JP5215806B2 - Protective bank construction method - Google Patents

Description

  The present invention relates to a method of constructing a protective dam for preventing damage caused by falling objects having large kinetic energy such as falling rocks, debris flows, and avalanches. More specifically, the present invention relates to a protective levee having a higher impact resistance than a conventional protective levee. It relates to a method that can be constructed.

  In order to prevent damage caused by falling objects with large kinetic energy such as falling rocks, debris flows, and avalanches, slopes in mountainous areas are provided. As such a protective levee, a concrete large retaining wall was used, but from the viewpoint of workability, it is now called a reinforced earth wall in which a reinforcing material (for example, geotextile) is embedded in the embankment. Things are used.

As a specific example of the above-mentioned reinforced earth wall, for example, a shock absorbing dam body disclosed in Patent Document 1 can be cited. In Patent Document 1, in a shock absorbing dam body having a receiving surface on the mountain side of a slope and having a plurality of reinforcing members arranged in a horizontal direction with a plurality of gaps therebetween, Determine the acting force of the impact force, assume the structure of the resistor, determine the sliding surface of the resistor, determine the sliding force due to the acting force that slides the resistor on the sliding surface along the sliding surface, Determine the resistance due to the load of the resistor on the surface and the reinforcing material, determine the safety factor from the ratio of the resistance and sliding force, and determine the structure of the resistor so that the safety factor falls within the specified range. An impact-absorbing dam body characterized by being obtained is disclosed.
JP 2004-11224 A

  In a conventional protective bank (for example, a resistor of Patent Document 1) in which a reinforcing material is embedded in the embankment, the reinforcing material is embedded in order to increase the strength of the protective bank by restraining the embankment material with the reinforcing material. It was. In addition, since the protective bank is constructed long in the longitudinal direction (direction parallel to the horizontal and slope), the restraining force in the transverse direction (direction perpendicular to the longitudinal direction and the vertical direction) is required to constrain the embankment material. Only need to be considered. Therefore, in the conventional protective levee, a reinforcing material having a particularly strong tensile strength in the transverse direction at the time of laying was employed.

  In the case of such a conventional protective bank, for example, when an impact is caused by falling rocks, the reinforcing material resists the impact mainly in the transverse direction. More specifically, as shown in FIG. 5 (a diagram schematically showing the force acting in the horizontal section when the conventional protective bank is impacted), the conventional protective bank 20 has a falling rock 21. When the impact 22 was received, the impact 22 was received by the resistance 23 acting in the transverse direction by the reinforcing material 1b (see FIG. 4) embedded in the protective bank 20.

  That is, in the conventional protective bank 20, the impact was received only in a narrow range (shaded portion shown in FIG. 5) centered on the location where the impact 22 was received by the falling rock 21 or the like. Therefore, when the impact 22 is applied by the falling rock 21 or the like, the conventional protective bank 20 may be locally destroyed.

  Then, this invention makes it a subject to provide the construction method of the protection bank excellent in impact resistance which can disperse | distribute the impact by rockfall etc. and can catch in a wide range.

  The present invention will be described below. In addition, in order to make an understanding of this invention easy, the reference sign of an accompanying drawing is attached in brackets, However, This invention is not limited to the form of drawing.

  The present invention includes a reinforcing material laying step (S1) in which the reinforcing material (1) made of geotextile is laid substantially horizontally, and a compacting step in which the embedding material (2) is placed on the laid reinforcing material and compacted. S2), and a method of constructing a protective levee (10) in which a plurality of reinforcing materials are embedded at predetermined intervals in the vertical direction by repeating the reinforcing material laying step and the compacting step to a predetermined height In this method, the plurality of reinforcing materials include a triaxial reinforcing material (1a) made of a geotextile having particularly strong strength in the three axial directions.

  The “banking material” that can be used in the present invention is not particularly limited, and locally generated soil such as sand and clay can be used. In addition, “a triaxial reinforcing material made of geotextile having particularly strong strength in the triaxial direction” means that when installed in a substantially horizontal direction, it has a particularly strong tensile strength in the triaxial direction in the horizontal plane. This means a reinforcing material having a truss structure that has a pseudo strength in the direction (360 degrees), and a specific example thereof is Geogrid disclosed in JP-A-2004-44374.

  In the construction method of the above-mentioned protection dam of the present invention, the plurality of reinforcing members (1) are a transverse reinforcing member (1b) made of a geotextile having a particularly strong strength in the transverse direction when laid, and a triaxial reinforcing member (1a). In the vertical direction, it is preferable to embed one or more triaxial strong reinforcing materials between the transverse reinforcing members. By setting it as this form, the protective wall construction method which has the effect which disperse | distributes the impact by falling rock etc. over a wide range can be provided, providing the force which restrains a banking material in a cross direction.

  ADVANTAGE OF THE INVENTION According to this invention, the construction method of the protection bank excellent in impact resistance which can disperse | distribute the impact by falling rocks etc. and can catch in a wide range can be provided.

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

  FIG. 1 is a flowchart schematically showing steps provided in the method of constructing a protective bank according to the present invention. FIG. 2 is a view schematically showing a vertical cross section of a protective bank constructed by the method of constructing a protective bank according to the present invention.

  As shown in FIG. 1, the protective bank construction method of the present invention includes a reinforcing material laying step S1 and a compacting step S2, and by repeating the reinforcing material laying step S1 and the compacting step S2 to a predetermined height, Is a method of constructing a protective bank 10 in which a plurality of reinforcing members 1, 1,. The plurality of reinforcing materials 1, 1,... Includes a triaxial reinforcing material 1a made of a geotextile having particularly strong strength in the three axial directions (hereinafter simply referred to as “triaxial reinforcing material 1a”). It is. Further, the reinforcing members 1, 1,... Have a transverse reinforcing member 1 b (hereinafter simply referred to as “crossing reinforcing member 1 b”) made of a geotextile having a particularly strong strength in the transverse direction when laid, and a triaxial reinforcing member. The material 1a is embedded in the vertical direction so that one or more triaxial reinforcing materials 1a are sandwiched between the transverse reinforcing material 1b and the other transverse reinforcing material 1b. preferable. By setting it as this form, the method of constructing the protective wall 10 which has the effect which disperse | distributes the impact by falling rock etc. over a wide range can be provided, providing the force which restrains the embankment material 2 in a cross direction.

  Each process with which the protection bank construction method of this invention is equipped is demonstrated in detail below.

1. Reinforcement laying process S1
Step S1 is a step of laying the reinforcing material 1 made of geotextile on the ground 100 or on the embankment material 2 after the compacting step S2, as shown in FIG. The method of fixing the reinforcing material 1 on the ground 100 or the embankment material 2 is not particularly limited, and a conventionally known method can be used.

2. Compaction process S2
Step S2 is a step of placing the embankment material 2 on the reinforcing material 1 and compacting it. The reinforcing material 1 is normally embedded at intervals of 30 cm, 60 cm, or 1.2 m in the vertical direction. Therefore, in step S2, the height of the embankment material 2 after compaction (the height from the ground 100 or the reinforcing material 1 laid on the lower side of the embankment material 2) is about 30 cm, 60 cm, or 1.2 m. The embankment material 2 is placed and compacted as shown. However, the interval at which the reinforcing material 1 is embedded in the present invention is not limited to the above interval.

  By repeatedly performing the above steps S1 and S2 to a predetermined height, the protective bank 10 in which a plurality of reinforcing members 1, 1,... Are embedded at a certain interval in the vertical direction is constructed. In the present invention, since the plurality of reinforcing materials 1, 1,... Include the triaxial reinforcing material 1a, at least one of the repeated steps S1 is performed using the triaxial reinforcing material 1a. . Further, the reinforcing members 1, 1,... Are a transverse reinforcing member 1b and a triaxial reinforcing member 1a, and in the vertical direction, between the transverse reinforcing member 1b and another transverse reinforcing member 1b, It is preferable to embed such that three or more triaxial reinforcing members 1a are sandwiched. That is, after performing step S1 once using the transverse direction reinforcing material 1b, the process S1 is performed at least once using the triaxial direction reinforcing material 1a, and then further using the transverse direction reinforcing material 1b. It is preferable to perform S1.

  More specifically, the preferred embodiment will be described. After performing the step S1 using the transverse reinforcing material 1b, the step S2 is performed so that the height of the embankment material 2 after compaction is about 30 cm. It is preferable to repeat the step of performing the step S1 using the axial reinforcing material 1a and further performing the step S2 so that the height of the embankment material 2 after compaction is about 30 cm to a predetermined height.

  In the protective bank construction method of the present invention, the configuration of the slope and the configuration of the top surface are not particularly limited, and construction can be performed by a conventionally known method.

  The principle that the protective levee constructed by the method of constructing the protective levee according to the present invention can disperse and receive impacts caused by falling rocks as compared with the conventional protective levee is shown in FIGS. Will be described.

  FIG. 3 is a diagram schematically showing the force acting on the horizontal cross section when the protective bank 10 constructed by the method of constructing the protective bank of the present invention receives an impact. FIG. 4 is a diagram schematically showing a vertical section of a conventional protective bank. FIG. 5 is a diagram schematically showing a force acting in a horizontal section when a conventional protective bank is impacted. FIG. 6A is a diagram schematically showing an example of a tensor (transverse reinforcing material 1b) having a particularly strong tensile strength in one axial direction. FIG. 6B is a diagram schematically showing an example of a tensor (triaxial reinforcing material 1a) having a particularly strong tensile strength in the triaxial direction. FIG. 7 is a diagram showing the tensile strength of the triaxial reinforcing member 1a. In FIG. 7, concentric circles indicate the strength, and the numbers on the outer side of the outermost circle mean the direction (angle) having the strength. A broken line 71 indicates the tensile strength of the triaxial reinforcing member 1a, and a circle 72 drawn by a solid line inside the region surrounded by the broken line 71 passes through the strength in the direction in which the tensile strength of the triaxial reinforcing member 1a is the weakest. It is a circle.

  As shown in FIG. 4, in the conventional protective bank 20, only the transverse direction reinforcing material 1b as shown in FIG. 6 (a) is embedded as the reinforcing material. Therefore, as shown in FIG. 5, when an impact 22 caused by the falling rock 21 is received, the resistance 23 acts in the transverse direction by the transverse reinforcing members 1b, 1b,. Only the shaded portion shown in FIG. 5) received the impact 22. Therefore, when the impact 22 is applied by the falling rock 21 or the like, the conventional protective bank 20 may be locally destroyed.

  On the other hand, as shown in FIG. 2, the dike 10 constructed by the dike construction method of the present invention has a triaxial reinforcement 1a as shown in FIG. 6 (b) in addition to the transverse reinforcement 1b. Buried. As shown in FIG. 7, the triaxial reinforcing member 1 a has particularly strong strength in the triaxial directions (0 ° -180 °, 60 ° -240 °, and 120 ° -300 °), and the size of the circle 72 Is big. That is, the triaxial reinforcing member 1a has strong strength in many directions. Therefore, the load applied from the horizontal direction can be widely dispersed. Therefore, as shown in FIG. 3, when receiving an impact 12 due to the falling rock 11, the resistance forces 13, 13, 13 work from a wide range by the triaxial reinforcing members 1 a, 1 a,. The impact 12 is received in a wide range (shaded area shown in FIG. 3).

  As described above, the protective bank 10 is superior in impact resistance and can be prevented from being locally destroyed because it can disperse the impact caused by falling rocks and the like in a wide range as compared with the conventional protective bank 20. The

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. Rather, modifications can be made as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a method of constructing a protective bank with such changes is also included in the technical scope of the present invention. Must be understood.

It is the flowchart which showed roughly the process with which the protection bank construction method of this invention is equipped. It is a figure which shows roughly the vertical direction cross section of the protective bank constructed by the protective bank construction method of this invention. It is a figure which shows roughly the force which acts on a horizontal direction cross section, when the protective bank constructed by the protective bank construction method of this invention receives an impact. It is a figure which shows roughly the vertical direction cross section of the conventional protective bank. It is a figure which shows roughly the force which acts on a horizontal direction cross section, when the conventional protective bank receives an impact. (A) is a figure which shows roughly the example of the transverse direction reinforcing material 1b. (B) is a figure which shows roughly the example of the triaxial direction reinforcing material 1a. It is a figure which shows the tensile strength of the triaxial reinforcement 1a.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reinforcement material 1a ... Triaxial reinforcement material 1b ... Transverse reinforcement material 2 ... Embankment material 10 ... Guard bank 11 ... Falling rock 12 ... Impact 13 ... Resistance 20 ... Conventional protection bank 21 ... Falling stone 22 ... Impact 23 ... Resistance Power 100 ... Ground

Claims (1)

Laying the reinforcing material up to a predetermined height, comprising a reinforcing material laying step of laying a reinforcing material made of geotextile substantially horizontally, and a compacting step of placing a filling material on the laid reinforcing material and compacting By repeating the steps and the compaction step, a method of constructing a protective levee in which a plurality of the reinforcing materials are embedded with a certain interval in the vertical direction,
The plurality of reinforcing materials are a transverse reinforcing material made of a geotextile having a particularly strong strength in the transverse direction at the time of laying, and a triaxial reinforcing material made of a geotextile having a particularly strong tensile strength in the triaxial direction ,
One or more said 3 axial direction reinforcement materials are embed | buried between the said transverse direction reinforcement materials in a perpendicular direction , The protective bank construction method characterized by the above-mentioned .

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