JP2013053461A - Method for stabilizing slope, reinforcement rod, and stabilized structure of slope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stabilizing a slope with high workability, which effectively prevents corrosion of a reinforcement rod so as to maintain the strength of a stabilized structure for a long time.SOLUTION: A method for stabilizing a slope includes the steps of: boring an excavation hole 3 in a slope S; inserting a reinforcement rod 1 provided with a main portion 10 having a straight bar shape and a head portion 11 which is arranged at one end of the main portion 10 in the axis direction and has a diameter larger than the head portion 10 into the excavation hole 3 such that the head portion 11 is exposed on the slope S; injecting and curing grout in the excavation hole 3; and spraying and curing fresh mortar or fresh concrete in a spray frame 2 formed on the slope S so as to form a pressure plate 7 containing the head portion 11 of the reinforcement rod 1. The head portion 11 of the reinforcement rod 1 has a plurality of cylindrical portions 11a,... which are coaxially connected to each other, having a larger diameter as positions are closer to the end.

Description

  The present invention relates to a slope stabilization method. The present invention also relates to a reinforcing bar suitable for the stabilization method and a slope stabilization structure obtained by the stabilization method.

On slopes such as cut slopes, embankment slopes, and slopes of natural ground (hereinafter collectively referred to as slopes), there are unstable places that have dangers such as collapse and landslide. Stabilization methods such as a reinforced earth method and an earth anchor method are known as techniques for stabilizing the slope excluding such dangers, and the following conventional method 1 and conventional method 2 are exemplified.
(Conventional method 1)
After assembling the wire mesh formwork on the cut slope, fresh mortar or fresh concrete (hereinafter referred to as fresh mortar) is sprayed to form a grid-like pressure receiving plate, and holes are formed at the intersections of the pressure receiving plate. A construction method in which a reinforcing bar which is provided and poured into a cut slope is fixed by pouring grout into the surface of the pressure receiving plate and fixed by tightening a nut.
(Conventional method 2)
Blow fresh mortar etc. on the entire surface of the cut slope, harden it, apply an iron plate to the surface, pour the grout into the cut slope, stick out the reinforcing bar that sticks to the surface of the iron plate, Method of fixing by tightening.

  In these conventional reinforced earth methods, the reinforced earth structure may lose its strength due to corrosion of reinforcing bars, nuts, iron plates and the like. In the conventional method 1, an attempt has been made to cover and protect a portion protruding from the pressure receiving plate T2 of the reinforcing bar T1 and a metal portion such as the nut T4 and the plate T5 with a protective cap T6 made of resin. Rainwater, seawater, sea breeze, etc. may enter from the lower end of T6 and the metal part may be corroded (see FIG. 11A). For the same purpose, there is an example in which protective concrete T7 covering the metal part is placed. However, since the protective concrete T7 is prepared separately from the pressure receiving plate T2, both Rainwater, seawater, sea breeze, etc. may enter from the boundary of the seawater and cause corrosion (see FIG. 11B).

  The inventor of the present invention conceived that the upper end portion of the reinforcing bar is included in the pressure receiving plate in order to solve the problems such as corrosion, and invented a plurality of methods. For example, a reinforcing bar is bent into a U shape using a fiber reinforced resin bar, and both legs bent into the U shape are inserted into a cut slope with an excavation hole and cement milk. This is a reinforced earth method for a cut slope in which concrete is cast and applied so as to include the upper end portion of the reinforcing bar on the cut slope (see, for example, Patent Document 1). ).

  Further, for example, one reinforcing bar of two reinforcing bars bent in an L shape is inserted into one excavation hole excavated at two locations in the cut slope, and the other reinforcing bar Including reinforcing bars that are exposed on the cut slope after being inserted into the other excavation holes in a state of being floated parallel to the cut slope and poured into the other excavation holes. In this way, it is a reinforced earth construction method for a cut slope that is constructed by placing concrete as described above (see, for example, Patent Document 2).

Japanese Patent No. 3558603 Japanese Patent No. 3803272

  However, in the reinforced earth method of the cut slope described in the above-mentioned Patent Document 1, since a reinforcing bar material bent in a U-shape is used, two parallel bars are arranged in accordance with the interval between both legs of the reinforcing bar material. There was a need to drill exactly. When the position and angle of the excavation hole are shifted, there is a problem that the reinforcing bar cannot be accurately set up at the center of the excavation hole on the cut slope. Further, when the reinforcing bar is made of reinforcing bars, the reinforcing bar becomes heavier and the moment is increased, so that there is a problem that workability is deteriorated.

  According to the reinforced earth method for cut slope described in Patent Document 2, the position and angle of the excavation hole are shifted by using two L-shaped reinforcing bars in order to solve these problems. However, the work can be performed, and the weight and moment of the reinforcing bar are reduced and workability is improved. However, since the portion of the two reinforcing bars that appears on the cut slope is used as the main bar of the pressure receiving plate, when the excavation hole is not perpendicular to the cut slope, the portions are arranged substantially parallel to each other. It was necessary to adjust the bending. In addition, the weight and moment of the reinforcing bar are large compared to the bar steel used in the conventional method, and there is a slightly inferior workability.

  The present invention further improves the technique described in Patent Document 2 and provides a slope stabilization method with higher workability that can effectively suppress the corrosion of the reinforcing bar and maintain the strength of the stabilization structure for many years. The issue is to provide.

The first invention for solving the above-mentioned problems is
(A) A step of excavating a drilling hole in a slope (B) A reinforcing bar comprising a straight rod-shaped main portion and a head having a larger diameter than the main portion provided at one end in the axial direction of the main portion, The step of inserting into the excavation hole so that the head appears on the slope (C) The step of injecting grout into the excavation hole and hardening it (D) The hardened by spraying fresh mortar or fresh concrete on the spray frame formed on the slope Including the steps (A) to (D) performed in the order of steps for forming the pressure receiving plate including the head of the reinforcing bar,
This is a slope stabilization method having a plurality of columnar portions in which the heads are coaxially connected to each other and have a larger diameter as they approach the end.

  The second invention is the slope stabilization method according to the first invention, wherein the step (D) is performed by placing the head of the reinforcing bar in a projection frame protruding from the upper part of the spray frame. is there.

  According to a third aspect of the present invention, a bentonite mat having a water-permeable bag containing dried bentonite and a water-impermeable bag made of biodegradable plastic that wraps the water-permeable bag is placed on the slope at the bottom of the spray frame. The slope stabilization method of the first or second aspect of the invention in which the step (D) is performed.

The fourth invention is:
A plurality of locking portions whose lower ends made thin are inclined outward and upward, are projected in the radial direction of the head,
The slope stabilization method according to any one of the first to third inventions, wherein the locking portion is locked to a reinforcing bar disposed substantially parallel to the slope in the spray frame, and the step (D) is performed. It is.

The fifth invention is:
The slope stabilization method according to any one of the first to third inventions, wherein a cylindrical portion having a thin lower end is connected to and provided coaxially with a columnar portion on a head.

The sixth invention is:
A head having a diameter larger than that of the main part is provided at one end in the axial direction of the main part of the straight rod shape.
The head is a reinforcing bar having a plurality of cylindrical portions that are coaxially connected to each other and have a larger diameter as they approach the end.

The seventh invention
The reinforcing bar according to the sixth aspect of the present invention, wherein a plurality of locking portions whose lower ends that are thin are inclined outwardly and upwardly project in the radial direction of the head.

  The eighth aspect of the invention is the reinforcing bar according to the sixth aspect of the present invention, wherein a cylindrical portion having a thin lower end is connected to and provided coaxially with the columnar portion at the head.

The ninth invention
An excavation hole excavated on a slope, a reinforcing bar inserted in the excavation hole and having a head disposed on the slope, and the reinforcing bar filled in the excavation hole. It is a slope stabilization structure comprising a grout hardened to be fixed in a drilling hole and a pressure receiving plate formed on the slope and including the head of a reinforcing bar.

  A tenth aspect of the invention is the slope stabilization structure of the ninth aspect of the invention, in which the head of the reinforcing bar is arranged in a protrusion that is integrally provided with the pressure receiving plate and protrudes from the upper part thereof.

  The eleventh invention is the slope stabilization structure of the ninth or tenth invention, wherein the water-permeable bag containing bentonite is included in the pressure receiving plate with its lower end in contact with the slope.

  According to the slope stabilization method of the present invention, since the upper end portion of the reinforcing bar is included in the pressure receiving plate, the reinforcing bar is not exposed to rainwater, seawater, sea breeze, or the like. Moreover, since it is not necessary to tighten the part which protrudes from the pressure receiving plate of a reinforcement bar with a nut like the conventional method, it is not necessary to use a nut or an iron plate. Therefore, corrosion of the reinforcing bar and other metal members is suppressed, and the strength of the stabilization structure can be maintained for many years.

  The head portion of the reinforcing bar has a plurality of columnar portions whose diameters become larger as they approach the end, and the overall shape of the head portion is a substantially truncated cone shape that gradually increases in diameter toward the end. In the step (D), fresh mortar or the like is usually sprayed obliquely from above on the spray frame formed on the slope. When the reinforcing bar is used, fresh mortar or the like is also applied to the lower surface of the cylindrical portion. Is easily filled and does not easily generate bubbles. The pressure receiving plate thus formed has sufficient strength to withstand the tensile force of the reinforcing bar.

  Since the reinforcing bar according to the present invention is manufactured separately from the main bar of the pressure receiving plate and inserted one by one into the individually excavated hole, the position and angle of the excavation hole with respect to the pressure receiving plate are strictly determined. It is not necessary to adjust the bending distance as in the L-shaped reinforcing bar. Since the reinforcing bar is separate from the main bar of the pressure plate, it is not necessary to form a spray frame on the slope, and the spray frame is assembled at a predetermined position on the slope after the spray frame is assembled at another place (for example, flat ground below the slope). It can be installed and construction with high workability is possible.

  Since the reinforcing bar is in the shape of a straight bar, the weight and moment are smaller than those of the U-shaped or L-shaped reinforcing bar, and improvement in workability is also achieved in this respect. Further, since the area required for placing the reinforcing bar is small, it is advantageous for storage and transportation. The U-shaped or L-shaped reinforcing bar is required to have a shape and size suitable for an individual construction site, but the reinforcing bar according to the present invention is a mass-produced product with a predetermined length. Since it can be cut into a suitable length, the construction cost can be reduced.

  When the head of the reinforcing bar is placed in the projection frame and the step (D) is performed, the formed pressure receiving plate has a projection on the top, and the projection includes the head of the reinforcing bar. The As a result, the effective height of the pressure receiving plate is increased, and it is possible to withstand a greater tensile force. Since the protrusion is formed integrally with the remaining part of the pressure receiving plate, there is no boundary between which rainwater, seawater, sea breeze, etc. enter, and the risk of corrosion of the reinforcing bar is reduced by them. .

  According to the stabilization method using a bentonite mat, a pressure receiving plate including the mat is formed in the lower part. Since the impermeable bag is made of biodegradable plastic, it is gradually degraded by the action of microorganisms present on the slope. As a result, the lower end of the water-permeable bag comes into contact with the slope, and the pressure receiving plate includes the water-permeable bag containing bentonite in the lower part. Since moisture gradually infiltrates from the slope into the water permeable bag, the bentonite swells and the volume of the water permeable bag containing the swell increases, so a force is applied to the pressure receiving plate to push it upward. Since the lower part of the reinforcing bar is fixed in the excavation hole by the grout cured product, a tension force is applied to the reinforcing bar due to the swelling of bentonite, and the pressure receiving plate is more stably fixed to the slope.

  When the head portion of the reinforcing bar has a locking portion, a robust pressure receiving plate is formed by locking them to the reinforcing bars and performing the step (D), and the pressure receiving plate is more stable on the slope. It is fixed.

  In the case where the head portion of the reinforcing bar has a cylindrical portion, the reinforcing bar and the pressure receiving plate are more firmly coupled to each other so that the pulling out resistance is increased, so that a stabilizing structure that can withstand a larger load is obtained.

  The reinforcing bar of the present invention is a reinforcing bar suitable for the slope stabilization method of the present invention, and has the effects described above. The slope stabilization structure of the present invention is obtained by the slope stabilization method of the present invention, and has sufficient strength as described above, and can maintain the strength for many years.

It is a principal part side view which shows the head vicinity of the reinforcing bar which concerns on this invention. It is drawing which shows the head vicinity of the reinforcing bar which concerns on another embodiment, (a) is a principal part side view, (b) is the sectional view on the AA line of (a). It is drawing which shows the head vicinity of the reinforcing bar material which concerns on another embodiment, (a) is a top view, (b) is the BB sectional drawing of (a). It is drawing which shows the head member based on this invention, (a) is a perspective view, (b) is side sectional drawing. It is side view sectional drawing which shows embodiment of the stabilization method of the slope of this invention. It is side view sectional drawing which shows embodiment of the stabilization method of the slope of this invention. It is a perspective view which shows the pressure receiving plate which concerns on this invention. It is side view sectional drawing which shows another embodiment of the stabilization method of a slope. It is a top view which shows another embodiment of the stabilization method of a slope. It is a perspective view which shows the pressure receiving plate which concerns on another embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which shows the stabilization method by a conventional method, (a) is side sectional drawing which shows the construction method using a protective cap, (b) is a side view which shows the construction method after which protective concrete is laid. It is sectional drawing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto.

  First, the reinforcing bar according to the present invention will be described. Examples of the reinforcing bar 1 according to the present invention include reinforcing bars 1A, 1B, 1C, and 1D shown in FIGS. 1 to 4, respectively. As shown in these drawings, the reinforcing bar 1 is provided with a head 11 having a diameter larger than that of the main part 10 at one end in the axial direction of the main part 10 having a straight bar shape. Are connected to each other and have a plurality of columnar portions 11a,...

  As shown in FIG. 1 to FIG. 3, the reinforcing bar 1 may have a main portion 10 and a head portion 11 that are integrally formed with each other. As shown in FIG. It may be produced by being externally fitted and bonded to one end of 13.

  The main portion 10 has a straight bar shape. The cross-sectional shape is not particularly limited. For example, round steel, square steel, or deformed steel bar can be used, but threaded joint steel bar is preferably used as in the conventional method.

  As shown in FIG. 1, the head 11 has a plurality of columnar portions 11 a,... Having a diameter larger than that of the main portion 10 and interconnected. The cylindrical portion 11a,... Has a radius that gradually increases as it approaches the end of the reinforcing bar 1, so that the overall shape of the head 11 is substantially frustoconical. The lower end surface of each cylindrical portion 11a has a shape in which the area of the portion appearing on the surface for the adjacent cylindrical portion 11a or the main portion 10 is small, and bubbles do not easily stay when spraying fresh mortar or the like. In addition, since the overall shape is substantially frustoconical, even if a bubble is generated, the bubble escapes radially outward and rises. Since these head-shaped characteristics make it difficult for bubbles to be included, the pressure receiving plate 7 obtained by spraying fresh mortar or the like obliquely from above has sufficient strength to withstand the tensile force of the reinforcing bar 1.

  As shown in FIG. 2, the head 11 may be provided with a plurality of engaging portions 11 b,. The engaging portions 11b,... Are portions that are engaged with the reinforcing bars 20, when the reinforcing bars 20,. The pressure receiving plate 7 formed in this way is robust in structure and is stably fixed to the slope S because the reinforcing bar 1B is locked to the reinforcing bars 20,.

  The lower end of the locking part 11b is thin, and has a shape in which bubbles do not easily stay in step (D). The shape is not particularly limited, and may be, for example, a shape having a sharp ridge at the lower end or a shape having a flat bottom end surface having a narrow width, in addition to a shape having a rounded lower end. The fact that the lower end of the locking portion 11b is inclined upward in the radial direction is also advantageous for eliminating bubbles, and contributes to the robustness of the pressure receiving plate 7 and stable fixing. The engaging portions 11b and 11b shown in FIG. 2 are connected to all positions from the upper end to the lower end of the head 11, and have a shape in which the length in the vertical direction is shortened toward the outside, but the lower end is outwardly upward. The shape is not particularly limited as long as it has an inclination toward the top, and for example, the locking portions 11b, 11b having a certain width in the vertical direction may be provided obliquely. The number of the locking portions 11b,... Is not particularly limited as long as it is plural, but normally, the reinforcing bar 1B is disposed between the two reinforcing bars 20, 20 arranged substantially parallel to each other, and the reinforcing bars 20 are arranged. , 20 are locked to the locking portions 11b,...

  FIG. 3 shows a reinforcing bar 1C according to still another embodiment. The head portion 11 may be provided with a cylindrical portion 11c having a thin lower end that is coaxially connected to the columnar portions 11a,. Like the locking portions 11b,..., The connecting portions 11d that connect the columnar portions 11a,... And the cylindrical portion 11c have a shape in which the lower ends are thin and the lower ends are inclined outward and upward. Yes. For this reason, the reinforcing bar 11C has a shape advantageous for eliminating air bubbles, like the reinforcing bar 11B. By providing the cylindrical portion 11c, the reinforcing bar 1C is more firmly coupled to the pressure receiving plate. Therefore, the resistance to pull-out increases, and a stabilized structure that can withstand a larger load is obtained.

  FIG. 4 shows a head member 12 of a reinforcing bar 1D according to still another embodiment. By reinforcing and attaching the head member 12 to one end of the steel bar 13, the reinforcing bar 1D is formed. The portion where the head member 12 is bonded to the steel bar 13 becomes the head 11, and the remaining part of the steel bar 13 becomes the main part 10. The steel bar 13 shown in FIG. 4 is a screw-shaped deformed steel bar, and the head member 12 is provided with a screw hole 12a having an opening at one end and an inflow hole 12b communicating the screw hole 12a with the outside. Has been. The head member 12 is screwed into the steel bar 13 by screwing the screw hole 12a to one end of the steel bar 13, and is further bonded by an epoxy resin adhesive that flows into the screw hole 12a from the inflow hole 12b. . The head member 12 is not necessarily screwed to the steel bar 13. For example, the head member 12 having a hole in one end opening in which the inner peripheral wall is not screwed is externally fitted to one end of the steel bar 13. However, it is preferable that the head member 12 is screwed to be firmly connected. Although the inflow hole 12b is not essential, it is preferable to provide the inflow hole 12b in order to easily adhere to the steel bar 13 after the head member 12 is externally fitted. When the head member 12 provided with the inflow hole 12b is used, the reinforcing bar 1D can be produced at the construction site by cutting the steel bar 13 of the same standard into a desired length, so that the construction cost can be reduced.

  Next, the slope stabilization method of the present invention will be described. Hereinafter, the reinforced earth method will be described as an example, but the present invention is also applicable to the earth anchor method.

The slope stabilization method of the present invention is
(A) Step of drilling the excavation hole 3 in the slope S (B) A straight rod-shaped main portion 10 and a head portion 11 provided at one end in the axial direction of the main portion 10 and having a larger diameter than the main portion 10. Inserting the reinforcing bar 1 into the excavation hole 3 so that the head 11 appears on the slope S (C) Injecting and hardening the grout into the excavation hole 3 (D) Blowing formed on the slope S The steps (A) to (D), which are performed in the order of steps of forming the pressure receiving plate 7 including the head 11 of the reinforcing bar 1 by spraying fresh mortar or fresh concrete onto the attachment frame 2 and curing it, are included. As described above, the head 11 of the reinforcing bar 1 has a plurality of columnar portions 11a,... That are coaxially connected to each other and have a larger diameter as they approach the end.

(A) Excavation process As shown in FIG. 5, an excavation hole 3 is excavated on the slope S by boring or the like. It is assumed that the excavation hole 3 is substantially perpendicular to the slope S and the lower end reaches the stable ground.

(B) Reinforcing Bar Inserting Step The reinforcing bar 1 is inserted into the excavation hole 3. At this time, the lower end of the reinforcing bar 1 reaches a position slightly higher than the lower end of the excavation hole 3 so that the head 11 appears on the slope S. The height position of the head 11 is a position that gives a sufficient effective height to the pressure receiving plate 7. By externally fitting spacers 5... Similar to those in the conventional method to the main portion 10 of the reinforcing bar 1, the spacers 5 are brought into contact with the inner wall of the excavation hole 3. Arranged at substantially the center.

(C) Grout injection step The grout is injected into the excavation hole 3 and cured, and the reinforcing bar 1 is fixed in the excavation hole 3 by the obtained grout cured product 4. As the grout, cement milk is usually used, but is not necessarily limited thereto, and fresh mortar or the like can also be used. After injecting the grout, wait a while for the grout to harden.

(D) Spraying process Fresh mortar or the like is sprayed onto the spray frame 2 formed on the slope S and enclosing the head 11 of the reinforcing bar 1 and cured to form the pressure receiving plate 7.

  First, the spray frame 2 necessary for this process is assembled. The shape and arrangement of the pressure receiving plate 7 of the present invention are not limited. For example, a large number of pressure receiving plates 7A,... Having a substantially rectangular parallelepiped shape having a longitudinal direction in the lateral direction (a direction connecting substantially the same height of the slope S) are staggered. It is possible to form a line (see FIG. 7) or to form a lattice-shaped pressure receiving plate 7B as one body (see FIG. 10). Hereinafter, the spray frame 2A and the spray frame 2B suitable for forming the pressure receiving plates 7A and 7B of the above two examples will be described as examples, but the shape and arrangement of the spray frame 2 are not necessarily limited to these, The pressure receiving plate 7 is suitable for the shape and arrangement. The assembly of the spray frame 2 is not necessarily performed at the beginning of the step (D), and can be performed before the step (C), for example.

  5 and 6 show a blowing frame 2A for forming a substantially rectangular parallelepiped pressure receiving plate 7A. In the vicinity of both ends in the longitudinal direction of the spray frame 2A, a substantially rectangular parallelepiped spray frame 2A having an open top is assembled so that one reinforcing bar 1 and 1 is disposed. The position and the number of the reinforcing bars 1,... Relative to the spray frame 2A are not necessarily limited to this. For example, one or three or more reinforcing bars 1,... Are arranged in one spray frame 2A. Alternatively, the reinforcing bars 1,... May be arranged at positions deviated from the approximate center in the short direction of the spray frame 2A. Inside the spray frame 2A, four reinforcing bars 20,... Left and right, right and left are arranged substantially parallel to each other in the longitudinal direction, and an iron wire fitting 21 composed of vertical lines 21a,... And horizontal lines 21b,. Are arranged at substantially constant intervals. .. Are disposed on the side surfaces of both ends of the spray frame 2A in the longitudinal direction and the short direction, and the ends of the horizontal lines 21b of the metal fittings 21 are disposed at both ends in the short direction. 22 is locked. The above configuration is a configuration for stably arranging the blowing frame 2A to form the robust pressure receiving plate 7A. However, if the same purpose can be achieved, the structure is not limited to the above. Instead of ..., a substantially rectangular stirrup may be provided. Moreover, it is also possible to form the pressure receiving plate 7A by placing mortar or concrete without spraying. In this case, for example, a wooden, paper, or synthetic resin plate is used as the wire mesh 22,. Use instead of.

  On the other hand, FIG.8 and FIG.9 shows the spraying frame 2B for forming the lattice-shaped pressure receiving plate 7B. A grid-like spray frame 2B is assembled so that the reinforcing bar 1 is arranged at the intersection of the grid. The position of the reinforcing bar 1 is not necessarily limited to this. For example, one or more reinforcing bars 1,... May be disposed between two intersections of the grid. In order to fix it stably, it is preferable that the reinforcing bar 1 is disposed at least at the intersection of the lattice. Except for the overall shape of the spray frame 2B, the internal configuration is substantially the same as that of the spray frame 2A. A projecting frame 23 is assembled at the position of the grid intersection of the spray frame 2B. The projecting frame 23 has two trapezoidal metal meshes 24, 24 disposed at positions facing each other by connecting both lower ends to the upper ends of the concave ridges formed by the metal meshes 22, 22, and upper portions of the metal meshes 24, 24. It consists of two wires 24a, 24a that interconnect the corners. When the blowing frame 2B having the protruding frame 23 projecting upward is used, the pressure receiving plate 7B having the projections 7a at the portion corresponding to the protruding frame 23 is formed by blowing fresh mortar or the like. When the reinforcing bar 1 is arranged so that the head 11 is included in the protruding frame 23, the pressure receiving plate 7B having a high effective height is formed. Moreover, since the protrusion 7a is formed integrally with the remaining portion of the pressure receiving plate 7B, there is no boundary for rainwater, seawater, sea breeze and the like to enter. The shape and material of the projection frame 23 are not particularly limited as long as the head 11 of the reinforcing bar 1 can be disposed therein. The projection frame 23 can also be provided on the above-described rectangular parallelepiped spraying frame 2A.

  When the spray frame 2 is assembled, the bentonite mat 6 can be placed on the slope S at the lower part of the spray frame 2 as shown in FIGS. 5 and 6. The bentonite mat 6 has a water permeable bag 6b containing a dried bentonite 6a and a water-impermeable bag 6c made of biodegradable plastic that wraps the water permeable bag 6a. When the bentonite mat 6 is placed and fresh mortar or the like is sprayed onto the spray frame 2, a pressure receiving plate 7 including the bentonite mat 6 is formed at the bottom. Thereafter, the water-impermeable bag 6c made of biodegradable plastic is gradually decomposed by the action of microorganisms present on the slope S. As a result, the lower end of the water permeable bag 6b comes into contact with the slope S, and the pressure receiving plate 7 includes the water permeable bag 6b including the dried bentonite 6a in the lower part. Water gradually infiltrates from the slope S into the water-permeable bag 6b, and the water is absorbed by the dried bentonite 6a. As a result, the bentonite swells and the volume of the water-permeable bag 6b including the bentonite increases, so that the pressure receiving plate 7 is applied with a force pushing it upward. Since the lower part of the reinforcing bar 1 is fixed in the excavation hole 3 by the grout cured product 4, a tension force is applied to the reinforcing bar 1 by the swelling of bentonite, and the pressure receiving plate 7 is more stably fixed to the slope S. . In the stage of spraying and curing fresh mortar or the like, moisture does not enter the impermeable bag 6c, and the dried bentonite 6a does not swell. Therefore, the pressure plate is prevented from being distorted or cracked due to unintentional swelling of bentonite.

  The thickness of the bentonite mat 6 is not particularly limited as long as it is sufficiently smaller than the height of the spray frame 2 and the strength of the pressure receiving plate 7 is not lowered. Further, the number arranged in one spray frame 2 can be arbitrarily selected within a range in which the strength of the pressure receiving plate 7 is not lowered. The bentonite mat 6 can be arranged with its outer end protruding from the spraying frame 2, but it is arranged so that it is entirely contained in the spraying frame 2 in order to cover and protect it with mortar or concrete. Is preferred. Further, the particle size and other physical properties of the dried bentonite 6a are not particularly limited.

  The material of the water permeable bag 6b is not particularly limited as long as it has water permeability, and natural fibers such as hemp and cotton and chemical fibers such as polyethylene and polyamide are used. Hemp which is preferred and is strong and has high water permeability is most preferred. Although the water-permeable bag 6b may be single, it can also be composed of double or more bags so that the bentonite does not break even if it swells.

  Examples of the material of the water-impermeable bag 6c include polylactic acid and starch-polycaprolactone copolymer, but are not particularly limited as long as they are water-impermeable biodegradable plastics. The water-impermeable bag 6c is made of a biodegradable plastic sheet or film so that a large gap is not generated in the pressure receiving plate 7 even if it is decomposed by microorganisms. However, even if the dry bentonite 6a and the water-permeable bag 6b are wrapped, It shall have sufficient strength that cannot be easily broken.

  After assembling the spray frame 2, fresh mortar or the like is sprayed on the spray frame 2 and cured to form the pressure receiving plate 7. Since the head 11 of the reinforcing bar 1 is included in the spray frame 2, the pressure receiving plate 7 including the head 11 of the reinforcing bar 1 is formed. As described above, the head 11 of the reinforcing bar 1 is easily filled with fresh mortar or the like on the lower surface of the columnar portion 11a, so that bubbles are not easily generated. Even if bubbles are generated, the bubbles are easily discharged. Shape. Therefore, the formed pressure receiving plate 7 has sufficient strength to withstand the tensile force of the reinforcing bar 1.

  The reinforcing bar 1, the reinforcing bar 20, the metal fitting 21, the wire mesh 22, the wire mesh 24, the wire 24a, and the spacer 5 according to the present invention are all made of a metal or an alloy. The material is not particularly limited, and for example, it can be made of fiber reinforced plastic, synthetic resin, or the like. When the material is a corrosive metal or alloy, it is preferable to perform a surface treatment such as epoxy resin coating, galvanizing, or glass coating. A steel material that has high strength and corrosion resistance and is easily available and whose surface is coated with an epoxy resin is most preferably used. Further, the types of the wire mesh 22 and the wire mesh 24 according to the present invention are not particularly limited, but a crimp wire mesh is preferably used.

1, 1A, 1B, 1C, 1D, T1 Reinforcing bar 2, 2A, 2B Spray frame 3 Drilling hole 4, T3 Grout cured product 5 Spacer 6 Bentonite mat 6a Dry bentonite 6b Permeable bag 6c Impervious bag 7, 7A, 7B, T2 Pressure plate 7a Protrusion 10 Main part 11 Head 11a Columnar part 11b Locking part 11c Cylindrical part 11d Connecting part 12 Head member 12a Screw hole 12b Inflow hole 13 Steel bar 20 Rebar 21 Metal 21a Vertical line 21b Horizontal line 22, 24 Wire mesh 23 Projection frame 24a Wire S Slope T4 Nut T5 Plate T6 Protective cap T7 Protective concrete

Claims (11)

(A) A step of excavating a drilling hole in a slope (B) A reinforcing bar comprising a straight rod-shaped main portion and a head having a larger diameter than the main portion provided at one end in the axial direction of the main portion, The step of inserting into the excavation hole so that the head appears on the slope (C) The step of injecting grout into the excavation hole and hardening it (D) The hardened by spraying fresh mortar or fresh concrete on the spray frame formed on the slope Including the steps (A) to (D) performed in the order of steps for forming the pressure receiving plate including the head of the reinforcing bar,
A slope stabilization method characterized in that the heads have a plurality of columnar parts that are coaxially connected to each other and have a larger diameter toward the end.   2. The slope stabilization method according to claim 1, wherein the step (D) is performed by placing the head of the reinforcing bar in a protruding frame protruding from the upper part of the spray frame.   A bentonite mat having a water-permeable bag containing dried bentonite and a water-impermeable bag made of biodegradable plastic that wraps the water-permeable bag is placed on the slope at the bottom of the spray frame, and the step (D) The slope stabilization method according to claim 1 or 2, characterized in that: A plurality of locking portions whose lower ends made thin are inclined outward and upward, are projected in the radial direction of the head,
The process (D) is performed by engaging the engaging portion with a reinforcing bar disposed substantially parallel to the slope in the spray frame, and performing the step (D). The slope stabilization method described.   4. The slope stabilization work according to claim 1, wherein a cylindrical portion having a thin lower end is connected to and provided coaxially with the columnar portion at the head. Law. A head having a diameter larger than that of the main part is provided at one end in the axial direction of the main part of the straight rod shape.
A reinforcing bar having a plurality of columnar portions in which the heads are coaxially connected to each other and have a larger diameter toward the end.   The reinforcing bar according to claim 6, wherein a plurality of engaging portions whose bottom ends that are thinned are inclined outward and upward are projected in a radial direction of the head.   The reinforcing bar according to claim 6, wherein a cylindrical portion having a thin lower end is connected to and provided coaxially with the columnar portion on the head.   The excavation hole excavated in the slope, the reinforcing bar according to any one of claims 6 to 8, wherein the head is disposed on the slope and inserted into the excavation hole, and the excavation hole is filled and reinforced. A slope stabilization structure comprising: a grout hardened material for fixing a bar in an excavation hole; and a pressure receiving plate formed on the slope and including a head of a reinforcing bar.   10. The slope stabilization structure according to claim 9, wherein the head portion of the reinforcing bar is disposed in a protrusion protruding from an upper portion thereof integrally with the pressure receiving plate.   11. The slope stabilization structure according to claim 9, wherein the water-permeable bag containing bentonite is included in the pressure receiving plate with a lower end in contact with the slope.

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