JPH054493B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for constructing a reinforced soil structure using a unique reinforcing material with a small number of members as a tensile reinforcing material buried in an embankment layer. The present invention relates to a method for constructing a reinforced earth structure that exhibits a reliable reinforcing effect even when using soft earth and sand with low frictional force, has excellent workability, and has little deformation.

[Conventional technology]

When constructing reinforced earth structures (earth retaining structures),
Conventionally, a construction method is known in which a plurality of linear flexible reinforcing materials are laid in layers and soil is piled up. (Refer to Special Publication No. 44-25174). This construction method uses soil particles,
Since the earth retaining structure is maintained only by the frictional force generated between the reinforcement material and the reinforcing material that comes into frictional contact with the earth retaining structure, it is not suitable for soils with low frictional force.

In order to solve this drawback, as shown in FIG. It has been proposed to use a reinforcement consisting of a wall panel 4 connected to the free end 3 of the wall panel. but,
With this method, when earth pressure is applied to the wall panel 4, stress is concentrated only on the pressure-bearing panels 2, 2...2, so
The pressure-bearing panels 2, 2...2 are easily displaced to the front.

In addition, when constructing this reinforcing material, first, the bearing panels 2, 2...2 are installed on the embankment layer, soil is poured out from above, and it is compacted and buried in the embankment layer, but at this time, The reinforcing material is deformed due to embankment and compaction, and the surface of the bearing panel cannot be held correctly parallel to the wall panel 4. For this reason, the first
As shown in Fig. 0 b, grooves 6, 6...6 are formed in the embankment layer 5.
Dig the grooves 6, 6...6 and install the bearing panels 2, 2...
2 is accurately placed and backfilled, and then reinforcement is buried above it in the embankment layer, as shown in Figure 10c.

However, in this construction method, the trenches 6 must be dug in the embankment layer 5, which complicates the process, and furthermore, the embankment around the bearing panels 2, 2, . . . 2 becomes loose. When the embankment is further compacted, the bearing panel 2,
2...2 tends to tilt back and forth or left and right as shown in FIG. 10c. For this reason, the pull-out resistance against the earth pressure acting on the wall panel 4 is significantly reduced compared to the original design. The reason for this is that if the areas of the pressure-bearing panels 4 are the same, the pressure-bearing panels 4
This is because the maximum pull-out resistance is obtained when the tensile member is perpendicular to the surface of the tension member, but the pull-out resistance decreases significantly as the inclination of the pressure-bearing panel 4 increases with respect to the tension member. .

In addition, since the buried soil around the bearing panel 4 inside the groove 6 is difficult to be compacted, when earth pressure acts on the wall panel 4 and pull-out force acts on the reinforcing material, the bearing panel 4 As a result, the wall panel 4 is also displaced forward, resulting in an embankment structure with large deformation. Further, even when using a square pressure-bearing panel as shown in FIG. 10, the pressure-bearing panel must be thick in order to withstand the bending stress caused by resistive earth pressure. For this reason, the above-mentioned known reinforcing materials not only have extremely complicated workability, but also require a large number of members, cause large displacements of the wall surface, and are difficult to obtain a reliable reinforcing effect.

Further, reinforcing materials made by combining rod-shaped bodies in a mesh shape are also known. (Tokuko Showa 59
-Refer to Publication No. 20821). In this reinforcing material, the vertical members of the mesh act as tension members, and the horizontal members act as pull-out resistors, so it can be effectively used even in soils with low frictional force, and during construction, it can be installed as is on the embankment layer. It can be put into use by simply rolling out the soil and compacting it.

Further, as shown in FIG. 11a, a pressure receiving body 7 having a horizontally elongated upright resistance plate, and a plurality of pressure receiving bodies passing through this pressure receiving body and fixed to the pressure receiving body with screw grooves 8 at desired intervals. A reinforcing material consisting of a book rod-shaped tensile material 1 has also been developed. 9 is a bag nut, and 9' is a nut.

As mentioned above, a reinforcing material in which a plurality of tensile members are connected to a resistor in the transverse direction, such as a reinforcing material in which rod-shaped bodies are combined in a mesh shape or the reinforcing material shown in FIG. 11a, has a large pull-out resistance; In addition, since multiple tensile members in the longitudinal direction are continuous with each other in the transverse direction, they maintain their own shape and have structural strength, so even if they are installed on an embankment and the soil is rolled out and compacted, no deformation will occur. Moreover, it has the advantage of being excellent in workability and reinforcing effect. However, as shown in FIG. 11b, a large bend occurs in the cross member (pressure receiving body 7) due to the resistance earth pressure P resisting the pulling force F, and in order to reduce the bending, the longitudinal tensile member 1 This results in an uneconomical structure because the spacing between them must be made smaller than necessary.

Further, FIG. 12 shows an example of a reinforcing material in which a triangular steel rod 1a is attached to the end of the steel rod 1 on the wall panel 4. When such a reinforcing material is used, when earth pressure is applied to the wall panel 4, the steel rod 1a is distorted and deformed as shown by the dotted line, and as a result, the wall panel 4
is displaced forward and becomes a highly deformed retaining wall.

In general, what is essentially required for reinforcement with transverse members is that the transverse members have a surface area sufficient to accommodate the required earth pressure resistance, and the longitudinal members have sufficient surface area to withstand the earth pressure. If the area is sufficient, and if the transverse members are made to have almost no bending, the number of longitudinal and transverse members can be reduced, and very rational reinforcement can be achieved. However, in conventional construction methods, no reinforced earth construction method using reinforcing materials has been developed that focuses on these points.

[Problem that the invention seeks to solve]

Therefore, in order to create a reinforced soil retaining wall in a rational manner, the present inventors believe that longitudinal tensile members should be used that have the minimum number (or cross section) necessary for the earth pressure applied to the wall panel, and that The present invention has been completed by focusing on a structure that can provide the necessary pull-out resistance without causing almost any bending in the lateral members even if the distance between the tensile members in the direction is made as large as possible.

The purpose of the present invention is to use a unique reinforcing material with few parts as a tensile reinforcing material, so that even if soft earth and sand with low frictional force is used as embankment, it can achieve a reliable reinforcing effect, have excellent workability, and have little deformation. ,
It is an object of the present invention to provide a method for constructing a reinforced earth structure that improves the drawbacks of the above-mentioned known techniques.

[Means for solving problems]

In order to achieve the aforementioned object, according to the present invention:
In the method of constructing reinforced soil structures, a tensile reinforcing material is laid on the ground to be embanked, earth and sand is poured out on top of this, and the soil is compacted to form an embankment layer. and an arcuate portion bridging adjacent linear portions, and the arcuate portion swells in the direction in which resistive earth pressure acts.

Hereinafter, the present invention will be explained in detail using the accompanying drawings.

FIG. 1a is a plan view of a specific example of the tensile reinforcing material used in the present invention, which has a straight portion 10 and an arcuate portion 11, and an arbitrary plurality of straight portions 10 are arranged in parallel, Also, the arcuate portion 11 is the straight portion 10
It bridges adjacent comrades and is arranged so as to bulge in the direction of the arrow where resistance earth pressure P acts. F is the tensile force.

The tensile reinforcing material A constructed in this way is shown in Fig. 1b.
As shown in FIG. 7, the end portion 10a of the straight portion 10 is connected to the wall panel 12 with a nut 13 or the like, and a reinforcing structure X is constructed as shown in FIG. 7c, which will be described later.

The above-mentioned tensile reinforcing material A may have a linear portion 10 and an arcuate portion 11 integrally continuous as shown in the first figure, or may have connecting surfaces 11a at both ends as shown in FIG. 2a. A band-shaped arcuate portion 11 having a diameter 11a is bridged between adjacent straight portions 10, 10 as shown in FIG. 2b, and a connecting surface 11a is formed.
The straight portion 10 and the arcuate portion 11 may be configured as separate bodies by connecting them with a nut 14. Further, one arcuate portion 11 may be arranged between the straight portions 10, 10 as shown in the first diagram, and in this case, the arcuate portion 1
1 is preferably at the tip of the straight portion 10 as shown in the first figure. Furthermore, as shown in FIG. 2b, a plurality of arcuate portions 11 may be arranged at arbitrary intervals between the straight portions 10, 10; in this case,
As shown in the third diagram, the resistive earth pressure P is received by the plurality of arcuate portions 11, 11...11, and the tensile force F increases significantly. Furthermore, since the straight portion 10 is connected by the plurality of arcuate portions 11, 11...11, the tensile reinforcing material A itself has structural strength, and therefore the ground 15
Even when the tensile reinforcing material A is laid on top, soil is poured out, and the embankment layer 16 is formed by compaction, the tensile reinforcing material A maintains its shape, making workability easier.

Furthermore, as shown in FIG. 4a, the above-mentioned tensile reinforcing material A has linear portions 10 provided with connecting pieces 10b at the ends as shown in FIG. As shown in FIG. 4c, a plurality of bolts may be connected at the connecting piece 10b using bolts and nuts 17, or as shown in FIG.
Using a material that is twisted and held horizontally (sideways) except for the connecting piece 10b, this straight part 10 is connected to a band-shaped arcuate part 11 at the vertically (vertically facing) connecting piece 10b. Furthermore, as shown in FIG. 5b, the strip-shaped vertically oriented straight portion 10 and the strip-shaped vertically oriented arcuate portion 11 may be integrally and continuously configured.

The end portion 10a of the straight portion 10 and the wall panel 12 may be connected by the method shown in FIGS. 6a and 6b, in addition to the method shown in FIG. 1b. That is, a T-shaped groove 18 may be formed in the upper surface 12a of the wall panel 12, and one end 19 of the tensile reinforcing material A may be locked in this groove 18 for connection. 6th
FIG. 6b is a sectional view taken along line A--A in FIG. 6a.

As the material for the above-mentioned tensile reinforcing material A, a material having steel properties that can be laid on the ground 15 or the embankment layer 16 and maintain its shape is suitable, and specifically, it is preferably made of steel. Furthermore, FRP,
It is possible to use fibers such as aramid fibers and carbon fibers, which have a large tensile force and little strain, and which are impregnated with vinyl chloride or the like as a binder to provide rigidity.

In constructing the reinforced earth structure of the present invention using such a tensile reinforcing material A, first, as shown in FIG. It is laid on the ground 15 so as to bulge, and the end portion 10a is connected to the wall panel 12 with a nut 13.

Next, as shown in FIG. 7b, earth and sand is poured out onto the laid tensile reinforcing material A and compacted to form an embankment layer 16, and the tensile reinforcing material A is further placed on this embanking layer 16 as described above. Lay it in the same way and end 10
A is connected to the wall panel 12 with nuts 13.

Furthermore, the above-mentioned operation is repeated to construct the reinforced earth structure X according to the present invention as shown in FIG. 7c.

In addition, in FIG. 7c, Y is an active area, that is, a slack area, and in this active area Y, it is more rational for the arcuate portion 11 to swell in the direction of the wall panel 12. In this case, arcuate portion 1
1 produces an effect of reducing the active earth pressure acting on the wall panel 12. In this region Y, a plate may be used instead of the arcuate portion 11, or a geotextile net or sheet may be used.

Figure 8 shows a reinforced earth structure X using a semi-elliptical corrugated wall panel 12;
is the same as

Furthermore, Fig. 9 shows Fig. 9 a as a tensile reinforcing material A.
As shown in Fig. 2b, a round rod-shaped reinforcing material in which a straight line portion 10 and an arcuate portion 11 are integrally connected is used, and a wall panel 12 is formed by stacking thin plates in the vertical direction as shown in Fig. 2b. Each layer 20 of the wall panel 12 arranged in the horizontal direction was stacked in a staggered manner as shown in FIGS. 9b and 9c, and the rest was constructed in the same manner as in FIG. 7c. A reinforced earth structure X is shown. FIG. 9c is a partial plan view of FIG. 9b.

[Effect]

The present inventor has developed a tensile reinforcement material with resistance earth pressure P
(shown in Figures 1a and b), the final stable shape of the pressure receiving part almost matches an arc shape, so the shape of the pressure receiving part is formed in an arc shape from the beginning, and moreover, It was discovered that if the bulge is oriented in the direction in which the resisting earth pressure P acts, the tensile reinforcing material hardly deforms, and the present invention was completed. That is, the present invention has, as a tensile reinforcing material, a plurality of straight line portions arranged in parallel and an arcuate portion bridging adjacent comrades of the straight line portions,
By using a reinforcing material with almost no deformation, the arc-shaped part is positioned so that it bulges in the direction in which resisting earth pressure acts, a reliable reinforcing effect can be achieved even when using soft earth and sand with low frictional force as embankment. Therefore, it is possible to construct a reinforced soil structure that exhibits excellent construction properties and exhibits less deformation.

In addition, the stress acting on the tensile reinforcement is shown in Figure 1a,
As shown in b, since the tensile force F is calculated from the earth pressure acting on the wall panel in the straight section and the resistance earth pressure P in the arcuate section, there is no need to consider bending, and therefore, the straight line Even if the interval between the parts is increased, as long as the area of the arcuate part corresponds to the resistance earth pressure P, the minimum number of tensile reinforcing members is sufficient.

As described above, in the present invention, the shape of the pressure-receiving part of the tensile reinforcing material is made into an arc shape, and this bulge is directed in the direction in which resistive earth pressure acts, so that almost no bending occurs in the pressure-receiving part, and tensile force always acts on it. The thin material can resist large earth pressures. For example, a reinforced earth retaining wall with a wall height of 10 m is made using the known reinforcement materials shown in Fig. 11, and in this case, the pressure receiving body 7 is an equilateral angle steel (SS41 100 x 100 x 10 mm), and the longitudinal reinforcing bars are
If SD30 deformed steel bars are used, in order to keep the bending stress acting on the pressure receiving body 7 within an allowable range, the steel bars must be arranged at intervals of 0.34 m in the longitudinal direction. On the other hand, by making the shape of the pressure receiving body arcuate as in the present invention and directing this bulge in the direction of the resisting earth pressure, the arcuate portion is half-sized with a thickness of 3 mm and a length of 10 cm, with the same spacing between the steel bars. A circular steel plate is sufficient, reducing the amount of material used compared to conventional methods.

〔Effect of the invention〕

As described above, the present invention uses the above-mentioned structure with few members as a tensile reinforcing material.
To construct a reinforced earth structure that exhibits a reliable reinforcing effect even if soft earth and sand with low frictional force is used as embankment, has excellent workability, has little deformation, and improves the drawbacks of the above-mentioned known techniques.

[Brief explanation of the drawing]

Figures 1a and 1b are explanatory diagrams showing the relationship between resistance earth pressure and tensile force of the tensile reinforcing material used in the present invention, and Figure 2 a is a perspective view of the arc-shaped portion of the tensile reinforcing material according to the present invention. Fig. 2b is a plan view of a specific example of the tensile reinforcing material having an arc-shaped portion in Fig. 1, and Fig. 3 is an explanation showing the relationship between resistance earth pressure and tensile force of the reinforcing material in Fig. 2. FIG. 4A is another example of an arcuate portion, FIG. 4B is an example of a straight portion, and FIG.
Figure c is a plan view of the tensile reinforcement according to Figures 4a and b, Figures 5a and b are respectively perspective views of other embodiments of the tension reinforcement according to the invention, and Figure 6a is a plan view showing the method of connecting the tensile reinforcing material and the wall panel, and FIG. 6b is a cross-sectional view taken along the line A-A.
7a, b, and c are cross-sectional views showing the construction steps of the method of the present invention, FIG. 8 is a perspective view of another specific example of the structure of the present invention, and FIG. 9a is a A specific example of a tensile reinforcement material, FIG. 9b is a perspective view of a structure constructed using this material, and FIG. 9c is a perspective view of a structure constructed using this material.
FIG. 10a, b, and c are explanatory diagrams showing a known construction process, FIG. 11a is a perspective view of a known tensile reinforcing material, and FIG. 11b is a diagram showing its resistance. It is an explanatory diagram showing the relationship between earth pressure and tensile force,
FIG. 12 is a plan view of another known tensile reinforcement. 10... Straight line part, 10a... End part, 11...
Arc-shaped portion, 12... wall panel, 15... ground,
16... Embankment layer, 19... One end, A... Tensile reinforcing material, X... Reinforced earth structure.

Claims (1)

[Scope of Claims] 1. In a method for constructing a reinforced soil structure, in which a tensile reinforcing material is laid on the ground to be filled, earth and sand is poured out on top of the ground, and earth and sand is poured out and compacted to form an embankment layer, the tensile reinforcing material is A method for constructing a reinforced earth structure consisting of a plurality of straight line sections arranged in parallel and an arcuate section bridging adjacent comrades of the straight line sections, the arcuate section bulging in the direction in which resistive earth pressure acts. . 2. The method of claim 1, wherein the ends of the straight sections are connected to wall panels.