JPH0453204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a stabilization method accompanying the construction of an embankment and a structure thereof.

(Prior Art) In recent years, from the viewpoint of rising land prices or effective use of land, there has been a demand for reinforcement of embankments and construction of embankments having vertical or nearly vertical steep slopes.

Conventionally, as a method for reinforcing embankments and constructing vertical slopes, the Terre Alme method disclosed in Japanese Patent Publication No. 1973-25174 has been known, and since then, many of the construction methods related to reinforced soil have been based on this method. share a common thought.

The skin and reinforcing material, which are the basic components of the Terre Alme construction method, are considered as shown below.
In other words, this skin is a means of retaining soil particles located on or near the free surface of a non-integral particulate material with reinforcement, and does not contribute to the stability of the structure. It was believed that the skin itself must be flexible enough to adapt to the deformation of the soil.

On the other hand, reinforcement materials must be able to withstand large tensile forces so that the integrity of the reinforced soil is not lost.

FIG. 1 is a diagram showing the skin of a conventional reinforced embankment, and FIG. 2 is an explanatory diagram of the concept of reinforcing materials in a conventional reinforced embankment.

In actual design, as shown in Figure 2, the balance of horizontal forces in the horizontal plane ABCD at each height,
In other words, the design is based on a balance between the earth pressure acting on the horizontal piece and the anchoring force obtained by ef, and therefore the reinforcing material is designed to extend far beyond the assumed slip surface toward the top of the embankment. It is necessary to ensure that the material is resistant to pulling out. In other words, based on the idea that the skin has no mechanical meaning in terms of the stability of the entire structure, the reinforcing materials are arranged in such a way that the horizontal forces of each piece are balanced. It was designed to. In FIGS. 1 and 2, 1 is a free surface, 2 is a reinforcing material, 3 is an assumed slip surface, and 4 is a dividing wall surface (skin).

As mentioned above, the conventional way of thinking about reinforced soil retaining walls, as typified by the Terre Armé construction method, is that they make almost no mechanical contribution to the stability of the embankment, and therefore reinforcement materials are placed deeper than the virtual slip surface. It was necessary to make sure that it was firmly fixed on the side.

(Problem to be solved by the invention) In this way, the conventional way of thinking about reinforced soil walls is not to stabilize the embankment structure, but rather to prevent soil from spilling out from the back, and to provide reinforcement material from ultraviolet rays and fire. Since the main purpose was to protect the walls, no consideration was given to the rigidity of the walls in the design.

However, many years of research have revealed that a well-constructed wall structure can greatly contribute to the stability of reinforced embankments. In other words, the following are the roles that retaining walls play in stabilizing reinforced soil.

(a) It has the role of preventing local compression failure of soil by providing partial bending stiffness (local stiffness).

(b) It has the role of sharing part of the load by providing longitudinal rigidity to the whole.

(c) It has the role of transmitting earth pressure downward by providing bending rigidity to the entire structure.

(d) The wall itself has the role of resisting the embankment earth pressure due to its own weight.

By the way, most of the built structures are subjected to larger loads after construction is completed than during construction, and therefore greater safety (safety factor) is required. Law is no exception.

In this way, the present invention can be said to be a new construction method that focuses on the effects of wall rigidity on the bearing capacity of reinforced embankments, and the differences in applied loads and safety during and after embankment construction.

(Means for Solving the Problems) In order to solve the above problems, the present invention is a method for stabilizing reinforced embankments, and in embankment construction,
A reinforcing material is laid at the planned embankment site, a sandbag unit is placed on the slope side end of the reinforcing material, and embankment equal to the thickness of the sandbag unit is rolled onto the reinforcing material to form the upper surface of the sandbag. A sandbag unit is placed so as to form the same plane and press the edge of the reinforcing material laid on top of the same plane, and these operations are repeated to create a bank at a predetermined height and create a slope that is approximately vertical. An embankment body is formed, and a formwork is installed only on the outside so that it can absorb the embankment earth pressure along the outer surface of the sandbag wall, and the other surfaces are replaced by the sandbag wall surface, concrete is poured, and concrete is poured into the sandbag. Alternatively, a retaining wall was constructed by filling concrete between the sandbags to stabilize the entire embankment.

In addition, in reinforced embankment structures, reinforcing materials are laid in horizontal layers in the embankment, and reinforcement is achieved by friction between soil particles and the reinforcing materials. A retaining wall is constructed by placing concrete along the outer surface of the sandbag wall to absorb the earth pressure of the embankment, and placing concrete in or between the sandbags. It was designed to provide a.

Furthermore, the sandbag is made of a material with drainage properties, and the retaining wall is provided with a drainage pipe.

(Operation) To outline the basic procedure of the present invention,
As shown in FIG. 4, during embankment construction, a reinforcing material 2 is laid on the planned embankment ground 10, and a drainage sandbag 11, which is a sandbag unit, is placed on the slope side end of the reinforcing material 2.
is placed, and the embankment 12 corresponding to the thickness of the sandbag unit is rolled onto the reinforcing material 2 to form approximately the same plane as the top surface of the sandbag, and the end of the reinforcing material 2 laid on top of the sandbag is further compressed. Place the drainable sandbag 11 as shown below.
These operations are repeated to fill the soil to a predetermined height to form an embankment body with a substantially vertical slope, and formwork is installed only on the outside so that it can absorb the earth pressure of the embankment along the outer surface of the sandbag wall. The other side of the embankment was replaced by a sandbag wall, concrete was poured, and a retaining wall was constructed by placing concrete in or between the sandbags to stabilize the entire embankment.

To specifically explain the function of the present invention from a design standpoint, as shown in Figure 3, the earth pressure acting on GF is handled between EF and the lower end of the retaining wall, so that the whole is integrated and stabilized. Even if the area where the reinforcing material is placed is inside the virtual slip planes efg and efh, in other words, even if the reinforcing material is short, sufficient stability is ensured. can.
Here, 8 is an integral wall body.

The basic prerequisites for the above idea are the installation of sufficiently dense reinforcing materials and rigid walls, etc., and as a result, the present invention attempts to achieve the same stability as conventional reinforced embankments. If so, the breaking strength and tensile rigidity are relatively small compared to conventional reinforcing materials, and stability can be ensured even with short reinforcing materials.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First, as shown in Figure 4, a reinforcing material 2 with a length of approximately 20 to 50 degrees Celsius, which is the height of the retaining wall to be constructed, is laid on the planned embankment ground 10, and a material with drainage properties is used. Place the sandbag 11 on the end of the reinforcing material 2. At this time, the reinforcing material 2 and the sandbag 11 can also be fixed by a method such as rolling the reinforcing material 2 together. At that time, the height △H of the sandbag and the compacted finished thickness of the back fill shown in Figure 4-2 should be approximately equal to each other, approximately 30
cm, and then construct embankment 12. The above steps are considered as one step, and are repeated until a predetermined height H is reached, as shown in FIG. 4. After that, as shown in Fig. 4, after constructing the drain pipe 13, formwork is installed only on the outside, and the other surfaces are replaced by the sandbag walls.
A rigid wall 14 is cast by pouring concrete and placing the concrete in or between the sandbags.

Figure 5 is a diagram showing an example of construction of a raised embankment.
Figure 5 1 shows that in the case of conventional reinforced embankment,
FIG. 2 is a diagram showing a case where the reinforced embankment construction method of the present invention is used (shaded areas are areas that must be removed).

In Figure 5, 2 is a reinforcing material, 6 is a wall with local rigidity, 8 is an integral wall, 17 is an existing embankment, 1
Reference numeral 8 indicates a sloped embankment, and 19 indicates an area that must be scraped off when constructing the sloped embankment.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the following effects can be achieved.

(1) By absorbing the earth pressure with sandbags and retaining walls for the reinforced embankment, the reinforcement material to be laid can be kept shorter than conventional ones, and even low-strength materials can be used. The range of material selection has expanded, making it possible to reduce material costs.

Furthermore, even if the depth of the reinforcing material is much shorter than conventional ones, the stability of the embankment can be sufficiently ensured. Even in places where it was not possible to do so, this method has made it possible to do so.

(2) In the case of embankment, where the land is widened by further embanking on the existing slope, conventionally the reinforcing material had to be laid quite long, which required large-scale construction work such as removing a considerable amount of the existing embankment. However, in the present invention, since the depth can be shortened, only a small amount of scraping is required, making it possible to shorten the construction period and reduce costs.

(3) Since sandbags are used in the present invention, the sandbags serve as a temporary frame during the work.
It can prevent soil from spilling out during embankment and compaction, and from collapsing the slope.

(4) Since a retaining wall made of sandbags is constructed for each layer of embankment, it is now possible to bring transport vehicles and work vehicles closer to the slope, improving work efficiency. .

(5) Since the work process involves placing sandbags, embanking, laying reinforcing material, and compacting, by making sandbag units of a certain size,
The height of the sandbag has become a kind of unit scale, and it has become possible to easily check the amount of embankment, the spacing of reinforcing materials, leveling, etc., and it has become possible to standardize and homogenize on-site workability.

(6) In the type of retaining wall that is cast on site, the poured concrete penetrates and bites into the uneven surface formed by the accumulation of sandbags.
There is no need to connect the retaining wall to the embankment using special locking members, making construction extremely easy.

(7) Since the position of the formwork can be set freely, even if the embankment or sandbag pile is constructed with relatively rough dimensions, precise dimensions can be obtained by adjusting the position of the formwork when pouring the retaining wall. This makes it especially effective when working along railroad tracks or roads with tight margins.

(8) Groundwater collected via the reinforcing material passes through the sandbag body made of drainage material and drains out of the retaining wall from the drainage pipe, so This eliminates the need for extensive backfilling work, significantly shortening the work period.

As described above, the present invention has an endless list of effects, but it can be said to be an extremely effective means, especially in Japan, where it is necessary to make effective use of national land.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the skin of a conventional reinforced embankment, Figure 2 is an explanatory diagram of the concept of reinforcing materials in a conventional reinforced embankment, Figure 3 is a basic conceptual diagram of the present invention, and Figure 4 is an implementation of the present invention. FIG. 5 is a diagram showing an example of a construction procedure, and FIG. 5 is a diagram showing an example of construction of a sloped embankment. DESCRIPTION OF SYMBOLS 1... Free surface, 2... Reinforcement material, 3... Assumed slip surface, 4... Divided wall surface (skin), 6... Wall with local rigidity, 8... Integral wall, 10... Ground, 11... Drainage sandbag, 12... Embankment, 13
...Drainage pipe, 14...Strong wall cast in place, 17...Existing embankment, 18...Further embankment,
19... Area that must be removed when constructing the embankment.

Claims (1)

[Scope of Claims] 1. In embankment construction, reinforcing material is laid in the planned embankment area, a sandbag unit is placed on the slope side end of the reinforcing material, and the embankment is reinforced by the thickness of the sandbag unit. The embankment is compacted onto the material to form approximately the same plane as the top surface of the sandbag.
Further, a sandbag unit is placed so as to pinch the end of the reinforcing material laid on top of the sandbag, and these operations are repeated to form an embankment body with a substantially vertical slope. Furthermore, a formwork is installed only on the outside so that it can absorb the earth pressure of the embankment along the outer surface of the sandbag wall, and the other surfaces are replaced by the sandbag wall surface, and concrete is placed inside or between the sandbags. A method for stabilizing reinforced embankments that is characterized by stabilizing the entire embankment by building retaining walls. 2. Reinforcing materials are laid in a horizontal layer in the embankment and reinforced by friction between soil particles and the reinforcing materials, and in embankments with approximately vertical slopes, they are stacked along the slope to maintain the slope. A retaining wall is constructed by placing concrete along the outer surface of the sandbag wall so as to absorb the earth pressure of the embankment, and placing concrete in or between the sandbags. Reinforced embankment structure. 3. The reinforced embankment structure according to claim 2, wherein the sandbag is made of a material with drainage properties, and the retaining wall is provided with a drainage pipe.