JPS58142089A - Method of reducing angle of bend of bent duct in method of construction of piping in existing pipe - 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] The present invention relates to a method for relaxing the bending angle of a curved pipeline in an existing pipe piping method. In an existing pipe piping method using a conventionally known ductile pipe, for example, as shown in FIG. If a curved pipe 8 is formed between the existing pipes 1 and 11 with a bending angle larger than the permissible bending angle of the joint of the new pipe 3 (usually 3 degrees), it will not be possible to continue as is. It is impossible to continuously insert the new pipe 3 with the joint part joined in the starting hole 4 toward the destination hole bK via jacks etc. and pass it through the curved pipe line 2. It is necessary to provide a separate vertical shape. However, if this part cannot be constructed vertically due to traffic or housing conditions, this construction method is inconvenient. In order to prevent this inconvenience, conventional methods have been to shorten the length of the inserted new tube, but it is extremely impossible to shorten the length of the new tube indefinitely, making it impractical. There is.

This invention was made in view of the above circumstances,
The purpose of the present invention is to provide a method that allows a new pipe to pass through a curved pipe line without impairing the performance of the joint by relaxing the bending angle of the curved pipe line without shortening the length of the new pipe. .

This invention will be described with reference to embodiments shown in FIG. 2 and subsequent figures.

In this embodiment, the same parts as in the conventional one (FIG. 1) are denoted by the same reference numerals. [Detailed explanation will be omitted, and new parts will mainly be explained.

In FIG. 2.3, the bending angle θ of the positive curved pipe line 2 is larger than the allowable bending angle ψ of the joint of the new pipe 3, so the new pipe 3 cannot pass through the curved pipe line 2. For such cutting, first, the curved pipe 2 is cut at the center of the corner of the inner pipe portion in the front-rear direction using a cutting machine (not shown) or the like. The length of this cut part is that the length of the base of the triangular part 10 formed with the cough cut part as the two oblique sides is the length J of the new tube 3, and both ends a of the bottom of the armpit,
The length is set so that the bending angle θ with respect to the existing pipe 1', 1''K of a is 4, which is half the bending angle θ of the curved pipe 2.Then, the triangular part 10 in contact with the cut pipe part is made. The earth and sand are excavated and removed so that the cut surface #A connecting both ends a and a of the base becomes a straight line when viewed from the plane.The maximum width of this field cut is determined by the bending of the curved pipe 2 as described above. The angle is relaxed to half of the previous angle. After the bending angle of the curved pipeline 3 is relaxed as described above, a guide 12 of an appropriate shape is inserted in the direction of excavation in the outer pipe part facing the triangular part 1° filled with 1lllllll of earth and sand. Place it parallel to.

After that, the new pipe 3 with the joint part joined from the starting hole 4'
When inserted into the existing pipe one after another, the new pipe 3 becomes curved pipe 2K.
M and pass along the guide 12,
When the first application pipe reaches the destination hole SK, the new pipe 3 in the curved pipe line 2 is piped so that the joint part is properly connected to the other new pipe adjacent to it within the allowable bending angle range. Ru.

Figure 4.5 shows a new pipe 3 located between the existing pipes 1' and 1''.
An example is shown in which two curved pipes 2' and f are formed having a bending angle l larger than the allowable bending angle of the joint part. In this case, as in the previous embodiment, After cutting the inner pipe parts of each of the curved pipes l and f, the earth and sand in the triangular parts 11' and 11'' are excavated and removed, and the wrinkled curved pipe @
The bending angle of 2' and 2' is relaxed to half of the previous one. By relaxing the bending angle of each curved pipe line 7, 2' in this way, it is possible to pass the new pipe 3 inserted through the guide 13, and the joint part after piping is placed in the normal joint shape 11. It puts pressure on people.

The relaxation of the plurality of curved conduits 2', l as described above is usually carried out by the second
, 3, the bending angle θ of the curved pipe line 2 is reduced to 1/! in the embodiment shown in FIG. As a result of the relaxation, the new pipe 3 to be inserted may still be unable to pass through the pipe line 2, or it may be possible to pass through the pipe line 2, but the pipe succeeding flat part is not within the allowable bending angle range and the joint This is done when performance is likely to be impaired. Therefore, in such a case, the curved pipe line 2'
The bending angle θ' of curved pipe line 2 is equal to 4 of the bending angle of curved pipe line 2, and the bending angle of curved pipe line l and f, in which this bending angle θ' is relaxed, is equal to the bending angle of curved pipe line 2. I feel exhausted.

In addition, when excavating the earth and sand in the triangular part in each of the above embodiments, if the ground in this part is soft and there is a risk that the ground will collapse due to the cutting of the pipe, it is recommended to strengthen the ground by injecting chemicals in advance. becomes easier.

This invention is as described above, in which the existing pipe is provided with a shaft opening on the side at both ends of the pipe, one of the shafts is used as a starting shaft, and a new pipe is continuously inserted into the existing pipe toward the other end shaft. In the method of piping by inserting the pipe into the pipe, if the pipe is a curved pipe with a bending angle in the middle that is larger than the allowable bending angle of the joint of the new pipe, the inner pipe of the curved pipe is inserted at that corner. The length of this cut is determined by the length of the base of the triangular part formed with the cut part as the two hypotenuses, which is approximately the length of the new tube, and the length of the cut at both ends of the base of the carcass. The length KL is such that the bending angle with respect to the existing pipe line corresponds to the bending angle of the curved pipe line, and then the excavation surface connecting both ends of the base is made from a flat surface. If you excavate and remove it so that the joint between the new pipe installed in the triangular part and another new pipe is properly joined within the allowable bending angle range, it will become a straight line. The bending angle of the pipe can be relaxed, and even if it is difficult for a new pipe to pass through a curved pipe, it is possible to pass the new pipe without shortening the length, and the performance of the first joint is not impaired. It can be installed without any piping. Furthermore, since the amount of excavated soil can be reduced to a minimum of a, it has excellent effects such as very good workability.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing an example of a conventional piping construction method within an existing pipe in which a curved pipe line is formed in the middle of the existing pipe line, Fig. 2.3 shows an embodiment of the present invention, and Fig. 2 3 is a schematic cross-sectional view of the curved pipe line in FIG. 2, FIG. 4-5 shows a second embodiment of the present invention, and FIG. 4 is an enlarged view of the main part FIG. S is a schematic cross-sectional view of the curved pipe line in FIG. 4.

Claims (1)

[Claims]! , a vertical shape with an opening on the side of the existing pipe is provided at both 3° ends of the pipe, one of these verticals is used as a starting hole, and a new pipe is continuously inserted into the existing pipe toward the other destination hole. In the piping construction method, the pipe line has a bend angle that is smaller than the permissible bending angle of the joint of the new pipe in the middle. In the case of a curved pipe with a large bending angle, the inner pipe of the curved pipe is cut in the front-rear direction at the center of the corner, and the length of this cut is 2. The length of the base of the triangular part formed as two hypotenuses is the length of the new bald pipe, and the bending angle of both ends of the base of the cough with respect to the existing pipe is 4 times the bending angle of the curved pipe. Then, the excavated surface connecting both ends of the base is straight when viewed from a plane, and the new pipe to be piped to the triangular part and other new pipes are connected to each other. A method for easing one bending angle of a curved pipe in an existing pipe piping construction method, characterized by excavating and removing the joint so that the joint is properly joined within the range of an allowable bending angle.