JP2002356851A - Reinforcement structure and method of embankment - Google Patents

Abstract

(57) [Abstract] [Problem] To create an embankment reinforcement technique effective for preventing an embankment built on soft ground from sliding and breaking due to shear force or the like at the time of an earthquake or flood. SOLUTION: A cutting material 7 having smooth front and back surfaces is laid between a base 1b of an embankment 1 and a foundation ground 3, and the embankment 1 and the foundation ground 3 are cut off. The laying direction of the trimming material 7 is as follows.
Either the width direction or the longitudinal direction of the embankment 1 may be used. Edge cutting material 7
Does not necessarily have to be laid at the center of the top end of the embankment 1, which has a high effective loading pressure and is difficult to liquefy. Edge cutting material 7 shape
It may be flat, but may have a smooth curved surface like a U-shaped sheet pile for improving rigidity. Further, a steel material in which rust prevention treatment is applied to the upper and lower surfaces is preferable. An earth retaining member for embankment of the buttock is fixedly provided at the end of the butt edge on the butt end. Edge cutting material 7
May be buried in the case of a new embankment, but in the case of reinforcing an existing embankment, the embankment is laid horizontally at the bottom 1a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for reinforcing an embankment against an external force that may cause the embankment to collapse, such as when an earthquake or flood occurs, and more particularly, to an embankment built on soft ground. The present invention relates to an embankment reinforcing technique that is effective for preventing sliding and destruction due to shear force or the like.

[0002]

2. Description of the Related Art Reinforcement of embankment structures such as river embankments, roads, railways, etc. is carried out for each type of embankment structure in consideration of its function and structural characteristics, earthquake, flood, infiltration or washing. Countermeasures for each phenomenon such as excavation have been proposed and implemented.

[0003] The following embankment methods have been conventionally implemented.

[0004] 1. FIG. 5 shows a schematic vertical sectional view for explaining the steel sheet pile cutoff method. The steel sheet pile cutoff method is as shown in the figure.
In order to prevent the embankment 1 from being destroyed, a sheet pile 2 such as a steel sheet pile is driven into the bottom 1a of the embankment 1 and, depending on the rigidity of the sheet pile wall 2, the foundation ground 3 directly below the base of the embankment 1 or further the supporting ground 4 In order to prevent deformation of the embankment 1 by embedding it to a depth reaching the depth (referred to as “prior art 1”). That is, in this construction method, the embankment 1 is formed by driving the sheet pile wall 2 to form a kind of structural skeleton portion 5 that includes the embankment 1 and the foundation ground 3, so that the embankment 1 is soft under the base of the embankment 1. By closing the foundation ground 3 from the foundation ground 3 in another area, the deformation of the embankment is suppressed.

However, when the foundation ground 3 contains a remarkably thick soft layer or when the scale of the embankment 1 is remarkably large, the external force acting on the foundation ground 3 or the embankment 1 becomes remarkably large in the steel sheet pile closing method. Therefore, the original purpose of the method may not be achieved.

[0006] 2. Ground improvement method FIG. 6 is a schematic vertical sectional view for explaining the ground improvement method. In the ground improvement method, as shown in the figure, the portion of the inner soft layer 8 of the foundation ground 3 is removed / replaced by a sand replacement method, a consolidation method, a compaction method, or the like to improve the foundation ground 3, and thus the soil is improved. This is intended to suppress the collapse of the embankment 1 (referred to as “prior art 2”). In other words, this construction method aims to prevent the collapse of the embankment 1 immediately above the ground by suppressing the softening and deformation of the foundation 3 by improving the foundation 3 to be solid.

However, when the foundation ground 3 contains a remarkably thick soft layer, or when the size of the embankment 1 is extremely large, the foundation improvement method is applied to the foundation ground 3 and the embankment 1 similarly to the steel sheet pile closing method. Since the acting external force becomes extremely large, the original purpose of the method may not be achieved.

[0008] 3. Geogrid Method and Its Improved Technology FIG. 7 shows a schematic vertical sectional view for explaining the geogrid method. Geogrid method, as shown in the figure,
An embankment reinforcing material generally referred to as a geogrid material 6 such as a high-strength synthetic fiber or a synthetic resin net is used as a kind of tension material and laid inside the embankment 1 (referred to as “prior art 3”). In this way, the embankment 1 itself is strengthened to suppress its collapse.

As an improved technique of the geogrid method, Japanese Patent Application Laid-Open No. H11-269880 discloses that a plurality of thin steel sheets having a large number of embossed projections or punched projections formed as a tensile material 2 are laid in an embankment 1 in plural layers. , Tensile material 2
There is disclosed a technique for strengthening and improving the fixation between the ground 1 and the embankment 1 (referred to as “prior art 4”). Prior art 4 is intended to suppress the collapse by strengthening the embankment 1 itself, similarly to the geogrid method.

According to the prior art 4, the reinforcement of the embankment 1 can be further improved as compared with the geogrid method. However, the reinforcement concept of the embankment 1 in the prior art 4 is intended to suppress the collapse of the embankment 1 by strengthening the fixation between the tension member 2 and the embankment 1 and strengthening the embankment 1 itself, similarly to the geogrid method. However, the following problem remains.

That is, although the embankment 1 itself is reinforced, in the prior art 4, since a large shear force is easily transmitted to the ground of the embankment 1, the embankment 1 is easily cracked when an earthquake occurs.
Once a crack is formed, in the embankment 1 provided on the ground where the water level around the river or the like may become relatively high, the crack becomes a water supply (Mizumichi), and the penetration failure of the embankment 1 may be caused. is there. On the other hand, in the prior art 4, it is expected that the effect of suppressing the occurrence of cracks inside the embankment 1 at the time of an earthquake or the like is expected by laying the tension members 2 in the embankment 1 in a plurality of steps. However, in that case, there is a problem that the construction period and the cost are increased.

[0012]

As described above, the prior arts 1 to 4 have an effect of improving their intended purposes and are effective techniques, but on the other hand, the above-mentioned problems have not been solved. is the current situation.

Therefore, the present inventors have improved the above-mentioned problems comprehensively, and especially when a large vibration such as an earthquake occurs, the foundation ground softens and the embankment causes fatal destruction. Ground structures that can prevent
It is an object of the present invention to develop a technique for constructing in a method with good workability and excellent economy.

In order to achieve the above object, the present inventors have proposed that in the present invention, instead of the tensile material 2 which is a laying material conventionally used as a reinforcing material for the embankment 1, the embankment 1 may be used in the embankment 1. Using a laying material as a new reinforcing means of the embankment 1, which is provided with a function of suppressing the shearing of the embankment and a function of preventing the propagation of the shear force from the foundation ground 3 to the embankment 1.
The task was to create an embankment reinforcement technique.

[0015]

The present invention has been intensively studied in view of the above-mentioned object and solution of the present invention.

There are various forms of embankment failure.
As shown in FIG. 8, as the case where the most fatal destruction occurs, the base ground 3 immediately below the embankment 1 is liquefied and loses the bearing capacity at the time of the earthquake, and the liquefied base ground 3 flows to the side, Following this, attention was paid to the form of destruction in which the upper embankment 1 flows, sinks, and collapses. In the figure, the foundation ground 3
Is indicated by 3, and the state after the embankment 1 subsides or collapses is schematically indicated by a thick chain line 11.

In order to prevent the destruction of the embankment 1 caused by such softening and flow of the foundation ground 3 at the time of occurrence of an earthquake or the like, the foundation 1b in contact with the base 1b of the embankment 1 and immediately below the embankment 1 3 and an edge material such as a steel plate is interposed therebetween, and the front and back surfaces of the edge material are formed smoothly to reduce the friction coefficient. If the embankment 1 and the foundation ground 3 are trimmed in this way, and the frictional force between the trimming material and the foundation ground 3 and between the trimming material and the embankment 1 is reduced, even if the embankment 1 slides and breaks. Even if it occurs, even if the foundation ground 3 liquefies and flows to the side when an earthquake occurs, the embankment 1 does not follow it, and the softened foundation ground 3 also has an uneven load of 1 weight on the embankment. And concentrated load does not act, and it is possible to avoid catastrophic damage.

The inventors have obtained the above-mentioned original idea.
Then, in order to verify the effect of the idea, an effective stress analysis method was tried. The following is an example of the verification result.

The main analysis conditions are as follows, and the analysis was made for the case where no measures were taken and the case where the edge cutting material was applied to reinforce the embankment base.

Analysis model: embankment height = 5 m, embankment top width =
3 m, slope = 1: 2 Reinforcement plate (edge material): Material = steel plate, Young's modulus E = 2.1
× 10 ⁷ (tf / m ² ), thickness = 5 mm, cross-sectional area A = 5.
0 × 10−3 (m ² / m), second moment of area I =
7.0 × 10 −9 (m ⁴ / m) FIG. 1 illustrates the above analysis results. FIG. 7A shows the result when no measures are taken, and FIG. 10B shows the reinforcing material (edge cutting material).
Is applied to reinforce the embankment base.

According to the figure, in the case where no countermeasures are taken, the foundation ground 3 is greatly deformed due to softening due to the earthquake, and the embankment 1 is largely settled ((a) in the figure). When the embankment base is reinforced, it is confirmed that the foundation ground 3 is deformed to some extent due to softening due to the earthquake, but the deformation of the embankment 1 and its subsidence are suppressed ((b) in the same figure).

The present inventors have made the present invention based on the above findings. The summary is as follows.

In the reinforcing structure for an embankment according to the first aspect of the present invention, a smooth edge-cutting material is buried or driven between the base of the embankment and the upper surface of the foundation ground of the embankment. In addition, the embankment and the foundation ground are cut off by the cutting material.

Here, the material of the edge-cutting material, its size and shape must be rigid enough to be cast on the base of the existing embankment and penetrate the full width of the embankment.
However, in the case of a reinforcing structure in which an edge-cutting material is buried when embanking a new embankment, the rigidity that can withstand the above-described casting is unnecessary. The laying work can be performed without any problem by arranging it on the foundation ground and burying the trimming material on it so that the base of the embankment comes on it, and it breaks or holes due to the embankment weight It is necessary that there is nothing. However, it is necessary that both the existing embankment and the new embankment have corrosion resistance as a cutting material.

In the present invention, the reason why both the front and back surfaces of the trimming material are required to be smooth is to reduce the frictional resistance at the interface between the trimming material and the embankment and the interface between the trimming material and the foundation ground. The purpose of this is to prevent the deformation of the foundation ground softened by the occurrence of an earthquake or the like from being transmitted to the embankment as much as possible, thereby aiming at contributing to the suppression of the slip failure of the embankment.

Further, in the present invention, in the reinforcing structure in which the edge cutting material is “buried” or “poured” into the embankment,
"Buried" refers to the reinforcement structure of the embankment when a new embankment is constructed by arranging trimming materials on the upper surface of the foundation ground and then embankment is laid. The term “reinforcement” is used to refer to a reinforcement structure of an embankment in a case where an edge material is newly driven into the base of the embankment with respect to an existing embankment. In this specification, as a term including both burying and casting,
The term "laying" is used.

According to a second aspect of the present invention, in the reinforcing structure for an embankment, in the first aspect of the present invention, the boundary area between the embankment and the foundation ground by the margin material is a boundary between the embankment and the foundation ground. Does not exist in the whole area of the boundary, but exists only in a part of the boundary. Moreover, the marginal area is formed by extending from the bottom of each slope of the slope located on both sides of the embankment to a predetermined position toward the center of the top of the embankment, near the top ends of both sides. Is limited to the above-mentioned boundary region.

[0028] As in the second aspect, the trimming material is laid only in an area within a predetermined range near the slope of the embankment,
The reason why the embankment reinforcing structure of the type not laid at the center of the embankment top end also contributes to achieving the object of the present invention is as follows. That is, the base ground area (referred to as “P area” in this specification) corresponding to the zone immediately below the center of the embankment top end is the base ground area (referred to as “Q As compared to the "area", the pressing force tightened by the embankment weight is larger, and therefore, the degree of softening and flowing in the foundation ground is smaller in the "P area" than in the "Q area". Therefore, although it depends on the width and scale of the embankment, it is sufficient if the trimming material is laid only in an area within a predetermined range near the slope of the embankment, and the construction period and cost are reduced, so that it is economical. This is advantageous.

The reinforcing structure of the embankment according to the third aspect of the present invention is the embankment reinforcing structure according to the first or second aspect, wherein the length direction of the edge cutting material has the following characteristics. That is, it is characterized in that the length direction of the trimming material is buried or cast at right angles to the longitudinal direction of the embankment.

The third aspect of the present invention refers to a reinforcing structure of an embankment when reinforcement work is performed on an existing embankment or when an embankment is laid first and then a reinforcement work is performed. . In the case where the trimming material is to be cast later on the completed embankment, the setting direction of the trimming material should be substantially perpendicular to the longitudinal direction of the embankment.
It is realistic considering the possibility of construction. Also, in the construction work for newly embankment, a border material is disposed on the upper surface of the foundation ground, and even when the embankment is formed thereon, the size of the normal embankment width is set to several meters to 10 m. Assuming that the length is about several meters, from the viewpoint of workability such as handling of the trimming material at the time of construction, for example, the moving direction of the hoist (crane truck or the like) when laying the trimming material and the efficiency of the arm expanding and contracting operation, etc. The embedding direction of the trimming material, that is, the laying direction, is desirably substantially perpendicular to the longitudinal direction of the embankment.

The reinforcing structure of the embankment according to the fourth aspect of the present invention is characterized in that, in the first to third aspects of the present invention, the shape of the edge cutting material is substantially flat.

Here, the phrase "the shape of the edging material is substantially flat" means that the edging material is, for example, a cut plate-shaped steel plate, a thin steel plate wound around a coil, or a thinner hoop-shaped thin plate. This means that a flatness sufficient to be obtained when the steel sheet is cut to a predetermined length suitable for the embankment width while unwinding the steel sheet is sufficient.

According to a fifth aspect of the present invention, in the reinforcing structure for an embankment, in the invention according to the third aspect, the shape of the edging material that is driven at right angles to the longitudinal direction of the embankment is such that the edging material has It is characterized in that the cross-sectional shapes when cut in the vertical direction at any position parallel to the longitudinal direction of the embankment are all similar and exhibit a shape including a smooth curved portion.

A fifth aspect of the present invention relates to an embankment reinforcing structure which is desirable in terms of workability, particularly when the edge cutting material is cast or buried long in the width direction of the embankment, particularly when the edge cutting material is "casted". is there. As the shape of the edge cutting material, for example, a U-shaped steel sheet pile having a “stiffness increased” cross-sectional shape becomes practical, so the case where the edge is cast on an existing embankment is particularly taken up, and the edge cutting at that time is taken up. This limits the shape of the material to the desired shape.

Further, since the edge material has a smooth curved portion in the vertical cross-sectional shape like a U-shaped steel sheet pile, the above-mentioned "increase in rigidity" of the edge material is exerted, and the durability of the edge material is improved. Contribute to improvement.

According to a sixth aspect of the present invention, in the reinforcing structure for the embankment, in the first aspect of the present invention, the edge cutting member is formed of a steel plate having both upper and lower surfaces subjected to a rust-proof treatment. Is characterized by the fact that

Here, the edging material is subjected to a rust-proof treatment,
And since it is provided on the upper and lower surfaces of the trimming material, it contributes to the improvement of the corrosion resistance. In particular, when a steel plate is used as the edging material, it contributes to improving the durability of the edging material by enduring the severe corrosive environment in the embankment.

According to a seventh aspect of the present invention, in the reinforcing structure for an embankment according to any one of the first to sixth aspects, the edge of the edge-cutting material on the side of the butt end is filled with a butt-side embankment. It is characterized in that the fastening members are fixedly provided at both ends of the trimming member.

Since the earth retaining members of the embankment are fixed to both ends of the trimming material, a stopper function against a shift between the trimming material and the embankment at the time of an earthquake or the like is exerted, and the trimming material is used. The embankment reinforcement effect is further enhanced.

Next, a method of reinforcing an embankment according to the invention of claim 8 relates to a method of reinforcing a new embankment. That is, on the upper surface of the foundation ground, a flat edge material having both a smooth surface and a predetermined width and a predetermined length and length, or a smooth edge having a smooth curved surface formed in part and having a flat shape as a whole. Laying materials. Then, embankment is laid on the upper surface of the trimming material to reinforce the embankment.

As described above, it is possible to easily lay the edge-cutting material, thereby preventing slip failure of the embankment on soft ground.

According to a ninth aspect of the present invention, in the reinforcing method of the embankment, in the invention of the eighth aspect, a range of an area where the edge cutting material is laid at a boundary portion between the foundation ground and the embankment is defined as:
The present invention is characterized in that the embankment is limited to a predetermined position from the bottom of each side slope of the embankment toward the center of the top end of the embankment.

In this method, the laying area of the trimming material is limited only to the vicinity of the slope of the embankment, except for the center of the top end of the embankment, which has a high effective loading pressure and is hard to liquefy even during an earthquake. That is. Even with this construction method, measures are taken for a soft layer where liquefaction is likely to occur, so that it is possible to prevent slip failure of the embankment on soft ground.

An embankment reinforcing method according to a tenth aspect of the present invention relates to a method for reinforcing an existing embankment. That is, in the direction perpendicular to the longitudinal direction of the embankment and in the horizontal direction from the bottom of the existing embankment, the front and back surfaces are both smooth, and the flat edged material having a predetermined width and length, or a part thereof. This is a method in which the embankment is reinforced by placing a trimming material having a smooth curved surface and exhibiting a flat plate shape as a whole.

According to this method, the laying of the trimming material can also prevent the sliding failure of the embankment in the soft ground, in accordance with the laying of the trimming material for the new embankment in the invention according to claim 8.

According to the eleventh aspect of the present invention, there is provided a method of reinforcing an embankment according to the tenth aspect of the present invention, wherein the area of the edge cutting material to be cast from the bottom of the existing embankment to the inside of the embankment. Of the embankment is limited to a predetermined position from the bottom of each side of the embankment to the center of the top of the embankment. According to this method, the laying of the trimming material can prevent the sliding failure of the embankment in the soft ground, in accordance with the laying of the trimming material on the new embankment in the invention according to claim 9.

[0047]

Next, an embodiment of the present invention will be described.

FIG. 2 explains a preferred embodiment of the present invention, and is a schematic sketch including a vertical section of a part of the reinforcing structure of the embankment.

An edge material 7 is laid between the base 1b of the embankment 1 and the upper surface of the foundation ground 3, and the embankment 1 and the foundation ground 3 are cut off by the edge material 7.
A long edge cutting member 7 is laid in parallel with the width direction of the embankment 1. In this case, the edge material region by the edge material 7 extends over the entire boundary region between the embankment 1 and the foundation ground 3. As the edging material 7, a steel plate whose front and back surfaces (upper and lower surfaces) are somewhat smooth is used. In addition, since it is desired that the edge cutting member 7 has corrosion resistance in a soil environment, it is preferable to use, for example, a steel plate or the like whose front and back surfaces are subjected to rust prevention treatment such as hot-dip galvanizing. The thickness and width of the steel plate should be appropriately determined according to the height and width of the embankment 1, and the thickness is determined in consideration of the service life. The smaller the gap between the adjacent trimming members 7 is, the smaller the frictional resistance between the trimming material 7 and the embankment 1 and the frictional resistance between the trimming material 7 and the foundation ground 3 are.
Even if the soft foundation ground 3 is deformed, it is desirable to suppress the deformation of the embankment 1 that attempts to follow the deformation. Edge cutting material 7
It is also an important condition that the front and back surfaces of the steel sheet as described above are smooth for the above reasons.

Regarding the laying direction of the edging material 7, even if the edging material 7 is laid in a direction perpendicular to the laying direction in FIG. Since the relationship between them is similar to the case in FIG. 2, the edge cutting member 7 exhibits the same operation and effect as in FIG. 2 when an earthquake occurs.

Regarding the material and form of the edging material 7, any material can be used as long as the function of the edging material 7 can be exhibited.
It is not necessary to limit to the steel sheets as described above. As described above, a thin steel sheet wound around a coil or a hoop-shaped thin steel sheet having a smaller width may be unwound and cut into a predetermined length suitable for the embankment width. However,
In this case, it is necessary to provide specifications having sufficient strength, rigidity, and durability so that the function of the edge cutting member 7 is sufficiently exhibited.

From the viewpoint of ensuring strength and rigidity, metals such as steel are desirable, and cheap materials are preferred. Regarding the form, a curved surface may be formed as long as the front and back surfaces of the edge cutting member 7 are somewhat smooth from the viewpoint described above. Particularly, from the viewpoint of securing the rigidity, for example, U-shaped sheet piles are desirable.

FIG. 3 is an explanatory diagram of an example of a reinforcing structure of the embankment in the case where a U-shaped steel sheet pile is used as a edging material at the base in the reinforcing structure of the embankment described in FIG. In this case, since the cross section R of the curved portion on the front and back surfaces of the edge material 7 is relatively large, the frictional resistance between the edge material 7 and the foundation ground 3 and between the edge material 7 and the embankment 1 are suppressed to be small. Others
Even the edge cutting material 7 using flat steel sheet piles is desirable because it conforms to U-shaped steel sheet piles.

Next, a description will be given of an embankment reinforcing structure in the case where the trimming material is laid only in the vicinity of the bottom of the embankment on both sides of the embankment, but not at the center of the top end of the embankment. FIG.
Is an explanatory view of such an embodiment.

In FIG. 4, even if the foundation ground 3 was originally soft, the foundation ground located in the lower part of the center of the top end of the embankment 1 is solid due to the action of the large load received from the embankment 1. The basic ground zone 3a can be formed. In such a solid foundation ground zone 3a, generally,
Softening and deformation of the ground during an earthquake or the like are suppressed. Therefore, even if the foundation ground 3 is originally soft, if such a firm foundation ground zone 3a is formed therein, the border between the foundation ground zone 3a and the embankment 1 is cut off. The material 7 may not be laid. Here, the evaluation regarding the formation of the solid foundation ground 3a is "Judgment of liquefaction of sandy ground in 7-5 of Road Bridge Specifications and Explanation V Seismic Design Section 5".
May be performed based on

A member for preventing the embankment at the bottom of the embankment from collapsing at the time of an earthquake or the like is fixed to all the edge cutting members 7 described above at the end of the bottom of the embankment. Is desirable. As the retaining member for such purpose, for example, a rectangular steel plate is bent and formed into an L-shape such that the cross-sectional shape parallel to the short side thereof is such that the included angle of two sides is substantially equal to the inclination angle of the embankment 1. Using a member, a portion corresponding to the bottom surface of the retaining member is fixed to both ends of the trimming member 7 by tightening bolts and nuts. In this way, a stopper function against the gap between the edge material and the embankment at the time of occurrence of an earthquake or the like is exhibited, and the effect of reinforcing the embankment by the edge material is further improved.

Here, in order to maintain the scenery after the reinforcement work of the embankment 1, the sloped portion of the edging material retaining member is
It is desirable to be buried inside the embankment 1. Therefore, it is preferable that the rising position of the inclined surface of the L-shaped fitting be somewhat inward.

Next, a method of constructing the embankment structure having the embankment reinforcing structure according to the present invention will be described.

1. First, an embodiment of a method for reinforcing the embankment when a new embankment is installed will be described.

In FIG. 2, an edge-cutting material 7 is laid on the upper surface of the soft foundation ground 3. Next, a predetermined embankment 1 is buried thereon. The edge cutting member 7 is a flat plate having both smooth front and back surfaces, or a smooth curved surface formed in a part thereof, but a flat plate shape is used as a whole. At this time, the laying direction of the edging material 7 is to be laid in a direction perpendicular to the longitudinal direction of the embankment 1 in the same figure, but the operation and effect of the edging material 7 exhibited in the present invention described above. From the perspective,
The laying direction may be parallel to the longitudinal direction of the embankment 1.
However, it is desirable from the viewpoint of the above effect to minimize the gap between the edge cutting member 7 and the adjacent edge cutting member in the longitudinal direction and the width direction.

Further, as a range of the area where the trimming material is laid, it is not always necessary to lay the entire area of the boundary area between the foundation ground and the embankment. As described above, it is not necessary to lay a border material in the boundary area between the foundation ground and the embankment, which corresponds to the upper part of the area where the solid foundation ground zone 3a shown in FIG. 4 exists.

[0062] 2. Next, an embodiment of a method for reinforcing an embankment with respect to an existing embankment will be described.

In FIG. 2, a predetermined edge-cutting material 7 is cast horizontally from the bottom 1 b of the existing embankment 1 laid on the soft foundation ground 3 toward the inside of the embankment 1. Use a commonly used casting machine. The specifications of the trimming material 7 conform to those in the embodiment of the method for reinforcing the new embankment. However, in the method of reinforcing the existing embankment, a construction is adopted in which the rim material 7 is driven into the soil.
Use a stiffener that is higher in rigidity than the trimming material used to reinforce the new embankment and has sufficient rigidity so that it will not buckle or break when it is cast.

Also, as for the range of the area where the edge cutting material is laid, it is not always necessary to lay the entire area of the boundary area between the foundation ground and the embankment, as in the case of the reinforcement of the new embankment.
It is not necessary to lay a trimming material in the boundary area between the foundation ground and the embankment, which corresponds to the upper part of the area where the solid foundation ground zone 3a shown in FIG. 4 exists.

In any of the above-mentioned reinforcing methods of the new embankment and the existing embankment, regarding the form and material of the edge cutting material, the steel plate or the U-shaped steel sheet pile has a small surface friction coefficient, a high rigidity, and durability. It is desirable because it is excellent. In addition, in the reinforcement of the new embankment, the laying of the edge cutting material is not necessary because it does not need to be cast, so it is not limited to the steel plate cut plate, it is cut to the appropriate length while rewinding the steel coil or steel hoop. It is also possible to provide Further, in order to ensure corrosion resistance in a soil environment, steel sheets which have been subjected to surface rust prevention treatment using, for example, molten zinc are advantageous in terms of cost. In addition, by providing an earth retaining member for embankment at the bottom of the edge of the edge material, the gap between the edge material and the embankment at the time of an earthquake or the like can be suppressed.

[0066]

As described above, according to the embankment reinforcing method and the reinforcing method of the present invention, the following effects can be obtained. That is,
(1) By using a marginal material such as a steel plate as a laying material, a marginal structure can be formed between the embankment and its foundation, so that the foundation ground softens and flows when an earthquake occurs. Accordingly, it is possible to prevent slip failure of the embankment that is fatal to the embankment.

(2) In the boundary region between the embankment and the foundation ground, for example, at the base of the embankment, a laying material having a function as an edge cutting material, not a laying material having a function as a conventional tensile material, Moreover, it is not necessary to provide a plurality of steps in the embankment as in the prior art, and a desired effect can be sufficiently exerted only by laying one step. Therefore, the reinforcement of the embankment can be simply and quickly performed, and the construction cost can be significantly reduced as compared with the conventional method.

According to the present invention, it is possible to provide an embankment reinforcing structure and a reinforcing method which can obtain the above-mentioned effects, and industrially useful effects are brought.

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of comparing the effectiveness of the present invention in the case of laying a “border material” and reinforcing the embankment base with the case where no measures are taken using an effective stress analysis method.

FIG. 2 illustrates an example of a preferred embodiment of the present invention;
It is a schematic sketch containing a partly perpendicular cross section of the reinforcement structure of an embankment.

FIG. 3 is a view for explaining another example of the preferred embodiment of the present invention, and is an explanatory view of an example of a reinforcing structure of an embankment when a U-shaped steel sheet pile is used as a rim material in FIG. 2;

FIG. 4 is a view for explaining still another example of the preferred embodiment of the present invention, in which the trimming material in FIG. 2 is laid only in the region near the bottom of the embankment on both sides of the embankment, It is explanatory drawing of the embankment reinforcement structure example in case it is not laid.

FIG. 5 is a diagram illustrating a steel sheet pile shutoff method as an example of a conventional technique.

FIG. 6 is a diagram illustrating a ground improvement method as another example of the related art.

FIG. 7 is a diagram illustrating a geogrid method as another example of the related art.

FIG. 8 shows the settlement of an embankment during an earthquake according to the prior art.
It is a schematic diagram explaining a collapse state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Embankment 1a Hojiri 1b Embankment base 2 Tensile material 3 Foundation ground 3a Solid foundation ground zone 4 Supporting ground 5 Structural skeleton 6 Geogrit material 7 Edge material 8 Soft layer 9 Removal replacement part 10 Replacement unnecessary part 11 Subsidence of embankment Schematic shape of collapse 12 River 13 Sliding surface

Claims (11)

[Claims] In a reinforcing structure for an embankment, a smooth edge material is buried or laid between a base portion of the embankment and an upper surface portion of a foundation ground of the embankment, and the edge material is used for the embankment. An embankment reinforcing structure, wherein the embankment and the foundation ground are cut off. 2. In a boundary between the embankment and the foundation ground by the marginal material, a marginal area is a part of the boundary, and a top end of the embankment is measured from respective slopes of both side slopes of the embankment. The embankment reinforcing structure according to claim 1, wherein the embankment is limited to an area of the boundary near the both side slopes extending to a predetermined position toward a center. 3. The embankment according to claim 1, wherein a length direction of the trimming material is buried or cast at right angles to a longitudinal direction of the embankment. Reinforcement structure. 4. The reinforcing structure for an embankment according to claim 1, wherein the shape of the edge cutting material is a flat plate. 5. The shape of the trimming material, which is formed at right angles to the longitudinal direction of the embankment, is such that the vertical cross-sectional shape of the trimming material at an arbitrary position parallel to the longitudinal direction of the embankment is similar. 4. The embankment reinforcement structure according to claim 3, wherein the reinforcement structure includes a smooth curved portion. 6. The reinforcing structure for an embankment according to claim 1, wherein the edge cutting member is made of a steel plate having both upper and lower surfaces subjected to a rust prevention treatment. 7. The material for embankment of a slope end embankment is fixedly attached to the edge cutting material at the end of the edge cutting material on the side of the slope end. The embankment reinforcement structure described in Crab. 8. A method for reinforcing an embankment, wherein a flat edged material having both a smooth surface and a predetermined width and a predetermined length and length, or a smooth curved surface partially formed on an upper surface portion of a foundation ground. A method for reinforcing a newly-built embankment, comprising: laying a trimming material having a flat plate shape as a whole, and then embanking an embankment on an upper surface portion of the trimming material. 9. A range of a region where the edge-cutting material is laid at a boundary portion between the foundation ground and the embankment extends from respective bottoms of both side slopes of the embankment toward a center of a top end of the embankment. The method for reinforcing a new embankment according to claim 8, wherein the embankment is limited to a predetermined position. 10. A method for reinforcing an embankment, wherein both the front and back surfaces are smooth and have a predetermined width and length from the bottom of the existing embankment in a direction perpendicular to a longitudinal direction of the embankment and in a horizontal direction. A method for reinforcing an existing embankment, comprising casting a flat edge material, or a flat edge material having a smooth curved surface partially formed and exhibiting a flat shape as a whole. 11. The range of the area where the edge-cutting material is cast from the bottom of the bank of the existing bank to the inside of the bank is from the bottom of each side of the bank of the bank, to the top of the bank. The method for reinforcing an existing embankment according to claim 10, wherein the embankment is limited to a predetermined position toward the center.