JP6310140B1 - Pressure receiving plate, pressure receiving structure and slope stability structure - Google Patents

Abstract

The present invention provides a pressure receiving plate capable of adjusting the angle of a tensile reinforcing material upward from the vertical direction of a slope, and further improves the reinforcing effect of the tensile reinforcing material even on a natural slope having a gentle inclination angle. A pressure-receiving plate for stabilizing a slope that engages with a tensile reinforcement provided on a slope, comprising a flat plate portion, a recess formed near the center of the flat plate portion, and protruding from the back surface of the flat plate portion. A vertically long slot provided in the recess, the recess being a circular arc portion that exhibits an arc in the longitudinal section of the pressure receiving plate, and a straight line positioned below the arc portion in the longitudinal section. A pressure receiving plate comprising a combination of a linear portion exhibiting [Selection] Figure 1

Description

  The present invention relates to a pressure receiving plate for stabilizing a slope, a pressure receiving structure using the pressure receiving plate, and a slope stabilizing structure.

Depending on the geological structure of the natural ground, the installation angle of the tensile reinforcement should be set for the slope bolting method, such as rock bolt construction, natural ground reinforcement earthwork, cut reinforcement earthwork, and reinforcing bar insertion. It is known that the reinforcing effect increases when the angle is closer to the horizontal plane.
Traditionally, the slope stabilization method has been used as a method to prevent the collapse of artificial slopes cut with steep slopes, so the installation angle of the tensile reinforcement is sufficiently loose even in the direction perpendicular to the slope, and additionally installed on the ground surface In order to fix the pressure receiving plate and the tensile reinforcing material by screwing, an angle adjusting pedestal that makes the axis of the tensile reinforcing material and the perpendicular of the pressure receiving plate a right angle is separately installed, or the ground of the pressure receiving plate installing portion is further steeply inclined In many cases, it has not been done to set the installation angle loosely.
However, in recent years, the slope is looser than the artificial cut slope, and natural slope stabilization work has been carried out, but the installation angle of the tensile reinforcement is set near the right angle of the slope, similar to the conventional artificial cut slope. In many cases, the installation angle of the tensile reinforcing material is 45 degrees or more downward from the horizontal plane, and the reinforcing effect is not sufficiently exhibited.

  Here, the slope stability calculation will be described in detail. There are two methods of calculation: a limit balance method in which a slip surface is given and the safety factor is determined by the ratio of resistance and sliding force, and a method of examining the safety factor by numerical analysis such as the finite element method, but the former method is usually used. Is calculated by

In the limit balancing method, the safety factor is expressed as resistance / sliding force. If the safety factor is 1.0, it means a limit state where the sliding force and the resistance force are balanced, and as the safety factor becomes larger than 1.0, the slope shows a higher stability state. Since the shape of the slip surface is often unknown on slopes where no collapse has occurred, the unit weight γ (KN / m ³ ), shear resistance angle φ (°), adhesion obtained from geological surveys conducted in the field, etc. Using ground constants such as force c (KN / m ² ), the safety factor is calculated for a number of possible slip surfaces, and the slip surface with the lowest safety factor is assumed as the assumed slip surface.

  When the sliding force Q and the resistance force S1, the safety factor Fs is expressed by the following equation.

上記の計算で求められた安全率が計画安全率以下であれば、補強などの対策が必要と判断する。計画安全率は斜面の重要度等に応じて設定されるが、経験的に１．２とする場合が多い。

If the safety factor obtained by the above calculation is less than or equal to the planned safety factor, it is determined that measures such as reinforcement are necessary. The planned safety factor is set according to the importance of the slope, but it is often empirically 1.2.

  Here, it is calculated how the safety factor changes depending on the installation angle of the tensile reinforcement material on the slope where the slope height is 10 m, the slope angle is 1: 1.2, and the moving mass is distributed in parallel with the slope slope angle. The design conditions are set as follows.

なお、移動土塊の粘着力ｃは、無補強時の安全率が１．０となるように数式１から逆算により求めた。
引張補強材の配置は、横間隔２ｍ、設置段数６段として、削孔径６５ｍｍ、法面工の低減係数μ＝０．７、補強材の低減係数λ＝０．７とする。

In addition, the adhesive strength c of the moving mass was obtained by back calculation from Equation 1 so that the safety factor when unreinforced is 1.0.
The tensile reinforcing material is arranged with a lateral interval of 2 m, the number of installation steps of 6, a hole diameter of 65 mm, a slope reduction factor μ = 0.7, and a reinforcing material reduction factor λ = 0.7.

FIG. 9 shows a graph in which the angle θ formed between the slope perpendicular and the tensile reinforcement is the horizontal axis and the safety factor after reinforcement is the vertical axis.
From this figure, it can be seen that the safety factor Fs tends to increase when the reinforcing member is disposed at a gentler angle, that is, when θ is increased, but the maximum value is θ = 45 °. Further, since the safety factor Fs needs to be 1.2 or more, θ = 25 ° or more is preferable.
In addition, the thickness of the moving soil block is optimal as an application condition of 2 to 3 m. This is because the application range of the slope stabilization method is about 3 m or less, and for minor slips of 2 m or less, the stability calculation is omitted and the specifications of the reinforcing material obtained empirically are used. is there.

Next, FIG. 10 shows the effect when the installation position of the tensile reinforcing material is set below the center of the pressure receiving plate.
This graph shows the ground reaction force q1 in the vertical direction of the slope acting on the upper end of the pressure receiving plate when the pressure receiving plate width is set to 0.4 m and the tensile force of the tensile reinforcing material is set to 40 KN. When the position is at the center of the pressure plate, q1 is about 130 KN / m ² at the maximum, but the maximum value of q1 is 100 KN by moving the tensile reinforcing material installation position 25 mm downward from the center of the pressure plate and reducing the eccentricity. / ^{m 2} about to become can be seen that small.

  In the prior art disclosed in Patent Document 1 and Patent Document 2 below, the axis of the tensile reinforcement material is moved with respect to the pressure-receiving plate perpendicular by sliding the fitting surface composed of the upper spherical portion and the lower spherical portion. Although it can be inclined, the size of the spherical surface portion is small, and as is apparent from the figure, the angle adjustment range is limited to about 15 degrees from the pressure receiving plate normal. In addition, the spherical surface portion is located above the pressure receiving plate, and the tensile reinforcing material does not intersect the pressure receiving plate grounding surface and the ground at a right angle at a location where the tensile reinforcing material is in contact with the pressure receiving plate and the ground.

  In the prior art disclosed in Patent Document 3 below, the spherical surface portion is located at the lower portion of the pressure receiving plate, but the angle adjustment is performed on the upper spherical surface portion formed at the bottom of the nut as in Patent Document 1 and the lower portion installed on the washer side. The angle adjustment range is limited to about 20 degrees from the pressure receiving plate normal. In addition, since the tensile reinforcing material insertion portion is located at the substantially central portion of the pressure receiving plate, the tensile reinforcing material does not intersect the pressure receiving plate and the ground at a right angle at the location where the tensile reinforcing material is in contact with the pressure receiving plate and the ground. It is.

Japanese Patent No. 3819013 Japanese Patent Laid-Open No. 5-59723 JP 2007-16544 A

  In view of the above-described state of the prior art, the present invention provides a pressure receiving plate capable of adjusting the angle of a tensile reinforcing material upward from the vertical direction of the inclined surface, and the reinforcing effect of the tensile reinforcing material on a natural inclined surface with a gentle inclination angle. The purpose is to further improve.

A first invention of the present application is a pressure receiving plate for stabilizing a slope, which is engaged with a tensile reinforcement provided on a slope, and is formed near the center of the flat plate portion and the flat plate portion, and protrudes from the back surface of the flat plate portion. a recess, provided in the recess, an elongated groove hole to the pressure receiving plate in a state of being placed on the inclined surface, made, the recess, longitudinal section with respect to the pressure receiving plate in a state of being placed on the inclined surface And a straight line portion that is located on the lower side of the inclined surface on which the pressure-receiving plate is installed and presents a straight line in the longitudinal cross section. A pressure receiving plate is provided.
The second invention of the present application is the pressure receiving plate of the first invention, wherein the groove is formed in the longitudinal section with respect to the pressure receiving plate in a state of being installed on a slope, and the tensile reinforcement member inserted through the groove is the flat plate portion. The pressure receiving plate is provided over a direction perpendicular to the flat plate portion and at a 45 ° angle to the flat plate portion.
The third invention of the present application is the pressure receiving plate of the first invention or the second invention, wherein the recess is located below the center in the longitudinal direction with respect to the pressure receiving plate in a state of being installed on the inclined surface of the flat plate portion. A pressure receiving plate is provided.
According to a fourth invention of the present application, the pressure receiving plate according to any one of the first to third inventions, the tensile reinforcing material inserted through the groove, and the tensile reinforcing material are inserted into the recess of the pressure receiving plate. The pressure receiving structure is characterized in that the pressure receiving structure has a semicircular shape in sectional view having the same curvature as the arc portion of the concave portion.
The fifth invention of the present application is a method for installing the pressure receiving structure of the fourth invention on an inclined surface, wherein the pressure receiving plate tensions the tensile reinforcement by human force, pushing by a drilling machine or other machines, or a hydraulic jack. An installation method is provided, wherein the concave portion is pushed into the slope by being pushed in and installed on the slope.
A sixth invention of the present application comprises a plurality of tension members attached in directions intersecting with each of the slopes, and a pressure receiving structure according to the fourth invention provided on the slope and connected to any of the intersections of the plurality of tension members. Provide slope stabilization structure.

According to the present invention, the following effects can be obtained.
(1) Since the installation angle of the tensile reinforcing material with respect to the slope and the pressure receiving plate can be changed, the tensile reinforcing material can be brought closer to a horizontal surface than in the prior art, and the reinforcing effect can be increased particularly in a viscous ground.
(2) By forming the concave part where the tensile reinforcement material is in contact with the pressure receiving plate and the ground as an arc portion, the tensile reinforcement material is shaped to intersect the pressure receiving plate and the ground at a right angle, and when the axial force acts on the tensile reinforcement material, the slope upwards The sliding resistance against the direction component is improved.
(3) By disposing the concave portion of the pressure receiving plate downward from the center so that the position where the tension reinforcing material installed at an inclination angle higher than the direction perpendicular to the slope and the ground is in the ground is near the center of the pressure receiving plate. When an axial force acts on the tensile reinforcement, the ground reaction force acting on the upper portion of the pressure receiving plate can be reduced, and uneven settlement of the pressure receiving plate can be reduced.

The perspective view of the pressure receiving structure of this invention Plan view of pressure receiving plate of the present invention Sectional view of the pressure receiving plate of the present invention Sectional view (1) of the pressure receiving structure of the present invention Sectional drawing (2) of the pressure receiving structure of this invention Explanatory drawing of tension reinforcement with hydraulic jack Explanatory drawing of the stabilization structure of the slope of this invention Explanation of slope stability calculation Graph of tensile reinforcement placement angle and safety factor Graph showing the effect of placing the tensile reinforcement below the pressure plate

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

(1) Pressure receiving plate The pressure receiving plate 1 of the present invention engages with the tensile reinforcing material 3 and tightens and fixes the nut 5 with a cap via the pedestal 4 inserted through the tensile reinforcing material 3 to thereby fix the tensile reinforcing material 3. The pressure receiving structure 2 is configured to transmit the tensile force acting on the slope to stabilize the slope (FIG. 1).
The pressure receiving plate 1 includes a flat plate portion 11 of a substantially square plate body, a concave portion 12 formed near the center of the flat plate portion 11, and a vertically long slot 13 provided in the concave portion 12 (FIG. 2).
The material of the pressure receiving plate 1 is preferably a metal.
The dimension of the flat plate portion 11 of the pressure receiving plate 1 is desirably 200 mm to 1000 mm on a side. However, the shape of the pressure receiving plate 1 is not particularly limited, and various shapes can be adopted without being limited to a substantially square shape, and may be, for example, a triangular shape or a circular shape.

(1.1) Concave portion The concave portion 12 is formed to protrude from the front surface of the flat plate portion 11 to the back surface.
In the longitudinal direction (AA direction) cross section of the pressure receiving plate 1, the recess 12 has an arc portion 121 that exhibits an arc, and a linear portion that presents a straight line that is provided below the arc portion 121 in the longitudinal direction of the pressure receiving plate 1. 122 (FIG. 3).

(1.2) Groove hole The groove hole 13 is formed in the circular arc part 121 of the recessed part 12 along the longitudinal cross-section (AA direction) of the pressure receiving plate 1.
The tensile reinforcement member 3 is inserted into the groove 13, and the groove 13 forms 45 degrees with respect to the flat plate portion 11 from the direction (FIG. 4) orthogonal to the flat plate portion 11. It is formed vertically long across the direction (FIG. 5). In accordance with this, the linear portion 122 is also formed to form 45 degrees with respect to the flat plate portion 11.
By configuring in this way, the angle of the tensile reinforcement 3 can be adjusted up to 45 degrees with respect to the flat plate portion 11.
In this embodiment, the angle of the tensile reinforcement member 3 can be adjusted up to 45 degrees. However, if the maximum angle is 25 degrees to 45 degrees, a high safety factor can be obtained.

(1.3) Arrangement of Recesses The recesses 12 are preferably provided below the longitudinal center of the flat plate part 11.
By providing the concave portion 12 on the lower side, the installation position of the tensile reinforcing material 3 becomes lower than the center of the pressure receiving plate 1, and the ground reaction force at the upper portion of the pressure receiving plate 1 can be reduced.

(2) Pressure receiving structure In the pressure receiving structure 2 of the present invention, the pressure receiving plate 1 is installed on the slope S by inserting the tensile reinforcing material 3 previously placed on the slope S through the groove 13 and protrudes from the recess 12. A hemispherical pedestal 4 having an insertion hole 41 at the center is inserted into the tensile reinforcement member 3 placed in the recess 12 and a nut 5 with a cap is screwed onto the head of the tensile reinforcement member 3 protruding from the pedestal 4. Then, the pressure receiving plate 1 is configured to be fixed on the slope S (FIG. 4). In addition, the nut 5 with a cap is good also considering a cap and a nut as a separate structure.

  The pressure receiving plate 1 is embedded by pushing the concave portion 12 into the ground of the slope S. As a method, the pressure receiving plate 1 is pushed by manpower, a drilling machine or other machines, or by tensioning the tensile reinforcement 3 with a hydraulic jack. Is desirable, but if the slope S is hard and difficult to push in. The pressure receiving plate 1 and the slope S can be brought into close contact with each other by excavating the slope S in advance and filling the gap between the pressure receiving plate 1 and the slope S with mortar.

(3) Pedestal The pedestal 4 is hemispherical and has an insertion hole 41 through which the tensile reinforcement member 3 is inserted.
The spherical bottom surface of the pedestal 4 is formed inside the recess 12 even if the angle of the tensile reinforcement 3 inserted through the pedestal 4 with respect to the pressure receiving plate 1 changes by setting the arc portion 121 of the recess 12 of the pressure receiving plate 1 to the same curvature. The tensile reinforcement member 3 can be followed while being arranged (FIGS. 4 and 5).
The size of the pedestal 4 is preferably 100 mm or more in order to mount the hydraulic jack 9 used when tensioning the tensile reinforcement member 3 (FIG. 6). Since the pressure receiving plate 1 of the present invention has the straight portion 122, the flat plate portion 11 does not interfere with the hydraulic jack 9 even if the tensile reinforcement member 3 is inclined.
In addition, the recessed part 12 and the base 4 should just be the same curvature, and the recessed part 12 and the base 4 are good also as a semi-cylinder shape.

(4) Slope Stabilization Structure The slope S stabilization structure using the pressure-receiving structure 2 of the present invention has crossing directions such as the vertical direction and horizontal direction of the slope S, and the right diagonal direction and left diagonal direction. The intersections of the plurality of tension members 7 attached to the are connected by the connecting member 8, and any of the intersections is connected to the pressure receiving structure 2.
The arrangement shape of the pressure-receiving structure 2 on the slope S is preferably a staggered arrangement (FIG. 7A), but may be a square arrangement (FIG. 7B) or a rectangular arrangement.

  The ground between the pressure receiving plates 1 that are installed along the slope S can be subjected to vegetation work such as a vegetation base material spraying work when erosion is assumed.

DESCRIPTION OF SYMBOLS 1 Pressure receiving plate 11 Flat plate part 12 Recessed part 121 Arc part 122 Linear part 13 Groove hole 2 Pressure receiving structure 3 Tensile reinforcement 4 Base 41 Insertion hole 5 Nut with cap 6 Anchor hole 7 Tension member 8 Connecting material 9 Hydraulic jack

Claims (6)

A pressure receiving plate for stabilizing a slope, which is engaged with a tensile reinforcement provided on the slope,
A flat plate part;
A recess formed near the center of the flat plate portion and protruding from the back surface of the flat plate portion;
A vertically long groove hole with respect to the pressure receiving plate in a state of being provided on the slope provided in the recess,
The concave portion has an arc portion that exhibits an arc in a longitudinal section with respect to the pressure receiving plate in a state of being installed on a slope, and the arc portion in the longitudinal section is below the slope on which the pressure receiving plate is installed. It is characterized by being combined with a straight line portion that is positioned and presents a straight line,
Pressure plate. The pressure receiving plate according to claim 1,
In the longitudinal section relative to the pressure-receiving plate in a state where the groove is installed on a slope, the groove hole is 45 to the flat plate portion from a direction perpendicular to the flat plate portion. It is provided over a direction that makes a degree,
Pressure plate. In the pressure receiving plate according to claim 1 or 2,
The concave portion is located below the center in the longitudinal direction with respect to the pressure receiving plate in a state of being installed on the slope of the flat plate portion,
Pressure plate. A pressure receiving plate according to any one of claims 1 to 3,
The tensile reinforcement inserted through the groove;
A pedestal that is inserted through the tensile reinforcement and disposed in the recess of the pressure receiving plate, and
The pressure receiving structure according to claim 1, wherein the pedestal has a semicircular cross-sectional view having the same curvature as the arc portion of the concave portion. A method for installing the pressure-receiving structure according to claim 4 on a slope,
The installation method is characterized in that the pressure plate is installed on the slope by pushing the concave portion into the slope by pushing by human power, a drilling machine or other machine, or by pushing the tension reinforcing member with a hydraulic jack. . A plurality of tension members attached in directions intersecting each of the slopes;
The pressure receiving structure according to claim 4, wherein the pressure receiving structure is provided on a slope and connected to any one of intersections of the plurality of tension members.
Slope stabilization structure.

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