JP5743610B2 - Protective levee, protective levee construction method, and protective dam design method - Google Patents

Description

  The present invention relates to a protective bank for preventing damage caused by falling objects having large kinetic energy, such as falling rocks, debris flows, and avalanches, a method for constructing the protective bank, and a method for designing the protective bank.

  On the slopes of mountainous areas, a protective bank is provided to prevent damage caused by falling objects with large kinetic energy such as rock fall, debris flow, and avalanche (hereinafter sometimes referred to as “falling rock”). . Conventionally, a retaining wall made of concrete has been used as such a protective bank. A concrete retaining wall resists impact by its own mass. Therefore, it is necessary to increase the mass of the retaining wall in order to withstand a large impact caused by falling rocks, etc., and the ground on which the retaining wall is installed is required to have a strong supporting force. When the strength of the ground was insufficient, it was necessary to separately perform ground improvement work.

  Thus, the concrete retaining wall has problems in terms of workability and cost. Therefore, what is called a reinforced earth wall formed by embedding a reinforcing material (for example, geotextile) in the embankment is sometimes used. As a specific example of the reinforced earth wall, for example, a shock absorbing dam body disclosed in Patent Document 1 can be cited. In Patent Document 1, a resistor formed by placing a plurality of reinforcing materials in the horizontal direction with a plurality of gaps between the embankments, and sand or the like enclosed in a cylindrical bag body, and substantially perpendicular to the ground. A plurality of shock absorbers installed in the standing position on the mountain side of the resistor, and a shock absorber stacked on the mountain side of the resistor in a posture that is almost parallel to the ground, with sand or the like enclosed in a cylindrical bag body And a construction method for the same.

JP 2004-11224 A

  In the conventional protective bank construction methods such as the construction method of the shock absorbing bank body disclosed in Patent Document 1 above, it has been studied whether the protective bank can withstand the impact of falling rocks. Sufficient investigation has not been made on the degree of breakage when impacted by falling rocks. In other words, it was unclear whether the protective dam obtained by the conventional construction method would be damaged to the extent that it could be repaired or damaged to the extent that it would need to be reconstructed when impacted by falling rocks, etc. . When a protective bank composed of soil receives an impact from one slope side (mountain side) due to falling rocks or the like, the other slope side (valley side) is also deformed according to the magnitude of the impact. If the wall material on the valley side is severely broken or misaligned, it will be difficult to repair the protective levee and it will be necessary to reconstruct it.

  Accordingly, the present invention provides a protective levee designed in consideration of the degree of breakage when subjected to an impact, and a protective levee capable of constructing a protective levee having a strength according to the application, taking into consideration the degree of breakage when subjected to an impact. It is an object of the present invention to provide a construction method and a design method of a protection dam that can design a protection dam with a strength according to the application in consideration of the degree of breakage when subjected to an impact.

  In order to solve the above problems, the present invention takes the following means.

A first aspect of the present invention is a protective dam comprising a banking structure and a plurality of bank reinforcements embedded in the banking structure with a predetermined interval in the height direction. Based on the energy E (kJ) possessed by the object that is expected to collide with the slope side, the other of the protective levee is obtained from the following equation (1) when the object collides with one slope side of the protective levee: The maximum displacement amount δfmax ₁ (mm) generated on the slope side is a protective levee that is equal to or smaller than a permissible displacement amount δa (mm) set in advance as a displacement amount that can be permitted by the protective levee.
δfmax ₁ = α ₁ × exp (1.22 × 10 ⁻³ × E) (1)
However, 3.00 ≦ α ₁ ≦ 67.00.

In the above equation (1), various protective levees are actually produced, and an object having energy E of various strengths is caused to collide with one slope side for each of the protective levee, and the protective levee is caused by the collision. This is an approximate expression obtained from the relationship between the maximum displacement amount δfmax ₁ generated on the other slope side and the energy E when the maximum displacement amount δfmax ₁ is generated. In the present invention, the “maximum displacement amount” means, unless otherwise specified, when the protective levee receives an impact from one slope side, among the displacements generated on the other slope side of the protective dam, It means the displacement of the most displaced part. Hereinafter, of the slopes of the protection levee, the side where falling rocks fall and collide may be referred to as “mountain side” or “receiving surface side”. Further, the side facing the “mountain side” or the “receiving surface side” may be referred to as the “valley side”.

  Further, in the present invention, the “banking structure” means a dam-like structure formed by raising a banking material. In addition, the “banking material” that can be used in the present invention is not particularly limited, and those conventionally used can be used. As the embankment material, for example, locally generated soil such as sandy soil or cohesive soil can be used. Further, in the present invention, the “banking reinforcing material” means a member that can be embedded in the banking structure to reinforce the banking structure. The embankment reinforcing material used for this invention will not be specifically limited if it is used for the conventional embankment structure. Further, in the present invention, the “allowable displacement amount” is the maximum displacement amount generated on the other slope side of the protective bank when the protective bank is impacted from the one slope side, and can be repaired. Means the amount of displacement. The allowable displacement amount is an amount that is appropriately set according to the use or type of the protective bank. In the present invention, the “type of protection bank” means the height and width of the protection bank, the type and amount of embankment material, the installation method, the type of embankment reinforcing material, the number of installations, the installation method, and the embankment structure. When the slope is covered with a wall material, it is determined by the type of wall material, the number of installations, and the installation method. is there.

A second aspect of the present invention is a protective dam comprising a banking structure and a plurality of bank reinforcements embedded in the banking structure with a predetermined interval in the height direction, Protected when an object collides with one slope side of the protective dam, obtained from the following equation (2) based on the impact force P (kN) that the object colliding with the slope side is assumed to give to the protective levee The maximum amount of displacement δfmax ₂ (mm) generated on the other slope side of the levee is a protective levee having an allowable displacement amount δa (mm) which is preset as a displacement amount allowable for the protective levee.
δfmax ₂ = α ₂ × exp (5.80 × 10 ⁻⁴ × P) (2)
However, 6.00 ≦ α ₂ ≦ 49.00.

The above formula (2) actually creates various protective dams, and gives each of the protective dams impact strength P of various strengths on one slope side, and applies the impact force P to one of the protective dams. An approximate expression obtained from the relationship between the maximum displacement amount δfmax ₂ generated on the other slope side of the protective levee when applied to the slope side and the impact force P when the maximum displacement amount δfmax ₂ is generated. It is.

According to a third aspect of the present invention, there is provided an embankment structure, a plurality of embankment reinforcements embedded in the embedding structure with a predetermined interval in the height direction, and one of the slope structures, A guard levee provided with one or two rows of strikers along the slope, and an object assumed to collide with the slope side where the guard of the guard levee is provided The maximum amount of displacement that is obtained from the following equation (3) based on the energy E (kJ) that is generated on the other slope side of the protective bank when the object collides with the slope side where the guard body of the protective bank is provided δfmax ₃ (mm) is a protective levee having an allowable displacement amount δa (mm) or less that is set in advance as an allowable displacement amount of the protective levee.
δfmax ₃ = α ₃ × exp (β ₃ × E) (3)
However, when the impact body is in one row, the depth of the impact body is 0.5 m or more, 0.50 ≦ α ₃ ≦ 18.00, β ₃ = 1.56 × 10 ⁻³ , In the case of two shooters, the total depth of the shooters in the two rows is 1.0 m or more, 26.00 ≦ α ₃ ≦ 66.00, and β ₃ = 3.80 × 10 ⁻⁴ .

In the above equation (3), various protection levees are actually produced, and an object having energy E of various strengths is caused to collide with one slope side for each of the protection levee, and the protection levee is caused by the collision. This is an approximate expression obtained from the relationship between the maximum displacement amount δfmax ₃ generated on the other slope side and the energy E when the maximum displacement amount δfmax ₃ is generated.

According to a fourth aspect of the present invention, there is provided the embankment structure, a plurality of embankment reinforcements embedded in the embedding structure with a predetermined interval in the height direction, and one of the slope structures, If the object which collides with the slope side where the interceptor of the protective levee is provided is applied to the protective levee, Based on the assumed impact force P (kN), it is obtained from the following equation (4), and occurs on the other slope side of the protective bank when the object collides with the slope side where the guard body of the protective bank is provided. The maximum amount of displacement δfmax ₄ (mm) is a protective dam that is equal to or less than an allowable displacement amount δa (mm) preset as a displacement amount that can be permitted by the protective levee.
δfmax ₄ = α ₄ × exp (β ₄ × P) (4)
However, when the impact body is in a single row, the depth of the impact body is 0.5 m or more, 1.00 ≦ α ₄ ≦ 15.00, β ₄ = 6.00 × 10 ⁻⁴ , In the case of two rows of shooters, the total depth of the two rows of strikers is 1.0 m or more, 19.00 ≦ α ₄ ≦ 44.00, and β ₄ = 2.30 × 10 ⁻⁴ .

The above equation (4) actually creates various protective dams, and gives each of the protective dams impact forces P of various strengths on one slope side, and applies the impact force P to one of the protective dams. Approximate expression obtained from the relationship between the maximum displacement amount δfmax ₄ generated on the other slope side of the protective bank and the impact force P when the maximum displacement amount δfmax ₄ is generated. It is.

  In the protective levee according to the third or fourth aspect of the present invention, the impact body is filled with a frame having a plurality of cells that are open at the top and are formed continuously in a substantially horizontal direction. It is preferable that the layer provided with the filling material is laminated in the vertical direction. Moreover, it is preferable that the embankment reinforcing material and the upper surface or lower surface of a frame are substantially flush. Furthermore, it is preferable that the impactor can be replaced layer by layer.

  In the present invention, “a frame having a plurality of cells open at the top and continuously formed in a substantially horizontal direction” means a cylindrical shape having at least the upper side opened when installed horizontally. This means that a plurality of cells are continuously provided in the horizontal direction. In addition, “the embankment reinforcing material and the upper surface or lower surface of the frame body are substantially flush” means that the embedded embankment reinforcing material is regarded as one surface, and the upper surface or lower surface of the frame body is on one surface. It means that these surfaces are substantially flush with each other.

  In the protective levee according to the third or fourth aspect of the present invention, it is preferable that at least the receiving surface side and the top surface side of the receiving body are covered with an impact absorbing mat or an impact absorbing sheet.

  In the protective bank according to the third or fourth aspect of the present invention, it is preferable that the impactor is wrapped in a series of reinforcing members in a cross-sectional view in the vertical direction. Moreover, it is preferable that a series of reinforcements that wrap around the impactor include a truss structure reinforcement made of a geotextile having particularly strong tensile strength in the triaxial direction.

  In the present invention, “a series of reinforcing materials” means a single reinforcing material integrally formed or a plurality of reinforcing materials connected together.

  In the protection levee according to the first to fourth aspects of the present invention, it is preferable that the slope of the embankment structure is covered with a wall surface material, and the wall surface materials adjacent in the horizontal direction are connected to each other with a connection portion material.

  In the protective levee according to the first to fourth aspects of the present invention, it is preferable that at least one of the plurality of embankment reinforcing materials is a truss structure reinforcing material made of a geotextile having particularly strong tensile strength in the three axial directions. Further, the plurality of embankment reinforcements are a transverse reinforcement made of a geotextile having a particularly strong strength in the transverse direction at the time of laying, and a truss structure reinforcement, and in the vertical direction, one transverse reinforcement and another transverse It is preferable that one or more truss structure reinforcing materials are embedded between the directional reinforcing materials.

  In the present invention, the “crossing direction” means a direction from one slope of the embankment structure toward the other slope. In the following description of the present invention, the length in the transverse direction may be referred to as “depth”.

  A fifth aspect of the present invention is a method for constructing a protective bank comprising a bank structure and a plurality of bank reinforcements embedded in the bank structure at predetermined intervals in the height direction. Calculates the maximum amount of displacement that is expected to occur on the other slope side of the protective levee when an impact is received from one slope side, and the maximum displacement amount is set in advance as the allowable displacement amount of the protective levee This is a method of constructing a protective bank, including a design process for designing a structure that is equal to or less than the allowable displacement.

  In the design step of the construction method of the protective levee according to the fifth aspect of the present invention, the maximum displacement is calculated based on the energy of an object that is supposed to collide with one slope side of the protective levee, and the maximum displacement It is preferable to design the structure so that the amount is equal to or less than the allowable displacement amount.

  In the design process of the construction method of the protection levee of the fifth aspect of the present invention, the maximum displacement is calculated based on the collision force assumed to be received on one slope side of the protection levee, and the maximum displacement is allowable. It is preferable to design the structure so as to be less than the displacement amount.

  In the construction method of the protective levee of the fifth aspect of the present invention, the protective levee includes a frame having a plurality of cells that are open at the top and are formed continuously in a substantially horizontal direction, and the cells are filled An embankment structure production process for producing an embankment structure, comprising an impact body configured by vertically laminating a layer including a filling material on one slope side of the embankment structure, and an impact body It is preferable to include the impactor preparation process of producing.

  In the construction method of the protection levee according to the fifth aspect of the present invention, the embankment structure preparation step includes laying the embankment reinforcing material substantially horizontally, placing the embankment material on the embankment reinforcing material, Including a step of compacting, including a step of compacting, including a step of repeating the reinforcing material laying step and the compacting step until the height of the structure obtained through the reinforcing material laying step and the compacting step reaches a predetermined height. The body preparation process includes a frame installation process in which the frame body is installed substantially horizontally on the mountain side of the embankment structure, and a filling material filling process in which the cells of the frame body are filled with the filling material, and the frame body is laid Including the step of repeating the frame laying step and the filling step for filling the filling material until the height obtained by laminating the layers obtained through the step and the filling material filling step in the vertical direction reaches a predetermined height, It is preferable to perform the impactor manufacturing process in parallel.

  In the construction method of the protective bank according to the fifth aspect of the present invention, it is preferable to use a truss structure reinforcing material made of a geotextile having a particularly strong tensile strength in at least one of the plurality of embankment reinforcing materials in the triaxial direction.

  In the construction method of the protective bank of the fifth aspect of the present invention, a plurality of embankment reinforcing materials are used in a vertical direction using a transverse reinforcing material made of a geotextile having a particularly strong strength in the transverse direction when laid and a truss structure reinforcing material. In this case, it is preferable to embed one or more truss structure reinforcing materials between one transverse reinforcing material and another transverse reinforcing material.

  It is preferable that the construction method of the fifth aspect of the present invention includes a step of covering the receiving surface side and the top surface side of the receiving body with an impact absorbing mat or an impact absorbing sheet in a vertical sectional view.

  In the construction method of the fifth aspect of the present invention, it is preferable to include a step of wrapping the impactor with a series of reinforcing members in a sectional view in the vertical direction.

  In the construction method of the protective bank of the fifth aspect of the present invention, it is preferable to use a truss structure reinforcing material made of a geotextile having a particularly strong tensile strength in the triaxial direction as a series of reinforcing materials for wrapping the impactor.

  The sixth aspect of the present invention is a design method for a protective levee comprising a banking structure and a plurality of bank reinforcements embedded in the banking structure at predetermined intervals in the height direction. The maximum amount of displacement that is assumed to occur on the other slope side of the protective levee when the levee is impacted from one slope side is calculated, and the maximum displacement amount is preliminarily determined as the allowable displacement amount of the protective levee. This is a design method for a protective levee that is designed to have a structure that does not exceed the set allowable displacement.

  According to the first to fourth aspects of the present invention, it is possible to provide a protective bank designed in consideration of the degree of breakage when subjected to an impact. In addition, according to the fifth aspect of the present invention, it is possible to construct a protective bank having a strength according to the application in consideration of the degree of breakage when receiving an impact. Furthermore, according to the sixth aspect of the present invention, it is possible to design a protective levee having a strength according to the application in consideration of the degree of breakage when receiving an impact.

  In the case of falling rocks at the construction site, the conventional protective bank is selected based on the assumption that the protective bank will not be deformed by the falling rocks, and the depth and height of the embankment structure, the depth of the receiver The number of installations was appropriately determined and designed. For this reason, a protection dyke with an excessive specification is actually constructed, and it takes a long time to complete the protection levee, and it is difficult to shorten the construction period. There is also a problem that construction costs such as extra labor costs and material costs increase. In post-construction management, the amount of displacement increases due to human inspection at the construction site, and when it is confirmed that there is a risk of breakage of the protective dam, it is common practice to perform repair work on the protective levee. It was the target. For this reason, there is a problem that maintenance at each construction site is complicated.

  On the other hand, the first to fourth aspects of the present invention are designed so that the maximum displacement amount of the protective bank calculated from the rockfall energy and the impact force of the protective bank at the time of a rockfall collision is less than the allowable displacement amount of the protective bank. Thus, the presence / absence of the impactor, the number of impactors, and the like are determined, and the optimum type of the protection bank is selected. Therefore, according to the first to fourth aspects of the present invention, it is possible to provide an optimal type of protective levee at the construction site and to predict in advance when the protective levee needs maintenance. This makes it possible to perform regular maintenance at the installation location and to facilitate the management of the protection levee.

It is a figure which shows schematically the cross section of the perpendicular direction and the crossing direction of the protection bank of this invention concerning one Embodiment. It is a figure which shows roughly the vertical cross section and transverse direction of the protection bank of this invention concerning other embodiment. It is a perspective view which shows roughly the attitude | position before the expansion of the frame which can be used for this invention. It is a perspective view which shows roughly the attitude | position after the expansion of the frame shown in FIG. It is a figure which shows roughly the vertical cross section and transverse direction of the protection bank of this invention concerning other embodiment. It is a flowchart which shows one example of embodiment roughly about the construction method of the protection bank of this invention. It is a figure for demonstrating the examination process of design wall height. It is a flowchart explaining a construction process more specifically. It is a figure for demonstrating the process of wrapping an impactor with a reinforcing material. It is a perspective view which shows roughly a part of part which connected wall surface materials with the connection site | part material concerning one example. Fig.11 (a) thru | or FIG.11 (e) is a figure explaining the method of connecting wall surface materials with the connection site | part material concerning another example.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments. In the drawings, for convenience of illustration and understanding, the scale and vertical / horizontal dimension ratios may be appropriately changed and exaggerated from those of the actual ones. Moreover, the same code | symbol is attached | subjected to the thing of the same structure in each drawing. Further, in some cases, it may be simplified for ease of viewing, a part of repeated reference numerals may be omitted, or a constituent member that will not be described may be omitted.

1. Protective embankment The protective levee of the present invention includes a banking structure and a plurality of bank reinforcements embedded in the banking structure at predetermined intervals in the height direction. Further, in the protective bank of the present invention, the maximum displacement amount that is assumed to occur on the other slope side when receiving an impact from the one slope side is equal to or less than an allowable displacement amount that is set in advance as an allowable displacement amount. It is characterized by being. Hereinafter, embodiments of the present invention will be described in detail with reference to embodiments.

1.1. 1st Embodiment FIG. 1: is a figure which shows schematically the cross section of the perpendicular direction and the crossing direction of the protection bank 100 of this invention concerning 1st Embodiment. 1 includes a banking structure 10 and a plurality of banking reinforcements 1, 1,... Embedded in the banking structure 10 at a predetermined interval in the height direction. ing. Hereinafter, the protective bank 100 will be described in detail.

(Fill structure 10)
The embankment structure 10 is formed by embedding embankment materials 2, 2,... On the ground 50, and embedding the reinforcement materials 1, 1,. The embankment materials 2, 2,... Can be used without particular limitation as long as they are used as conventional embankment materials. As the embankment material, for example, locally generated soil such as sandy soil or cohesive soil can be used.

  The slope of the slope of the embankment structure 10 is not particularly limited, but is generally about 1: 0.2 to 1: 0.5. The slope of the slope on the mountain side and the slope of the slope on the valley side of the embankment structure 10 may be the same or different.

  In the protection embankment of the present invention, the configuration of the slope and the top surface of the embankment structure 10 is not particularly limited, and can be the same as a conventional well-known embankment structure. For example, the slope of the embankment structure 10 can be covered with a known wall material (not shown) such as expanded metal or wire mesh. Moreover, when the slope of the embankment structure 10 is covered with the several wall surface material, it is preferable that the wall surface materials adjacent in a horizontal direction are connected with the connection site | part material. Thus, the impact resistance of the protective bank 100 can be further improved by connecting the wall surface material with the connection part material.

  Although the method of connecting the wall materials adjacent in the horizontal direction is not particularly limited, a specific example thereof will be described with reference to FIGS. FIG. 10 is a perspective view schematically showing a part of a portion in which wall surface materials are connected by a connecting part material according to one example. FIGS. 11A to 11E are views for explaining a method of connecting wall surface materials with a connecting portion material according to another example.

  As a connection part material which connects wall surface materials, the coil-shaped member 13 as shown, for example in FIG. 10 is mentioned. As shown in FIG. 10, the wall surface material 11 and the wall surface material 12 are connected by entwining the coil-shaped member 13 between the end portion of one adjacent wall surface material 11 and the end portion of the other wall surface material 12. Can do. The size, thickness, material, and the like of such a coil-shaped member are appropriately determined depending on the load applied to the coil-shaped member after construction of the protective bank, the height of the wall surface material to be connected, the structure of the wall surface material, and the like. The length of the coil-shaped member must be at least long enough to fix the wall materials, preferably 2/3 or more of the height of the wall materials, more preferably 3/3 of the height of the wall materials. 4 or more.

  Moreover, as a connection site | part material which connects wall surface materials, the wire clip 14 as shown to Fig.11 (a) thru | or FIG.11 (e) is also mentioned. The wall material 11 and the wall material 12 can be connected by bundling the vertical stripe at the end of one adjacent wall material 11 and the vertical stripe at the end of the other wall material 12 with a wire clip 14. FIG. 11A is a view of the connecting portion between the wall surface material 11 and the wall surface material 12 as seen from the slope side. FIG.11 (b) is a bb arrow line view of Fig.11 (a). 11 (e) is a view taken along the line ee of FIG. 11 (a), and FIGS. 11 (c) to 11 (e) show the wall material 11 and the wall material using the wire clip 14 viewed from the same viewpoint. FIG.

  In order to connect the wall surface material 11 and the wall surface material 12 using the wire clip 14, first, as shown in FIG. 11A and FIG. The vertical stripes at the end of the material 12 are brought into contact with each other. Then, the vertical bars of the wall surface material 11 and the wall surface material 12 which are adjacent to each other are bound by the wire clip 14. In order to explain more specifically, the configuration of the wire clip 14 will be described. As shown in FIG. 11E, the wire clip 14 is a member formed of a U-shaped member 14a, a fastener 14b, and nuts 14c and 14c. The end of the U-shaped member 14a is threaded and can be screwed into the nuts 14c and 14c. The fastener 14b has two holes through which the end of the U-shaped member 14a threaded can pass.

  In order to connect the wall surface material 11 and the wall surface material 12 using the wire clip 14, first, as shown in FIG. 11 (c), the wall surface material 11 and the wall surface material 12 are in contact with the vertical stripes at the end. To match. Next, the U-shaped member 14a is hooked between adjacent vertical bars. Next, as shown in FIG. 11D, the U-shaped member 14a is passed through the fastener 14b. Finally, as shown in FIG. 11E, the wall surface material 11 and the wall surface material 12 can be connected by screwing nuts 14c and 14c into the U-shaped member 14a.

  The size of the wire clip and the number of wire clips used, that is, the installation interval of the wire clip, the load applied to the wire clip after constructing the protective bank, the thickness of the vertical stripe at the end of the wall material to be connected, the connection It is determined appropriately depending on the height of the wall material to be used.

(Filling reinforcement 1)
For the embankment reinforcement 1 provided in the protective bank 100, a conventional embankment reinforcement can be used without particular limitation, but a resin net-like body having a high tensile strength such as a known geogrid is suitable. It is. However, as the embankment reinforcing material 1, a metal material such as a wire mesh can be used. In addition, when the protective bank 100 receives an impact caused by falling rocks or the like, the mesh opening is substantially triangular as the embankment reinforcing material 1 from the viewpoint that the impact can be dispersed in a wide range within the protective bank 100. As a result of having a particularly strong tensile strength in the triaxial direction, a truss structure reinforcing material made of a geotextile having a truss structure having pseudo strength in all directions (360 degrees) (for example, JP 2004-44374 A) It is preferable to use Geogrit, which is disclosed in Japanese Patent Publication.

  Furthermore, in the present invention, as the embankment reinforcements 1, 1,..., Using the transverse reinforcement made of geotextile having a particularly strong strength in the transverse direction when laid and the truss structure reinforcement, It is preferable to embed in the embankment structure 10 so that one or more truss structure reinforcing materials may be sandwiched between the transverse reinforcing material and another transverse reinforcing material. By setting it as this form, while providing the force which restrains the embankment material 2 in a cross direction with a cross direction reinforcement material, the effect which disperse | distributes the impact by falling rocks etc. by a truss structure reinforcement material can be show | played.

(Strength of the protective bank 100)
As described above, the protective levee according to the present invention is configured such that the maximum displacement amount that is assumed to be generated on the other slope side when an impact is received from one slope side is set as an allowable displacement amount that is set in advance. It is characterized by being less than the amount of displacement.

More specifically, the protective dam 100 is an object obtained from the following equation (1) based on energy E (kJ) of an object that is supposed to collide with one slope side of the protective dam 100. The maximum displacement amount δfmax ₁ (mm) generated on the other slope side of the protective bank 100 when it collides with _one slope side of the protective bank 100 is an allowable displacement set in advance as a displacement amount that the protective bank 100 can allow. It is designed to be less than or equal to the amount δa (mm).
δfmax ₁ = α ₁ × exp (1.22 × 10 ⁻³ × E) (1)
However, 3.00 ≦ α ₁ ≦ 67.00.

The above formula (1) actually creates various protective dams 100, and for each of the protective dams 100, an object having energy E of various strengths is caused to collide with one slope side, and the collision causes the It is an approximate expression obtained from the relationship between the maximum displacement amount δfmax ₁ generated on the other slope side of the protective bank 100 and the energy E when the maximum displacement amount δfmax ₁ is generated.

α ₁ is a coefficient derived from the maximum displacement amount δfmax ₁ generated on the other slope side when an object having energy E of various strengths collides with _one slope side of the protective bank 100. α ₁ is 3.00 or more, preferably 10.00 or more, more preferably 13.00 or more, still more preferably 16.00 or more, 67.00 or less, preferably 65.00 or less, more preferably Is 60.00 or less, more preferably 55.00 or less.

Further, the protective dam 100 is an object obtained from the following equation (2) based on an impact force P (kN) that is assumed to be applied to the protective dam 100 by an object that collides with one slope side of the protective dam 100. The maximum displacement amount δfmax ₂ (mm) generated on the other slope side of the protective bank 100 when it collides with one slope side of the protective bank 100 is an allowable displacement set in advance as a displacement amount that the protective bank 100 can allow. It is designed to be less than or equal to the amount δa (mm).
δfmax ₂ = α ₂ × exp (5.80 × 10 ⁻⁴ × P) (2)
However, 6.00 ≦ α ₂ ≦ 49.00.

The above equation (2) actually creates various protective dams 100, and gives an impact force P of various strengths to one slope side of each of the protective dams 100. Obtained from the relationship between the maximum displacement amount δfmax ₂ generated on the other slope side of the protective bank 100 and the impact force P when the maximum displacement amount δfmax ₂ is generated. Is an approximate expression.

α ₂ is derived from the maximum displacement amount δfmax ₂ generated on the other slope side when an object that gives impact force P of various strengths to the protection bank 100 is caused to collide with one slope side of the protection bank 100. It is a coefficient. α ₂ is 6.00 or more, preferably 14.00 or more, more preferably 17.00 or more, and further preferably 19.00 or more, 49.00 or less, preferably 47.00 or less, more preferably Is 45.00 or less, more preferably 40.00 or less.

  The breakwater 100 is designed in consideration of the degree of breakage when subjected to an impact as described above, so that the degree of breakage is suppressed to a level that can be repaired even if it is impacted by falling rocks. Can do.

1.2. 2nd Embodiment FIG. 2: is a figure which shows schematically the cross section of the perpendicular direction of the dike 200 of this invention concerning 2nd Embodiment. 2 includes the embankment structure 10 and a plurality of embankment reinforcements 1, 1,... Embedded in the embankment structure 10 at a predetermined interval in the height direction. ing. Furthermore, the protection slab 200 includes a receiving body 20 along one slope on the one slope side of the embankment structure 10. 2, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. Hereinafter, the protective bank 200 will be described in detail.

(Shock 20)
The striker 20 includes layers 27, 27,... Each including a frame having a plurality of cells that are open at the top and are formed continuously in a substantially horizontal direction, and a filling material filled in the cells. It is configured by stacking up and down. The striker 20 is provided along the slope of the embankment structure 10 on the mountain side of the embankment structure 10.

  First, the frame body will be described. The frame body that can be used for the impact body 20 has a plurality of cells. When the frame body is laid horizontally, each cell has a cylindrical shape with an opening at the top, and the horizontal direction It is formed continuously. A specific example of the frame will be described with reference to FIGS. 3 is a perspective view schematically showing a posture of the frame body 21 that can be used in the present invention before the expansion, and FIG. 4 is a perspective view schematically showing a posture of the frame body 21 shown in FIG. 3 after the expansion. FIG.

  The frame body 21 is provided with a plurality of cells 22, 22,... Whose upper portions are open. The cells 22, 22,... Have a plurality of strip materials 24, 24,. It is comprised by couple | bonding with the coupling | bond part 25,25, ... provided by the space | interval. As shown in FIG. 3, the frame 21 can be easily transported by placing the cells 22, 22,... In a closed position as shown in FIG. 3, and from the posture shown in FIG. By pulling in the direction and spreading, the cells 22, 22,... Can be opened as shown in FIG.

  Further, from the viewpoint of improving the drainage of the layer 27, it is preferable to provide a plurality of holes 26, 26,.

  The frame body 21 used in the present invention can be selected to have an appropriate height according to the usage situation. Further, the width of the frame body 21 (the length in the back / front direction in FIG. 2) is not particularly limited, and a plurality of frame bodies 21 can be used in parallel or connected in accordance with the size of the protective bank 200. Further, the depth of the frame body 21 (the length in the left-right direction in FIG. 2) is not particularly limited, and can be selected according to the magnitude of the impact that the protective bank 100 is assumed to receive. That is, it is preferable to increase the depth of the impact body 20 as the impact assumed to be received by the protective dam 200 is larger. In this case, the depth of the impact body 20 is increased by increasing the depth of one frame body 21. The length of the impact receiving body 20 may be increased by arranging a plurality of frame bodies 21 in parallel, as in a protective bank 300 described later.

  The depth of the impactor 20 should be appropriately determined in consideration of the maximum displacement amount obtained from the rock fall energy E or the impact force P of the fall rock against the protection dike 200, 300 and the allowable displacement amount of the protection dike 200, 300. Can do. When the impact bodies 20 are in one row, the depth of the impact body 20 is 0.5 m or more, preferably 0.6 m or more, and more preferably 0.8 m or more. When the impact bodies 20 are in two rows, the total depth of the impact bodies 20 in the two rows is 1.0 m or more, preferably 1.2 m or more, and more preferably 1.6 m or more. If the depth of the impactor 20 is equal to or greater than the above numerical value, the protective bank can sufficiently withstand the collision of falling rocks having energy E or the collision of falling rocks that gives impact force P. The upper limit of the depth of the impact body 20 can be determined as appropriate. From the viewpoint of construction time and construction cost, when the impact body 20 is in one row, it is preferably 2.0 m or less, more preferably 1. When it is 9 m or less and the impact bodies 20 are in two rows, it is preferably 4.0 m or less, more preferably 3.8 m or less.

  Specific examples of such a frame 21 include “Terracel (registered trademark)” manufactured by Tokyo Ink Co., Ltd.

  As shown in FIG. 4, after the frame body 21 is stretched, the cells 27 are filled in the cells 22, 22,. The filling material 23 is not particularly limited as long as it can easily disperse the impact when the protective dam 200 receives an impact. For example, in addition to gravel materials such as crushed stone, sandy soil, viscous soil, etc. Locally generated soil can be used.

  When the impact body 20 is provided, it is preferable that the embankment reinforcing material 1 and the upper surface or the lower surface of the layer 27 (frame body 21) constituting the impact body 20 are substantially flush. For example, by making the vertical interval in which the embankment reinforcing material 1 is embedded substantially the same as the height of the layer 27 (frame body 21), the embankment reinforcing material 1 and the layer 27 (frame frame constituting the receiving body 20). The upper or lower surface of the body 21) can be substantially flush. Thus, by making the embankment reinforcing material 1 and the upper surface or lower surface of the layer 27 constituting the impact body 20 substantially flush, the upper surface of the portion where the embankment material 2 is compacted during construction of the protective bank and the impact are received. Since it can construct so that the upper surface of the body 20 may become substantially flush | planar, work efficiency will increase and it will become easy to correct | amend the height of the receiving body 20. FIG.

  As described above, by configuring the impact body 20 with the plurality of layers 27, the impact body 20 can be exchanged for each layer 27. In this way, by making the impactor 20 replaceable for each layer 27, only the impactor 20 in a portion that needs to be repaired can be easily repaired.

  Further, a base 40 made of concrete or the like may be provided in the lower part of the impact body 20. By providing the foundation 40 when the foundation ground is soft or uneven, it is possible to prevent uneven settlement of the impactor 20 and to adjust the unevenness.

(Other configurations)
From the viewpoint of further improving the impact resistance of the protective bank 200, it is preferable to include a series of reinforcing members that wrap the impactor 20 in a vertical sectional view. By wrapping the impactor 20 with a series of reinforcing materials, when the protective dam receives an impact on the impactor 20 side, the reinforcing material can disperse the impact and suppress damage to the protective dam. The reinforcing material may be an integrally molded reinforcing material, or a plurality of reinforcing materials connected together. From the viewpoint of further dispersing the impact received by the impactor 20, it is preferable to use the truss structure reinforcing material as the reinforcing material.

  Moreover, impact resistance can also be improved by providing a buffer between the embankment structure 10 and the receiving body 20. Examples of constituents of the buffer include locally generated soil such as sand, crushed stone, and gravelly soil. Since energy due to the impact of falling rocks is absorbed by the deformation of the buffer, crushed stone having a single particle size is preferable as the buffer. By providing such a buffer, the impact received by the impactor 20 can be reduced by the buffer and transmitted to the embankment structure 10.

  Furthermore, from the viewpoint of further improving the impact resistance of the protective dam 200, and suppressing the filling material from jumping out of the impactor 20 when the protective dam 200 is impacted by falling objects such as falling rocks, It is preferable to cover the receiving surface side and the top surface side of the receiving body 20 with an impact absorbing mat (not shown) or an impact absorbing sheet (not shown). The shock absorbing mat and the shock absorbing sheet can disperse the shock to some extent when the protective bank 200 receives an impact from a falling object such as a falling rock. The material is not particularly limited as long as the material can prevent the material from popping out, and can be a mat or sheet. Examples of such an impact absorbing mat or impact absorbing sheet include the above truss structure reinforcing material and LANDLOK300 manufactured by PROPEX.

  FIG. 2 illustrates a protective bank 200 provided with one row of strikers 20 along one slope on one slope side of the embankment structure 10. It is not limited to such a form. The protective bank according to the present invention includes, for example, two rows of receiving bodies 20 along one slope on the one slope side of the embankment structure 10 like a protective bank 300 shown in FIG. It may be. Increasing the number of impact bodies 20 makes it easier to improve the impact resistance of the protective bank.

(Strength of the protective bank 200, 300)
As described above, the protective levee according to the present invention is configured such that the maximum displacement amount that is assumed to be generated on the other slope side when an impact is received from one slope side is set as an allowable displacement amount that is set in advance. It is characterized by being less than the amount of displacement.

The protection dams 200 and 300 are obtained from the following equation (3) based on the energy E (kJ) possessed by the object that is supposed to collide with the slope side where the impactor 20 of the protection dams 200 and 300 is provided. The maximum displacement δfmax ₃ (mm) generated on the other slope side of the protective bank 200, 300 when the object collides with the slope side where the impactor 20 of the protective bank 200, 300 is provided is the protective bank 200. , 300 is designed to be equal to or smaller than a preset allowable displacement amount δa (mm) as an allowable displacement amount.
δfmax ₃ = α ₃ × exp (β ₃ × E) (3)
However, when the impact body 20 is in one row, the depth of the impact body is 0.5 m or more, 0.50 ≦ α ₃ ≦ 18.00, β ₃ = 1.56 × 10 ⁻³ , When the body 20 has two rows, the sum of the depths of the two rows of the hit bodies is 1.0 m or more, 26.00 ≦ α ₃ ≦ 66.00, and β ₃ = 3.80 × 10 ⁻⁴ .

The above equation (3) actually creates various protective dikes 200, 300, and for each of the protective dikes 200, 300, an object having energy E of various strengths collides with one slope side, It is an approximate expression obtained from the relationship between the maximum displacement amount δfmax ₃ generated on the other slope side of the protective bank 200, 300 by the collision and the energy E when the maximum displacement amount δfmax ₃ is generated.

α ₃ is the maximum generated on the other slope side of the protection dike 200, 300 when an object having energy E of various strengths is caused to collide with the slope side on which the striker of the protection dike 200, 300 is provided. This is a coefficient derived from the displacement amount δfmax ₃ . When the impact body 20 is in one row (the depth of the impact body 20 is 0.5 m or more), α ₃ is 0.50 or more, preferably 1.00 or more, more preferably 2.00 or more, and further preferably 3 It is 0.00 or more, 18.00 or less, preferably 17.00 or less, more preferably 16.00 or less, and further preferably 15.00 or less. Further, when the number of the impact bodies 20 is two rows (the total depth of the two rows of impact bodies 20 is 1.0 m or more), α ₃ is 26.00 or more, preferably 28.00 or more, more preferably 30. 00 or more, more preferably 32.00 or more, 66.00 or less, preferably 64.00 or less, more preferably 62.00 or less, and further preferably 60.00 or less.

In addition, the protective dams 200 and 300 are based on an impact force P (kN) that is assumed to be applied to the protective dams 200 and 300 by an object that collides with the slope side where the interceptor 20 of the protective dams 200 and 300 is provided. The maximum displacement amount δfmax ₄ generated on the other slope side of the protective bank 200, 300 when the object collides with the slope side on which the striker 20 of the protective bank 200, 300 is provided, obtained from the following equation (4). (Mm) is designed to be equal to or less than a permissible displacement amount δa (mm) set in advance as a permissible displacement amount of the protective dams 200 and 300.
δfmax ₄ = α ₄ × exp (β ₄ × P) (4)
However, when the impact body 20 is in one row, the depth of the impact body is 0.5 m or more, 1.00 ≦ α ₄ ≦ 15.00, β ₄ = 6.00 × 10 ⁻⁴ , When the body 20 has two rows, the sum of the depths of the two rows of impact bodies is 1.0 m or more, 19.00 ≦ α ₄ ≦ 44.00, and β ₄ = 2.30 × 10 ⁻⁴ .

The above equation (4) actually produces various protective dams 200 and 300, and each of the protective dams 200 and 300 has impact strengths P of various strengths on one slope side where the impactor is provided. And the maximum displacement amount δfmax ₄ generated on the other slope side of the protective bank 200, 300 when the impact force P is applied to the one slope side of the protective bank 200, 300, and the maximum displacement amount δfmax ₄ is an approximate expression obtained from the relationship with the impact force P when ₄ is generated.

α ₄ is on the other side of the slope when an object that applies impact force P of various strengths to the protective dams 200 and 300 is caused to collide with the slope side on which the receiving body 20 of the protective dams 200 and 300 is provided. This is a coefficient derived from the maximum displacement amount δfmax _{4 that} occurs. If受撃body 20 is a row of (depth of受撃body 20 over 0.5 m), alpha ₄ 1.00 or more, preferably 2.00 or more, more preferably 3.00 or more, more preferably 4 0.000 or more, 15.00 or less, preferably 14.00 or less, more preferably 13.00 or less, and further preferably 12.00 or less. When the impact bodies 20 are in two rows (the total depth of the two rows of impact bodies 20 is 1.0 m or more), α ₄ is 19.00 or more, preferably 21.00 or more, more preferably 23.00. More preferably, it is 25.00 or more, 44.00 or less, preferably 42.00 or less, more preferably 40.00 or less, and further preferably 39.00.

  The protection dike 200, 300 is designed in consideration of the degree of breakage when subjected to an impact as described above, so that even if the impact is caused by falling rocks, the degree of breakage can be repaired. Can be suppressed.

  In the protective dams 100, 200, and 300, the allowable displacement amount δa is equal to or less than the maximum displacement amount calculated by the above formulas (1) to (4). The permissible displacement amount δa varies depending on the type of the protection bank from the empirical rule so far. In the case of a type that does not have an impactor (for example, type I described in the embodiment), the allowable displacement δa is 450 mm or less, preferably 350 mm or less, and more preferably 150 mm or less. In addition, in the case of a protective bank of a type having an impact body (the impact body is one row: for example, type II explained in the embodiment, and the impact body is two rows: eg, type III explained in the embodiment), it is acceptable. The displacement amount δa is 700 mm or less, preferably 450 mm or less, more preferably 300 mm or less.

  The value of the allowable displacement amount δa is a value confirmed by an actual experiment. For example, in the type (type I) that does not have the impactor 20, it is confirmed that the protective levee will not collapse if the maximum displacement when the falling rock collides with the protective levee is 450 mm or less. In addition, when the impact body 20 is in a single row (type II) and when the impact body 20 is in a double row (type III), the accumulated maximum displacement after colliding a plurality of weights may be 700 mm. For example, it has been confirmed that the protective bank will not collapse.

  If the allowable displacement amount δa is equal to or less than the above value, an impact force that is caused when a falling rock having a certain energy collides with one slope side of the protective bank, or when a falling rock collides with one slope side of the protective bank. Is applied to the protective bank, the other slope side (wall material) of the protective bank is only partially deformed or partially damaged, and the protective bank can function as a protective bank after that.

2. Next, the design method and construction method of the protective bank according to the present invention will be described. The design method of a protective bank according to the present invention is a method of designing a protective bank including a bank structure and a plurality of bank reinforcement members embedded in the bank structure at predetermined intervals in the height direction. In addition, the design method of the protective levee according to the present invention calculates the maximum amount of displacement that is assumed to occur on the other slope side of the protective levee when the protective dam is impacted from one slope side, The maximum displacement amount is designed to be a structure that is equal to or smaller than a preset allowable displacement amount as a displacement amount that can be permitted by the protective levee, and a protective levee having a strength corresponding to the application can be designed. Moreover, the construction method of the protection bank of this invention is characterized by including the design process which implements the design method of the protection bank of this invention, and can construct the protection bank of the intensity | strength according to a use.

  FIG. 6 is a flowchart schematically showing one embodiment of the construction method of the protective bank according to the present invention. The protection bank construction method of the present invention shown in FIG. 6 includes a design condition confirmation step S1 (hereinafter simply referred to as “step S1”), a rockfall energy calculation step S2 (hereinafter simply referred to as “step S2”). Assuming process S3 (hereinafter simply referred to as "process S3"), rockfall impact force calculation process S4 (hereinafter simply referred to as "process S4"), displacement checking process S5 (hereinafter simply referred to as "process") S5 ”), a step S6 for comparing the maximum displacement amount and the allowable displacement amount (hereinafter simply referred to as“ step S6 ”), a design wall height examination step S7 (hereinafter simply referred to as“ step S7 ”), Design top width examination step S8 (hereinafter simply referred to as “step S8”), internal stability calculation step S9 (hereinafter simply referred to as “step S9”) and construction step S10 (hereinafter simply referred to as “step S10”). .) In addition, the process (design process) equivalent to the design method of the protective bank of this invention is process S1-process S9. Each step shown in FIG. 6 will be described below.

<Process S1>
Step S1 is a step of confirming the design conditions of the protective bank in order to calculate the energy of the falling rock and the impact force when the falling rock collides with the protective bank as described below. Specifically, the average slope of the slope where rockfall is expected to occur (hereinafter referred to as “slope slope”), the slope of the slope where the protective bank is constructed (the slope of the slope on the mountain side of the protective bank), rockfall (Such as rock shape, volume, weight) and embankment conditions (unit volume weight, internal friction angle, adhesive strength, etc.).

<Process S2>
Step S2 is a step of calculating the energy of falling rocks. For example, the energy E of falling rocks can be calculated by the following equation (5).
E = (1 + β) × {1− (μ / tan θ)} × W × H (5)
Here, (1 + β) × {1− (μ / tan θ)} ≦ 1.0
However, when (1 + β) × {1− (μ / tan θ)}> 1.0, (1 + β) × {1− (μ / tan θ)} = 1.0.
In Eq. (5), E is rock fall energy (kJ), β is rotational energy coefficient, μ is equivalent friction coefficient, θ is slope gradient (°), W is rock weight (kN), and H is rock fall. The drop height (m).

<Step S3>
Step S3 is a step of assuming the type of the protective bank. Depending on the structure of the dike, the energy of falling rocks varies depending on the structure. Therefore, the rock fall energy that they can withstand is calculated for a plurality of types of breakwaters, and an appropriate type of breakwater is assumed in step S3 based on the rock fall energy E obtained in step S2. .

  The structure of the protective bank which can be used for this invention is not specifically limited. However, the present invention is characterized in that it includes a step of checking the amount of displacement on the valley side of the protective bank, which is assumed when the protective bank is impacted on the mountain side by falling rocks. Such things as those that are not supposed to be displaced when impacted by falling rocks are excluded. Specific examples of the protective bank that can be used in the present invention include the above-described protective bank 100, 200, and 300.

<Step S4>
Step S4 is a step of calculating the impact force received by the protective bank due to falling rocks. For example, the impact force P due to falling rocks can be calculated by the following equation (6).
P = 2.108 × (m × g) ^2/3 × λ ^2/5 × H ′ ^3/5 (6)
In Equation (6), P is the impact force (kN) due to the falling rock, m is the mass (t) of the falling rock, g is the acceleration of gravity (m / s ² ), λ is the Ramé constant, and H ′ is as follows: The converted fall height (m) obtained from the equation (7) can be used. λ is a value that can be obtained through experiments, and varies depending on the structure of the protective bank.
H ′ = {1− (μ / tan θ)} × H (7)
In equation (7), μ is the equivalent friction coefficient, θ is the slope gradient (°), and H is the falling height (m) of the falling rock.

<Step S5>
Step S5 is a step of checking how much the valley side of the protective bank is displaced when the protective bank is impacted by the falling rock from the mountain side. The amount of displacement on the trough side of the protective bank when impacted from the mountain side by falling rocks (hereinafter, the amount of displacement on the trough side of the protective bank when impacted from the mountain side by falling rocks is simply referred to as “displacement amount”) Depends on the structure of the protective bank. The maximum amount of displacement in the environment where the protective levee is constructed (the maximum amount of displacement assumed in the environment) can be calculated by experiment. For example, the relational expression between the rock fall energy E and the displacement amount obtained in step S2 and the relational expression between the impact force P and the displacement amount obtained in step S4 can be obtained, and the maximum displacement amount can be calculated from these expressions. . Specific examples of this relational expression include the above-described expressions (1), (2), (3), and (4).

<Step S6>
Step S6 is a step of determining whether the maximum displacement amount obtained in step S5 is equal to or smaller than the allowable displacement amount or larger than the allowable displacement amount. The allowable displacement amount is a value that can be set as appropriate depending on the structure of the protective bank and the environment in which the protective bank is constructed. For example, what amount of displacement is required only to repair the vicinity of the impacted part depends on the structure of the protective bank. Also, the allowable displacement varies depending on the importance of the protective bank. In other words, if the probability and scale of rock fall are large or the social and economic impacts are significant, the allowable displacement will be small, but the probability and scale of rock fall will be small, When the influence of is relatively small, the allowable displacement amount becomes large. Furthermore, the allowable displacement changes depending on the setting of the limit state of the protective bank.

  As described above, the allowable displacement amount is appropriately set, and if the maximum displacement amount obtained in step S5 is equal to or less than the allowable displacement amount, the process proceeds to step S7, and if the maximum displacement amount obtained in step S5 is larger than the allowable displacement amount, Returning to Step 2, the type of the protection bank is re-assumed, and Steps S3 to S6 are repeated. The maximum amount of displacement used in step S6 is only one of the relational expression between energy E and displacement obtained in step S2 and the relational expression between impact force P and displacement obtained in step S4. However, from the viewpoint of safety and the like, it is preferable to compare the maximum displacement amount obtained from both relational expressions with the allowable displacement amount.

<Step S7>
Step S7 is a step of examining the required height Hb of the protective bank. The specific method is not particularly limited, and can be calculated by the following method, for example.

The required height Hb of the protective bank can be determined by the jump height of the falling rock. According to the "Opponishi Countermeasure Handbook (Japan) Road Association", the standard rock jump height is 2.0m. The calculation method of the required height Hb of the protection bank in this case is demonstrated using FIG. FIG. 7A shows a case where the flat field distance L (hereinafter simply referred to as the flat field distance L) between the slope of the slope 61 where the falling rock 60 falls and the mountain side surface of the protective bank 200 is zero. FIG. 7B schematically shows a case where the flat field distance L is not zero. In FIG. 7, H ₁ is the falling rock jump height, H ₂ is the falling rock radius, H ₃ is the margin obtained from the actual experiment, θ _β is the angle of the mountain side slope of the protective bank to the vertical plane, and θ ₂ is The slope of the slope 61 is shown. The formula for calculating the required height Hb of the protective bank is divided according to the length of the flat field distance L. That is, the required height Hb of the protective bank can be obtained by any of the following formulas (8) to (10).
When L = 0 Hb> (H ₁ + H ₂ ) × cos θ _β × sec (θ ₂ −θ _β ) + H ₃ (8)
_{· 0 <L ≦ (H 1} + H 2) × {tan (θ 2/2) -tanθ β} For _{Hb = {(H 1 + H} 2) / cos (θ 2 -θ β)}
−L {sin θ ₂ / sin (90 ° −θ ₂ + θ _β )} × cos θ _β + H ₃ (9)
_{· L> (H 1 + H} 2) If × of _{{tan (θ 2/2)} -tanθ β} Hb = H 1 + H 2 + H 3 (10)

<Step S8>
Step S8 is a step of examining the top edge width of the protective bank. In the process so far, several parameters have been determined using numerical values obtained from experiments conducted on a pre-constructed protective bank. Therefore, if the embankment material actually used is different from the embankment material used in the experiment, the top of the embankment structure will be adjusted so that the actual strength of the protection embankment is greater than the strength of the protection embankment constructed in the experiment. It is necessary to adjust the end width. By widening the top end width, the weight of the embankment structure is increased, and the strength of the protection dam equipped with the embankment structure can be increased.

<Step S9>
Step S9 is a step of examining whether or not the constructed bank is stable internally in a steady state. The method for determining whether or not it is internally stable is not particularly limited, and a conventional method can be used.

<Step S10>
Step S10 is a step of actually constructing a protective dam based on the conditions determined through steps S1 to S9. There is no particular limitation on the method of actually constructing the protective slats. A specific example of step S10 will be described with reference to FIG. FIG. 8 is a flowchart for more specifically explaining step S10.

  Step S10 includes an embankment structure manufacturing step S20 (hereinafter simply referred to as “step S20”) and an impact body manufacturing step S30 (hereinafter simply referred to as “step S30”), and these steps are performed in parallel. And do it. In addition, like the protective bank 100 shown in FIG. 2, when the impactor 20 is not provided, step S30 is omitted.

<Step S20>
The step S20 includes a reinforcing material laying step S21 (hereinafter simply referred to as “step S21”) and a compacting step S22 (hereinafter simply referred to as “step S22”), and is obtained through the steps S21 and S22. This is a step of repeating step S21 and step S22 until the height of the structure reaches a predetermined height.

(Process S21)
Step S21 is a step of laying the embankment reinforcing material 1 on the ground 50 or on the embankment material 2 after the compacting step S22 described later. The method for fixing the embankment reinforcing material 1 on the ground 50 or the embankment material 2 is not particularly limited, and a conventionally known method can be used.

(Step S22)
Step S22 is a step of placing the embankment material 2 on the embankment reinforcing material 1 and compacting it. The embankment reinforcements 1, 1,... Are usually embedded at intervals of 30 cm, 60 cm, or 1.2 m in the vertical direction. Therefore, in step S22, the height of the embankment material 2 after compaction (height from the ground 50 or the embankment reinforcing material 1 laid on the lower side of the embankment material 2) is about 30 cm, 60 cm, or 1.2 m. Put the embankment material 2 so that it becomes. However, in the present invention, the intervals at which the embankment reinforcements 1, 1,... Are embedded are not limited to the above intervals.

  By repeating step S21 and step S22 until the height of the structure obtained through step S21 and step S22 reaches a predetermined height, a plurality of embankment reinforcements 1 having a predetermined interval in the vertical direction, The embankment structure 10 in which 1... Are embedded is constructed.

  As described above, in the dike constructed by the method of constructing the dike of the present invention, it is preferable that the plurality of embankment reinforcements 1, 1,. For this reason, at least one of the repeated steps S21 is performed using the truss structure reinforcing material. Further, the embankment reinforcements 1, 1,... Are a transverse reinforcement and a truss structure reinforcement, and in the vertical direction, one or more between one transverse reinforcement and another transverse reinforcement. It is preferable to embed the truss structure reinforcing material so as to be in a positional relationship. That is, after step S21 is performed once using the cross direction reinforcing material, step S21 is performed using the truss structure reinforcing material at least once, and then step S21 is further performed using the cross direction reinforcing material. Is preferred.

  More specifically, the preferred embodiment will be described. After performing step S21 using the transverse reinforcing material, step S22 is performed so that the height of the embankment material 2 after compaction is about 30 cm, and then the truss structure. The step of performing step S21 using a reinforcing material, and further performing step S22 such that the height of the embankment material 2 after compaction is about 30 cm is the height of the structure obtained through steps S21 and S22. Is preferably performed repeatedly to a predetermined height.

  In addition, in the construction method of the protection bank of this invention, the structure of the slope of the embankment structure 10 and the structure of a top surface are not specifically limited, It can construct by the conventionally well-known method. For example, it is preferable to connect the wall surfaces adjacent to each other in the horizontal direction with a known connecting portion material so that the slope of the embankment structure 10 is covered with the wall surface material. It is also preferable to connect the wall material to the embankment reinforcing material 1.

<Step S30>
The process S30 includes a frame laying process S31 (hereinafter simply referred to as “process S31”) and a filling material filling process S32 (hereinafter simply referred to as “process S32”), and the process S31 and S32 are performed. This is a step of repeating step S31 and step S32 until the height at which the obtained layer 27 is stacked vertically (vertical direction) reaches a predetermined height.

(Process S31)
Step S31 is a step of laying the frame body 21 substantially horizontally on the mountain side of the embankment structure 10. The frame body 21 is laid in a stretched posture (see FIG. 4). The number of laying frames 21 is appropriately determined according to the size of the protective levee and the magnitude of the impact expected to be received by the protective levee. That is, the number of laying frames 21 in the width direction (back / front direction in FIGS. 2 and 5) is determined according to the width direction (back / front direction in FIGS. 2 and 5) of the protective bank (banking structure). The number of laying frames 21 in the depth direction (left and right direction in FIGS. 2 and 5) is determined according to the type of the protective levee.

(Process S32)
Step S32 is a step of filling the cells 22, 22,... Of the frame body 21 with the filling materials 23, 23,. Since the components constituting the filling materials 23, 23,... Have already been described, the description thereof is omitted here.

  By repeating the steps 31 and 32 until the height obtained by stacking the layers 27 obtained through the steps S31 and 32 reaches a predetermined height, the impact body 20 having a predetermined height can be manufactured. . The layers 27, 27,... Are obliquely stacked along the slope of the embankment structure 10.

(Other processes)
The protective bank according to the present invention may be configured to include the impactor 20 as in the protective bank 200, 300 shown in FIGS. In this case, the impact body 20 may be in the form of being wrapped with the reinforcing material 28. A process for wrapping the impactor 20 with the reinforcing material 28 will be described with reference to FIG. First, as shown in FIG. 9A, before the first step S31, one end 28a side of the reinforcing material 28 is laid on the ground 50, and the layer 27 is formed thereon through the steps S31 and S32. At this time, the other end 28b side of the reinforcing member 28 is stretched so as to come on the structure obtained through the steps S21 and S22. Thereafter, as shown in FIG. 9 (b), the other end 28b side of the reinforcing material is stretched over the structure obtained through the steps S21 and S22, while the steps S21, S22, S31 and Step S32 is executed. Finally, as shown in FIG. 9C, the impact body 20 can be wrapped with the reinforcing material 28 by connecting the end 28 a and the end 28 b of the reinforcing material 28. The reinforcing material 28 does not need to be formed of a single sheet, and a plurality of reinforcing materials can be connected to form the reinforcing material 28 as necessary. As described above, it is preferable to use a truss structure reinforcing material for the series of reinforcing materials that wrap the impactor 20.

  Moreover, the protection bank of this invention can also be set as the form provided with the transmission body between the embankment structure 10 and the receiving body 20 as mentioned above. When it is set as the form provided with the transmission body between the embankment structure 10 and the receiving body 20, the space | interval is provided between the embankment structure 10 and the receiving body 20, and the material which comprises a transmission body in this space | interval Lay down. That is, in parallel with the process S21, the process S22, the process S31, and the process S32, a transmission body is configured between the structure obtained through the process S21 and the process S22 and the layer 27 obtained through the process S31 and the process S32. By performing the process of spreading the material, it is possible to provide a form in which a transmission body is provided between the embankment structure 10 and the receiving body 20.

  Furthermore, as described above, the protective bank of the present invention preferably covers the receiving surface side and the top surface side of the receiving body with an impact absorbing mat or an impact absorbing sheet. The method of installing the shock absorbing mat or the shock absorbing sheet is not particularly limited as long as it can be fixed so that the shock absorbing mat or the shock absorbing sheet does not come off naturally. For example, after producing the impactor, the impact surface and the top surface of the impactor are covered with an impact absorbing mat or impact absorbing sheet, and the impact absorbing mat or the impact absorbing sheet is covered with a pile or the like. The method of fixing to can be considered.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the examples.

In this example, 12 types of protective slats shown in Table 1 were constructed in advance and tested. As a result of the experiment, the Lame constant λ, the maximum displacement δfmax _E due to the rock E energy E, the maximum displacement δfmax P due to the impact force _P , and the allowable displacement δa were obtained. Constants Lame λ in Table 2, the maximum displacement Derutafmax _E by rockfall energy E, the maximum displacement Derutafmax _P due to the impact force P, and the allowable displacement δa shown in Table 3.

The lame constant λ is obtained by performing an experiment in which a weight having a different mass collides with the protective dam and averaging the lame constants calculated from the numerical values obtained in each experiment. Allowable displacement amount δa is 150 mm for types IA, IB, IB-1, IB-2, and IC, and types II-A, II-B, II-B-1, II-B-2, III-A, III-A-1, and III-A-2 were 300 mm. The maximum displacement amount δfmax _E is an approximate expression obtained from the relationship between the energy E of the weight and the displacement amount on the valley side of the protective dam by causing a weight having a different mass to collide with the protective dam. The maximum displacement amount δfmax _P is an approximate expression that is obtained from the relationship between the impact force P caused by the weight and the displacement amount on the trough side of the protective dam by causing a weight having a different mass to collide with the protective levee.

In Table 1, “applicable range standard” is determined by substituting into the displacement equation fmax _E in Table 3 below based on the actual experiment results.
“Type name” indicates the name of the constructed breakwater.
“Reinforcing material” indicates the name of the embankment reinforcing material embedded in the embankment structure, “SR” is a uniaxial reinforcing material, Tensor SR type (manufactured by Mitsubishi Plastics), and “SS” is biaxial. Tensor SS type (made by Mitsubishi Plastics Co., Ltd.) and “TX” of directional reinforcing material mean Tensor Triax (made by Mitsubishi Plastics Co., Ltd.) which is a truss structure reinforcing material. In addition, two types of reinforcing materials are described as being embedded so that two types of reinforcing materials are alternately arranged in the height direction of the embankment structure.
"Front formwork" indicates the thickness of the plated iron wire that forms the wall material used on the valley side of the embankment structure, and "Back formwork" constitutes the wall material used on the mountain side of the embankment structure The thickness of the plated iron wire is shown. As the wall material, “AZ form” (manufactured by Tokyo Ink Co., Ltd.) made of an alloy-plated iron wire of aluminum and zinc was used.
In the “Cross sectional view” column, a diagram corresponding to the schematic cross sectional view of the produced protective bank is described. That is, types IA, IB, and IC do not include an impactor, and types II-A and II-B include an impactor along a mountain surface of the embankment structure. III-A is provided with two rows of strikers along the mountain side surface of the embankment structure. The impactor was configured by filling Terracel TW (manufactured by Tokyo Ink Co., Ltd.) with a filling material.

In the present embodiment, the protection dam was designed with the design conditions shown below.
Slope gradient: θ = 60 °
Slope slope (see Fig. 7) at the position of the protective bank (the mountain side of the protective bank): θ ₂ = 59 °
The distance of the flat field between the slope slope and the slope on the mountain side of the protective bank: L = 0.0m
Conditions of stones expected to fall Falling rock shape: 1.500m x 1.500m x 1.500m cube Falling rock volume: V = 3.375m ³
Diameter when rock fall is converted to a spherical shape: d = (6 × V / π) ^1/3
Falling rock weight: W = 87.750kN
Unit volume weight of rock fall: γ _R = 26.0 kN / m ³
Filling material conditions Unit volume weight: γ = 17,000 kN
Internal friction angle: φ = 30 °
Adhesive strength: c = 0 kN / m ³
Slope of slope of embankment structure Mountain side 1: 0.2
Valley side 1: 0.3

Next, the energy of rock fall under the above conditions was calculated. That is, in equation (5), rotational energy coefficient β = 0.1, equivalent friction coefficient μ = 0.15 (see Table 4 below), slope gradient θ = 60 °, falling rock weight W = 87.750 kN, falling rock fall Substituting height H = 40.0 m, E was obtained.
E = (1 + β) × {1− (μ / tan θ)} × W × H (5)
Here, (1 + β) × {1− (μ / tan θ)} ≦ 1.0
In this embodiment, since (1 + β) × {1− (μ / tan θ)} = 1.005> 1.0, as described above, (1 + β) × {1− (μ / tan θ)} = 1 Calculated as 0.0, E = 3510 kJ.

  Next, based on the result of the above calculation, the type of protective bank to be constructed was assumed. That is, since E = 3510 kJ, among the types described in Table 1 above, it was assumed as a type of a protective levee for constructing III-A.

Next, the impact force due to falling rocks was calculated. That is, the mass of rock fall m = 8.775t, the gravitational acceleration g = 9.8 m / s ² , and the Lame constant λ = 1800 are substituted into Equation (6), and H ′ is obtained by Equation (7). The converted fall height H ′ = 36.536 m was used. The equivalent friction coefficient μ = 1.5, slope gradient θ = 60 °, and falling rock height H = 40.0 m were substituted into equation (7). P = 7132.8 kN.
P = 2.108 × (m × g) ^2/3 × λ ^2/5 × H ′ ^3/5 (6)
H ′ = {1− (μ / tan θ)} × H (7)

Next, the displacement was checked. Substituting E = 3510 kJ and P = 7132.8 kN into the equations shown in Table 3, the maximum displacements δfmax _E and δfmax _P were determined. δfmax _E = 199 mm and δfmax _P = 181 mm. That is, δfmax _E and δfmax _P were less than the allowable displacement δa (300 mm). Therefore, it was judged that there was no need to re-assum the type of the protection bank.

Next, the required height Hb of the protective bank was examined. In this example, since the flat field distance L is 0.0 m, Hb was obtained from the following equation (8). That is, according to the following formula (8), the falling rock jump height H ₁ = 2.000 m, falling rock radius H ₂ = 0.931 m, marginal height H ₃ = 0.500 m (value obtained by experiment), Angle θ _β = 11.31 with respect to the vertical surface of the mountain side slope (since the slope of the slope is 1: 0.2, from tan ⁻¹ 0.2 °), protection bank installation position (mountain side of the protection bank) The slope gradient θ ₂ = 59 ° was substituted.
Hb> (H ₁ + H ₂ ) × cos θ _β × sec (θ ₂ −θ _β ) + H ₃ (8)

The following formula was obtained from the formula (8).
Hb> 4.769 m
The height of the dike is usually a multiple of 0.3m. This is because the embankment reinforcing material is buried at intervals of 0.3 m. Therefore, the required height Hb of the protective bank is set to 4.800 m.

Next, the width of the top of the protective bank was examined. As described above, the embankment constructed in advance for experiments (six types of protection proposals shown in Table 1) uses a banking material of unit volume weight γ _E = 18,000 KN / m ³ , As described above, a banking material having a unit volume weight γ = 17,000 kN is used for the protective bank constructed in this embodiment. Therefore, the top width is adjusted so as to be equal to or more than the weight of the embankment embankment structure constructed in advance for experiments.

As described above, the weight _{W E} of the embankment structure protection bank in the case of using the fill material used in the experiment (unit volume weight γE = 18.000kN / ^{m 3)} is 224.640KN. Therefore, in order to obtain an embankment structure having a weight of 224.640 kN or more using an embankment material having a unit volume weight γ = 17.0000 kN / m ³ , the top width may be set to 1.553 m or more.

  As explained so far, the design is made so that the amount of displacement on the valley side that is assumed when the protective bank receives an impact from the mountain side is less than the allowable displacement amount. A protective bank that can be repaired can be constructed.

  Although the present invention has been described in connection with embodiments that are presently considered to be practical and preferred, the present invention is not limited to the embodiments disclosed herein, and It can be changed as appropriate without departing from the gist or philosophy of the invention that can be read from the entire document, and the protection dam, the method of construction of the protection dam, and the method of designing the protection dam accompanying such changes are also within the technical scope of the present invention. It must be understood as included.

DESCRIPTION OF SYMBOLS 1 Embankment reinforcement 2 Embankment material 10 Embankment structure 20 Impactor 21 Frame body 22 Cell 23 Filling material 24 Strip material 25 Connection part 26 Hole 27 Layer 40 Foundation 50 Ground 60 Fall rock 61 Slope 100, 200, 300

Claims (9)

A bank embankment structure, and a plurality of embankment reinforcements embedded at a predetermined interval in the height direction in the embankment structure,
A maximum displacement amount δfmax assumed to be generated on the other slope side of the protective dam is calculated based on energy E of an object assumed to collide with one slope side of the protective levee, and the maximum A method of designing a protective levee, including a design step of designing a structure in which a displacement amount δfmax is equal to or less than an allowable displacement amount δa set in advance as an allowable displacement amount of the protective levee. A bank embankment structure, and a plurality of embankment reinforcements embedded at a predetermined interval in the height direction in the embankment structure,
The maximum displacement amount δfmax is calculated based on the collision force P (kN) assumed to be received on one slope side of the protective bank, and the maximum displacement amount δfmax is equal to or less than the allowable displacement amount δa. A method of designing a breakwater, including the design process of designing. A construction method of a protective dam designed by the method of designing a protective dam according to claim 1 or 2 ,
The protective bank is vertically stacked with a layer including a frame having a plurality of cells that are open at the top and continuously formed in a substantially horizontal direction and a filling material filled in the cells. The configured receiver is provided on one slope side of the embankment structure,
A method for constructing a protective bank, including a bank structure manufacturing process for manufacturing the bank structure and a receiver manufacturing process for manufacturing the receiver. The embankment structure preparation step comprises laying the embankment reinforcing material substantially horizontally, a reinforcing material laying step, and placing and embedding the embankment material on the laid embankment reinforcing material, and a compacting step, Including a step of repeating the reinforcing material laying step and the compaction step until the height of the structure obtained through the reinforcing material laying step and the compacting step reaches a predetermined height,
The impact body preparation step includes a frame body installation step in which the frame body is installed substantially horizontally on the mountain side of the embankment structure, and a filling material filling step in which cells in the frame body are filled with a filling material. The frame laying step and the filling material filling step are repeated until the height obtained by vertically stacking the layers obtained through the frame laying step and the filling material filling step reaches a predetermined height. Including steps,
The construction method of the protection bank of Claim 3 which performs the said embankment structure preparation process and the said impact body preparation process in parallel. The construction method of the protection bank of Claim 4 using the truss structure reinforcement material which consists of a geotextile which has especially strong tensile strength in a triaxial direction for at least 1 among these several embankment reinforcement materials. The plurality of embankment reinforcements, using a transverse reinforcement made of a geotextile having a particularly strong strength in the transverse direction at the time of laying, and the truss structure reinforcement, and in the vertical direction, the one transverse reinforcement and the other The construction method of the protective bank of Claim 5 which embeds one or more said truss structure reinforcement materials between the said cross direction reinforcement materials. The method for constructing a protective bank according to any one of claims 3 to 6 , further comprising a step of covering a receiving surface side and a top surface side of the receiving body with a shock absorbing mat or a shock absorbing sheet in a sectional view in a vertical direction. . The construction method of the protective bank according to any one of claims 3 to 6 , including a step of wrapping the impactor with a series of reinforcing members in a cross-sectional view in the vertical direction. The construction method of the protective bank of Claim 8 using the truss structure reinforcement material which consists of a geotextile which has especially strong tensile strength in a triaxial direction for the said series of reinforcement material which wraps the said impactor.

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