ANCHOR HAVING FIXING DEVICE AT SIDE OF PRESSURE PLATE TO DEPRESS LAND SLOPE AND METHOD OF INSTALLING SAME

The present invention relates to an earth retaining structure for reinforcing a slope, and more particularly, to an anchor including a fixing body at a pressure plate side for compressing a slope and a method for installing the anchor in the slope. The anchor including a fixing body at a pressure plate side for compressing a slope capable of preventing tension of the anchor from being lost by installing a friction type pressure plate fixing body in a steel pipe form that is integrated with the pressure plate at the pressure plate side of the anchor, installing a primary packer at a middle part of the anchor to conduct pressurized-grouting to fix a tip end side fixing body of the anchor, compressing a large pressure plate compressing the slope by introducing a tensile force to the tension member of the anchor together with the pressure plate side fixing body, expanding a secondary packer, and conducting secondary pressurized-grouting, is provided.

BACKGROUND

The present invention relates to an earth retaining structure for reinforcing a slope, and more particularly, to an anchor including a fixing body at a pressure plate side for compressing a slope and a method for installing the anchor in the slope.

2. Description of Related Art

Generally, in civil engineering works for constructing a road, a railway, a bank, portals of a tunnel, an apartment complex, etc., a cut slope or an embankment slope often occur. In such a cut slope or an embankment slope, sliding and erosion occur. For prevent the sliding and the erosion and being in harmony with the natural environment, an environmental-friendly slope reinforcement method has been required.

A soil nailing method that has been generally performed as the slope reinforcement method has a problem in that it has a structure in which the slope is reinforced only by a frictional force of a nail, thus a larger number of nails are needed for reinforcement as compared to a structure of reinforcement using tension of an anchor.

As another slope reinforcement method, a reinforced concrete retaining wall has been mainly used. However, it is disadvantageous in that a large cost and time are required for installation of a reinforced concrete structure, thus an anchor is additionally installed while being integrated with the reinforced concrete retaining wall. However, this reinforcement method is also disadvantageous in that large costs are required for earthworks and banking works, and an entire size of a structure is also increased.

If the slope is cut, stress distribution is changed, and an underground water level is lowered such that the ground is subsidence. The phenomenon as described above occurs to a remarkable degree in a relatively soft soil and weathered rock ground. Accordingly, even when an anchor is installed at the time of excavating the slope and the slope is compressed using a large pressure plate, the pressure plate part is subsidence over time, such that a tension of the anchor is lost, as a result, there is no reinforcing effect.

Further, in a region having clear four seasons, the soil is softened due to repetition of freezing and thawing, thus the pressure plate bearing continuous compression is subsidence, as a result, the tension of the anchor is lost.

SUMMARY

An object of the present invention is to provide an anchor including a fixing body at a pressure plate side for compressing a slope capable of preventing tension of the anchor from being lost by installing a friction type fixing body in a steel pipe form that is integrated with the pressure plate at a tension side of the anchor, installing a primary packer at a middle part of the anchor to conduct pressurized-grouting to fix the fixing body at a tip end side of the anchor, compressing a large pressure plate compressing the slope by introducing a tensile force to the tension member of the anchor together with the pressure plate side fixing body at the pressure plate side, expanding a secondary packer, and conducting secondary pressurized-grouting, and a method for installing the same.

According to an aspect of the present invention, an anchor including a fixing body at a pressure plate side for compressing a slope that is configured of a tension member for introducing a tensile force by connecting the pressure plate installed to compress the slope and a tip end side fixing body fixed to an original ground by grouting, the anchor includes a primary packer installed at a middle part of the tension member to conduct primary grouting on the tip end side fixing body and fixing the tip end side fixing body, a secondary packer installed at the pressure plate side fixing body, and the pressure plate side fixing body coupled to a pressure plate compression ring configured to be fixed by secondary grouting after the secondary packer is expanded to be integrally behaved with the pressure plate capable of exhibiting a support force even at a soft ground slope.

DETAILED DESCRIPTION

Hereinafter, an anchor according to the present invention will be described in detail with reference to the accompanying drawings.

Describing terms in the present invention in detail, a part fixed to the ground by grouting or bearing on a ground pressure is defined as a “fixing body”, the fixing body at a right tip end ofFIG. 1is defined as a “tip end side fixing body6” and the fixing body having the pressure plate and a head of the left side is defined as a “pressure plate side fixing body5”. In the present invention, the “soft ground” refers to the ground in which an exposed part of a slope is soil or a weathered rock and the pressure plate is subsidence due to a prolonged tension of the anchor.

FIGS. 1 to 8are views generally illustrating an anchor50according to the present invention, in which the anchor is inserted into a drilled hole22and grouting is performed to compress a pressure plate1to a slope. Throughout the drawings, the same reference numeral denotes the same component.

FIG. 1is a view generally illustrating the anchor50according to the present invention, and the anchor that is configured of a tension member9for introducing a tensile force by connecting a pressure plate1installed to compress the slope and a tip end side fixing body6fixed to an original ground by grouting, includes a primary packer7installed at a middle part of the tension member9to conduct primary grouting on the tip end side fixing body6and fixing the tip end side fixing body, a secondary packer8installed at the pressure plate side fixing body5, and the pressure plate side fixing body coupled to a pressure plate compression ring4configured to be fixed by secondary grouting after the secondary packer8is expanded to be integrally behaved with the pressure plate1capable of exhibiting a support force even at a soft ground slope.

The anchor50according to the present invention includes the tension member9having a length longer than a length of the drilled hole22and a thickness of the pressure plate1, an anchor head2and a tip end side anchor head15formed at both ends of the tension member9, an anchor cap3covering the anchor head2, the pressure plate1compressing the slope at a left side of the tension member9, the pressure plate side fixing body5coupled to the pressure plate compression ring4that is fitted into the hole19of the pressure plate1by welding or using a coupling means such as a screw, the tip end side fixing body6positioned opposite to the pressure plate side fixing body5, the primary packer7positioned at the middle part of the tension member9, two shrinkable tubes10fitted on the tension member9and positioned at both sides of the primary packer7while being spaced apart from the primary packer7by a predetermined distance, the secondary packer8installed at the pressure plate side, a secondary injection hose13installed in the anchor50, a primary packer injection hose11extending over the tip end side fixing body6through the pressure plate side fixing body5, a primary injection hose12, a discharge hose14, a secondary packer injection hose16, a temporary packer blocking the pressure plate compression ring at the time of secondary grouting, and a hose cutter21for cutting the primary injection hose12.

The tension member9is formed of a single wire or a plurality of wires, and is coated with a PE tube24so that it is smoothly elongated at the time of extension after cement grouting, thereby preventing an injecting grouting material is not attached. In the present specification, a case in which the tension member9formed of four groups is installed is illustrated.

The pressure plate side fixing body5ofFIG. 2is configured to be integrally behaved when the pressure plate compression ring4in a flange form is coupled to a tip end of a steel pipe18by welding or using a coupling means such as a screw, and the pressure plate compression ring4coupled to the hole19of the pressure plate and the fixing body in the steel pipe form extend the tension member9using the anchor head2. At this time, the pressure plate compression ring4need not necessarily have a circular shape, but may have various shapes such as a tetragonal shape, a hexagonal shape, and the like.

The steel pipe18of the pressure plate side fixing body5is configured to have uneven parts formed at an outer surface thereof and have large friction force by grouting, a steel pipe hole17is formed in the tip end side of the steel pipe from the secondary packer8so that the injecting grouting material in the inside is also injected to the outside of the steel pipe at the time of grouting, the secondary packer8has a bag-packer form, is formed on the outside of an imperforate steel pipe part, and is provided with the secondary packer injection hose and a secondary discharge hose penetrating through the packer, and the primary injection hose and the primary packer injection hose penetrate therethrough to be additionally installed. In a more preferable embodiment, in order to prevent leakage of the secondary packer, the pressure plate side fixing body5is configured so that the primary injection hose12through which the primary injection is completed and the primary packer injection hose11are cut by the hose cutter21at a depth of about 2 m of the drilled hole, and only the secondary packer is installed.

The tip end side fixing body6ofFIG. 3is a friction type fixing body, and the tip end side anchor head15serves to fix the tension member9. As a fixing body outside the tension member9, various types of fixing body such as a bearing type, a combination type of the bearing type and the friction type, and the like may be applied.

FIG. 4is a cross-sectional view taken along line A-A′ inFIG. 1, which illustrates a position where the secondary bag-packer is mounted in a state in which the tip end side fixing body6is fixed by grouting and the pressure plate side fixing body5is installed in the drilled hole22.

FIG. 5is a cross-sectional view taken along line B-B′ inFIG. 1, which illustrates a cross section of the tension member configured of the primary bag-packer, the primary injection hose12for first fixing the tip end side fixing body6by grouting, the primary packer injection hose11, the discharge hose14, the tension member9, and the secondary injection hose13.

FIG. 6is a cross-sectional view taken along line C-C′ inFIG. 1, which illustrates the tip end side fixing body6.

FIG. 7illustrates the hose cutter21that is configured to be installed at an angle of 40 to 50 degrees, preferably, 45 degrees on a long steel rod23, and formed with a sharp blade at an inner side of a steel plate of hose cutter with a hole so that when the injection hoses11and12or the discharge hose14is put into the hole of the hose cutter and pulled, the injection hoses11and12or the discharge hose14is cut. The hose cutter21is used at the time of cutting the injection hoses11and12, and the discharge hose14in the drilled hole22.

FIG. 8is view illustrating pressure plates having various shapes such as a cross shape, a tetragonal shape, etc., and cross-shaped pressure plates1may be connected to each other to form a lattice form.

The anchor which is configured of the tension member9for introducing a tensile force by connecting the pressure plate1installed to compress the slope and the tip end side fixing body6fixed to the original ground by grouting, includes the primary packer7installed at a middle part of the tension member9to conduct primary grouting on the tip end side fixing body6and fixing the tip end side fixing body6, the secondary packer8installed at the pressure plate side fixing body5, and the pressure plate side fixing body5coupled to the pressure plate compression ring4configured to be fixed by secondary grouting after the secondary packer8is expanded to be integrally behaved with the pressure plate1capable of exhibiting a support force even at a soft ground slope.

As the main technical idea and characteristics of the present invention, if the slope is cut, restrained stress is released to change stress distribution, and an underground water level is lowered, such that plastic deformation of the soft ground occurs. The phenomenon as described above occurs to a remarkable degree in a relatively soft soil and weathered rock ground. Accordingly, even when the anchor50is installed at the time of excavating the slope and the slope is compressed using the large pressure plate1, the pressure plate1part is subsidence over time, such that a tension of the anchor50is lost, as a result, there is no reinforcing effect.

Further, in a region having clear four seasons, the soil is softened due to repetition of freezing and thawing, thus the pressure plate1bearing continuous compression is subsidence, as a result, the tension of the anchor50is lost.

In order to solve the above problems, the friction type pressure plate side fixing body5in a steep pipe form integrated with the pressure plate is installed at the tension side of the anchor50, thereby preventing loss of tension of the anchor50.

Further, the primary packer is installed at a middle part of the anchor50to conduct pressurized-grouting to fix the fixing body6at the tip end side of the anchor, the large pressure plate1compressing the slope is compressed by introducing a tensile force to the tension member9of the anchor together with the pressure plate side fixing body, the secondary packer8is expanded, and the secondary pressurized-grouting is conducted, thereby completing the process.

According to a preferred embodiment of the present invention, a method for installing an anchor includes: forming a drilled hole22in a slope of the soft ground such as soil and weathered rock, inserting the anchor50in which a tip end side fixing body6and a tension member9are coupled, and then conducting grouting up to a part where a primary packer7is installed at a middle part of the anchor50for grouting of the tip end side fixing body6of the anchor; installing a pressure plate1on a tension member9of the anchor and fitting a pressure plate side fixing body5to which a pressure plate compression ring4is coupled on the tension member9to be inserted and installed in the drilled hole22; expanding a secondary packer8installed at a tip end of the pressure plate side fixing body5; installing an anchor head2on the pressure plate1and extending the tension member9; and conducting secondary grouting.

Considering site conditions, according to a second embodiment of the present invention, a method for installing an anchor includes: inserting an anchor50in which a tip end side fixing body6, a tension member9, and a pressure plate side fixing body5are integrally assembled into a drilled hole22in a slope, and expanding a packer to conduct grouting; fitting a pressure plate1on the pressure plate side fixing body5and then screw-coupling a pressure plate compression ring to be fastened; and extending and fixing a tension member9of the anchor that protrudes from a pressure plate hole19using an anchor head2.

The pressure plate side fixing body5is configured to be integrally behaved when the pressure plate compression ring4in a flange form is coupled to a tip end of a steel pipe by welding or using a screw, and the pressure plate compression ring4coupled to the pressure plate hole and the pressure plate side fixing body5in the steel pipe form extend the tension member9by a hydraulic jack using the anchor head2.

The steel pipe18of the pressure plate side fixing body5is configured to have uneven parts formed at an outer surface thereof and have large friction force by grouting, a steel pipe hole17is formed in the tip end side of the steel pipe18from the packer so that the injection material in the inside is also injected to the outside of the steel pipe18at the time of grouting, the secondary packer8has a bag-packer form, is formed on the outside of an imperforate steel pipe part, and is provided with a secondary packer injection hose16and a secondary discharge hose penetrating through the packer, and a primary injection hose12and a primary packer injection hose11penetrate therethrough to be installed. In a more preferable embodiment, in order to prevent leakage of the packer, the primary injection hose12through which the primary injection is completed and the primary packer injection hose11are cut by a hose cutter21at a depth of about 2 m of the drilled hole22. By cutting the hoses as described above, the primary packer injection hose11and the primary injection hose12do not penetrate through the secondary packer8, the secondary packer8is simply configured and may be easily installed. At the time of secondary grouting, the discharge hose is not needed, and a temporary packer is installed at the pressure plate compression ring of the pressure plate side fixing body5to inject a grout solution. At the time of secondary injection, in a case of the ground in which the pressure plate1and the slope are compressed closely, the secondary packer8may be omitted.

As the tip end side fixing body6, various existing fixing bodies may be used. InFIG. 3, the tip end side fixing body6of the anchor50is a friction type fixing body, and the tip end side anchor head15serves to fix the tension member9. As a fixing body20outside the tension member coupled to the anchor head2, various types of fixing body such as a bearing type, a combination type of the bearing type and the friction type, and the like may be applied.

In designing the anchor, a support ability of the pressure plate and the pressure plate side fixing body needs to be larger than a tensile load of the tension member, and a support ability of the tip end side fixing body also needs to be larger than the load introduced to the tension member.

According to the present invention, the friction type pressure plate side fixing body in a steel pipe form that is integrated with the pressure plate and behaved integrally at the pressure plate side of the anchor, are installed deeper than the freezing depth, such that it is possible to prevent the settlement caused by the phenomenon that the soil is softened due to repetition of freezing and thawing occurring in the region having clear four seasons.

Even in the soft ground that may not bear the bearing pressure of the pressure plate, the friction type pressure plate side fixing body in a steel pipe form may reinforce the support force for the soft ground by a frictional force.

The friction type pressure plate side fixing body in a steel pipe form that is integrated with the pressure plate are installed deeper than the effect zone from the slope, such that it is possible to prevent additional settlement of the pressure plate bearing continuous compression and loss of tension of the anchor, in spite of the lowering of the underground water level and the change in stress.

Further, the pressure plate side fixing body has the same effect as the nailing, and since the pressure plate is fixed to the friction type pressure plate side fixing body in a steel pipe form, deformation of a tensile force does not occur, and it is possible to safely perform extension even when there is a need to perform extension again.

DESCRIPTION OF REFERENCE NUMERALS

4pressure plate compression ring

5pressure plate side fixing body

6tip end side fixing body

15tip end side anchor head

17steel pipe hole

19pressure plate hole

23long steel rod