Reinforced soil wall construction method

Abstract

To provide a reinforced soil wall construction method eliminating dripping of a filler such as sediment from a front face of a retaining wall while securing stability of a wall face material.SOLUTION: A wall face material comprises geo-cells 2 having restraining parts 7 where a plurality of approximately strip-like strip members 5 are formed by being joined at each predetermined interval and which restrain a filler by separating non-connected parts between the strip members 5 from each other, wherein the geo-cell 2 includes a specific geo-cell 92 provided with a plurality of normal strip members 5 with the approximately same height dimension to each other, and specific strip members 50 larger than the normal strip members 5 arranged on a forefront line. In a process of forming a wall part 3 by stacking the plurality of specific geo-cells 92 vertically, the specific strip members 50 are arranged on the forefront line. When vertically stacking other specific geo-cells 92 on the upper stage of the specific geo-cells 92, lower end parts of the specific strip members 50 of the upper specific geo-cells 92 on the upper stage are stacked so as to be overlapped on a rear part of upper end parts of the specific strip members 50 of the specific geo-cells 92 on the lower stage.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a reinforced earth retaining wall method in which wall materials are stacked vertically on the front surface of a natural ground to form a retaining wall, and the natural ground is reinforced by the retaining wall.

Background Art

[0002] Conventionally, when constructing a new, widened or restored earth retaining wall for roads, sites, etc. in mountains, etc., a reinforced earth retaining wall method has been adopted in which a retaining wall is formed on the front surface of the natural ground to reinforce the earth retaining wall. In this reinforced earth retaining wall method, earth fill is placed on the back side of the wall material constituting the retaining wall surface, and an anchor member fixed to the back of this wall material is extended in a substantially horizontal direction into the earth fill, thereby restraining this wall material against the earth fill and achieving structural stabilization of the wall material (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional reinforced earth retaining wall method using a wall material and an anchor member, for example, like the retaining wall 100 that reinforces the natural ground 120 shown in FIG. 8 to form a mountain road R, the anchor member 104 attached to the back of the foremost wall material 102 erected vertically in the vertical direction needs to be extended to a horizontal dimension Q that is approximately the same dimension or more as the height dimension P of the wall material 102 in order to satisfy the stability and structural strength of the wall material 102. Therefore, not only does the amount of earth fill 111 placed on the back side of the wall material 102 increase, but in some cases, the front part 125 of the natural ground 120 is excavated to form an inclined surface 123 in order to obtain an extension area for the anchor member 104, resulting in an increase in the construction cost and construction days required for constructing such a reinforced earth retaining wall structure.

[0005] Therefore, a reinforced earth retaining wall construction method as shown in FIGS. 9 and 10 has been proposed. That is, a retaining wall 150 made of a wall material is constructed on the front side of the natural ground 220, and the natural ground 220 is reinforced by the retaining wall 150. The wall material is composed of a geocell 200 having a restraint portion 7 for restraining a filler by joining a plurality of strip members 500 having a substantially strip shape at predetermined intervals, and non-joining portions between the strip members 500 being separated from each other (see FIG. 6). A first step of forming a first wall portion 300 by stacking a plurality of geocells 200 vertically on the front side of the natural ground 220, and a second step of forming a second wall portion 400 by continuously arranging a plurality of geocells 200 in the front-rear direction from the rear surface of the first wall portion 300 toward the natural ground 220. At least these steps are provided, and a method of injecting a filler 12 into the restraint portion 700 of the geocell 200 has been proposed. According to such a construction method, a second wall portion 400 that acts as a pseudo pile by the geocells 200 continuously arranged in the front-rear direction is bridged between the first wall portion 300 that is stacked vertically on the front side of the natural ground 220 and constitutes the wall material and the front surface 230 of the natural ground 220. Since the rear end portion of the second wall portion 400 abuts on the stable front surface 230 of the natural ground 220 where earth pressure does not occur and is supported in the vertical direction, the first wall portion 300 can be leaned against the natural ground 220 and stabilized via the second wall portion 400 without requiring construction to largely separate the first wall portion 300 from the natural ground 220, and a reinforced earth retaining wall structure with ensured structural strength can be obtained.

[0006] However, according to such a reinforced soil wall construction method, since the first wall portion 300 constitutes a straight wall that is vertically stacked in the vertical direction, it is difficult to stack the frontmost strip members 500, 500 of the first wall portions 300 stacked vertically along the line of the upper edge of the lower strip member 500 so that the lines of the lower edges of the upper strip members 500 are aligned, and a gap Δ may inevitably occur between the upper and lower strip members 500, 500 (see Fig. 10). When the earth and sand D as the filling material 12 leaks from the gap Δ to the front side, the earth and sand D falls on the road surface of the sidewalk and roadway in the lower region 210 or into the side ditch, making it difficult for pedestrians to walk and vehicles to travel and potentially filling the side ditch with the earth and sand D. In addition, problems such as the strength of the retaining wall 150 itself being impaired due to the earth and sand D as the filling material 12 leaking from the gap Δ to the front side, and the aesthetics being impaired due to the gap Δ being visible from the front of the retaining wall 150 have occurred.

[0007] The present invention has been made paying attention to such problems, and while maintaining a reinforced soil wall construction method capable of ensuring the stability of the wall material and suppressing the construction cost and construction days, an object of the present invention is to provide a new reinforced soil wall construction method in which filling materials such as earth and sand do not leak from the front of the retaining wall.

Means for Solving the Problems

[0008] In order to solve the above problems, the reinforced soil wall construction method of the present invention is a reinforced soil wall construction method in which a retaining wall made of a wall material is constructed on the front side of the natural ground and the natural ground is reinforced by the retaining wall, the wall material is composed of a geocell having a restraint portion that restrains the filling material by non-joint portions of a plurality of substantially strip-shaped strip members being joined at predetermined intervals and being separated from each other, the geocell includes a specific geocell including a plurality of normal strip members having substantially the same height dimension and a specific strip member arranged in the front row and having a larger height dimension than the normal strip members. In the step of forming a wall portion by stacking a plurality of the specific geocells vertically on the front side rather than the ground mountain, the wall portion is arranged such that the specific band members of the specific geocells are in the frontmost row, and a filling material is introduced while separating non-joint portions between the band members of the specific geocells by a predetermined width in the front-rear direction. When stacking another specific geocell vertically on the upper stage of the specific geocell, it is stacked such that the lower end portion of the specific band member of the upper-stage specific geocell overlaps behind the upper end portion of the specific band member of the lower-stage specific geocell. According to this feature, when constructing a pseudo straight wall which is a substantially vertical wall surface, for the specific geocells stacked vertically to form the wall surface, it facilitates the positioning of the upper-stage specific geocell with respect to the lower-stage specific geocell, suppresses the leakage of the filling material from between the specific band members of the specific geocells stacked vertically, and can enhance the aesthetic appearance of the retaining wall.

[0009] The height dimension of the specific band member is characterized in that it is about 5 to 10% larger than the height dimension of the normal band member. According to this feature, when stacking the specific geocells vertically, by forming the overlapping portion above and below the specific band member arranged in the frontmost row to be about 5 to 10% larger than the height dimension of the normal band member, it is possible to suppress the filling material from leaking from the wall surface.

[0010] The uppermost joint portion between the specific band member and the normal band member joined thereto is joined at a position separated downward by a predetermined distance from the upper end of the normal band member. According to this feature, since the free ends of the normal band member and the specific band member above the uppermost joint portion support each other, it is possible to maintain the self-support of the free ends while allowing deformation by an external force, and it is difficult for the external force to be transmitted to the joint portion, preventing damage to the joint portion.

[0011] The geocell includes, in addition to the specific geocell, a normal geocell provided with a plurality of normal band members having substantially the same height dimension as each other. It is characterized by having a second step of continuously arranging the normal geocells from the rear surface of the specific geocell constituting the wall portion toward the natural ground. According to this feature, since the geocells continuously arranged in the front-rear direction act as a pseudo pile, the structural strength can be increased.

[0012] In the second step, it is characterized in that a plurality of the normal geocells are arranged vertically spaced apart from each other. According to this feature, the structural strength of the wall portion spanned over the natural ground can be increased by the minimum necessary number of normal geocells arranged vertically spaced apart from each other.

[0013] In the second step, it is characterized in that the front and rear surfaces of the specific geocell and the normal geocell are brought into contact with each other and connected. According to this feature, a strong geocell can be formed by connecting the specific geocell and the normal geocell.

[0014] In the second step, it is characterized in that the front and rear surfaces of the specific geocell and the normal geocell are spaced apart from each other. According to this feature, the operation of connecting and joining the specific geocell and the normal geocell can be omitted.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0016] The embodiments for carrying out the reinforced earth wall method according to the present invention will be described below based on examples.

Examples

[0017] The reinforced earth wall method of the present invention will be described with reference to FIGS. 1 to 7. Hereinafter, the right side of the paper surface of FIG. 1 will be described as the front side (front side) of the retaining wall.

[0018] Reference numeral 1 in FIG. 1 is a retaining wall to which the present invention is applied. This retaining wall 1 reinforces the front side (right side in the drawing) of the natural ground 20 which is an earth wall, and serves as a foundation structure such as a mountain road R or a site provided on its upper surface. This retaining wall 1 is mainly composed of a first wall portion 3 formed by stacking a plurality of geocells 2 vertically on the front side of the natural ground 20, and a second wall portion 4 formed by connecting a plurality of geocells 2 in series from the rear surface of the first wall portion 3 toward the natural ground 20, and is constructed sequentially from bottom to top.

[0019] First, as construction before the construction of the retaining wall 1, the natural ground 20 to be reinforced by the present invention is formed by cutting the lower region 21, so that the front surface 23 of the natural ground 20 is formed as an inclined surface inclined rearward as it goes upward, and a horizontal surface 24 is formed at the end of the natural ground 20.

[0020] As shown in FIGS. 3, 4, and 6, the geocell 2 (82, 92) is composed of a plurality of substantially strip-shaped belt members 5 (50) formed of a flexible material such as synthetic resin. These belt members 5 (50) are arranged such that their width directions are perpendicular and their longitudinal directions are substantially horizontal, and are joined at predetermined intervals in the longitudinal direction in a state where the belt members 5 (50) are laminated on each other. The joining portions between the belt members 5 (50) are joining portions 6 that are welded or pressure-bonded while applying pressure.

[0021] The geocell 2 has two types of geocells, namely, "normal geocell 82" and "specific geocell 92". The "normal geocell 82" is composed of a plurality of belt members 5 having substantially the same height as shown in FIG. 6. Further, the "specific geocell 92" is configured by making the height of the belt member (hereinafter referred to as "specific belt member") 50 arranged in the forefront row (as shown in FIGS. 2 to 5) higher by a height dimension H than the height of the belt members (hereinafter referred to as "normal belt members") 5 other than the forefront row (the same height as the belt members 5 of the normal geocell 82).

[0022] As shown in FIGS. 2 to 4, the specific geocell 92 is composed of one specific strip member 50 and five normal strip members 5, and the bottom surfaces 50c of these specific strip members 50 and the bottom surfaces 5c of the normal strip members 5 are joined with their height positions aligned. More specifically, the specific strip member 50 in the frontmost row and the normal strip members 5 in the second row are joined at joints 6 at predetermined intervals in the longitudinal direction. As shown in FIGS. 4(a) to (c), the specific strip member 50 is taller by a height dimension H than the normal strip member 5 in the vicinity of the joint 6. Further, the uppermost joint of the joint 6 is provided at a position spaced downward by a predetermined distance (M1) from the upper end surface 5a of the normal strip member 5, and a free end portion 5b of length M1 is formed above the uppermost joint of the normal strip member 5. Similarly, the uppermost joint is provided at a position spaced downward by a predetermined distance (M2) from the upper end surface 50a of the specific strip member 50, and a free end portion 50b of length M2 is formed above the uppermost joint of the specific strip member 50. As shown in FIGS. 4(b) and (c), the free end portion 5b of the normal strip member 5 and the free end portion 50b of the specific strip member 50 are in contact with each other at a portion that is curved and warped upward above the uppermost joint. Therefore, the respective free end portions 5b and 50b stand upright independently, and the respective free end portions 5b and 50b support each other. And even when the free end portions 5b and 50b are about to be deformed by an external force such as the earth pressure of the filling material described later, they deform flexibly while maintaining the state of rubbing against each other and being in contact. Thus, while allowing deformation by the external force, the independence of the free end portions 5b and 50b is maintained, and the flexibility of the free end portions 5b and 50b makes it difficult for the external force to be transmitted to the joint 6, preventing damage to the joint 6.

[0023] Further, the normal belt member 5 in the second row and the normal belt member 5 in the third row are joined at the middle of the joints 6, 6 arranged in the longitudinal direction between the specific belt member 50 in the foremost row and the normal belt member 5 in the second row. Hereinafter, the joints 6 between the normal belt member 5 in the third row and the normal belt member 5 in the fourth row, and the joints 6 between the normal belt member 5 in the fifth row and the normal belt member 5 in the sixth row are joined at the same position as the joint 6 between the specific belt member 50 in the foremost row and the normal belt member 5 in the second row. Also, the joint 6 between the normal belt member 5 in the fourth row and the normal belt member 5 in the fifth row is joined at the same position as the joint 6 between the normal belt member 5 in the second row and the normal belt member 5 in the third row. Note that the specific geocell 92 is not limited to being composed of the above-mentioned one specific belt member 50 and five normal belt members 5, and may be composed of one specific belt member 50 and a predetermined plurality of normal belt members 5.

[0024] As shown in FIG. 2, the height of the specific belt member 50 is higher than the height X of the normal belt member 5 by a height dimension H. In the embodiment, the height X of the normal belt member 5 is 200 mm, the height of the specific belt member 50 is 210 mm, the height dimension H is 10 mm, and the thickness T of the normal belt member 5 and the specific belt member 50 is 4 mm. Considering that the gap Δ between the upper and lower specific geocells 92 when stacking the upper specific geocell 92 on the lower specific geocell 92 in forming the first wall portion 3 is about 2 to 3 mm, the height dimension H has a dimension sufficiently larger than the gap Δ. Also, if the height dimension H is 10 mm, it is 2.5 times the thickness T of 4 mm, that is, less than 3 times, so there is little risk that the free end 50b of the specific belt member 50 cannot stand independently and will fall. In this embodiment, the height dimension H is about 5% of the height X of the normal belt member 5, but an appropriate height can be selected according to the strength of the belt member and the material of the filler. For example, it is also possible to set the height dimension H to 20 mm, that is, about 10% of the height X of the normal belt member 5.

[0025] The specific belt member 50 that constitutes the foremost row and the other normal belt members 5 are colored in a blackish hue. Note that the color of the specific geocell 92 may be appropriately changed according to the construction site. Also, when this specific geocell 92 is expanded in the front-rear direction, non-joint portions excluding the joint portions between the specific belt member 50, the normal belt members 5, and between the normal belt members 5 are separated from each other, thereby forming a restraint portion 7 for restraining a filler such as earth and sand. This restraint portion 7 is arranged in a zigzag or honeycomb shape. A filler such as earth and sand is put into this restraint portion 7 and compacted (see Fig. 5) to form a first wall portion 3, and a plurality of first wall portions 3 can be stacked vertically to form a layer structure.

[0026] A plurality of small through-holes 8 are formed in the normal belt member 5 of this specific geocell 92, and the mutual restraint portions 7 are communicated by the through-holes 8. Note that no through-holes 8 are formed in the specific belt member 50 in the foremost row so that the earth and sand in the restraint portion 7 do not flow out. Also, since the specific geocell 92 has flexibility, it can be wound up and conveyed in a compact state, and can also be cut to a length suitable for the current situation at the construction site.

[0027] Fig. 6 shows a normal geocell 82. The normal geocell 82 has the same shape as the conventional geocell 2, does not have a specific belt member 50 in the foremost row like the specific geocell 92, and is composed only of normal belt members 5 of the same size in which a plurality of small through-holes 8 are formed. The six normal belt members 5 that constitute the normal geocell 82 are joined at joint portions 6 at intervals in the longitudinal direction in the same manner as the specific geocell 92. This normal geocell 82 is mainly used as the geocell 2 of the second wall portion 4.

[0028] Note that in the retaining wall 1 described below, the first wall portion 3 and the second wall portion 4 are arranged continuously in the front-rear direction in the lowermost layer, but this can be omitted depending on conditions such as the height of the retaining wall 1 and the terrain, and it is not an essential configuration.

[0029] As shown in FIGS. 5 and 7, when constructing a retaining wall on the front surface of the natural ground 20, as a first step, a filler 12 is placed in the restraint portion 7 of the specific geocell 92 constituting the first wall portion 3 and compacted to form the first wall portion 3, and the first wall portions 3 are stacked vertically. Further, the lower end of the front surface of the specific belt member 50 of the specific geocell 92 of the upper first wall portion 3 to be stacked is arranged to overlap front and rear so as to contact the rear surface of the height dimension H portion of the specific belt member 50 of the lower first wall portion 3. Then, the restraint portion 7 of the lower first wall portion 3 is arranged so as to cover substantially all of the restraint portion 7 of the upper first wall portion 3.

[0030] Specifically, as shown in FIGS. 5 and 7, the first wall portion 3 to be stacked is formed as follows. Three rows of restraint portions 7 are formed in the front-rear direction of the first wall portion 3 at the first stage (the lowermost stage), and the restraint portion 7 in the front row of the first wall portion 3 is arranged so as to cover substantially all of the area of the restraint portion 7 in the front row of the upper first wall portion 3, and is arranged to be located T mm behind the thickness dimension T of the front specific belt member 50. Similarly, the first wall portions 3 are stacked upward, and the embankment 11 is filled and compacted between the first wall portion 3 and the natural ground 20 to form each layer of the first wall portion 3. The first wall portion 3 stacked in this way is formed by the self-weight of the filler 12 restrained by the restraint portion 7 of the upper first wall portion 3 pressing against the lower first wall portion 3. That is, the first wall portion 3 of this embodiment is constructed as a so-called pseudo-vertical wall that faces a substantially vertical direction that is slightly inclined backward upward. More specifically, according to the embodiment, for every 200 mm of the height X of the normal belt member stacked vertically, the upper first wall portion 3 retreats 4 mm backward with respect to the lower first wall portion 3 by the thickness dimension T of the belt member and inclines, so that the inclination angle θ becomes a pseudo-vertical wall of 88.9°. In the present invention, the pseudo-vertical wall refers to a retaining wall with an inclination angle θ in the range of 88° to 89°. This pseudo-vertical wall has a structure that is less likely to collapse and is stable because it is slightly inclined backward compared to a vertical wall erected at 90°.

[0031] And as described above, when stacking the upper specific geocell 92 on top of the lower specific geocell 92, a vertical gap Δ is formed between the first wall portions 3 of the upper and lower stages (Fig. 7). However, the lower end of the front surface of the specific band member 50 of the specific geocell 92 of the first wall portion 3 of the upper stage to be stacked is arranged to overlap front and back so as to contact the rear surface of the height dimension H portion of the specific band member 50 of the first wall portion 3 of the lower stage. Therefore, not only can the filler 12 not leak from the gap Δ, but a highly safe retaining wall 1 can be constructed. Moreover, since the gap Δ is hidden when viewed from the front surface of the retaining wall 1, the front surface of the retaining wall 1 can be regarded as a continuous surface, enhancing the aesthetic appearance.

[0032] Note that the lower end of the front surface of the specific band member 50 of the specific geocell 92 of the first wall portion 3 of the upper stage to be stacked and the rear surface of the height dimension H portion of the specific band member 50 of the first wall portion 3 of the lower stage may be separated front and back without contact. However, by having both surfaces in contact as in this embodiment, it is possible to prevent dust generated when filling the filler 12 from leaking.

[0033] Next, the lamination of the first wall portion 3 and the second wall portion 4 will be described with reference to Fig. 1. As described above, the first wall portions 3 are stacked upward in order from the lowermost stage, and the space between the first wall portion 3 and the natural ground 20 is filled with the embankment 11 and compacted. Further, at predetermined stages (the 1st, 6th, 11th, 16th, and 21st stages from the bottom in this embodiment), as a second step, as described above, a second wall portion 4 using a normal geocell 82 is horizontally continuously provided on the rear side of the first wall portion 3 using the specific geocell 92. Here, for example, on the upper surface of the first wall portion 3 of the 1st stage and the second wall portion 4 disposed on the rear side thereof, the first wall portion 3 of the 2nd stage is stacked so as to cover it, and the embankment 11 is filled in the space on the rear side thereof. By repeating this process, the second wall portions 4, 4,... are disposed on the rear side of the first wall portion 3 in a vertically spaced state.

[0034] The first wall portions 3 stacked in this manner are formed into an integral wall by being pressed against each other by the self-weight of the earth and sand restrained by the restraining portions 7. Then, by disposing the second wall portion 4 on the rear side of the stacked first wall portions 3, the second wall portion 4 and the surrounding embankment 11 act as a pseudo-pile in a substantially horizontal direction, and the middle position in the height direction of the stacked first wall portions 3 is supported. That is, in FIG. 1, since the second wall portions 4 disposed at a plurality of positions in the height direction and spaced apart from each other on the rear side of the stacked first wall portions 3 act as pseudo-piles, the stacked first wall portions 3 and the second wall portions 4 on the rear side are integrated, and a strong retaining wall 1 can be constructed without using piles or the like.

[0035] Note that the first wall portion 3 and the second wall portion 4 are arranged adjacent to each other with the specific geocell 92 and the normal geocell 82 abutting against each other front and back. Note that the specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4 may be connected and disposed with a clip or the like in order to connect the two and enhance the integrity. Further, in order to omit the connection work and improve the work efficiency, a slight gap may be provided between the specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4, and the front and rear surfaces of both wall portions may be spaced apart and arranged.

[0036] Next, as shown in FIG. 7, an aspect of filling the restraining portion 7 with earth and sand as the filling material 12 will be described. Each of the restraining portions 7, 7,... constituting the first wall portion 3 described above is filled with a filling material 12 having a certain filling amount reaching at least the height X of the normal belt member 5 inside, so that the non-joint portion of the belt member is widened in the front-rear direction by a predetermined dimension L.

[0037] In this embodiment, as the filling material to be put into the restraining portion 7 of the geocell 2, earth and sand collected at the construction site is used. Then, indigenous species of plants living in the earth and sand will grow naturally inside the restraining portion 7 of the geocell 2. After construction, when a predetermined period has elapsed, the roots of the plants grown inside the restraining portion 7 of the geocell 2 will enter the through holes 8 (see FIGS. 3 and 5) of the normal belt member 5 and wrap around the normal belt member 5. And the roots of the plants wrapped around this normal belt member 5 extend deep into the soil.

[0038] In this way, the roots of the plants growing spontaneously within the restraint part 7 are usually entangled in the through holes 8 of the band member 5, improving the frictional force between the geocell 2 and the earth and sand, and the geocells 2 are connected to each other and the first wall part 3 and the second wall part 4 are connected via the roots of the plants, so that the strength of the retaining wall 1 can be improved.

[0039] Also, the surface of the band member 5 of the geocell 2 is subjected to embossing to form minute uneven portions (not shown). These minute uneven portions can improve the frictional force between the earth and sand within the restraint part 7 and the geocell 2, thereby improving the strength of the retaining wall 1. Further, earth and sand enters the through holes 8 of the band member 5, and these through holes 8 can improve the frictional force between the earth and sand within the restraint part 7 and the geocell 2, thereby improving the strength of the retaining wall 1.

[0040] As shown in FIG. 7, after filling the filling material 12 into each of the restraint parts 7, 7,... of the first-stage specific geocell 92 from the bottom, the second-stage specific geocell 92 is laminated on the first-stage specific geocell 92. At this time, since the height dimension H portion of the foremost specific band member 50 of the first-stage specific geocell 92 protrudes upward from the surface of the filling material filled therein, the lower end portion of the foremost specific band member 50 of the second-stage specific geocell 92 is abutted and positioned inside the height dimension H portion, and the second-stage specific geocell 92 is laminated. Then, like the first stage, the filling material 12 is filled into each of the restraint parts 7, 7,... of the second-stage specific geocell 92. Thereafter, similarly, the process is repeated until the first wall parts 3 of the required number of stages (23 stages in the embodiment; see FIG. 1) are formed.

[0041] In the conventional reinforced earth retaining wall method as shown in FIGS. 9 and 10, the geocells 200 constituting the first wall portion 300 are usually of the same shape as the geocell 82, and are composed of a plurality of strip members 500 having substantially the same height. Therefore, when stacking the upper geocells 200 on the lower geocells 200, it is impossible to accurately position the upper strip member 500 on the lower strip member 500 for the foremost strip member 500. Also, since it is extremely difficult to evenly fill the filling material 12 on the surface of the lower geocell 200, it is difficult to align and stack the lower edge line of the upper strip member 500 along the upper edge line of the lower strip member 500 that constitutes the lower geocell 200, and a vertical gap Δ is generated between the upper and lower strip members 500, 500. Then, there was a risk that the earth and sand D, which is the filling material 12, would leak to the front side of the retaining wall 1 from the gap Δ (see FIG. 10).

[0042] In the present invention, as described above, when stacking a plurality of specific geocells 92 vertically, the lower end portion on the front surface of the specific strip member 50 of the upper specific geocell 92 is arranged and stacked so as to be in contact with the upper end portion on the rear surface of the specific strip member 50 of the lower specific geocell 92 with overlap in the front-rear direction. Therefore, when constructing a pseudo straight wall, which is a substantially vertical wall surface, it is possible to easily position the upper geocell with respect to the lower geocell for the geocells stacked vertically that constitute the wall surface, and to suppress the filling material from leaking from the gap between the strip members of the vertically stacked geocells. Thus, it is possible to prevent the earth and sand, which is the filling material 12, from leaking to the front side of the retaining wall from the gap between the strip members of the geocell, making it difficult to walk or drive by dropping earth and sand on the road surface of the sidewalk S or the road RW in the lower region 21 or in the side ditch G, filling the side ditch G with earth and sand, or hitting the pedestrians walking on the sidewalk S in the lower region 21 or the vehicles driving on the road RW with earth and sand, which would cause a risk of damage to the pedestrians and vehicles, and it is possible to provide a retaining wall 1 with extremely high safety. Also, since the earth and sand, which is the filling material 12, does not leak to the front side from the gap, the strength of the retaining wall 1 itself is not impaired, and it is possible to provide a retaining wall 1 with high structural strength. Furthermore, since the gap Δ between the upper and lower specific geocells 92 is hidden when viewed from the front of the retaining wall 1, the aesthetics can be enhanced.

[0043] Further, according to the reinforced soil wall construction method of the present invention, the second wall portion 4 that acts as a pseudo pile by the geocells 2 (82, 92) continuously arranged in the front-rear direction has its extension dimension in the front-rear direction adjusted, so that it is laminated vertically on the front side of the ground 20 to form a wall surface material. It is spanned between the first wall portion 3 and the front surface of the ground 20, and the rear end portion of the second wall portion 4 abuts against the stable ground 20 where earth pressure does not occur and is supported in the vertical direction. Therefore, even without requiring construction to greatly separate the first wall portion 3 from the ground 20, the first wall portion 3 can be leaned against the ground 20 via the second wall portion 4 and stabilized, and a reinforced soil wall structure with ensured structural strength can be obtained.

[0044] Furthermore, in the second step, by arranging a plurality of the second wall portions 4 vertically spaced apart, the structural strength of the first wall portion 3 spanned over the ground 20 by the minimum necessary second wall portions 4 can be enhanced.

[0045] As described above, the embodiments of the present invention have been described with reference to the drawings. However, the specific configuration is not limited to these embodiments, and even if there are changes or additions within the scope not departing from the gist of the present invention, they are included in the present invention.

[0046] For example, in the above embodiment, the specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4 are geocells in which normal belt members 5 of the same size are laminated with each other except for the frontmost specific belt member 50. However, it is not limited to this. The specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4 may use different-sized belt members laminated with each other to form joined geocells of different standards.

[0047] Also, in the above embodiment, the specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4 are configured separately, and their front and rear surfaces are in contact with each other. However, these separate geocells may be spaced apart in the front-rear direction, or a structure in which the specific geocell 92 constituting the first wall portion 3 and the normal geocell 82 constituting the second wall portion 4 are integrally configured may be used.

[0048] In addition, in the above embodiment, the geocells 2 that form the second wall portion 4 usually use ordinary geocells 82, but specific geocells 92 may also be used. In this case, since the first wall portion and the second wall portion are formed by arranging the specific geocells 92 in series, only the specific geocells 92 need to be prepared, and there is no need to prepare a plurality of types of geocells 2, so the cost can be suppressed.

[0049] In addition, in the above embodiment, the restraint portions 7 of the geocells 2 are arranged in a staggered pattern or a honeycomb pattern, but the arrangement of the restraint portions 7 of the geocells 2 is not limited to this, and they may be arranged in a grid pattern or in other arrangement forms.

[0050] In addition, in the above embodiment, as the filling material 12 filled in the restraint portion 7 of the geocell 2 and the embankment 11 which is the backfill material put on the back side of the retaining wall 1, the earth and sand of the same soil quality collected at the construction site are adopted, but it is not limited to this. For example, crushed stones, clay, concrete, etc. may be adopted in the restraint portion 7.

Explanation of reference numerals

[0051] 1 Retaining wall 2 Geocell 82 Ordinary geocell 92 Specific geocell 3 First wall portion 4 Second wall portion 5 Ordinary strip member 50 Specific strip member 6 Joint portion 7 Restraint portion 10 Retaining wall 12 Filling material 20 Natural ground 23 Front surface

Claims

1. A reinforced earth retaining wall construction method in which a retaining wall made of a wall material is constructed on the front side of the ground and the ground is reinforced by the retaining wall, wherein the wall material is composed of a geocell having a restraint portion for restraining a filling material by joining a plurality of substantially strip-shaped belt members at predetermined intervals and separating non-joined portions between the belt members from each other, the geocell includes a specific geocell including a plurality of normal belt members having substantially the same height dimension and a specific belt member arranged in the front row and having a larger height dimension than the normal belt members, in the step of forming a wall portion by stacking a plurality of the specific geocells vertically on the front side of the ground, the wall portion is arranged such that the specific belt members of the specific geocells are in the front row, and a filling material is charged by separating non-joined portions between the belt members of the specific geocells by a predetermined width in the front-rear direction. When stacking another specific geocell vertically on the upper stage of the specific geocell, the lower end portion of the specific belt member of the upper-stage specific geocell is stacked so as to overlap behind the upper end portion of the specific belt member of the lower-stage specific geocell. A reinforced earth retaining wall construction method characterized by this.

2. The reinforced earth retaining wall construction method according to Claim 1, wherein the height dimension of the specific belt member is about 5 to 10% larger than the height dimension of the normal belt member.

3. The reinforced earth retaining wall construction method according to Claim 1, wherein the uppermost joint portion between the specific belt member and the normal belt member joined thereto is joined at a position separated downward by a predetermined distance from the upper end of the normal belt member.

4. The geocell includes, in addition to the specific geocell, a normal geocell including a plurality of normal belt members having substantially the same height dimension, The reinforced earth retaining wall construction method according to any one of Claims 1 to 3, further comprising a second step of continuously providing the normal geocell from the rear surface of the specific geocell constituting the wall portion toward the ground.

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