JPH1060903A - Construction method for stabilizing slope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To install a pressure receiving structure of precast concrete in agreement with a ground anchor that is driven at an appropriate angle regardless of an angle of a slope. SOLUTION: A slope 1 excavated partly to form a steep slope 2 and a berm 5 at the foot of the slope 2. A ground anchor 3 is inserted into a hole 6 that is excavated from the steep slope 2 into a ground, and anchored. A pressure receiving structure 4 is installed along the steep slope 2 and passed through by a projecting part of the anchor 3 from the ground surface to be anchored and fixed. Therefore, the structure 4 is installed along the partly formed steep slope 2, not along an angle of the slope 1, to be always installed at an appropriate angle in agreement with the anchor 3 that is driven at an appropriate angle, and receive a load effectively. Because the berm 5 supports the structure 4, execution of work becomes easy. A space that is formed by excavating the steep slope 2 is filled by soil brought from another place or backfilled by sediment so that trees are planted therein.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slope stabilization method for preventing a slope from collapsing, and more particularly to a slope stabilization method for fixing a precast concrete block to a slope with a ground anchor to prevent the collapse.

[0002]

2. Description of the Related Art The slope angle of a slope in design is determined not only by requirements for stable design of the slope, but also by consideration of disaster prevention due to rainfall, aesthetics, and planting. That is, if the slope has a slope that is too steep, the possibility of slope collapse or landslide is increased, the appearance is not good, and the slope is not suitable for planting. Therefore, the actual slope of the entire slope is not always steep in most cases.

On the other hand, in order to prevent the slope from collapsing in recent years, a block made of precast concrete has been adopted as a pressure receiving structure receiving a sediment load on the slope, inserted into a hole formed in the ground, and grouted into the hole. A method of fixing the pressure receiving structure to a ground anchor fixed by injecting a material and pressing down the ground has been performed. When precast concrete products are standardized in manufacturing shape and mass-produced, the advantages are exhibited due to the high product quality and the superiority of on-site construction.

[0004]

However, as described above, when the pressure receiving structure is installed as it is on a relatively steep slope, and is fixed to an anchor cast in the ground,
A situation as shown in FIG. 10 occurs. That is, as shown by the arrow in the figure, since the earth and sand load acts obliquely downward substantially parallel to the slope, it acts on the anchor b in the crossing direction, and hardly acts on the pressure receiving structure a. However, the pressure receiving structure a for suppressing the collapse of the slope does not function at all. In order for the pressure receiving structure to function effectively, as shown in FIG. 11, the anchor b is arranged in a substantially horizontal direction as parallel as possible to the direction of action of the sediment load, and the pressure receiving structure a is capable of responding to the sediment load. It is an important requirement to function effectively that they are installed only orthogonally.

[0005] On the other hand, there is a constructional restriction on the angle at which the ground anchor is cast, and in order to facilitate grouting into the drill hole, the drill hole must be inclined to a certain depth so as to be deeper toward the back. The drilling angle must be at least 1
5 to 20 degrees is required. If the pressure receiving structure is to be installed so as to be as perpendicular to the inclined ground anchor as possible, the installation surface must have a considerably steep slope, and the slope angle must be at least 55 degrees. No. However, the design slope is not necessarily a steep slope as described above, and often cannot be formed in a manner that is convenient for the construction and design of anchors and pressure receiving structures. There were many cases.

[0006] Further, it is difficult to carry the pressure-receiving structure made of precast concrete on a steep slope, and there is a danger and difficulty in installing the structure on a steep slope when installing the structure. It had to be constructed so that it would not slip off, and still involved many dangers and difficulties.

[0007]

According to the slope stabilization method of the present invention, a part of a slope is formed on a steep slope, and a pressure receiving structure is installed on the slope. This makes the angle between the structure and the anchor closer to the ideal one.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The slope stabilization method according to the present invention forms a steep slope partly on a slope. The slope may be a slope formed by cutting or a slope such as a mountainous area. A steep surface is formed in this part. The steep slope means that the slope is greater than the slope of the entire slope, and the slope angle of the steep slope is calculated from the anchor placement angle. For example, when the inclination angle of the ground anchor is 20 degrees, it is normally desirable that the installation surface of the pressure receiving structure is perpendicular to the anchor. This is because it is not preferable that the anchor bends largely with respect to the pressure receiving structure in order to accurately apply a prestressing force to the free length portion of the anchor. Therefore, it is desirable that the steeply inclined surface on which the pressure receiving structure is installed has an inclination angle of about 70 degrees. However, even if a precast member is used with a slight ground anchor angled to the pressure receiving structure, it can be practically used without any problem, and the limit of the adjustment angle of the member is about 15 degrees. Then, it is sufficient that the inclination angle of the steeply inclined surface is 55 degrees. If the slope of the entire slope is 45 degrees, the steep slope is formed to be inclined by 10 degrees from the entire slope.

The steep surface may be formed slightly larger than one pressure receiving structure, or may be formed horizontally and continuously for an area of a plurality of pressure receiving structures located at the same height. In any case, the steep surface should be formed large enough to allow the pressure receiving structure to be placed with a margin. A step is formed below the steep surface, and this step is used as a temporary scaffold. Drill holes are drilled from these steep surfaces toward the ground. A ground anchor having a plurality of tension members passed through the sheath is inserted into the hole, and grout such as cement milk is injected and fixed. As tensile material, besides PC steel wire and PC steel stranded wire,
Chemical fibers such as carbon fiber, aramid fiber, and polyester fiber can be used. When chemical fibers are used as the tensile material, the sheath may not always be used.

A pressure receiving structure made of precast concrete is installed on a steeply inclined surface. Since the pressure receiving structure can be supported by the step portion, the scale of the support work is significantly reduced, and an accident such as falling or falling of the structure is eliminated. Various shapes can be adopted as the shape of the pressure receiving structure.
Conventional pressure receiving structures used for stabilizing slopes, such as squares, circles, and crosses, can be widely used. Through the protruding portion of the ground anchor described above from the surface of the ground, a prestressing force is applied by being tensed with a jack. If it is a steel tensile material, it is fixed to the anchor head by wedges, etc.If it is a chemical fiber tensile material, it is folded on the ground and the part is arranged in the anchor hole of the pressure receiving structure and fixed with hardening material etc. To settle.

An earth retaining wall is installed along the edge of the step,
Fill the terrace with guest soil. You can plant it here. It is also possible to bury the excavated steep surface and the pressure receiving structure, and plant them on it.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment shown in the drawings. In the figure, 1 is a slope that has been cut off,
The inclination angle α1 is 45 degrees. A steep surface 2 is formed in a part thereof. In the embodiment, since the placing angle α2 of the ground anchor 3 is desired to be 20 degrees, if the pressure receiving structure 4 is orthogonal to the anchor 3 using the pressure receiving structure 4 as shown in FIG. 70, steep slope 2
Is ideally 70 degrees. However,
If the pressure receiving structure 4 in which the anchor hole 12 is inclined as shown in FIG. 9 is used, the pressure receiving structure 4 of the ground anchor 3 can be used.
About 15 degrees can be secured, and 70
−15 = 55, and the inclination angle α4 of the steeply inclined surface 2 is 55
Degree. That is, 55−45 = 10, and the angle α5 at which the steeply inclined surface 2 is inclined more than the inclined surface 1 is 10 degrees. Anchor hole 1 of pressure receiving structure 4 as shown in FIG.
The reason why the adjustment angle 2 is about 15 degrees is that, besides a problem in manufacturing a product, when the angle is 20 degrees or more, the horizontal force becomes too large, and the pressure receiving structure 4 is displaced upward and moved. Because there is. The steeply inclined surface 2 may be formed at each location where the pressure receiving structure 4 is installed as shown in FIG. 5, or a wide area where a plurality of pressure receiving structures 4 are installed horizontally and continuously as shown in FIG. Excavation may be performed. Below the steep surface 2, a horizontal step 5 is formed.

As described above, a hole 6 is excavated from the steeply inclined surface 2 toward the ground at an inclination angle of 20 degrees. In this, a free length sheath 7 made of synthetic resin and a deformable fixing sheath 8 made of steel are provided.
, A ground anchor 3 having a plurality of tensile members 9 made of PC steel strands is inserted, and a grout material 11 such as cement milk is injected and fixed. The projecting portion of the ground anchor 3 above the ground is passed through the anchor hole 12, and the pressure receiving structure 4 is installed along the steeply inclined surface 2. As the pressure receiving structure 4, a cross-shaped structure having a beam portion extending in all directions is used. The lower end of the pressure receiving structure 4 is placed along the step 5 so that a large-scale support work is not required and there is little danger. The tension member 9 of the ground anchor 3 is tensioned and fixed to the anchor head 13 with a wedge to fix the pressure receiving structure 4.

As shown in FIGS. 1 to 3, an earth retaining wall 14 is installed along the end of the step portion 5, and a rock bolt 15 or a reinforcing anchor penetrating vertically and an anchor taken from the pressure receiving structure 4. Fix with 16. Either one of the lock bolt 15 and the anchor 16 may be adopted. The earth retaining wall 14 for the soil can be made of precast concrete, sandbags, bamboo, wood, or other materials, or various materials. The soil 17 is packed on the step 5 inside the earth retaining wall 14 and planted. The pressure receiving structure 4 is hidden by the planted plants, and a slope landscape in harmony with nature can be created.

As shown in FIG. 4, a pressure receiving structure 4 is installed on a steeply sloped surface 2 formed by excavation, and earth and sand 18 are backfilled so as to bury the pressure receiving structure 4, and planting is performed thereon. It is also possible to completely cover the pressure receiving structure 4.

[0016]

The present invention has the above-described configuration, and can obtain the following effects. Because the pressure receiving structure is installed along the steep surface formed to match the appropriate angle of the ground anchor, not the slope angle of the slope, the pressure receiving structure made of precast concrete is used regardless of the design slope angle The structure can be installed. By vegetation and planting in the guest space and backfilled area formed in the steps, the precast pressure receiving structure is hardly visible or invisible, and a naturally moist slope landscape can be obtained. The anchor can be arranged almost horizontally, parallel to the sediment load, and the pressure receiving structure can be arranged close to the angle perpendicular to the sediment load, giving tension to the ground anchor more horizontally to the ground. Since the sediment load is received by the pressure receiving structure orthogonal to the earth pressure, the load transmission is more effective. Since the pressure receiving structure can be installed regardless of the inclination angle of the slope, construction can be performed freely according to the angle of the anchor and construction conditions at the site. A step is formed below the steep surface, so that the pressure receiving structure does not fall or fall without using a large-scale support, and the danger is significantly reduced. Since the entire slope is not steeply sloped but partly steeply sloped, it can be constructed as it is even in a mountainous area where it is natural, and economical construction becomes possible.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is a front view of the embodiment of FIG.

FIG. 3 is a cross-sectional view of the embodiment of FIG.

FIG. 4 is a longitudinal sectional view of another embodiment.

FIG. 5 is a front view of a pressure receiving structure installed on a steeply sloped surface formed separately.

FIG. 6 is a front view of a pressure receiving structure installed on a steep surface formed continuously horizontally.

FIG. 7 is a longitudinal sectional view in which the present invention is implemented entirely on a slope.

FIG. 8 is a partial cross-sectional view of one embodiment of the pressure receiving structure.

FIG. 9 is a partial sectional view of another embodiment of the pressure receiving structure.

FIG. 10 is a conventional example in which a pressure receiving structure is placed on an inclined surface.

FIG. 11 is an installation example of an ideal pressure receiving structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slope 2 Steep slope 3 Ground anchor 4 Pressure receiving structure 5 Step part 6 Drilling hole 7 Free length sheath 8 Deformed fixing part sheath 9 Tensile material 11 Grout material 12 Anchor hole 13 Anchor head 14 Soil wall for lands 15 Rock bolt 16 Anchor 17 Guest soil

Claims (3)

[Claims] 1. A part of a slope is excavated to form a steep surface and a step below the steep surface, and a pressure-receiving structure made of precast concrete is installed along the steep surface, and a ground is formed from the steep surface. A slope stabilization method comprising fixing a ground anchor inserted into and fixed in a borehole excavated toward a pressure receiving structure. 2. The slope stabilization method according to claim 1, wherein a soil retaining wall is provided along the step, and the step is filled with the soil and planted. 3. The slope stabilization method according to claim 1, wherein the excavated portion is backfilled with earth and sand, and the steep slope is buried together with the pressure receiving structure and planted.