Embankment slope structure and embankment slope repair method

Abstract

This invention provides an embankment slope structure and an embankment slope repair method that can ensure the stability of the upper part of the embankment even when large sandbags are left in place. [Solution] The structure comprises a stepped sandbag section 1 in which large sandbags are arranged in a staircase pattern, planar reinforcing members 21A-21E interposed between the top and second-tier large sandbags 11A and 11B of the stepped sandbag section and extending outwards from the front side of the large sandbags, connecting members 4 that are continuously inserted vertically into the lower part of the top-tier large sandbag 11A and the upper part of the second-tier large sandbag 11B, and a sloped section 5 covering the stepped sandbag section. The planar reinforcing members form the slope structure of the embankment embedded in the sloped section.

Description

Technical Field

[0001] The present invention relates to an embankment slope structure for repairing an embankment slope and a method for repairing an embankment slope.

Background Art

[0002] When railway embankments or road embankments are damaged by rainfall, earthquakes, etc., in order to quickly restore the traffic function, emergency restoration using large sandbags is widely used (see Patent Documents 1 and 2). Emergency restoration by simply stacking large sandbags is inferior in stability compared to before the disaster, so when using it, it is necessary to limit vehicle travel to slow speeds and set strict driving restriction values during rainfall.

[0003] In order to restore the original function of the embankment, full restoration is required. In this case, it is common to remove the sandbags and reconstruct the embankment again. On the other hand, in the wall construction method using a bag body disclosed in Patent Document 1, the sandbags are left in place, and a ground reinforcement material is driven into the embankment to enhance the integrity of the sandbags and the embankment, and the original function is restored.

[0004] Also, in the construction method of the embankment restoration work disclosed in Patent Document 2, by using a product different from the sandbag (for example, a basket frame) during emergency restoration, it can also be utilized during full restoration to form a structure that does not compromise stability.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] If the main restoration work involves removing the sandbags and rebuilding the embankment, there are challenges in terms of the scale of the construction period and costs. On the other hand, if the restoration is carried out by leaving the sandbags in place and covering the front with soil, it is expected that the construction period and costs will be reduced. However, if measures such as integrating the sandbags are not taken, the stacked sandbags will move individually, which can lead to low stability, especially at the top of the embankment, as will be described later.

[0007] Therefore, the present invention aims to provide an embankment slope structure and an embankment slope repair method that can ensure the stability of the upper part of the embankment even when large sandbags are left in place. [Means for solving the problem]

[0008] To achieve the above objective, the embankment slope structure of the present invention is an embankment slope structure comprising: a stepped sandbag section in which large sandbags are arranged in a stepped manner; a planar reinforcing member interposed between the uppermost and second steps of the stepped sandbag section and extending outwards to the front side of the large sandbags; a connecting member that is continuously penetrated vertically between the lower part of the uppermost large sandbag and the upper part of the second step large sandbag; and a slope section covering the stepped sandbag section, wherein the planar reinforcing member is embedded in the slope section.

[0009] Here, the planar reinforcing material is arranged in a stacked configuration, interposed between the uppermost large sandbag and the second large sandbag, and the portion protruding to the front can be positioned at different heights on the slope.

[0010] Furthermore, the planar reinforcing material may have holes that penetrate vertically, through which the connecting member is passed. In addition, it is preferable that the sloping portion on the front side of the uppermost and second-tier large sandbags is formed to have a higher resistance than the front side of the lower part of the staircase sandbag section.

[0011] Furthermore, the invention of a method for repairing an embankment slope is a method for repairing an embankment slope, comprising the steps of: shaping the surface to be repaired into steps and then arranging large sandbags in a stepped manner; interposing a planar reinforcing material between the uppermost and second-highest layers of the large sandbags stacked in a stepped manner, and penetrating a connecting member oriented vertically so as to be continuous between the upper part of the second-highest layer of large sandbags and the lower part of the uppermost layer of large sandbags; and covering the front side of the large sandbags with a slope formed by embankment material, wherein on the front side of the uppermost and second-highest layer of large sandbags, the planar reinforcing material is laid on the upper surface of the slope during construction, and then the embankment material is spread and compacted to form the slope. [Effects of the Invention]

[0012] In the embankment slope structure of the present invention configured as described above, a planar reinforcing material is interposed between the uppermost and second-to-last steps of the stepped sandbag section, and the uppermost and second-to-last large sandbags are connected by connecting members. Furthermore, the planar reinforcing material extending from the stepped sandbag section is embedded in the slope section covering the stepped sandbag section.

[0013] Even with large sandbags left in place, the large sandbags located on the upper part of the embankment are integrated by connecting members, and the integration of the upper slope, which forms the cover soil, with the large sandbags can be maintained through planar reinforcing materials, thus ensuring the stability of the upper part of the embankment. In other words, a stable slope structure that is less prone to collapse, including the upper part of the embankment, can be created.

[0014] Furthermore, in the invention of a method for repairing embankment slopes, the surface to be repaired is first shaped into steps, and then large sandbags are arranged in a stepped pattern, allowing for temporary repairs that enable train operation in a short period of time. In addition, the top and second layers of the stepped stack of large sandbags are connected with connecting members, and a continuous surface reinforcing material is laid up to the slope covering the front side.

[0015] With such a method, it is possible to enhance the stability of the upper part of the embankment with a small amount of work and also improve the seismic resistance.

Brief Description of the Drawings

[0016] [Figure 1] It is an explanatory diagram showing an overview of the slope structure of the embankment in this embodiment. [Figure 2] It is a flowchart explaining the steps of the method for repairing the embankment slope in this embodiment. [Figure 3] It is an explanatory diagram schematically showing the shape of the embankment before the disaster and the state after emergency restoration. [Figure 4] It is an explanatory diagram showing the state near the topmost step and the second step of the trough part of the stepped embankment. [Figure 5] It is an explanatory diagram exemplifying the arrangement relationship between the planar reinforcing material and the connecting member. [Figure 6] It is an explanatory diagram regarding the stability of the upper part of the embankment when placing large embankment troughs.

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing an overview of the slope structure of the embankment M in this embodiment. Further, FIG. 2 is a flowchart explaining the steps of the method for repairing the embankment slope in this embodiment. <0000?89> Due to large-scale earthquakes, heavy rains, etc., the slope of the embankment M may collapse (see FIG. 3). For example, when a track is provided at the top end of the embankment M, prompt restoration is required so that the train operation can resume for the damaged repair target surface. <?000092> In the embankment slope structure and the method for repairing the embankment slope of the present embodiment, in order to perform emergency restoration (temporary restoration), a large soil bag 11 as shown in FIG. 3 is used. Here, among the large soil bags 11 to be stacked, the topmost large soil bag 11A and the second-stage large soil bag 11B will be described separately with symbols. However, since the structure of the soil bags is the same in all cases, hereinafter, when the placement position is not relevant, the description will be made with respect to the large soil bag 11.

[0020] The weight of a normal soil bag is about 40 kg, but the weight of the large soil bag 11 ranges from 200 kg to several tons. Here, an example using a large soil bag 11 with a weight of about 1 ton, formed in a cylindrical shape with a diameter of about 1100 mm and a height of about 1100 mm, will be described.

[0021] The large soil bag 11 is produced, for example, by filling a non-woven fabric soil bag with a lid with earth and sand, crushed stone, etc. For example, by filling the earth and sand of the collapsed embankment M into the soil bag, the large soil bag 11 can be quickly produced on site.

[0022] Since the embankment slope structure constructed by the method for repairing the embankment slope of the present embodiment is for permanent restoration, it is preferable to use a highly weather-resistant material for the bags of the large soil bags 11. Around the large soil bag 11 produced in this way, a drainage function such as a drainage pipe or a drainage sheet is provided as necessary.

[0023] [[ID= / 15]] On the other hand, with respect to the repair target surface of the collapsed embankment M, in order to stack the large soil bags 11, as shown in FIG. 3, a stepped cut surface is provided. In short, the naturally collapsed slope is shaped while being excavated with an excavator such as a backhoe to form a stepped cut surface.

[0024] Although not shown in the figure, with respect to this cut surface, by laying a permeable material such as particle-size adjusted crushed stone, a highly permeable back permeable part is provided on the back side of the large soil bag 11. That is, a part of the back and bottom of the large soil bag 11 arranged on the innermost side of the embankment M for each step will be in contact with the back permeable part.

[0025] Although not shown in the diagram, the large sandbags 11 are arranged in multiple rows on each level as needed, stacking them in a staircase-like fashion. Figure 3 is a schematic illustration showing five levels stacked with one row on each level. The entire structure in which the large sandbags 11 are arranged in a staircase-like fashion will be referred to as the staircase sandbag section 1.

[0026] On the other hand, Figures 1 and 4 show enlarged views of the upper part of the embankment M slope structure in this embodiment. A planar reinforcing section 2 is interposed between the large sandbag 11A at the top of the embankment M, which is the uppermost step of the stepped sandbag section 1, and the second large sandbag 11B.

[0027] This planar reinforcement section 2 can be installed during emergency repairs, or it can be installed during permanent repair work after the uppermost large sandbag 11A has been temporarily removed. The planar reinforcement section 2 is constructed by overlapping one or any number of planar reinforcement materials.

[0028] Here, the stacked planar reinforcing materials will be described using the designations 21A, 21B, 21C, 21D, and 21E from top to bottom. However, since their configuration as embankment reinforcing materials is the same, in the following explanation, the designation 21A will be used when the placement position is irrelevant.

[0029] The planar reinforcing material 21A is laid along the top, bottom, and sides of the large sandbag 11. The planar reinforcing material 21A does not have to be made from a single piece of material, but when it is made from multiple pieces, adjacent sheets are joined together to form a single unit.

[0030] For the planar reinforcing material 21A, for example, a geogrid or geotextile made of a thermoplastic resin sheet with drainage holes can be used. For example, a high-strength, uniaxially or biaxially stretched mesh-like planar reinforcing material 21A made of polyolefin resin such as polyethylene or polypropylene, which has excellent water resistance and chemical resistance, can be used (see Figure 5).

[0031] The portion of the planar reinforcement section 2, in which multiple planar reinforcing materials 21A-21E are stacked, that is located inside the embankment M (hereinafter referred to as the "rear end") is interposed between the uppermost large sandbag 11A and the second-highest large sandbag 11B, as shown in Figure 4.

[0032] Specifically, the rear end of the planar reinforcing section 2 is laid on the upper surface of the second large sandbag 11B and the upper surface of the stepped cut behind it, and the uppermost large sandbag 11A is placed on top of it. The lower part of this uppermost large sandbag 11A and the upper part of the second large sandbag 11B are connected by a connecting member 4 that is continuously inserted vertically.

[0033] The connecting member 4 is formed from reinforcing bars, steel rods, or steel materials. Figure 5 is an explanatory diagram illustrating the arrangement relationship between the planar reinforcing material 21A and the connecting member 4. The connecting member 4 shown on the left side of Figure 5 is made of small diameter reinforcing bars, etc. If its outer diameter is smaller than the mesh (holes) of the grid of the planar reinforcing material 21A, the connecting member 4 can be positioned vertically by passing it through the mesh.

[0034] On the other hand, when using H-shaped steel or large-diameter reinforcing bars, as illustrated by the connecting member 4A on the right side of Figure 5, a cutout (hole) is made in the planar reinforcing member 21A to match its shape, and the connecting member 4A is passed through this cutout.

[0035] Furthermore, the planar reinforcing material 21A is fixed to the surface of the large sandbag 11 using fixing materials 3 such as bent reinforcing bars or binding wire. As shown in Figure 1, the planar reinforcing materials 21A-21E that protrude from the front side of the staircase sandbag section 1 are placed at different heights and embedded in the slope section 5.

[0036] At that time, the parts of the large sandbags 11A and 11B that are raised along the sides, and the parts of the hanging planar reinforcing material 21A-21E are fixed using the fixing material 3. If the fixing material 3 is a bent reinforcing bar, for example, the lower half of the bend is inserted into the large sandbag 11A, and the mesh of the planar reinforcing material 21A is hooked onto the upper half.

[0037] By using the fixing material 3 to enhance the integration between the large sandbags 11A and 11B and the planar reinforcing materials 21A and 21E, the inherent tension of the sandbags and the planar reinforcing materials 21A and 21E can be more effectively utilized.

[0038] In Figure 1, the five planar reinforcing members 21A-21E, which extend from the front side of the large sandbags 11A and 11B, are positioned at different heights on the slope 5. By distributing the planar reinforcing members 21A-21E, which are fixed to the stepped sandbag section 1, across the slope 5 at the top of the embankment, the stability of the upper slope 51 can be increased over a wide area.

[0039] The slope section 5 is constructed to cover the stepped sandbag section 1. The slope section 5 is formed in the same way as general embankment construction methods, using a layer thickness control material to manage the finished layer thickness of each layer and to manage construction conditions such as horizontal spreading.

[0040] The general slope section 52, located on the lower side of the slope section 5, is constructed by leveling embankment materials such as soil and graded crushed stone. On the other hand, it is preferable that the upper slope section 51 on the front side of the uppermost and second-highest large sandbags 1A and 1B is formed to have higher resistance than the general slope section 52 on the front side of the lower part of the stepped sandbag section 1.

[0041] For example, in the upper slope section 51, cement-improved gravel soil, which is made by cement stabilization treatment of high-quality materials such as graded crushed stone, can be used as embankment material. By using this configuration, resistance on the front side can be ensured when inertial forces act on the open side of the slope during an earthquake. Furthermore, by using cement-improved gravel soil in combination with the planar reinforcing material 21A, a configuration with even better deformation performance can be achieved.

[0042] Next, the steps of the embankment slope repair method according to this embodiment will be explained with reference to the flowchart shown in Figure 2. First, in step S1, the surface of the embankment M that has collapsed due to an earthquake or other event is excavated and shaped into steps, and then graded crushed stone is laid on the stepped surface.

[0043] Next, in step S2, as shown in Figure 3, the large sandbags 11 are stacked in a stepped pattern. Once the stacking of these large sandbags 11, 11A, and 11B is completed up to the shoulder of the embankment M, the train can be allowed to run at a reduced speed as an emergency repair.

[0044] The subsequent repair process will be carried out in parallel with train operations, and depending on the work, during times when trains are not running. In step S3, as shown in Figure 4, the rear ends of the planar reinforcing materials 21A-21E are laid between the top step and the second step of the large sandbags 11A and 11B of the staircase sandbag section 1.

[0045] It is preferable to interpose the planar reinforcement section 2 between the large sandbags 11A and 11B, and to perform the subsequent step S4, during emergency repairs. If these steps are not performed during emergency repairs, the uppermost large sandbag 11A should be moved before laying the planar reinforcement materials 21A-21E.

[0046] In step S4, the connecting member 4 is passed from above the planar reinforcing section 2 laid on the upper surface of the second large sandbag 11B toward the hole (mesh or missing part) of the planar reinforcing material 21A, and the lower part of the connecting member 4 is inserted into the upper part of the large sandbag 11B.

[0047] Next, the lower surface of the large sandbag 11A is placed against the upper part of the connecting member 4 that protrudes above the planar reinforcement section 2, and the upper part of the connecting member 4 is inserted into the lower part of the large sandbag 11A. As a result, the uppermost large sandbag 11A and the second-highest large sandbag 11B are connected by the connecting member 4 (step S4).

[0048] Then, in step S5, using embankment materials such as soil and graded crushed stone, a general slope section 52 is constructed on the front side of the lower part of the stepped sandbag section 1 by spreading and compacting the embankment material while laying the layer thickness control material (see Figure 1).

[0049] In step S6, the upper slope section 51 is constructed by embankment on the front side of the upper step sandbag section 1. In constructing the upper slope section 51, first, as shown in Figure 1, one layer of cement-improved gravel soil is spread on the top surface of the general slope section 52, compacted, and then the lowest layer of the upper slope section 51 is constructed.

[0050] Next, the lowest layer of the planar reinforcing material 21E of the planar reinforcing section 2 is extended from between the large sandbags 11A and 11B, and after being placed along the upper side of the second layer of large sandbags 11B, it is laid on the upper surface of the lowest layer of the upper slope section 51. Cement-improved gravel is spread on top of this planar reinforcing material 21E and compacted.

[0051] Then, similar to the planar reinforcing member 21E, the second planar reinforcing member 21D from the bottom is extended and laid on the compacted upper slope 51. The third planar reinforcing member 21C from the bottom should be extended almost horizontally.

[0052] Next, on the upper slope 51 formed on top of the planar reinforcing material 21C, a planar reinforcing material 21B is laid along the lower side of the uppermost large sandbag 11A. Similarly, after laying the uppermost layer of planar reinforcing material 21A, cement-improved gravel is spread up to the top surface of the embankment M and compacted to complete the upper slope 51.

[0053] Next, the method for repairing an embankment slope according to this embodiment, and the function of the embankment slope structure constructed thereby will be described. In this embodiment of the embankment slope repair method, the surface to be repaired is first shaped into steps, and then large sandbags 11, 11A, and 11B are arranged in a stepped pattern. This allows for temporary repairs (emergency repairs) that enable trains to run on the embankment in a short period of time.

[0054] Furthermore, when carrying out the permanent restoration, there is no need to remove the large sandbags 11 installed during the emergency restoration, or only the topmost large sandbag 11A needs to be temporarily moved. All of the large sandbags 11, 11A, and 11B installed during the emergency restoration can be used as they are for the permanent restoration work. This eliminates waste and allows for permanent restoration to be completed in a short period of time. In addition, this reduced workload makes it possible to improve the stability of the upper part of the embankment and enhance its earthquake resistance.

[0055] Furthermore, planar reinforcing members 21A-21E (planar reinforcing section 2) are interposed between the uppermost large sandbag 11A and the second largest sandbag 11B of the staircase sandbag section 1, and the uppermost and second largest sandbags 11A and 11B are connected by connecting members 4.

[0056] Then, the planar reinforcing members 21A-21E, which extend from the step-shaped sandbag section 1, are embedded in the upper slope section 51 of the slope section 5 that covers the step-shaped sandbag section 1. As a result, even if the large sandbags 11, 11A, and 11B are left in place, the stability of the upper part of the embankment can be ensured.

[0057] Here, Figure 6 is an explanatory diagram regarding the stability of the upper part of the embankment when large sandbags are placed. This Figure 6 schematically shows part of the results of a model shaking table experiment conducted to understand the seismic resistance of the embankment when the large sandbags 11 are left in place.

[0058] In the model shaking table experiment, when the material was excited with an acceleration of 400 gal, as shown in Figure 6(a), when the inertial force due to the excitation acted on the open side of the slope, the passive resistance from the soil cover was small, and the topmost sandbag was observed to tip over towards the front side while vibrating.

[0059] On the other hand, as shown in Figure 6(b), when inertial forces act on the back side, the amplitude of the sandbag vibration is relatively small due to the passive resistance of the backfill. However, the vibration of the sandbag creates a gap between the backfill and the sandbag, and the upper part of the backfill, which has less confinement pressure, is displaced into this gap, causing cracks to form on the surface of the slope. Furthermore, under excitation of 500 gal or more, the upper part of the backfill was severely damaged by a similar mechanism, and in some cases, it collapsed.

[0060] In other words, in an embankment constructed by stacking sandbags, the sandbags behave individually, and especially at the top of the embankment, there is less area of ​​covering soil that provides resistance. Compared to the embankment before the disaster, the ground and sandbags shake individually around the sandbags during an earthquake. Experiments have confirmed that this results in an increase in the response of the ground and an increase in settlement, leaving the seismic resistance reduced. Therefore, the slope structure of the embankment in this embodiment is designed to improve this.

[0061] In short, the large sandbags 11A and 11B located on the top of the embankment are integrated using the connecting member 4, and the integration of the upper slope portion 51, which will serve as the cover soil, with the large sandbags 11A and 11B is also maintained through the planar reinforcing members 21A-21E, creating a slope structure.

[0062] In particular, to enhance the restraint of the upper slope section 51 where the thickness of the backfill soil decreases, by laying planar reinforcing materials 21A-21E in a dispersed manner, or by using cement-improved gravel soil with high rigidity and strength in combination, the stability of the upper part of the embankment can be ensured, resulting in a stable slope structure that is less prone to collapse, including the upper part of the embankment.

[0063] While embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and any design modifications that do not depart from the spirit of the present invention are included in the present invention.

[0064] For example, the number of steps in the staircase sandbag section 1 described in the above embodiment and the number of large sandbags 11 arranged in one step are examples and are not limited to these, and can be arbitrarily set according to the conditions of the embankment M to be repaired.

[0065] Furthermore, although the above embodiment described a case in which the planar reinforcing section 2 is interposed only between the uppermost and second-tier large sandbags 11A and 11B, it is not limited to this, and the planar reinforcing section 2 can also be interposed between large sandbags 11B and 11 below the second tier, such as between the second and third tiers, to create a structure similar to the upper slope section 51. [Explanation of symbols]

[0066] 1: Staircase sandbag section 2: Planar reinforcement section 21A-21E: Planar reinforcing material 4,4A: Connecting member 5: Sloping section 51: Upper slope section M: Embankment

Claims

1. It is an embankment slope structure, The staircase sandbag section consists of large sandbags arranged in a stepped pattern, A planar reinforcing material is interposed between the top and second steps of the aforementioned staircase sandbag section and extends outwards from the front side of the aforementioned large sandbag, A connecting member is inserted vertically into the lower part of the uppermost large sandbag and the upper part of the second large sandbag, It comprises a sloped section that covers the aforementioned staircase sandbag section, The embankment slope structure is characterized in that the planar reinforcing material is embedded in the slope portion.

2. The embankment slope structure according to claim 1, characterized in that the planar reinforcing material is interposed between the uppermost large sandbag and the second large sandbag in a state in which multiple sheets are stacked, and the portion that protrudes to the front side is arranged at different heights of the slope.

3. The embankment slope structure according to claim 1 or 2, characterized in that the planar reinforcing material has holes formed therein that penetrate in the vertical direction, and the connecting member is passed through the holes.

4. The slope structure for an embankment according to claim 1 or 2, characterized in that the sloping portion on the front side of the uppermost and second-tier large sandbags is formed to have a higher resistance than the front side of the lower part of the staircase sandbag section.

5. A method for repairing embankment slopes, The process involves shaping the surface to be repaired into steps, and then arranging large sandbags in a stepped pattern. The process involves interposing a planar reinforcing material between the top and second layers of the large sandbags stacked in a staircase-like manner, and inserting a connecting member oriented vertically so as to be continuous between the upper part of the second layer of large sandbags and the lower part of the top layer of large sandbags, The process includes covering the front side of the large sandbag with a slope formed by embankment material, A method for repairing an embankment slope, characterized in that, on the front side of the uppermost and second-tier large sandbags, the planar reinforcing material is laid on the upper surface of the slope under construction, and then the embankment material is spread and compacted to form the slope.

6. The method for repairing an embankment slope according to claim 5, characterized in that the planar reinforcing material is interposed between the uppermost large sandbag and the second largest sandbag in a state in which multiple planar reinforcing materials are stacked, the portion of the uppermost planar reinforcing material that protrudes from the front side is raised and embedded in the slope, and the other planar reinforcing materials are embedded in the slope at a lower height.

Images