JPH02217518A - Reinforcing construction with earth bolt - Google Patents

Abstract

PURPOSE:To easily cut the ground of steep slope at a low cost and improve the strength characteristic of natural ground by inserting a plurality of earth bolts made of fiber reinforced-plastics, to be previously fixed into the natural ground to be cut, and by reinforcing the natural, ground. CONSTITUTION:Through the slope face 1 of natural ground G to be cut, the pit of a specified number arranged vertically and horizontally at equal intervals are bored, and into the respective pit, earth bolts 4 made of fiber reinforced- plastics are inserted, and pit internal-sections are filled up with solidifying agent, and the earth bolts 4 are fixed, and the stability of the natural ground G is secured. After that, from the slope face 1, excavation is started, and the ground is cut till a slope face 2 comes to a specified gradient, and after that, the extra length sections of the earth bolts 4 projected from the slope face 2 are respectively cut off. Accordingly to requirement, a fiber grid 5 is laid, and finally, it is sprayed with mortar 6, and the execution of work is completed, and with the bolts, the ground is resistant to land-sliding, and expanding accidents are suppressed.

Description

[Detailed description of the invention] "Industrial application field" This invention is an earth bolt reinforcement method in which the ground is reinforced in advance before carrying out cutting work on the ground, such as building land for housing or creating slopes. Regarding.

"Prior Art" Normally, the slope of the cut slope formed by cutting the slope of the ground is almost determined by the soil conditions of the original ground. For example, if the soil quality of the ground is clayey soil, the slope slope is 1:1.
The ratio is about 1:1.2. Therefore, when creating a cut slope with a steep slope, after cutting at a slope of 1:1, protective measures such as block retaining walls, leaning retaining walls, etc. are installed on the cut surface. A method is used to ensure the steepness of the cut slope.

In addition, if the ground has sufficient strength, instead of installing protective measures such as retaining walls on the cut surface, methods such as spraying mortar may be used to protect the steep cut slope. ing. Furthermore, even if the ground has sufficient strength, if the cut height is set higher, spraying mortar alone will ensure the stability of the entire ground surface, such as slipping on the slope. Since this is difficult, the so-called anchor method is used, which involves inserting reinforcing bars into the ground to ensure stability on the ground.

[Problem to be solved by the invention] However, in the former method, costs such as block laying costs, retaining wall construction costs, backfilling costs, etc. are added, which increases the labor and cost of construction, making it uneconomical. It was not a good construction. In addition, the latter anchor construction method has the problem of reinforcing steel corrosion due to groundwater, etc., so it is currently necessary to use it in conjunction with other construction methods (block laying, leaning retaining wall, concrete frame construction) as mentioned above. In the end, this resulted in an increase in construction costs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an earth bolt reinforcement method that can easily and inexpensively cut especially steep slopes while ensuring the stability of the strength of the ground. It is an object.

"Means for Solving the Problem" The earth bolt reinforcement method according to the present invention involves reinforcing the ground by inserting and fixing a plurality of earth bolts made of fiber-reinforced plastic in advance into the ground to be cut. be.

[Operation-1] According to the present invention, the strength characteristics of the ground are improved by driving the ground hole in the ground. Furthermore, the earth bolt resists slipping on the ground, and the protrusion of the cut slope after excavation is suppressed by the pull-out resistance of the earth bolt. Furthermore, since the earth bolt is made of fiber-reinforced plastic, there is no fear of corrosion from underground water or the like.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of the ground cut and constructed according to the present invention. In this figure, the reference numeral G indicates the ground, and to first briefly explain its cross-sectional structure, the ground G has a cut slope 2 and a cut slope 2 formed by cutting the slope 1 shown by the dotted line. A developed land 3 is formed at the lower end thereof. A plurality of earth bolts 4 extending from the cut slope 2 toward the inside of the ground G are buried inside the ground G. These earth bolts 4 are arranged at equal intervals vertically and at equal intervals left and right. A fiber grid 5 for protecting the surface from peeling is laid on the surface of the rough cut slope 2, and mortar 6 for protecting the cut slope 2 is sprayed onto it.

The earth bolt 4, as shown in FIGS. 3 and 4,
Fiber reinforced plastic (hereinafter simply referred to as FRP)
It consists of a rod-shaped cable 4a, and a spiral protrusion 1R4b formed over the entire outer surface of the cable 4a.

In the cable 4a, a resin material 8 is wound around a core material 7 such as a paper pipe or a PVC pipe, and within this resin material 8,
A plurality of continuous fibers 9 extending in the longitudinal direction of the core material 7 are embedded at intervals in the circumferential direction. As the continuous fiber 9, a continuous fiber bundle made of lightweight and high-strength long fibers such as glass fiber or carbon fiber is preferably used, but if necessary, synthetic resin fiber, ceramic fiber, metal fiber, etc. May be used in combination. Similarly, as the resin material 8, a resin that has good adhesion to the continuous fibers 9 and has sufficient strength properties itself, such as a vinyl ester resin, is preferably used. Further, other materials may be used depending on the material of the fibers 9 used. Examples of other resin materials include unsaturated polyester resin, epoxy resin, and phenol resin.

The protrusions 4b are for improving the adhesion characteristics of the cable 4a to the ground G, and are made of the continuous fibers 9.

The fiber grid 5 is made of the same material as Earthport 4, and is made of multiple layers of continuous fibers such as high-strength glass fibers, carbon fibers, and aramid fibers.

They are made by intersecting each other in the shape of a knot, impregnated with resin, and integrally molded.

Next, the procedure for creating a cut slope with the above configuration will be explained with reference to FIGS. 2(a) to (d).

(1) A predetermined number of holes H are bored on the slope 1 of the ground G to be cut using a drilling means such as a drilling machine or a boring machine, and an earth bolt 4 is inserted into each hole H.

(See Figure 2 (A) and (B)) (2) Spread the hardening agent 11 throughout the hole H using a grout injection machine or a capsule, and connect the cable 4a) of each earth bolt 4 to the hole H. Fixed inside.

This ensures the stability of the ground G. At this time,
Since a spiral protrusion 4b is formed on the surface of the cable 4a located at the perforation H, the solidifying agent 10 and the cable 4a
The adhesion strength is sufficiently strengthened. (See Figure 4) (
3) Start excavation with an excavator etc. from slope 1 of the ground G,
Cutting is performed until the slope 2 reaches a predetermined slope (1:0.6~, :1,2). The discharged waste may be transported to a predetermined location by means of transportation such as a truck and disposed of, or used for leveling the soil in the development site 3. (See FIG. 2 (c)) (4) When the excavation and cutting of the ground G is completed, the extra length of each earth hole 4 protruding from the cutting slope 2 is cut off.

(5) If the surface of the cut slope 3 is likely to peel off, such as when the ground G is clayey soil or the cut slope 3 is steep, or when spraying as described later, there is a risk that the mortar 6 will peel off. In some cases, the fiber grid 5 is laid over the entire surface of the slope.

This fiber grid 5 is joined to the tip of the earth bolt 4. This can also prevent the cut slope 2 from protruding.

(6) Finally, spray mortar 6 over the entire surface of the cut slope 2 to a thickness of 10 to 15 cm to protect the cut slope 2, and after leveling the created land 3 at the lower end. Work will be carried out to complete the slope preparation. (See FIG. 2(d)) Note that the shape, dimensions, etc. of the earth bolt 4 according to the present invention are not limited to those of the embodiment described above, and various modifications are possible. For example, a protrusion 4b may be provided only at the end of the earth bolt 4.
It is also possible to introduce a tension force by providing and fixing it to the inner bottom of the perforation H and fixing the other end to the cutting slope 2.

According to this embodiment, the following excellent effects can be achieved.

■ By reinforcing the ground G by driving an earth bolt 4 in advance, the strength characteristics of the ground G can be improved. Furthermore, the earth bolt 4 resists slippage caused in the ground G due to external forces such as earthquakes. Furthermore, protrusion of the cut slope 2 after excavation can be prevented by the pull-out resistance of the earth bolt 4.

(2) The cut height relative to the ground G can be increased by the action of the earth hold 4 as shown in (2) above. Furthermore, even if the ground G is clayey soil, excavation and cutting on a steep slope is possible. That is, the slope of the cut slope 2 can be determined without depending on the soil conditions of the ground G.

■ If slippage or other loosening of the ground G is observed during cutting, Earth Holt 4 can be placed immediately to reinforce the ground G.

- Since the earth bolt 4 is made of FRP, it is easier to cut after excavating the earth compared to conventional steel anchors. Also, there is no fear of corrosion due to underground water, etc. Therefore, it is possible to permanently install the earth bolt 4 within the ground G, and the earth bolt 4 cannot be installed permanently or as a temporary structure.
It can be treated as a permanent structure.

■ Since steep slope cutting is possible regardless of the soil conditions of the ground G, the flat area can be made wider, especially in residential development sites, and the land can be used more effectively.

■ When a steep slope is required in a location where the ground is not very good, such as in cohesive soil, conventional publications do not require stone masonry or retaining walls after gentle slope cutting, and the amount of excavated soil can be reduced. Therefore, it is not only an economically extremely advantageous construction method, but also shortens the construction period and simplifies the construction.

■ Since the cut slope 2 is protected by spraying mortar 6, there is no fear of erosion due to rainwater, etc. Mortar 6 for spraying
If there is a risk of peeling off, use fiber grid 5.
If the mortar 6 is sprayed after laying the mortar on the slope surface and fixing it to the end of the earth hole 4, its peeling can be prevented.

"Effects of the Invention" As explained in detail above, according to the present invention, a plurality of earth bolts made of fiber-reinforced plastic are inserted and fixed in advance into the ground to be cut, thereby reinforcing the ground. This makes it possible to increase the cutting height of the ground, as well as to cut steep slopes even in clayey ground, allowing the slope of the cutting surface to be adjusted to the soil conditions. It can be determined without relying on This not only enables economical construction, but also shortens the construction period and simplifies construction.

Furthermore, since the earth bolt is made of fiber-reinforced plastic, it is possible to permanently install the earth bolt within the ground, contributing to the reduction of repair work for cut slopes.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the earth cut and created by the earth bolt reinforcement method according to the present invention, Figs. FIG. 4 is an enlarged view of the chain line ■ in FIG. 1, and a front sectional view of the earth bolt. Figure 1! 2FM 2...Cut slope, 4...Earth bolt, G...Ground.

Claims (1)

[Claims] An earth bolt reinforcement method characterized by reinforcing the earth by inserting and fixing a plurality of earth bolts made of fiber-reinforced plastic in advance into the earth to be cut.