JP4575800B2 - Embankment reinforcement structure and reinforcement method - Google Patents

Description

  The present invention relates to a reinforcing structure and a reinforcing method capable of reinforcing a dike by combining soil improvement and laying of a reinforcing material.

  River banks, coasts, and lake bank embankments are softened by the infiltration of water or eroded by water. During a typhoon or heavy rain, if the water level of the river rises and the volume of water penetrating into the embankment increases, the embankment sand (the embankment soil) is liable to slip and the possibility of dam breakage increases. In that case, overflowing water (running water over the embankment) is likely to occur as the water level of the river rises, and erosion is accelerated by overflowing water on the opposite side of the surface of the embankment. In addition, earthquakes and land subsidence can be cited as factors causing embrittlement. Due to an earthquake or land subsidence, the embankment may be greatly deformed or cracked.

For this reason, strengthening of the dike is strongly requested. A concrete revetment is conventionally known as an embankment reinforcement (see Patent Document 1). In addition, in order to strengthen the embankment to a more stable structure, there is a countermeasure to reduce the slope (gradient) of the embankment.
JP 2003-206520 A

  Concrete revetment requires huge construction costs and only strengthens the surface of the levee, so if an earthquake or land subsidence causes a crack or the like, water easily penetrates into the levee and the levee It becomes impossible to protect the soil quality. In the coping method to relieve the slope (gradient) of the levee, since the cross section of the levee is widened, a large site is required and it may be difficult to apply.

  The present invention has been made paying attention to such problems, and has strong resistance to infiltration of water and erosion by water, and has a strong toughness against large deformation caused by an earthquake or underground underground. The purpose is to provide a reinforcing structure and a reinforcing method capable of realizing the above.

According to a first aspect of the present invention, there is provided a strengthened earth wall constructed so as to cover a slope of a levee with a mixture of soil, short fibers, and a solidified material as a material, and from the inside of the earth wall to the inside of the levee. and a reinforcing member that is laid in layers over the reinforcing member of the water surface and opposite side of the dike is characterized Rukoto comprising a water-permeable give draining function to the strengthened soil wall.

According to a second aspect of the present invention, in the embankment reinforcement method, a step of constructing a reinforced soil wall in stages so as to cover the slope of the levee with a mixture of soil, short fibers, and solidified material, and the water surface of the levee higher a step of excavating the slope of the embankment stepwise in accordance with the height of laying the reinforcement comprising a water-permeable give draining function to the strengthened soil the opposite wall, the reinforcing earth wall in the next step with a step from the upper surface of the reinforcing soil walls before backfilling sediment drilled into the embankment and covered with the reinforcing member over the stepped drilling surface of the embankment to be constructed, characterized in that it comprises a.

According to a third aspect of the present invention, in the reinforcement method for a levee, the step is made in accordance with the height of laying a reinforcing material having water permeability that gives a drainage function to a reinforced soil wall opposite to the water surface of the levee in contact with the slope of the levee. a step of constructing a Jo embankment, a step of constructing the reinforcing earth wall so as to cover the inclined surface of the embankment of a mixture of soil and short fibers and solidified material to material, the stepped embankment in the next step a step of laying the reinforcement from the upper surface of the reinforcing soil wall before raising building over the upper surface of the stepped embankment, characterized in that it comprises a.

  According to the first invention, the reinforced earth wall has large rigidity and proof strength due to the solidified material, and has a resistance to tensile load by including short fibers, so it has a stable structure that is resistant to deformation and is rich in strength and toughness. In addition to demonstrating great resistance to water penetration and erosion, it also demonstrates persistent resistance to large deformations caused by earthquakes and land subsidence. This earth wall suppresses the penetration of river water and the like into the dike and prevents breakage due to slippage and erosion of the dike soil (embankment earth). The inside of the reinforced earth wall and the inside of the embankment are connected by a reinforcing material, so that it has a structure that integrally resists water infiltration and erosion, earthquakes and land subsidence. In addition to reducing dams, it can resist breakage caused by slippage and erosion of the levee soil, thereby further enhancing the strength and toughness of the levee.

Also , on the opposite side of the water surface of the dike, the reinforced earth wall can be drained by a water-permeable reinforcing material, and while the reinforced earth wall suppresses the penetration of water into the dike, It becomes possible to discharge, and the prevention of breakage due to slippage and erosion of embankment soil can be effectively promoted.

According to the second invention, the construction of the reinforced earth wall and the laying of the reinforcing material can be performed efficiently and rationally. The step of excavating the slope of the embankment is performed in accordance with the progress of the step of constructing the reinforced earth wall in stages. In this case, by adding excavation for the thickness of the reinforced earth wall to the slope of the bank, the bank can be reinforced even when the section of the bank cannot be widened.

According to the third invention, when the cross section of the levee can be widened, it can be efficiently and rationally constructed in such a way that the existing levee is reinforced with the construction of the reinforced earth wall and the laying of the reinforcing material.

  FIG. 1 shows an embodiment of the present invention, and the reinforcement structure of a levee is formed by covering a slope of a levee with a mixture of soil, short fibers and a solidified material (short fiber mixed improved soil) as a material. Reinforced earth walls 10a and 10b to be constructed, and reinforcing members 11a and 11b laid in layers from the inside to the inside of the dike.

  The short fiber mixed improved soil is produced by mixing short fibers and a solidified material in the soil and stirring. Soil basically uses local soil. As the solidifying material, a material that matches the soil quality of the generated soil is used. For example, when the generated soil is sandy soil, a cement-based solidifying material is used, and when the generated soil is viscous soil, a lime-based solidifying material is used. As the short fiber, an elastic petrochemical fiber having a length of about 3 to 10 cm and a thickness of about several tens of microns is used.

  Reinforcing members 11a and 11b are transition zones (strengthening zone 2) that reduce the rigidity difference between reinforced earth walls 10a and 10b (strengthening zones 1 and 4) and levee earth and sand (existing portion) and enable continuous mechanical behavior. , 3). As the reinforcing members 11a and 11b, those (for example, geogrid) that can sufficiently obtain frictional resistance with the reinforced earth walls 10a and 10b and the levee earth and sand (embankment earth) are used. About the reinforcing material 11b on the opposite side to the water surface of the levee, not only the frictional resistance between the reinforced earth wall 10b and the levee earth is obtained, but also has a water permeability that gives the reinforced earth wall 10b a drainage function and has high strength. use.

  The thickness of the reinforced earth walls 10a, 10b and the length of the reinforcements 11a, 11b inside the dyke are designed according to the conditions of the levee's cross section, soil quality, etc., but prevent breakage due to slippage and erosion of the levee soil In order to efficiently secure the strength and toughness required for this, the higher one is set smaller and the lower one is set larger.

  In FIG. 1, 12a and 12b are method linings which coat | cover the outer surface of the reinforced earth walls 10a and 10b, and are comprised from a concrete panel or block. Reference numeral 13 denotes a rooting work of the method lining 12a on the water surface side of the levee. On the opposite side, a drainage groove 14 is formed along the lower end of the method lining 12b, and a drain portion 15 is buried in the lower portion of the levee. 10c is the upper part of the reinforced earth walls 10a and 10b, and covers the top surface of the bank. ▽ shows the water surface at the time of steady river, and ▽ HW1 shows the water surface at the time of river increase. About the short fiber mixed improvement soil which the reinforced earth walls 10a-10c construct | assemble, a hydraulic conductivity is set small with about 1/10-1/100 compared with a dike soil.

  Regarding the embankment reinforcement method, the steps of constructing the reinforced earth walls 10a and 10b in stages so as to cover the slope of the embankment with a mixture of soil, short fibers and solidified material, and the reinforcing materials 11a and 11b The step of excavating the slope of the dike in a step shape as shown by the dotted line in FIG. 1 according to the laying height, and the upper surface of the reinforced soil walls 10a, 10b before the reinforced soil walls 10a, 10b are built high in the next stage And burying the reinforcing materials 11a and 11b over the stepped excavation surface of the levee to backfill the earth and sand excavated in the levee.

  Concrete explanation of the reinforcement method on the water surface side of the levee is as follows: (1) Unwinding the short fiber mixed improved soil on the base, spreading it, compacting it by rolling, and contacting the levee slope The wall 10a is built to the laying height of the reinforcing material 11a. (2) Excavating the slope of the embankment in a step shape according to the laying height of the reinforcing material 11a. (3) The reinforcing material 11a is laid from the upper surface of the reinforced earth wall 10a before the reinforced earth wall 10a is built to the next stage to the stepped excavation surface of the bank, and is fixed with an anchor pin or the like. (4) A portion of the reinforcing material 11a is buried in the dike by refilling the excavated earth and sand into the dike. (5) Unwind the short fiber mixed improved soil on the upper surface of the existing reinforced earth wall 10a, level it, compact it by rolling, and touch the reinforced earth wall 10a to the restored slope. The remaining portion of the reinforcing material 11a is embedded in the reinforced earth wall 10a by building the reinforcing material 11a at the height of the laying material.

  By repeating these steps (1) to (5), the construction of the reinforced earth wall 10a and the laying of the reinforcing material 11a can be performed efficiently and rationally.

  Regarding the construction on the opposite side of the water surface of the dike, (a) the drain part 15 is buried in the dike. Thereafter, the same steps (1) to (5) as those on the water surface side of the dike are repeated, whereby the construction of the reinforced earth wall 10b and the laying of the reinforcing material 11b are efficiently and rationally performed.

  The reinforced earth walls 10a to 10c have large rigidity and proof strength due to the solidified material, and have a resistance to tensile load by including short fibers. Therefore, the reinforced earth walls 10a to 10c have a stable structure that is rich in strength and toughness and hardly deform, In addition to demonstrating great resistance to erosion, it also shows persistent resistance to large deformations caused by earthquakes and land subsidence. The soil walls 10a to 10c suppress the penetration of river water and the like into the levee, and can prevent breakage due to slippage and erosion of the levee soil.

  Since the inside of the reinforced earth walls 10a and 10b and the inside of the dike are connected by the reinforcing materials 11a and 11b, the reinforcing soil walls 10a and 10b have a structure that integrally resists water penetration, erosion, earthquakes, and ground subsidence. 11b not only reduces the earth pressure received by the reinforced earth walls 10a and 10b, but also resists breakage due to slippage and erosion of the levee soil, so that the strength and toughness of the levee can be further increased.

  The reinforced earth walls 10a to 10c can prevent water erosion and prevent sediment from flowing out of the dike. During typhoons and heavy rains, if the river level rises and the volume of water penetrating into the levee increases, the levee soil sand is liable to slip and increase the possibility of being connected to the levee, but the reinforced soil walls 10a to 10c Since the permeability coefficient is small, the penetration of river water and rainwater into the dike is also suppressed. In addition, erosion due to overflowing water can be suppressed. On the other hand, on the side opposite to the water surface of the levee, drainage facilities (drain portion 15 and drainage groove 14) are arranged, and the reinforcing material 11b has water permeability that gives the reinforced soil wall 11b a drainage function. In order to prevent destruction due to erosion, the water inside the dike is well maintained.

  The thickness of the reinforced earth walls 10a and 10b and the length of the reinforcing members 11a and 11b over the levee are small for the higher ones and larger for the lower ones. It is possible to efficiently secure the strength and toughness necessary for the manufacturing. The method linings 12a and 12b covering the outer surfaces of the reinforced soil walls 10a and 10b have a stable structure in which the levee is rich in strength and toughness and is not easily deformed by the reinforced soil walls 10a to 10c and the reinforcing materials 11a and 11b. Thinning is possible, and cost can be reduced. In this case, the method linings 12a and 12b are made of concrete panels, but can also be made vegetative from the aesthetic point of view by covering the reinforced soil wall (forming a soil layer). .

  In the illustrated embodiment, the cross section of the levee is widened by the thickness of the reinforced earth walls 10a, 10b (and the method linings 12a, 12b), but if the widening of the cross section is not allowed, In (1) and (2), by adding excavation for the thickness of the reinforced earth wall to the slope of the bank, the bank can be reinforced even when the section of the bank cannot be widened.

  In the case where the cross-section of the dike can be widened, (A) a step of constructing a stepped bank according to the height of the reinforcement material in contact with the slope of the dike, and (B) soil and short fibers A step of constructing a reinforced earth wall so that the slope of the embankment is covered with a mixture of the solidified material and (C) a step shape from the upper surface of the reinforced earth wall before constructing the stepped embankment high to the next stage And a process of laying a reinforcing material over the upper surface of the embankment of the earth, and efficiently and rationally form the reinforcement areas 1 and 4 and the reinforcement areas 3 and 4 as shown in FIG. It will be possible to construct. In this reinforcing method, the steps (A) to (C) are repeated so as to build up the reinforced areas 1 and 4 and the reinforced areas 3 and 4 in stages.

It is sectional drawing of the embankment showing embodiment of this invention.

Explanation of symbols

10a to 10c Reinforced earth wall 11a, 11b Reinforcement material 12a, 12b Method lining 14 Drainage groove 15 Drain part

Claims (3)

A reinforced earth wall constructed so as to cover the slope of the levee with a mixture of soil, short fibers and solidified material, and a reinforcing material laid in layers from the inside of the earth wall to the inside of the levee, provided,
The water surface opposite the reinforcement of embankment, reinforcing structure of embankments, wherein Rukoto comprising a water-permeable give draining function to the strengthened soil wall. A step of constructing a reinforced soil wall in stages so as to cover the slope of the dike with a mixture of soil, short fibers and solidification material ;
A step of excavating the slope of the embankment stepwise in accordance with the height of laying the reinforcement comprising a water-permeable give draining function to the strengthened soil wall water opposite the embankment,
A step of backfilling sediment drilled into the embankment laying the reinforcement from the upper surface of the reinforcing soil wall before over the stepped drilling surface of the embankment to increase constructing the reinforcing earth wall to the next step, An embankment reinforcement method characterized by comprising: A step of constructing a stepped bank according to the height of laying a reinforcing material having water permeability that gives a drainage function to the reinforced soil wall opposite to the water surface of the levee in contact with the slope of the levee ;
A step of constructing the reinforcing earth wall so as to cover the inclined surface of the embankment the mixture material of the soil and the short fibers and the solidifying material,
Reinforcement of embankment, characterized in that it comprises the steps of laying the reinforcement over the top surface of the reinforcing soil wall before the upper surface of the stepped embankment to increase constructing the stepped embankment in the next step Construction method.