JP7604358B2 - Embankment restoration work construction method - Google Patents

Description

The present invention relates to a construction method for restoration work on embankments where slopes have collapsed due to natural disasters, etc.

When the slope of an embankment built for a railway or road collapses due to a large-scale natural disaster such as an earthquake or heavy rain, rapid restoration is required to quickly restore transportation functions. Usually, large sandbags are used to quickly restore the embankment because they are cheap, easy to obtain, and easy to work with, but they are only temporary materials and cannot be used as permanent structures. If the embankment is reconstructed by covering it with soil while leaving the large sandbags in place, the large sandbags may be damaged in the soil, or the embankment may sink due to water paths formed in the gaps between the large sandbags during emergency work, making it unstable. In addition, there is a problem that it is difficult to infiltrate the solidification material when solidifying. Furthermore, the large sandbags may become boundaries during an earthquake, making the embankment unstable. Therefore, when carrying out actual restoration work, it is necessary to remove the large sandbags and carry out permanent restoration work.

However, if the large sandbags used as temporary materials are removed when the embankment slope has collapsed, the structure will not be stable enough to withstand the weight of trains traveling on the railway, so removal and full restoration must be completed within a limited time outside of train operating hours.

Non-Patent Document 1 discloses an embankment restoration method that can shorten work time by combining large sandbags with geotextiles and leaving the large sandbags in place during the actual restoration process to be used as structures.

On the other hand, when emergency restoration is performed using large sandbags and the large sandbags are removed during proper restoration while trains or other vehicles are running, temporary earth retaining structures have traditionally been constructed using piles or steel sheet piles. Non-Patent Document 2 discloses a restoration method in which steel sheet piles are cast as a temporary earth retaining structure.

Yoshinori Mori, Hiroaki Miyatake, Tetsuya Kubo, and Genki Inoue: Research on New Disaster Recovery Technology for Large-Scale Landslides, 71st Annual Conference of the Japan Society of Civil Engineers, 2016 Daisuke Endo and Masaki Takita: Overview of damage caused by the 8.9 rainfall on the Tazawako Line and restoration of the Ryukawa Bridge, 69th Annual Conference of the Japan Society of Civil Engineers, 2014

However, while the method disclosed in Non-Patent Document 1 has confirmed the short-term durability of large sandbags, its long-term durability has not been confirmed. In addition, the method of temporary retaining soil using piles and steel sheet piles as disclosed in Non-Patent Document 2 requires large-scale equipment such as cranes, which creates problems in terms of high costs and construction time.

The present invention was made in consideration of the above circumstances, and aims to provide a construction method for embankment restoration work that can quickly restore embankments after slope collapse, while still maintaining stability during train operations, even if temporary retaining work is omitted.

In order to solve the above problems, the present invention provides a construction method for restoring embankments where slopes have collapsed, comprising carrying out emergency construction work followed by main restoration work, the emergency construction work including the steps of shaping the collapsed slope into a stepped shape, laying planar reinforcement along the shaped stepped surface, and installing sandbags on the planar reinforcement, and the main restoration work including the steps of removing the sandbags, inserting rod-shaped reinforcement from above the planar reinforcement at the position where the sandbags were removed toward the slope, repeating the steps of removing the sandbags and inserting the rod-shaped reinforcement in this order, laying embankment reinforcement on each tier of the planar reinforcement laid in a stepped shape after all the sandbags have been removed, and constructing main restoration material on top of the embankment reinforcement .

It is preferable that the restoration work includes a step of installing a drainage pipe to drain water inside the embankment to the outside of the embankment.

The planar reinforcement may be a geotextile. The rod-shaped reinforcement may be a reinforcing bar having an anchoring portion at its base end for attachment to the planar reinforcement.

According to the present invention, a planar reinforcement material is laid on the back of a large sandbag during emergency restoration, and during main restoration, the large sandbag is gradually removed while the planar reinforcement material is fixed using rod-shaped reinforcement material, so that stability against the load of trains and the like can be maintained even after the large sandbag is removed. This makes it possible to omit temporary retaining work, which requires large-scale equipment, and allows restoration work to be carried out quickly.

1A to 1C are cross-sectional views for explaining a process sequence of emergency repair according to an embodiment of the present invention. 1A and 1B show a process of gradually removing sandbags in the restoration work according to an embodiment of the present invention, where FIG. 1A is a cross-sectional view and FIG. 1A and 1B show a process of inserting rod-shaped reinforcement materials into positions from which sandbags have been removed in the restoration work according to an embodiment of the present invention, where FIG. 1A is a cross-sectional view and FIG. 1A and 1B show a state in which all sandbags have been removed and rod-shaped reinforcement materials have been inserted in the restoration work according to the embodiment of the present invention, where (a) is a cross-sectional view and (b) is a side view. This is a cross-sectional view showing the state in which the restoration material has been installed on top of the planar reinforcement material after all the sandbags have been removed in the restoration work according to an embodiment of the present invention. FIG. 6 is a cross-sectional view showing the state in which a restoration material different from that shown in FIG. 5 has been installed in the restoration work according to an embodiment of the present invention.

The following describes an embodiment of the present invention with reference to the drawings. In this specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals to avoid redundant description.

Figures 1 to 4 show an example of the steps of a construction method for restoration work on embankments according to an embodiment of the present invention. Below, in this embodiment, the construction procedure for restoration work will be explained using a railway embankment as an example.

When the slope 11 of the embankment 10 formed for a railway collapses due to a natural disaster such as an earthquake or heavy rain, as shown in Figure 1 (a), emergency restoration work is first carried out. Figures 1 (b) to (e) show the steps of the emergency work. First, the collapsed slope 11 is shaped like steps (Figure 1 (b)), and planar reinforcement material 21 is laid in a step-like manner along the shaped surface (Figure 1 (c)). As the planar reinforcement material 21, a general geotextile or the like is used. After that, large sandbags 22 are piled up on the planar reinforcement material 21 (Figure 1 (d)), and when they reach a specified height (Figure 1 (e)), the emergency work is completed. In this state, trains 31 on the embankment 10 can operate.

After the emergency work is completed, the actual restoration work is carried out. Figures 2 to 4 show the process sequence of the actual restoration work. During the actual restoration work, the large sandbags 22 piled up in the emergency work are first removed in stages as shown in Figure 2. Figure 2(a) is a cross-sectional view of the embankment 10, and Figure 2(b) is a side view of the slope 11. In the example of Figure 2, the large sandbags 22 of the same height are removed at appropriate intervals from the high position, but each stage may be removed sequentially at appropriate intervals in the horizontal direction. In the part where the planar reinforcement 21 is thus exposed, the rod-shaped reinforcement 23 is inserted from above the planar reinforcement 21 toward the slope 11 as shown in Figure 3. The rod-shaped reinforcement 23 is preferably one that can be driven into the slope 11 by hand, and for example, a deformed steel bar or a rock bolt is used. If the planar reinforcement 21 is a mesh-like material, the rod-shaped reinforcement 23 is inserted into the opening of the mesh. At this time, to prevent the entire rod-shaped reinforcing material 23 from entering the mesh, it is preferable to provide an anchoring member 24 at the base end of the rod-shaped reinforcing material 23 and to anchor the anchoring member 24 to the surface of the planar reinforcing material 21.

As shown in FIG. 4(b), the rod-shaped reinforcement members 23 are preferably arranged alternately in the longitudinal direction of the embankment 10, for example in a staggered arrangement, on each step of the planar reinforcement member 21 laid in a stepped manner, and are preferably arranged approximately evenly over the entire surface of the planar reinforcement member 21. The diameter and number of the rod-shaped reinforcement members 23 are designed to meet the strength required by the condition of the slope 11 and trains 31 running on the embankment 10.

By laying the sheet-like reinforcement 21 on the back side of the large sandbags 22, the tension of the sheet-like reinforcement 21, the weight of the surrounding large sandbags 22, and the rod-like reinforcement 23 can ensure the stability of the slope 11 against the load of the train 31, even when the large sandbags 22 are being removed in stages. Therefore, the train 31 can operate even while the large sandbags 22 are being removed. Also, as shown in Figure 4, even when the restraint by the large sandbags 22 is no longer present, the tension of the sheet-like reinforcement 21 and the rod-like reinforcement 23 can sufficiently maintain the stability of the slope 11 with the load of the train 31 moving slowly.

After removing all the large sandbags 22 and inserting rod-shaped reinforcement materials 23 over the entire surface of the planar reinforcement material 21, as shown in Figure 5, reinforced embankment is constructed on top of the planar reinforcement material 21 as the final restoration material 25, completing the final restoration work. When constructing the reinforced embankment, it is preferable to lay sheet-like embankment reinforcement material 26 on each step of the stepped slope 11. It is also preferable to install drainage pipes 27 at appropriate intervals to drain water generated inside the embankment 10, including the final restoration material 25, to the outside of the embankment 10.

As described above, according to this embodiment, after emergency work is completed, the main restoration work can be carried out without stopping train operations, etc., and without the need for large-scale temporary retaining work when removing the large sandbags. Therefore, the time that traffic of vehicles and trains traveling on the embankment is stopped can be minimized, and the slope 11 of the collapsed embankment 10 can be restored quickly. In addition, since the planar reinforcement material 21 is fixed to the slope 11 and pressed down on top of it by the main restoration material 25, the earthquake resistance of the restored embankment can be improved. In addition, the main restoration material 25 protects the planar reinforcement material 21 from long-term ultraviolet rays, rainfall, etc., and enhances its durability.

In the present invention, the restoration material 25 is not limited to reinforced embankment. For example, as shown in FIG. 6, a cage frame 25a made of metal or reinforced fiber may be used as the restoration material and placed on the planar reinforcement material 21. Alternatively, the planar reinforcement material 21 may be covered with concrete.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these examples. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

The present invention is useful as a method for restoring embankments whose slopes have collapsed due to large-scale natural disasters, etc.

10 Embankment 11 Slope 21 Planar reinforcement material 22 Sandbag 23 Rod-shaped reinforcement material 24 Anchorage member 25 Main restoration material 26 Embankment reinforcement material 27 Drainage pipe 31 Train

Claims (4)

A construction method for restoring embankment where a slope has collapsed, comprising the steps of:
After carrying out emergency repairs, the main restoration work was carried out.
The emergency work is as follows:
A step of shaping the collapsed slope into a staircase shape;
A step of laying a planar reinforcement material along the shaped stepped surface;
and placing a sandbag on the planar reinforcement material.
The restoration work is as follows:
removing the sandbag;
A step of inserting a rod-shaped reinforcement material from above the planar reinforcement material at the position where the sandbag was removed toward the slope;
Repeating the step of removing the sandbag and the step of inserting the rod-shaped reinforcement material in this order;
A step of laying embankment reinforcement material on each step of the planar reinforcement material laid in a stepped manner after removing all of the sandbags;
and a step of constructing a restoration material on top of the embankment reinforcement material . 2. The method for carrying out embankment restoration work according to claim 1 , characterized in that the main restoration work includes a step of installing a drainage pipe for draining water inside the embankment to the outside of the embankment. 3. The method for carrying out embankment restoration work according to claim 1, wherein the surface reinforcement material is a geotextile. The method for carrying out embankment restoration work according to any one of claims 1 to 3 , characterized in that the rod-shaped reinforcement material is a reinforcing bar having an anchoring portion for the planar reinforcement material at its base end.

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