JPH0523910Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a jig used for laying large-diameter thin-walled steel pipes with little deformation due to earth pressure or the like.

[Conventional technology and its problems] In general, in the construction of buried steel pipes, after excavating a trench for burying the pipe, a foundation is established by compacting good quality soil (sand, etc.) at the bottom of the trench, and the steel pipe is moved by heavy machinery, etc. After suspending the pipe onto the foundation, centering it, and installing it, pipes are joined and the inside and outside surfaces are painted. Next, work is performed to compact and backfill with high-quality soil (sand, etc.) up to the top of the pipe, the top of the pipe + a predetermined height, or the ground surface, and further backfill with generated soil to the ground surface, if necessary.

In pipelines using such steel pipes, especially large-diameter steel pipes, it is necessary to make the steel pipes thinner in order to improve economic efficiency, but there are certain limits due to constraints such as deformation and stress of the steel pipes. . That is, as shown in FIG. 9, the buried steel pipe 1 deforms into a flat shape due to its own weight and the vertical soil load after backfilling.
In the case of large-diameter thin-walled steel pipes, the deformation is particularly significant, and there is a risk that the predetermined allowable stress and allowable amount of deformation will be exceeded. In particular, if the field foundation is weak, even if backfilling and compaction with good quality soil is performed, the good quality soil will move toward the field foundation and the compaction effect will not be sufficient, and after the construction is completed,
Due to the overburden load and vertical soil load, good quality soil on the pipe side moves to the field foundation, which tends to increase the deformation of the pipe. In addition, in the case of the sheet pile construction method, pulling out the sheet pile loosens the ground on the side of the pipe body, reduces the lateral resistance of the ground, and promotes flattening of the pipe body.

In order to prevent such flattening of buried steel pipes,
There are measures to increase the resistance of the ground on the side of the pipe by using higher grade soil and sufficient compaction, but this impairs the economic efficiency of construction and there are limits to compaction, so this effect is not sufficient. It's hard to say.

The present invention has been made in view of such conventional problems, and provides a jig used as a strut (restraint member) for laying large-diameter thin-walled buried steel pipes while properly preventing flattening of the pipes. That is. Generally speaking, it is possible to use extensible support materials such as rods, jacks, and aluminum water jacks, but since they are not specialized materials, there are the following problems.
That is, in the case of a rod jack, the axial force is small because it is manually operated, and therefore the number of rod jacks used is large, making handling complicated. Additionally, during removal, manual operation of the handle becomes difficult, so the support must be moved and removed using a hammer blow, which damages the inner surface coating of the pipe. Aluminum water jacks are lightweight and easy to handle, but
It is expensive and availability is limited. Also, when the diameter is large, a connecting shaft member is required.

[Means for solving the problem] This invention prevents deformation of piping due to earth pressure etc. during burial.
This provides a means to reduce strain, and utilizes the fact that the steel pipe deforms into a vertically elongated oval shape due to lateral earth pressure during burial. The installation jig of the present invention supports the inner wall surface of a large-diameter thin-walled buried steel pipe in tension, and has two main pipe members pivotally attached to the abutting piece that abuts the inner wall surface of the steel pipe. It is characterized by the provision of a connecting rod that is attached to the main material and fixed so that its opening angle can be adjusted.

The abutting piece has an abutting surface that abuts the inner wall surface of the steel pipe and a pivoting portion that pivots the two main pipe members. The pivoting means may be, for example, pinned so that it can rotate in one direction, or the end of the main pipe member may be spherical and supported so that it can rotate in any direction. It is desirable that a cushioning material be attached to the contact surface. Use hard rubber, cloth, plastic, etc. as the cushioning material.

The pipe main material is a support that supports the inner wall surface of the steel pipe in tension, and the two pipe main materials are usually of approximately the same length. Both pipe main members form a "V" shape from the point where one end is attached to the same abutment piece. It is preferable to attach a cover piece to the end of the main pipe material so as not to damage the inner wall surface of the steel pipe. By using a semicircular or hemispherical projecting piece on this lid piece, the end portion can be smoothly slid.

The connecting rod fixes the opening angle of both main pipes. The attachment position to both pipe main members may be at the end of each pipe main member or closer to the center. The attachment means must have the ability to rotate to adjust the opening angle, and methods such as pinning and hook engagement are used. A turnbuckle is provided in the middle of the connecting rod to adjust the opening angle (support height). The number of turnbuckles 4 is not limited to one, but may be more than one as shown in FIG. Connecting rods of different lengths may be prepared so that they can be used with steel pipes of different diameters.

It is preferable that each of these members has a structure that can be easily disassembled for convenience of transportation. The material may be made of aluminum in addition to steel.

The method of use is to carry it into a steel pipe, install it in the vertical direction of the steel pipe at a predetermined position, and tighten the turnbuckle to provide tension support to the inner wall surface of the steel pipe. It is best to install this at the point where the steel pipe is most deformed into an oblong circle due to side earth pressure. The degree of deformation of a steel pipe is determined by its own weight,
Make sure to take into consideration the overburden load, soil load, soil condition, etc. It is desirable to place cushioning materials such as hard rubber, cloth, or plastic at the ends of both main pipes to prevent damage or deformation of the inner wall surface of the steel pipes. The jigs 13 may be arranged at regular intervals in an inverted V shape as shown in FIG.
As shown in the figure, a V-shape and an inverted V-shape may be arranged alternately, or as shown in FIG. 8, a V-shape may be arranged.

In addition, when the degree of deformation of the steel pipe by the jig is large, it is also possible to prevent local deformation of the steel pipe by arranging a shaped steel pipe as a receiving material in the longitudinal direction of the steel pipe at the jig abutting part of the steel pipe.

[Function] When the steel pipe 1 is buried in the pipe burying trench 14, it becomes flattened by Δd due to its own weight, overburden load, and earth load, as shown in FIG. However, when compacted and backfilled with good quality soil such as sand, the area deforms into a vertically oblong circle by Δd' as shown in FIG. In this state, as shown in Fig. 11, the jig 13 of the present invention is installed to secure the amount of deformation by Δd'' and backfill to the ground surface.After that, when the jig 13 is removed, the amount of deformation given by the jig is confirmed. The deformation and stress of the steel pipe due to its own weight, overburden load, and overload are absorbed, and the steel pipe becomes a perfect circle or a nearly perfect circle as shown in FIG. 12.

In large-diameter thin-walled buried steel pipes, the earth and sand around the pipe body and the pipe body work together to support the earth load and overburden load. Therefore, the deformation and generated stress of the steel pipe due to the earth load etc. differ depending on the structure of the steel pipe itself as well as the state of the earth and sand around the steel pipe, and the amount of deformation Δd'' is determined based on these conditions.

[Example] FIG. 1 shows a side view of a state in which a laying jig according to an embodiment of the present invention is tension-supporting the inner wall surface of a large-diameter thin-walled buried steel pipe. As shown in the figure, one end of the two main pipe members 3 is rotatably connected with a pin to the contact piece 2 that contacts the inner wall surface of the steel pipe 1, and both main pipe members 3,
A connecting rod 5 having a turnbuckle 4 is connected and attached between the three.

The contact piece 2 is made of an elliptical plate, and as shown in FIG. 2, a hard rubber plate 6 is adhered to the surface that comes into contact with the inner wall surface of the steel pipe 1. A gusset plate 7 is fixed to the back surface, and the holes of eye plates 8 attached to the ends of both main pipe members 3 are rotatably bolted to the gusset plate 7.

As shown in FIG. 3, a semicircular protrusion 9 is attached to the lower end of the main pipe member 3, and abuts against the inner wall surface of the steel pipe 1 via a hard rubber plate 6. Further, a pin fixing piece 10 is fixed to the side near the lower end, and a hub plate 11 at the end of the connecting rod 5 is rotatably bolted to the pin fixing piece 10. This end is attached to the backing plate 1 as shown in FIG.
2 may further be brought into contact with the inner wall surface of the steel pipe.

There are two methods of burying large-diameter thin-walled steel pipes: bare excavation construction and sheet pile construction. Figure 13 shows the process of bare digging construction. As shown in FIG.
is excavated, and a foundation soil 15 of good quality soil is constructed at the bottom of the trench. Next, the steel pipe 1 is suspended using heavy machinery, etc., and the centering and
After the installation is performed and the steel pipes 1 are joined by welding or the like, the inner and outer surfaces of the on-site joint are painted. As shown in FIG. 2B, when the high-quality soil 16 is compacted and backfilled to the top of the pipe, the steel pipe 1 is deformed into a vertically oblong circular shape due to side earth pressure. In this state, the jig 13 of the present invention is installed at regular intervals, and the inner wall surface of the steel pipe is supported by tension. Then, backfilling 17 to the ground surface is performed and the jig 13 is removed, resulting in the state shown in Figure C.

In the case of the sheet pile construction method, as shown in Figure 14,
The sheet piles 18 are driven and constructed in the same manner as the bare excavation construction method, and finally the sheet piles 18 are pulled out and removed.

[Effects of the invention] By using the jig of the invention, it is possible to simply and easily eliminate strain and deformation during the installation of steel pipes and prevent damage to the steel pipes. Thereby, the steel pipe used can be made even thinner. The jig of the present invention is easy to manufacture and has a wide range of applications for steel pipes of different diameters. Production costs are also low. There is no damage to the inner wall surface of the steel pipe during use.

[Brief explanation of the drawing]

Fig. 1 is a side view showing the usage state of a jig which is an embodiment of the present invention, Fig. 2 is a side view of its abutting piece, and Fig. 3 is a partial side view of the vicinity of the lower end of the main pipe material. be. FIG. 4 is a partial side view showing a state in which a caul plate is used, and FIG. 5 is a partial side view showing an example in which two turnbuckles are installed in series. 6 to 8 are side views showing examples of the arrangement of jigs. Fig. 9 is a cross-sectional view showing the state in which the steel pipe is buried without using the jig of the present invention, and Fig. 10 shows the deformed state of the steel pipe when it is backfilled to the vicinity of the top of the pipe.
FIG. 11 is a cross-sectional view showing the steel pipe with the jig attached thereto, and FIG. 12 is a cross-sectional view showing the steel pipe after the jig has been removed after burying has been completed. FIG. 13 is a sectional view showing the construction process using the bare excavation method and FIG. 14 is the sheet pile construction method using the jig of the present invention. DESCRIPTION OF SYMBOLS 1... Steel pipe, 2... Contact piece, 3... Pipe main material, 4... Turnbuckle, 5... Connecting rod, 6...
...Hard rubber plate (buffer material), 9... Protrusion piece.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) Two main pipe members are pivotally connected to a contact piece that contacts the inner wall surface of the steel pipe, and a connecting rod having a turnbuckle is connected and attached between the two main pipe members. A installation jig that tensions and supports the inner wall surface of large-diameter thin-walled buried steel pipes. (2) The laying jig as set forth in claim 1 of the utility model registration claim, in which a cushioning material is affixed to the steel pipe abutting surface of the abutting piece. (3) The laying jig as set forth in claim 1 of the utility model registration claim, which comprises semicircular or hemispherical protrusions attached to the non-pivot side ends of both main pipe members.