JP2007146411A - Method of preventing buried pipeline from being uplifted due to liquefaction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of preventing a buried pipeline from being uplifted due to the liquefaction of a ground in an earthquake. <P>SOLUTION: In a manhole, a high-tension fiber material band-like member 10 is disposed on the inside bottom part of the buried pipeline in the longitudinal direction, and the pipelines are connected to each other. The method comprises the step of fixing both ends of the band-like members. Desirably, the high-tension fiber material is either of a carbon fiber material, a glass fiber material, and an aramid fiber material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for preventing a buried pipeline from being lifted due to liquefaction of the ground during an earthquake.

  Since the 1995 Hyogoken-Nanbu Earthquake, efforts to make sewers seismic resistant have been rapidly demanded. Under such circumstances, seismic joints installed at joints between manholes and pipes, and seismic culverts with pipe / pipe joints having expansion / contraction flexibility have been developed by manufacturers of sewerage materials. Under such circumstances, the present inventor has proposed a new method for preventing the floating due to liquefaction of the ground for manholes which are one component of the sewer (see Patent Document 1).

On the other hand, the buried pipeline which is another component of the sewer has the following characteristics.
(1) The buried pipeline is a light-weight structure with a space inside, and is liable to lift when lifting pressure acts on the bottom due to liquefaction of the ground.
(2) Pipelines buried by excavation may be lifted by liquefaction of backfill soil.
(3) Since the member thickness of the buried pipeline is thin, it is difficult to directly install the structural member for preventing the lifting.
(4) Although it is conceivable to place piles indirectly to prevent lifting, the behavior of piles during an earthquake is easily transmitted to buried pipes because of the high rigidity of the members such as piles. May act on the manhole as a load.
(5) In many cases, there are many other buried objects around the buried pipeline, and when the area to prevent lifting extends to other parts than the buried pipeline installation location, Relocation and protection of objects are necessary.
(6) Existing manholes are installed in existing urban areas, and the construction environment is narrow, making it difficult to construct with large machines.
(7) In the method involving re-excavation around the existing buried pipeline, the construction period becomes longer, and there is a concern about the influence on the surrounding environment due to the excavation.
(8) If the buried pipeline itself is increased in weight to prevent lifting, an excessive load may be applied to the ground.
(9) If a member for increasing the weight is secured, the flow down section is reduced, and it is difficult to secure a normal function.

JP 2005-24896 A

  Regarding the floating of the buried pipeline due to the liquefaction of the ground and backfill soil at the time of the earthquake, the fact that the buried pipeline has the above-mentioned characteristics has also affected the fact that effective measures have not yet been taken. Currently. On the other hand, if the buried pipeline rises during an earthquake, wastewater drainage from medical facilities, evacuation facilities, and disaster prevention facilities becomes impossible, which hinders medical activities, evacuation life, and disaster recovery activities. On the other hand, since the rainwater drainage function is not secured and there is a risk of inducing a secondary disaster, countermeasures for raising the buried pipes are an urgent issue regardless of whether they are newly established or existing.

  The present invention has been developed in view of such a situation, and an object of the present invention is to provide a method for preventing an uplift caused by liquefaction of the ground during an earthquake for an existing buried pipeline. Yes.

  According to the first aspect of the present invention, there is provided a method for preventing the floating of a buried pipe by arranging a belt-like member made of a high tensile strength fiber material at the bottom of the inner surface of the pipe over the length of the pipe, and the pipe is connected. Each of the manholes includes a step of fixing both end portions of the belt-shaped member.

  The method for preventing floating of the buried pipe according to claim 2 of the present invention is the method of claim 1, wherein the high tensile strength fiber material is any one of a carbon fiber material, a glass fiber material, and an aramid fiber material. It is characterized by.

  The method for preventing floating of the buried pipeline according to claim 3 of the present application further includes the step of covering the belt-like member disposed at the bottom of the inner surface of the pipeline in the method of claim 1 or 2. To do.

  According to claim 4 of the present invention, there is provided a method of preventing the floating of the buried pipe, in the method of claim 3, wherein the covering step builds an inner pipe inside the pipe, or mortar or It is performed by applying a paint.

  According to the present invention, a method for preventing floating of a buried pipeline without using a large machine, without affecting other buried objects, surrounding ground, structures, etc., and without re-excavating. Can do. Moreover, in the method of this invention, since it resists only uplift pressure, an excessive load is not given to the ground. Moreover, in the method of the present invention, unlike a rigid member such as a pile, the behavior of the belt-like member does not excessively affect the buried pipe line during an earthquake. Furthermore, the band-shaped member can be protected by covering the band-shaped member, and the service life can be extended when the method of the present invention is performed.

  Next, with reference to the attached drawings, a method for preventing a buried pipe from rising according to a preferred embodiment of the present invention will be described in detail. FIG. 1 is a schematic cross-sectional view showing a buried pipeline subjected to the lifting prevention method of the present invention and a manhole connected thereto.

  In the lifting prevention method of the present invention, the band-like member 10 is arranged on the bottom of the inner surface of the pipeline over the length direction of the target buried pipeline (see FIG. 2), and each of the manholes to which the buried pipeline is connected The both ends of the belt-like member 10 are fixed.

  The belt-like member 10 has a strength that resists the lifting of the pipeline when a lifting pressure is applied to the bottom of the buried pipeline, and has a small strain when a tensile force is applied (if the strain is large, Only allow the pipe to float). A material satisfying these conditions is a high tensile strength fiber material. Preferably, as the belt-like member 10 used in the present invention, a carbon fiber material, a glass fiber material, an aramid fiber material, or the like is used.

  FIG. 3 is a view showing an example of a fixing method at the end of the belt-like member 10. In this method, the end portion of the belt-like member 10 is divided into two parts (see FIG. 3A), and the divided end portions are grooves provided in the upper and lower fixing plates 12a and 12b arranged on the bottom surface of the manhole. The end of the belt-like member 10 is fixed by bundling the end passed through the groove by a predetermined method (see FIG. 3B). FIG. 4 is a view showing another example of the fixing method at the end of the belt-like member 10. In this method, the end of the belt-like member is sandwiched between the lower fixing plate 14a provided with a plurality of protrusions and the upper fixing plate 14b provided with a corresponding recess (see FIG. 4B), and the upper and lower fixing plates By fixing 14a and 14b with a volt | bolt etc., the edge part of the strip | belt-shaped member 10 is fixed. The fixing method of the edge part of the strip | belt-shaped member 10 is not limited to these methods.

  In addition, since the bottom surface of the manhole where the fixing plates 12a, 12b, 14a, and 14b are located is located below the bottom surface of the inner surface of the buried conduit, a certain amount of tension is applied to the belt-like member 10. However, it is not necessary to apply prestress (prestress) to the belt-shaped member 10 in particular. Moreover, the strip-shaped member 10 does not necessarily need to be in contact with the bottom of the inner surface of the buried pipeline.

  Preferably, the lifting prevention method of the present invention further includes a step of covering the belt-like member 10 arranged at the bottom of the inner surface of the buried pipeline. Although the inside of the pipe line may be washed with high-pressure water, this coating step serves to protect the band-shaped member 10 during such a washing operation, and can also be expected to have a corrosion prevention effect.

  As the coating step, for example, a material (lining material) impregnated with a thermosetting resin is inserted into the pipe while being reversely pressurized, and the resin is heated to cure the resin, thereby constructing an inner pipe inside the pipe. A so-called tube rehabilitation method may be used. Alternatively, in the case of a large-diameter pipe that allows an operator to enter the target pipe line, the belt-like member 10 may be covered by applying mortar or paint on the upper surface of the belt-like member 10. Good.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say, it is something.

  For example, the covering step described in the above embodiment is not an indispensable step, and the present invention can be configured only by the band member placing / fixing step.

  In addition, by using the method described in Patent Document 1 and the method of the present invention in combination, it is possible to prevent not only the buried pipeline but also the manhole from rising.

It is the schematic sectional drawing which showed the buried pipeline which performed the lifting prevention method of this invention, and the manhole connected to this. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. FIG. 3A is a view showing an example of a fixing method of the band-shaped member, and is a cross-sectional view taken along line 3a-3a in FIG. 1, and FIG. 3B is a view of FIG. It is the figure seen along line 3b-3b. 4A is a view showing another example of the fixing method of the band-shaped member, and is a view similar to FIG. 3A, and FIG. 4B is a line 4b− of FIG. 4A. It is the figure seen along 4b.

Explanation of symbols

10 Belt-like member 12a, 12b, 14a, 14b Fixing plate

Claims (4)

A method for preventing floating of an embedded pipeline due to liquefaction,
A strip-shaped member made of high tensile strength fiber material is arranged at the bottom of the inner surface of the pipeline over the length of the pipeline, and both ends of the strip-shaped member are fixed in each of the manholes to which the pipeline is connected. A method comprising the step of: The method according to claim 1, wherein the high tensile strength fiber material is any one of a carbon fiber material, a glass fiber material, and an aramid fiber material. The method according to claim 1, further comprising a step of covering the band-shaped member disposed on a bottom portion of the inner surface of the pipe line. The method according to claim 3, wherein the covering step is performed by constructing an inner pipe inside the pipe line or by applying mortar or paint to the upper surface of the strip-shaped member.

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