JPH0814352B2 - Pipe floating prevention method - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a method for preventing the floating of a pipe, and more particularly to FRP.
Pipe floating prevention method useful for burying pipes and FRPM pipes.

[Conventional technology]

Conventionally, ductile pipes have been mainly used as pipe materials for burial management.However, since ductile pipes are heavy, they are troublesome to carry out, and there is a risk of corrosion, FRP pipes or FRPM pipes are used. Attempts have been made to use it as a buried pipe.

[Problems of conventional technology]

However, while the FRP pipe or FRPM pipe has the advantage of being lightweight, its own weight is smaller than the volume per unit length, so buoyancy works in the fluidized soil for management return at the time of control return, and the pipe floats. There was a problem that caused it.

Therefore, when burying such a pipe material, after laying the pipe on the pipe base floor, it is necessary to bridge the pipe holding girder between the sidewalls of the trench and fix the pipe in the vertical direction. However, there is a drawback that the preparation work and the installation work of the girder are very troublesome.

Further, since members such as girders for preventing pipes that prevent floating are backfilled together with the pipes, there is a drawback that they cannot be reused.

[Problems to be Solved by the Invention]

In view of the above problems, the present invention prevents the floating of a lightweight pipe that is floated by fluidized treated soil for management return, and at the same time, the burial work can be greatly simplified, and an effective member for preventing the floating is effective. The purpose was to obtain a tube floating prevention method that can be used.

[Technology for solving problems]

That is, the pipe floating prevention method of the present invention is such that after the pipe is laid on the pipe base floor part that has been cast in advance, a saddle-shaped loading tool whose load point matches the center of gravity of the pipe is provided in the upper half of the pipe. Installed, put a load that can counter the buoyancy of floating the control return fluidized soil on the above-mentioned load, and then put the control return fluidized soil into the control return fluidized soil. The volume of the part surrounded by is larger than the volume of the part that causes excess buoyancy due to the other volume, and once the fluidized treated soil for management return is hardened, then the saddle-shaped loading tool and load are applied. After the removal, it is characterized in that the fluidized soil for management return is put into the remaining portion and buried.

〔Example〕

 Next, an example of the construction method of the present invention will be described.

FIG. 1 is a sectional view of an embodiment of the construction method of the present invention, and FIG. 2 is a sectional view of another embodiment.

In the pipe floating prevention method of the present invention, a lightweight pipe 3 such as an FRP pipe or a FRPM pipe is laid on a bottom surface of a groove 1 excavated along a pipe line, on a pipe base floor portion 2 which is previously cast with mortar or the like. rear,
A saddle-shaped loading tool 4 is installed in the upper half of the pipe 3, and thereafter the buoyancy B received by the pipe 3 is counteracted by the fluidized treated soil 5 for management return obtained by mixing on-site excavated soil, cement and water. A possible load W (> B) is placed on the loading tool 4, and then the fluidization-treated soil for management return 5 is introduced, and the volume b _{1 of the} portion surrounded by the fluidization-treated soil for management return 5 However, it is thrown in until it becomes larger than the volume of the portion that causes excess buoyancy due to the volume b ₂ other than that, the management-returning fluidized soil 5 is once hardened, and then the saddle-shaped loading device and the load are removed,
It consists of the step of filling and burying fluidized soil for management return (not shown) in the remaining part.

In the above, the saddle-shaped loading tool 4 is placed so that the load point coincides with the center of gravity G of the pipe, and specifically, the positioning is performed by using a pipe gravity center position mark (not shown) previously attached to the side surface of the pipe. To be done.

Further, the saddle-shaped loading tool 4 may have a structure for receiving the load W on both side surfaces of the pipe as shown in FIG. 1 or a structure for loading the load W on the upper surface of the pipe as shown in FIG. .

The load W may be of any shape such as a rod-shaped body or a granular body as long as it can withstand the buoyancy of the pipe 3, but in terms of handleability, a rod-shaped body such as a reinforcing bar or a steel rod is more advantageous. is there.

[Action]

In the present invention, the lightweight pipes 3 such as FRP pipes and FRPM pipes placed on the pipe base floor 2 that has been cast in advance are added with weight by the saddle-shaped loading device 4 and the load W, and then, Even if the management-returning fluidized soil 5 is added, it does not float and maintains a stable posture.

Further, as shown in FIG. 1 and FIG. 2, until the volume b _{1 of the} portion surrounded by the fluidized treated soil 5 for management return in the cross section of the pipe 3 becomes larger than the volume b _{2 of the} portion that causes excess buoyancy, Once the fluidization treated soil 5 for management return is put in and once hardened, even if the fluidized treated soil 5 for management return is put on it, no floating occurs.

Therefore, the saddle-shaped loading tool 4 and the load W can be removed at the time of hardening after the first fluidized soil 5 is added.

〔effect〕

As described above, according to the pipe floating prevention method of the present invention, if a load capable of counteracting the buoyancy is added by the saddle-shaped loading device in consideration of the position of the center of gravity of the pipe, the fluidization process can be performed safely thereafter. Since soil can be put in, the pipe backfilling work can be done very easily, and since the saddle-shaped loading tool and load can be repeatedly used, it has the effect of being economically usable.
If the pipe base is hardened to the extent that it can withstand the pipe and the load, the construction method of the present invention can be carried out, so that the construction period can be shortened and various effects are obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the construction method of the present invention, and FIG. 2 is a sectional view of another embodiment. 1 ... excavation groove, 2 ... pipe base, 3 ... pipe, 4 ... saddle-shaped loading tool, 5 ... fluidized soil, W ... load, B ... buoyancy.

Claims (1)

[Claims] 1. A pipe for laying a pipe on the base of a pipe that has been cast in advance, and then a saddle-shaped loading tool whose load point is aligned with the center of gravity of the pipe is installed in the upper half of the pipe, and the flow for management return is set. The load capable of counteracting the buoyancy force received by the tube by the chemical treatment soil is placed on the above-mentioned packing, and then the management return fluidization treatment soil, the volume of the portion surrounded by the management return fluidization treatment soil, It is thrown in until it becomes larger than the volume of the part that causes excess buoyancy due to the other volume, and the fluidizing treated soil for management return is once hardened, then the saddle-shaped loading tool and the load are removed, and then the remaining part is managed. A floating prevention method for pipes that is characterized by pouring and filling fluidized soil for return.