Background Art In general, a retaining wall is constructed to prevent and retain the wall surface of an excavated region that is likely to collapse due to earth pressure in various pit excavation works. Of methods of preventing the deformation of the retaining wall and stabilizing a ground behind the retaining wall, there is employed a soil nailing method. In a conventional soil nailing method, soil nail anchors in the form of inclined piles are formed by boring downwardly inclined holes into a ground behind the retaining wall, inserting reinforcing bars into the inclined holes, forming a solidified grout by injecting a grout material, such as mortar, and solidifying the grout material, and fastening the exposed ends of the reinforcing bars to a retaining wall using a bearing pressure plate and fastening nuts.

That is, in areas where various roads, a railroad, a levee, a dam, a lake, a reservoir, tunnel entrance and exit and apartment development are constructed, there may exist a cut ground slope, a underground excavated slope and a banked slope. Accordingly, there is required an environment-friendly slope reinforcing method that prevents the activity and wearing of a cut ground slope and a banked slope and harmonizes with the environment.

The device used for the same purpose in the case of rock other than soil is a rock bolt. The rock bolt is also a device that is deeply nailed into rock and is used to prevent the wear of the wall of a cave or a slope. A method of reinforcing a slope using a conventional soil nail or rock bolt is extensively applied to the permanent reinforcement of a slope. The minimization of deformation of a ground to minimize influence on adjacent structures in ground excavation works in a downtown becomes an important issue.

In conventional soil nailing, as disclosed in Korean Unexamined Patent Publication No. 2003-5884 entitled"Moving-type foamed urethane packer and pressure-type soil nailing method, "a plurality of holes having a downwardly inclined angle with respect to a slope are bored in a lattice pattern, soil nails formed of reinforcing bars are inserted into the bored holes, two grouting pipes together with each of the soil nails are inserted into each of the holes to perform primary and secondary grouting, the grouting pipe for the primary grouting is removed from the hole after the primary grouting, which is non-pressure grouting, is completed, and the grouting pipe for the secondary grouting is embedded in cement milk after the secondary grouting, which is pressurized grouting, is completed.

However, in the conventional soil nailing method, reinforcing bars are chiefly used as soil nails, so that the conventional soil nailing method is problematic in that it is difficult to connect the reinforcing bars, the weight of the reinforcing bars is heavy because lengthy reinforcing bars are used to fit the lengths of the bored holes, and it is difficult to insert the reinforcing bars into the bored holes. The work of the conventional soil nailing method is inconvenient in that the two grouting pipes are separately provided to perform the primary and secondary grouting and the grouting pipe for the primary grouting must be removed after the primary grouting.

The soil nails may be generally made of metal or Fiber Reinforced Polyester (FRP). When the soil nails are made of metal, the soil nails are problematic in that it is not easy to install the soil nails due to the heavy weight

thereof, like the reinforcing bars, and costs required for the prevention of rust incur because the soil nails rust under the surface of the ground. When the soil nails are made of FRP, the soil nails are problematic in that the soil nails must be thickened because the soil nails have required strength, so that the weight of the soil nails becomes heavy, like the metallic soil nails, thus causing the installation of the soil nails to be difficult and the costs of the soil nails to be expensive.

Disclosure of the Invention Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an environment-friendly soil nail, which reduces the costs of construction, facilitates construction and increases the recycling of wastes through the utilization of waste plastic.

In order to accomplish the above object, the present invention provides a round rod-type soil nail obtained by processing waste plastic (PolyEthylen Trephthalate (PET) bottles) into a soil nail body, forming threaded portions at both ends of the soil nail body, and engaging an anchor cone with one threaded portion of the soil nail body, and a bundle-type soil nail obtained by providing a bundle-type soil nail body including a bundle pipe composed of a plurality of nail strands, and fitting anchors made of PET, thermally fused to both ends of the bundle pipe and provided with threaded portions, each of the nail strands being formed by binding a plurality of nail lines together, and engaging an anchor cone provided with a threaded recess.

That is, in the installation of soil nails or rock bolts, by using round rod- type soil nails, which are obtained by recycling and reforming waste PET bottles and bundle-type soil nails obtained by attaching fitting anchors made of PET to both ends of a bundle pipe made of PET, as reinforcing members, instead of using reinforcing bars as reinforcing members, the recycling of waste plastic is increased, so that the protection of environment is ensured. Furthermore, by

using PET soil nails or rock bolts instead of reinforcing bars that are expensive and are difficult to handle and carry, inexpensive and easily installable soil nails are provided.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which : FIG. 1 is a view schematically showing the structure of a round rod-type soil nail; FIG. 2 is a cross-section taken along line A-A of FIG. 1; FIG. 3 is a view schematically showing the structure of an installed bundle-type soil nail; FIG. 4a is a view schematically showing the structure of the bundle-type soil nail; FIG. 4b is an enlarged perspective view of portion"b"of FIG. 4a; FIG. 4c is a cross-section taken along line B-B of FIG. 4a; FIG. 4d is a cross-section taken along line C-C of FIG. 4a; FIG. 4e is a cross-section taken along line D-D of FIG. 4a; FIG. 5 is a view showing the structure of a pipe-type soil nail; FIG. 6a is a view showing another embodiment of the present invention; and FIG. 6b is a cross-section taken along line E-E of FIG. 6a.

Best Mode for Carrying Out the Invention Reference should now be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.

An embodiment of the present invention is described in detail with reference to the attached drawings below.

FIG. 1 is a view schematically showing the structure of a round rod-type soil nail. FIG. 2 is a cross-section taken along line A-A of FIG. 1. FIG. 3 is a view schematically showing the structure of an installed bundle-type soil nail.

FIG. 4a is a view schematically showing the structure of the bundle-type soil nail.

FIG. 4b is an enlarged perspective view of portion"b"of FIG. 4a. FIG. 4c is a cross-section taken along line B-B of FIG. 4a. FIG. 4d is a cross-section taken along line C-C of FIG. 4a. FIG. 4e is a cross-section taken along line D-D of FIG. 4a. FIG. 5 is a view showing the structure of a pipe-type soil nail. FIG.

6a is a view showing another embodiment of the present invention. FIG. 6b is a cross-section taken along line E-E of FIG. 6a.

In accordance with an embodiment of the present invention, in a round rod-type soil nail that is manufactured to have a required length so as to be used in a soil nailing method or rock bolt method for stabilizing a wall surface of an excavated ground or a slope in various pit excavation works, a round rod-type soil nail body 10 is made of PET obtained by recycling waste plastic bottles and is provided with threaded portions 11, and an anchor cone 20 provided with a threaded recess 21 is engaged with the front end of the round rod-type soil nail body 10.

In accordance with another embodiment of the present invention, in a bundle-type soil nail that is manufactured to have a required length so as to be used in a soil nailing method or rock bolt method for stabilizing a wall surface of an excavated ground or a slope in various pit excavation works, a bundle-type soil nail body 30 includes a bundle pipe 32 composed of a plurality of nail strands 32 each composed of nail lines 35 and fitting anchors 33 made of polyethylene terephthalate, thermally fused to both ends of the bundle pipe and provided with threaded portions 34, and an anchor cone 20 provided with a threaded recess 21 is engaged with the front end of the round rod-type soil nail body 30.

Furthermore, there is a pipe-type soil nail according to another

embodiment of the present invention using waste plastic.

That is, a pipe-type soil nail 40 is made of PET obtained by processing waste plastic. A plurality of grouting holes 45 are formed in the wall of the pipe-type soil nail 40 to allow the inside of the pipe-type soil nail 40 to communicate with the outside of the pipe-type soil nail 40.

Such a soil nail is installed in a soil, such a rock bolt is installed in a rock, and the soil nail and the rock bolt have the same purpose and effect.

Accordingly, the present invention is applied to both the soil nail and the rock bolt.

As shown in FIG. 1, a PET soil nail body 10 is provided with threaded portions 11 at both ends thereof.

FIG. 2 is a cross-section taken along line A-A of FIG. 1, which shows a round rod-type member 10.

As shown in FIG. 3, an anchor cone 20 is engaged with a threaded portion 34 formed on a fitting anchor 33, and a nut 7 to be mounted on the outside of a support plate 28 is engaged with a threaded portion 5.

The structure of the round rod-type soil nail according to another embodiment of the present invention shown in FIGS. 3,4a, 4b, 4c and 4d is almost similar to the structure of the above-described soil nail, but is different from the structure of the above-described soil nail in that a bundle pipe 32 composed of a plurality of nail strands 31 each of which is formed by binding a plurality of nail lines 31 together, and fitting anchors 33 made of PET are thermally fused to both ends of the bundle pipe 32.

As shown in FIG. 6a showing another embodiment of the present invention and FIG. 6b showing a cross-section taken along line E-E of FIG. 6a, a multiple round rod type soil nail 55 composed of a plurality of round rods 50 may be used.

In a method of applying the present invention, a hole is perforated into an inclined surface or the wall of a cave and an anchor cone is pushed into the hole. A support plate is engaged with the rear threaded portion of the soil nail of

the present invention and is supported by a support surface, the outside surface of the soil nail is surrounded by soil or concrete, and the soil or concrete is hardened.

The soil or concrete supported in this way is prevented from being worn away.

Industrial Applicability In the installation of soil nails, by using round rod-type soil nails obtained by recycling and reforming waste PET bottles and bundle-type soil nails, which are obtained by attaching fitting anchors made of PET to both ends of each bundle pipe made of PET, as reinforcing members, instead of using reinforcing bars as reinforcing members, the recycling of waste plastic is increased, thus ensuring the protection of environment, and the installation of the soil nails are efficiently performed. Furthermore, an anchor cone is attached to the front end of the soil nails and, thus, pretension (tension previously applied) is applied, so that the time when displacement occurs is delayed and displacement is suppressed, thereby preventing the occurrence of excessive displacement.

Additionally, when an adjacent building exists, the length of the soil nail can be adjusted to be short during the application of the soil nail, so that the stability of application can be assured.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.