. At the site, after the lower pile is erected in the pre-bored hole, the original pipe attached to the upper pile is inserted into the other side of the joint with a specified thrust to join them together, and the area around the pile is backfilled. . In addition, if necessary, the installed landslide prevention piles will be filled with concrete.

Next, the operation of the present invention and the effects obtained thereby will be explained. The effects of the present invention can be roughly summarized into the following two points.

(1) On-site construction is extremely easy and construction time is short.

(2) The joint part has a bending strength equal to or higher than that of the original pipe.

The above features are explained in more detail as follows.

(1) Ease of construction and reduction of construction time It is easy to understand that the inner diameter of the tip of the joint 15 is larger than the outer diameter of the tip of the original pipe 11, which is the upper pile, so it is easy to insert. It is still necessary to insert the original pipe 11, which is the upper pile, into the joint 15 and then connect it with a predetermined thrust, but this can be done by a method such as using gravity or a small jack, so this is also extremely easy. It's easy. Furthermore, joint 1
Even if there is a slight error in the machining accuracy of the tapered portions 16 and 12 of the master tubes 11 and 11, there is no problem because it can be adjusted by adjusting the gap t between the tips of both the master tubes 11 and 11a.

(2) Regarding bending strength, the cross section of the joint between the original pipes 11, 11a and the joint 15 is such that the original pipe 11.11a and the joint 15 are tapered at a portion 12.12.
Since they are concentric rings that are in contact with each other via a and 16, if the sum of the wall thicknesses of both tapered parts 12.12a and 16 is made larger than the wall thickness of the original tube, its geometry will be In this sense, all the cross-sectional performances can be made greater than those of the master tubes 11 and 11a. However, in order to take advantage of this feature, the following two conditions must be satisfied.

(4) The joint 15 and the original tubes 11, 11a should not be displaced.

(B) The joint 15 maintains its cross section without causing local deformation within the elastic limit of the original pipes 11 and 11a (within the design load of the landslide prevention pile itself).

The greatest feature of the present invention is that it solves these two problems. First, regarding the problem of displacement (4), consider the slope of the tapered portions 12, 12a, and 16.

The problem was solved by adjusting the roughness of the machining finish and the thrust force during fitting. That is, the finish roughness W (JIS
-B-0601r surface roughness (according to the finish symbol of the surface roughness classification), if the taper slope is 115o to 1/2oO, the taper contact part is 2.0 to 5.5 times the diameter of the original tube 11. It has been theoretically and experimentally confirmed that by providing this, no misalignment occurs between the joint 15 and the original tube 11 when the original tube 11 is subjected to bending loading within its elastic limit.

In addition, to solve the problem of maintaining the cross section in (B), as shown in FIG.
This problem was solved by providing a non-contact part 17.13 at the tip of the. That is, the locations where stress is most concentrated and local deformation is most likely to occur during bending loading are sections a and b in FIG. 9. Therefore, a non-contact part 13.1 with a taper (excision part) with a larger slope than the taper part 12.16 is made on the outside of parts a and b.
7 is provided, and by applying stress thereto, local deformation of the Ja and b portions can be prevented and the cross section can be maintained. In addition to the above, in order to maintain the cross section, as shown in FIGS. 10, 11, and 12,
A reinforcing disk 21, a reinforcing hollow disk 22, or a reinforcing cross rib 23 may be fitted and welded to the tip of the reinforcing disk. moreover,
As shown in FIG. 16, FIG. 14, and FIG. 15, in addition to the reinforcement shown in FIGS.
Alternatively, reinforcing cross ribs 23a may be inserted and welded 24, or these may be combined as appropriate.

Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited thereto and may be modified as appropriate without departing from the gist of the present invention.

As is clear from the above description, according to the present invention, the joint part also has the same strength as the original pipe, and construction on the site is easy and the construction time can be significantly shortened. Since piles can be obtained, the effect of implementation is extremely large.

[Brief explanation of drawings]

Figures 1 to 6 are partial cross-sectional views showing the structure and connection state of the joints of conventional landslide prevention piles. Figure 1 is a butt-welded joint, and Figures 2 and 3 are internal fitting joints. , 4th
5 shows a coupling type joint, and FIG. 6 shows a flange type bolt joint. Fig. 7 is a front view of the embodiment of the present invention, Fig. 8 is a front view showing its combined state, Fig. 9 is a sectional view of the main part, Fig. 10 (a)
, (b) to FIG. 15(a) and (b) are a plan view and a front view, respectively, showing an example of maintaining the cross section of the original tube. 11.11a: Original tube, 15: Joint, 12, 12a. 16: Tapered part, 13.17: Non-contact part, 21: Reinforcement disk, 22: Hollow disk, 26: Cross rib. Agent Patent Attorney Sanro Kiku

Claims (6)

[Claims] (1) In a pile formed by joining a joint having a tapered part on the inner peripheral surface and a master pipe having a taper part having the same slope as the taper part on the outer surface of the end, the slope of the taper part A landslide prevention pile characterized in that both the joint and the original pipe are formed at an angle of 115° to 1/200°, and a non-contact portion is provided at the tip of a portion of the taper. (2) The pile for preventing ground bedding according to claim 1, characterized in that the length of the joint is 2.0 to 3.5 times the outer diameter of the original pipe. (3) The soil-slip prevention pile according to claim 1, characterized in that the surface of a portion of each of the tapers is finished with a JIS finishing symbol of W. (4) The taper part of the joint and the master pipe is configured so that when the upper and lower master pipes are connected to the joint, there is a gap of 20 to 30 square meters between the opposing ends of the master pipes. A pile for preventing earth bedding according to claim 1. (5) The earth bedding prevention pile according to claim 1, characterized in that a reinforcing disk, a reinforcing hollow plate, or a reinforcing cross rib is attached to the tip of the original pipe. (6) The anti-slip pile according to claim 1, wherein a reinforcing disk, a reinforcing hollow plate, or a reinforcing cross rib is attached to the tip end and the tapered end of the original pipe, respectively.