JP2010013845A - Method and structure for installing anchor plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a structure for installing an anchor plate capable of effectively protecting a slope by preventing the anchor plate from moving. <P>SOLUTION: This method for installing an anchor plate includes: a step of constructing, on the slope, a reinforcement frame 99 of generally latticed shape in plan view, a step of drilling an anchor insertion hole 95 which is opened in an inner ground surface 121 surrounded by the reinforcement frame 99 at the generally center position and which has a predetermined length; a step of inserting a ground anchor 90 into the anchor insertion hole 95 and fixing the fixing section B of the ground anchor to a rock R by pouring grout; a step of forming a leveled ground which extends over a predetermined area around the anchor insertion hole 95 and which is generally perpendicular to the ground anchor 90; a step of installing the anchor plate 21 in the leveled ground 20 and connecting the anchor head section 23 projecting from the anchor insertion hole 95 for the ground anchor 90 to the center of the anchor plate 21; and a step of applying a predetermined tension to the ground anchor 90. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing structure of an anchor plate used for ground anchor work, and in particular, a tensile material such as a high-strength steel material is inserted into a relatively small drilling hole, and this is fixed in a base, whereby the tensile strength of the steel material is increased. It is related with the installation method of the anchor plate used for the ground anchor work used as a landslide countermeasure work, and the installation structure of the anchor plate.

  Conventionally, ground anchors have been used as protective works for slopes in mountainous areas or planted land, slopes that may collapse or collapse, and as retaining works for temporary or permanent retaining walls. .

  The ground anchor is generally composed of a “fixing portion”, a “pull portion”, and an “anchor head portion”. The fixing part is formed by injecting grout, and is a resistance part for transmitting the tensile force from the tension part to the ground by frictional resistance or bearing resistance with the ground. The fixing part is usually a PC steel bar or PC steel. It is composed of stranded wire, multi-PC steel strand, tendon made of continuous fiber reinforcement, etc., and cement grout. The tension portion is a portion that transmits a tensile force from the anchor head to the fixing portion, and is composed of a tendon and a sheath for making the amount of elongation uniform. The anchor head has a function of reliably transmitting the tensile force generated in the tendon to the structure. The anchor head is composed of a wedge used for fastening and fixing the tendon, a fixing tool such as a nut, and a steel bearing plate for dispersing a large bearing load by the fixing tool.

  Ground anchors can be roughly divided into three fixing mechanisms depending on the fixing method of the fixing portion and the fixing ground. That is, a friction type anchor that transmits anchor pulling force to the fixing ground by frictional resistance between the peripheral surface of the fixing unit and the fixing ground, and resists anchor pulling force by a passive earth pressure that greatly expands the fixing unit and acts on the fixing unit. A bearing anchor, a composite anchor using both the friction type and the bearing type.

  The ground anchor work as a landslide countermeasure work is considered to have the following two deterrence functions, but may be designed with emphasis on one of the functions depending on the ground and slip surface conditions. The appropriate ground conditions are as follows.

(A) Tightening function: Increases the vertical stress on the sliding surface and increases the shear resistance.
・ Slip surface is relatively shallow, steep slope ・ Slide mass is large ・ Brock slip (b) Retaining function: The tensile force of the ground anchor is used as the reaction force of the slip force.
・ Slip surface is relatively deep ・ Slip surface slope is gentle ・ Slide mass is low

  FIG. 5 shows a conventional anchor plate installation structure. The anchoring portion B of the ground anchor 90 is fixed to the bedrock R below the assumed slip line S, and the tension portion 91 has the bearing plate 92 attached to the anchor plate 94 having the anchor head portion 93 installed on the slope 120. And a predetermined tensile force is set.

  Since slopes and slopes are assumed to flow along an assumed slip line S in the case of an earthquake or the like, the ground anchor 90 has a tensile force of the ground anchor 90 to ensure a reaction force 102 of the slip force 101. Therefore, the necessary pressing force is always applied to slopes and slopes. Here, a large number of ground anchors 90 are used in the protection work of slopes and slopes, but each ground anchor 90 used for the same construction site is set to an optimum angle as a whole in consideration of the entire construction site. In order to avoid mutual interference at (the angle θ with respect to the horizontal plane L), they are all installed in parallel with each other. Here, especially because the slope and slope are gentle, but there are important facilities under the slope and slope, there is a private house near the slope, or the soil quality of the slope is weak. This is likely to occur when the ground anchor 90 is installed on the gentle slope or slope for safety reasons. From the relationship between the slope of the slope 120 and the position of the ground anchor 90, the anchor plate 94 installed there The angle α formed by the tension portion 91 may be an acute angle. In this case, an upward lateral force 103 along the normal surface 120 is generated with respect to the anchor plate 94 by the action of the component of the tensile force of the pulling portion 91, and the anchor plate 94 extends along the normal surface 120 from a predetermined position. In other words, there is a possibility of moving upward from several mm to several tens of mm. When the anchor plate 94 moves from a predetermined position, there is a problem that the tensile portion 91 on which a strong tensile force is suspended is also displaced from the predetermined position.

Regarding these problems, in an anchor plate for stabilizing the slope, a technology for arranging an additional portion having a tapered cross section between the anchor plate and the ground surface in order to install the anchor plate perpendicular to the anchor (Patent Document) 1) and a technique related to the installation position of the anchor material in the lattice-like frame (see Patent Document 2), which relates to prevention of misalignment of the anchor plate due to the anchor tensile force There is nothing related to the relationship between anchor plates and legal frameworks.
JP 2000-133509 A JP 2006-132137 A

  An object of the present invention is to solve the above problems, to provide an anchor plate installation method and an anchor plate installation structure capable of preventing the movement of the anchor plate and performing effective slope protection. And

  In order to solve the above problems, the present inventor has stabilized the anchor plate by surrounding the ground surface on which the anchor plate is to be installed with a reinforcing frame and leveling the ground plate so as to be substantially perpendicular to the ground anchor. The present inventors have found that this can be done and have completed the present invention.

  (1) a step of constructing a plane substantially lattice-like reinforcing frame on the slope, a step of opening an approximately center of the inner ground surface surrounded by the reinforcing frame, and drilling a fixed length anchor insertion hole, Inserting a ground anchor into the anchor insertion hole, injecting a grout and fixing the anchoring portion of the ground anchor to a rock, and a predetermined range around the anchor insertion hole on the inner ground surface; and Forming a ground surface that is substantially perpendicular to the ground anchor; installing an anchor plate on the ground surface; and connecting an anchor head protruding from the anchor insertion hole of the ground anchor to the center of the anchor plate; Applying a predetermined tensile force to the ground anchor, and an anchor plate installation method.

  According to the anchor plate installation method in the invention of (1), even if a tensile force is applied to the anchor plate by forming the ground surface so that the inner ground surface of the reinforcing frame lattice is substantially perpendicular to the ground anchor. The anchor plate can be prevented from shifting. In addition, even if the ground leveling surface is formed by largely changing from the original inner ground surface, the reinforcing frame receives the dispersion force in the lateral direction of the pressing force received by the leveling ground because it is inside the reinforcing frame. Since it can stop, the leveling ground is stable, and the anchor plate installed there can stably press the leveling ground.

  (2) In the anchor plate installation method according to (1), the step of forming the leveling surface is an anchor plate installation method which is performed by substantially excavating the inner ground surface.

  (3) In the anchor plate installation method according to (1), the step of forming the leveling surface includes substantially excavating a lower side in the slope direction of the inner ground surface, thereby correcting the inner ground surface. An anchor plate installation method that is performed by substantially embedding the upper side of the surface inclination direction.

  The installation method of the anchor plate in the inventions of (2) and (3) can be properly used according to the situation of the slope to be constructed. In particular, according to the anchor plate installation method in the invention of (3), substantially excavating the slope lower side of the inner ground surface surrounded by the reinforcing frame, and substantially embanking the slope upper side, The soil can be reused inside the grid of the reinforcing frame, and it is unnecessary or less necessary to carry out the soil to the outside.

  (4) In the anchor plate installation method according to (1), when the anchor plate is installed on the leveling surface, a solidifying filler is filled between the anchor plate and the leveling surface, and the solidifying filler is An anchor plate installation method for performing a step of applying a predetermined tensile force to the ground anchor after solidification.

  According to the anchor plate installation method in the invention of (4), after the solidifying filler is solidified, the solidifying filler is brought into close contact with both the anchor plate and the leveling surface, and the pressure applied to the anchor plate is adjusted. Therefore, the leveling surface is more stable, and the anchor plate installed there can stably press the leveling surface.

  (5) A planar substantially lattice-shaped reinforcing frame constructed on the slope, an anchor insertion hole that opens to substantially the center of the inner ground surface surrounded by the reinforcing frame, and an anchor head projecting from the anchor insertion hole A ground anchor having a fixing portion fixed to the ground; a ground surface formed on the inner ground surface so as to extend over a predetermined range around the anchor insertion hole and substantially perpendicular to the ground anchor; and the ground surface An anchor plate installed on the ground plate, wherein the ground anchor is applied with a predetermined tensile force, and the anchor head is connected to the center of the anchor plate.

  According to the anchor plate installation structure in the invention of (5), a tensile force is applied to the anchor plate by forming a ground leveling surface so that the ground surface inside the lattice of the reinforcing frame is substantially perpendicular to the ground anchor. Can also prevent the displacement of the anchor plate. In addition, even if the ground leveling surface is formed by largely changing from the original inner ground surface, the reinforcing frame receives the dispersion force in the lateral direction of the pressing force received by the leveling ground because it is inside the reinforcing frame. Since it can be stopped, the leveling surface is stable.

  (6) The anchor plate installation structure according to (5), further including a solidifying filler layer solidified between the anchor plate and the leveling surface.

  According to the installation structure of the anchor plate in the invention of (6), the solidified solidifying filler is in close contact with both the anchor plate and the leveling surface, and the pressure applied to the anchor plate is uniformly transmitted to the leveling surface. Therefore, the leveling surface is further stable, and the anchor plate installed therein can stably press the leveling surface.

  (7) The anchor plate installation structure according to (5), wherein a length of the anchor plate in the normal direction is 50% or more of an interval in the normal direction of the reinforcement frame. .

  According to the anchor plate installation structure of the invention of (7), since the length of the anchor plate in the slope direction of the anchor plate is 50% or more of the interval in the slope direction of the reinforcement frame, a pressing force is applied to the reinforcement frame. It is close enough to the ground leveling that is done, and the stabilizing effect of the leveling ground by the reinforcing frame is even greater.

  (8) In the anchor plate installation structure according to any one of (5) to (7), the portion of the inner ground surface that is not covered with the anchor plate can be herbaceous vegetation. An anchor plate installation structure.

  (9) The anchor plate installation structure according to (8), wherein an upper surface of the anchor plate is covered with soil capable of herbaceous vegetation.

  According to the anchor plate installation structure of the invention of (8), grass and lawn can be grown on the topsoil surface around the anchor plate, and the anchor plate which is an artificial structure can be hidden and made inconspicuous. . Further, according to the anchor plate installation structure of the invention of (9), if the upper surface of the anchor plate is covered with soil, grass can be vegetated on the soil above the anchor plate, and greening is promoted and landscape conservation is achieved. Is further enhanced.

  ADVANTAGE OF THE INVENTION According to this invention, the fixing structure of the frame frame anchor plate which can prevent the movement of an anchor plate and can perform effective slope protection can be provided.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. This is merely an example, and the technical scope of the present invention is not limited to this.

[First embodiment]
FIG. 1 is a cross-sectional view showing a configuration of an anchor plate fixing structure 10. A concrete plane substantially lattice-shaped reinforcing frame 99 is installed on the slope 120 where the ground anchor is to be constructed, and an anchor insertion hole 95 is opened at substantially the center of the reinforcing frame 99. Here, the steps after the drilling step of the anchor insertion hole 95 of the ground anchor work are as follows.

(1) Drilling the anchor insertion hole 95 The ground anchor is drilled at a predetermined position by a drill pipe (not shown) so as to have a set drilling diameter, drilling length, anchor inclination angle, and anchor horizontal angle. After the drilling is completed, the inside of the drilling hole is washed with clean water so as not to disturb the surrounding ground.
(2) Grout injection Insert a grout hose (not shown) into the anchor insertion hole 95 to the bottom, inject the grout material from the grout hose, completely replace the drilling water in the hole with the grout material, and fill the grout material. Do.
(3) Insertion of tendon (not shown) As described above, tendon is usually made of a PC steel rod, a PC steel wire, a multiplex PC steel wire, a continuous fiber reinforcing material, or the like.
(4) Pressure injection of grout material (5) Application of tensile force After the grout has solidified and has reached a predetermined strength, it is fixed with a tension force planned by a jack (not shown).

  By this process, the fixing part B is fixed to the rock mass R below the assumed slip line S, and the ground anchor 90 made of steel wire has the anchor head 23 protruding from the anchor insertion hole 95 to the inner ground surface. . On the inner ground surface 121 of the reinforcing frame 99, a leveling surface 20 substantially perpendicular to the ground anchor 90 is formed by greatly excavating the lower portion of the slope in the slope direction. While installing the anchor plate 21 on the leveling surface 20, the anchor head 23 that protrudes from the anchor insertion hole 95 to the inner ground surface is engaged with the anchor plate 21 via the bearing plate 22. The ground anchor 90 is applied with a tensile force by a jack (not shown) so as to have a predetermined tension.

  Here, even when the angle formed by the ground anchor 90 and the internal ground surface 121 whose installation angle with respect to the horizontal plane is determined according to the situation of the entire construction site is an acute angle, the anchor plate 21 is substantially leveled with the ground anchor 90. Since it is installed facing 20, no lateral force is applied to the anchor plate 21 and it does not move.

  Further, the surface of the leveling surface 20 may be compressed and hardened by compressing a large number of pebbles or the like so as to withstand the compression of the anchor plate 21 for a long time.

  Further, when the anchor plate 21 is installed on the leveling surface 20, the solidifying filler 27 is filled between the anchor plate 21 and the leveling surface, and after the solidifying filler 27 is solidified, a predetermined tensile force is applied to the ground anchor 90. May be applied. In this case, the solidified filler 27 that is solidified adheres to both the anchor plate 21 and the leveling surface 20, and the pressure applied to the anchor plate 21 is evenly transmitted to the leveling surface 20. It is stable and the anchor plate 21 installed there can press the leveling surface 20 more stably.

  The length 25 of the anchor plate 21 in the normal direction is preferably 50% or more of the interval 26 of the reinforcing frame 99 in the normal direction. In this case, since the length 25 in the normal direction of the anchor plate 21 is 50% or more of the interval 26 in the normal direction of the reinforcing frame 99, the reinforcing frame 99 is placed on the leveling surface 20 to which a pressing force is applied. The reinforcing frame 99 can effectively receive the lateral dispersion force of the pressing force received by the leveling surface 20 close enough, and the stabilization effect of the leveling surface 20 by the reinforcing frame 99 is even greater.

[Second Embodiment]
FIG. 2 is a slope cross-sectional view of a natural ground showing an outline when a large number of ground anchors are installed in a wide area. FIG. 3 is a slope front view showing an outline when a large number of ground anchors are installed in a wide area using reinforcing frames. 4 is a cross-sectional view taken along line AA in FIG. 3 showing the configuration of the anchor plate fixing structure 10A, particularly the configuration in which a plurality of ground anchors are closely arranged in the slope direction of the slope. .

  FIG. 2 shows an outline in the case where a large number of ground anchors 90 are constructed in a wide area as a protective work for slopes and slopes. The natural ground 100 is formed by removing the earth and sand of the upper part 110 and has a two-step slope, but even if the slope 120 of the lower part is a gentle slope, important facilities are planned under the slope. For safety reasons, it may be necessary to install a large number of ground anchors 90 on the slope 120 because there is a private house near the slope or the soil is soft. The anchoring portion B of the ground anchor 90 needs to be anchored to a solid rock in the immovable layer deeper than the assumed slip line S, and the anchoring length is generally 3 m or more and 10 m or less. The installation position, anchor force, interval, and installation angle of the ground anchor 90 are determined so as to be optimal as a whole by looking at the entire slope 120 to be constructed, and based on the strength of the fixed ground and the depth of the sliding surface, Anchor diameter, anchor length, and tendon specifications are determined. Each ground anchor 90 is installed in parallel with each other at the same installation angle.

  FIG. 3 is a slope front view showing an outline when a large number of ground anchors are installed in a wide area using reinforcing frames. A concrete plane substantially lattice-shaped reinforcing frame 99 is installed over a wide range of the slope 120, and a circle indicates an anchor plate 21 (ground anchor) installed in the reinforcing frame 99.

  FIG. 4 shows a configuration of the anchor plate fixing structure 10A, particularly a configuration in which a plurality of ground anchors are closely arranged in the slope direction of the slope. In this embodiment, the leveling surfaces 20a, 20b, 20c and the anchor plates 21a, 21b, 21c are arranged between the reinforcing frames 99, 99a, 99b, 99c, respectively. Are as in the first embodiment. In this embodiment, regarding the formation of the leveling surfaces 20a, 20b, and 20c, the lower side of the slope of the inner ground surface surrounded by the reinforcing frame is substantially excavated, and the upper side of the slope of the inner ground surface is increased. Therefore, the soil can be reused inside the grid of the reinforcing frame, so that it is unnecessary or less necessary to carry out the soil to the outside.

  Further, grass and lawn can be grown on the top soil surfaces 29, 29a, 29b, 29c below the leveling surface 20 and the top soil surfaces (not shown) around the anchor plates 21, 21a, 21b, 21c connected thereto. The anchor plates 21, 21a, 21b and 21c, which are artificial structures, can be hidden and made inconspicuous. Thereby, harmony with the surrounding natural environment is not impaired. In this case, the upper surfaces of the anchor plates 21, 21a, 21b, and 21c can be covered with soil (not shown). If the top surfaces of the anchor plates 21, 21a, 21b, 21c are covered with soil, the grass above the anchor plates 21, 21a, 21b, 21c can be vegetated, and greening is promoted to further enhance landscape conservation. It is done.

  As mentioned above, although demonstrated using embodiment of this invention, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

It is sectional drawing which shows the structure of the fixing structure of the anchor plate which concerns on this invention. It is sectional drawing of the natural ground to which the anchor structure of the anchor plate which concerns on this invention is applied. It is a front view of a natural ground to which the anchor plate fixing structure according to the present invention is applied. It is sectional drawing which shows the structure of the fixing structure of another anchor plate based on this invention. It is sectional drawing which shows the structure of the fixing structure of the conventional anchor plate.

Explanation of symbols

20, 20a, 20b, 20c Leveling surface 21, 21a, 21b, 21c Anchor plate 23, 23a, 23b, 23c Anchor head 27 Solidifying filler 90 Ground anchor 95 Anchor insertion hole 99, 99a, 99b, 99c Reinforcement frame 120 Slope 121, 121a, 121b, 121c Internal ground surface B Anchorage R Rock bedrock

Claims (9)

A step of constructing a plane substantially grid-like reinforcing frame on the slope,
Opening at approximately the center of the inner ground surface surrounded by the reinforcing frame, and drilling a fixed length anchor insertion hole;
Inserting a ground anchor into the anchor insertion hole, injecting grout and fixing the anchoring portion of the ground anchor to the rock;
Forming a ground leveling surface on the inner ground surface over a predetermined range around the anchor insertion hole and substantially perpendicular to the ground anchor;
Installing an anchor plate on the leveling surface, and connecting an anchor head protruding from the anchor insertion hole of the ground anchor to the center of the anchor plate;
Applying a predetermined tensile force to the ground anchor, and installing the anchor plate.   2. The anchor plate installation method according to claim 1, wherein the step of forming the leveling surface is performed by substantially excavating the inner ground surface.   2. The anchor plate installation method according to claim 1, wherein the step of forming the leveling surface substantially excavates a lower side of the inner ground surface in the direction of the slope, and an upper side of the inner ground surface in the direction of the slope. The anchor plate is installed by substantially embanking.   2. The anchor plate installation method according to claim 1, wherein when the anchor plate is installed on the leveling surface, a solidifying filler is filled between the anchor plate and the leveling surface, and the solidifying filler is solidified. An anchor plate installation method for performing a step of applying a predetermined tensile force to the ground anchor. Reinforcement frame in a plane substantially lattice shape built on the slope,
An anchor insertion hole that opens to the approximate center of the inner ground surface surrounded by the reinforcing frame;
A ground anchor in which an anchor head protrudes from the anchor insertion hole and a fixing portion is fixed to the ground;
On the inner ground surface, over a predetermined range centered on the anchor insertion hole, and the ground level formed so as to be substantially perpendicular to the ground anchor,
An anchor plate installed on the leveling surface,
The ground anchor is an anchor plate installation structure in which a predetermined tensile force is applied and the anchor head is connected to the center of the anchor plate.   The anchor plate installation structure according to claim 5, further comprising a solidifying filler layer solidified between the anchor plate and the leveling surface.   6. The anchor plate installation structure according to claim 5, wherein a length of the anchor plate in the normal direction is 50% or more of an interval in the normal direction of the reinforcement frame.   The anchor plate installation structure according to any one of claims 5 to 7, wherein the portion of the inner ground surface that is not covered by the anchor plate is provided with an anchor plate in which grass can be vegetated. Construction.   The anchor plate installation structure according to claim 8, wherein the upper surface of the anchor plate is covered with soil capable of herbaceous vegetation.

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