Method of constructing a dam

Abstract

To provide a dam body construction method capable of constructing a dam body rationally.SOLUTION: A construction method of a dam body 1 includes: an internal structure construction step in which internal concrete is spread evenly and the internal concrete is compacted by applying vibrations from an outside to construct an internal structure 2; and an outer shell construction step in which external concrete is spread evenly outside the internal structure 2 and the external concrete is compacted by applying vibrations from an outside to construct an outer shell 3. The internal concrete is hard-mixed concrete with a slump value of 5.0 cm or less and has a maximum aggregate dimension of 80 mm or more and 200 mm or less, and the external concrete is hard-mixed concrete with a slump value of 5.0 cm or less and has a maximum aggregate dimension less than 80 mm. The external concrete has a larger unit cement content and a smaller water binder ratio compared to the internal concrete.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for constructing an embankment. [Background technology]

[0002] Patent Document 1 discloses a dam construction method that includes a CSG pouring step of receiving CSG and pouring CSG layers continuously, a formwork installation step of installing the precast formwork at a position maintaining a certain distance from the CSG layers, and a concrete pouring step of pouring protective concrete material between two layers of CSG and the precast formwork.

[0003] In the dam construction method disclosed in Patent Document 1, protective concrete is poured outside the internal area constructed by CSG to construct the outer shell. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2008-214914 [Overview of the project] [Problems that the invention aims to solve]

[0005] The dam construction method disclosed in Patent Document 1 requires the installation of formwork when pouring protective concrete. Such a construction method necessitates steps for installing and removing the formwork. Therefore, further rationalization was needed in the construction of the dam body.

[0006] The present invention aims to provide a method for constructing a dam that allows for more rational construction of the dam body. [Means for solving the problem]

[0007] The present invention relates to a method for constructing a dam body, comprising: an internal structure construction step of spreading and leveling internal concrete mixed with a binder, water, and aggregate, and compacting it by applying vibration from the outside to construct the internal structure of the dam body; and an outer shell construction step of spreading and leveling external concrete mixed with a binder, water, and aggregate on the outside of the internal structure, and compacting it by applying vibration from the outside to construct the outer shell of the dam body, wherein the internal concrete is a stiff-mixed concrete with a slump value of 5.0 cm or less and a maximum aggregate size of 80 mm or more and 200 mm or less, and the external concrete is a stiff-mixed concrete with a slump value of 5.0 cm or less and a maximum aggregate size of less than 80 mm, and the external concrete has a larger unit cement content and a smaller water-binder ratio compared to the internal concrete. Furthermore, the aggregates included in the exterior concrete are aggregates selected according to their size, such as coarse aggregates and fine aggregates. Alternatively, the aggregates included in the exterior concrete are washed aggregates.

[0008] Furthermore, the present invention relates to a method for constructing a dam body, comprising: an internal structure construction step of spreading and leveling internal concrete mixed with a binder, water and aggregate, and compacting it by applying vibration from the outside to construct the internal structure of the dam body; and an outer shell construction step of spreading and leveling external concrete mixed with a binder, water and aggregate on the outside of the internal structure, and compacting it by applying vibration from the outside to construct the outer shell of the dam body, wherein the internal concrete is a stiff concrete with a slump value smaller than the slump value specified as 4.0 cm ± 1.0 cm, and the maximum aggregate size is 80 mm or more and 200 mm or less; the external concrete is a stiff concrete with a slump value smaller than the slump value specified as 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm; and the external concrete has a larger unit cement content and a smaller water-binder ratio compared to the internal concrete. Furthermore, the aggregates included in the exterior concrete are aggregates selected according to their size, such as coarse aggregates and fine aggregates. Alternatively, the aggregates included in the exterior concrete are washed aggregates.

[0009] Furthermore, the present invention relates to a method for constructing a dam body, comprising: an internal structure construction step of spreading and leveling internal CSG, which is a mixture containing a binder, water, and unclassified soil, and compacting it by applying vibration from the outside to construct the internal structure of the dam body; and an outer shell construction step of spreading and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting it by applying vibration from the outside to construct the outer shell of the dam body, wherein the internal CSG has a unit cement content of 40 to 160 kg / m³. 3 The unit water volume is 80-140 kg / m³. 3 The maximum aggregate size is 80 mm or more and 200 mm or less, and the exterior concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is less than 80 mm, and the exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the interior CSG. Furthermore, the aggregate included in the exterior concrete is selected according to size, such as coarse aggregate and fine aggregate. Alternatively, the aggregate included in the exterior concrete is washed aggregate. .

[0010] Furthermore, the present invention relates to a method for constructing a dam body, comprising: an internal structure construction step of spreading and leveling internal CSG, which is a mixture containing a binder, water, and unclassified soil, and compacting it by applying vibration from the outside to construct the internal structure of the dam body; and an outer shell construction step of spreading and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting it by applying vibration from the outside to construct the outer shell of the dam body, wherein the internal CSG has a unit cement content of 40 to 160 kg / m³. 3 The unit water volume is 80-140 kg / m³. 3 The maximum aggregate size is 80 mm or more and 200 mm or less, and the exterior concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm, and the exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the interior CSG. Furthermore, the aggregate included in the exterior concrete is selected according to size, such as coarse aggregate and fine aggregate. Alternatively, the aggregate included in the exterior concrete is washed aggregate. . [Effects of the Invention]

[0011] According to the present invention, the process of installing and removing formwork is eliminated when constructing the outer shell, thus streamlining the process.

Brief Description of the Drawings

[0012] [Figure 1] It is a longitudinal sectional view of a dike body according to an embodiment of the present invention. [Figure 2] (A) It is a mixing table of internal concrete and external concrete according to an embodiment of the present invention. (B) It is a mixing table of internal CSG according to an embodiment of the present invention. [Figure 3] It is a view showing the working state of the internal structure construction process of the dike body construction method according to an embodiment of the present invention. [Figure 4] It is a view showing the working state of the outer shell construction process of the dike body construction method according to an embodiment of the present invention. [Figure 5] It is a view showing the working state of the outer shell construction process of the dike body construction method according to an embodiment of the present invention.

Modes for Carrying Out the Invention

[0013] Hereinafter, a method for constructing a dike body 1 according to an embodiment of the present invention will be described with reference to the drawings.

[0014] FIG. 1 is a longitudinal sectional view of the dike body 1 according to the present embodiment. The dike body 1 shown in FIG. 1 is, for example, a gravity-type concrete dam dike body in a dam. The dike body 1 is constructed of a concrete material or a CSG (Cemented Sand and Gravel) material. Note that the dike body 1 may be a dike body in a river embankment or the like.

[0015] As shown in FIG. 1, the dike body 1 has an internal structure 2 constructed inside the dike body 1 and an outer shell 3 constructed to cover the internal structure 2 on the outside of the internal structure 2. Note that a separate rock attachment portion may be provided between the joint surface between the ground G and the internal structure 2 and the joint surface between the ground G and the outer shell 3.

[0016] The internal structure 2 is constructed of a concrete material or a CSG material. The outer shell 3 is constructed of a concrete material. In this embodiment, among the concrete materials, the concrete material for constructing the internal structure 2 is referred to as "internal concrete", and the concrete material for constructing the outer shell 3 is referred to as "external concrete". Also, in this embodiment, the CSG material for constructing the internal structure 2 is referred to as "internal CSG".

[0017] First, the concrete material (internal concrete) and CSG material (internal CSG) used for constructing the internal structure 2 of the embankment body 1 will be described.

[0018] First, the internal concrete will be described.

[0019] The internal concrete in this embodiment is composed of a cementitious material produced by mixing cement (binder) and water with aggregates selected by size, and the slump value is defined as (central value) 4.0 cm ± (tolerance) 1.0 cm or less, that is, it is a stiff concrete with a slump value of 5.0 cm or less. The stiff concrete in this embodiment is a lean mix concrete with a reduced unit cement content C and unit water content W compared to a slump concrete material with a slump value greater than 5.0 cm. The specific mix of the internal concrete in this embodiment is shown in Fig. 2(A). As shown in Fig. 2(A), in the internal concrete, the maximum size of the coarse aggregate is 80 mm or more and 200 mm or less, and the mass of cement per unit volume (unit cement content C) [kg / m 3 is 100 kg / m 3 or more and 130 kg / m 3 or less, the mass of water per unit volume (unit water content W) [kg / m 3 is 80 kg / m 3 or more and 105 kg / m 3 or less, and the air content is 0.5% to 2.5% by volume.

[0020] In Figure 2(A), the "slump value" is a value indicating the softness of the cement-based material before hardening. A higher slump value means softer material. In this embodiment, the slump value is measured according to the slump test method specified in JIS (Japanese Industrial Standards) A 1101:2005. In concrete manufacturing, concrete is produced by mixing concrete materials in a predetermined mix, so the slump value cannot be set directly and has a certain range. Therefore, the tolerance for the slump value is set by referring to "Table 4 - Tolerance for Slump Value at Unloading Point" for ready-mixed concrete as specified in JIS (Japanese Industrial Standards) A 5308:2019. Specifically, if the central value of the slump is 1.0 cm to 4.5 cm, a range of ±1.0 cm is acceptable. Similarly, if the central value of the slump is 5.0 cm to 6.5 cm, a range of ±1.5 cm is acceptable. Therefore, the slump value of concrete is generally defined by the central value and the tolerance range.

[0021] The "maximum aggregate size" shown in Figures 2(A) and (B), and other "maximum aggregate size" figures, refer to those defined by JIS (Japanese Industrial Standards). Specifically, it is defined as "the size of the coarse aggregate indicated by the nominal size of the smallest sieve through which 90% or more of the aggregate by mass can pass."

[0022] In Figure 2(A), "air content" refers to the ratio of the volume of air contained in the concrete after placement. The air content in Figure 2(A) is measured according to JIS_A_1128 "Pressure Test Method for Air Content of Fresh Concrete". "Air content" is a representative value indicating the amount of entrained air. Entrained air refers to the fine, independent air bubbles generated in the concrete by the surface-active action of admixtures such as AE agents and AE water-reducing agents, which will be described later. Entrained air is generally nearly spherical, and its diameter varies somewhat depending on the type of admixture, but is approximately 25-250 μm. Entrained air has a significant effect on improving freeze-thaw resistance and workability; these effects are greater when the air content is the same, but the bubbles are smaller and the spacing between them is smaller.

[0023] In Figure 2(A), the "water-cement ratio (water-binder ratio) W / C" refers to the ratio of the unit amount of water W to the unit amount of cement C. Furthermore, in Figure 2(A), the "fine aggregate ratio" refers to the ratio of the mass of fine aggregate S per unit volume to the unit amount of aggregate (total amount of fine aggregate S and coarse aggregate G per unit volume).

[0024] As shown in Figure 2(A), an AE (Air Entraining) water-reducing agent is mixed into the internal concrete of this embodiment. Examples of AE water-reducing agents include polycarboxylic acid-based, naphthalene-based, aminosulfonic acid-based, and melamine-based agents. By mixing an AE water-reducing agent into the external concrete, the air-bubble entrainment ability is improved, and the unit water content W and unit cement content C can be reduced.

[0025] Next, I will explain the internal CSG.

[0026] CSG material is a cement-based material manufactured by mixing cement and water with excavated soil materials (also called locally sourced materials) such as sand, gravel, and rock fragments obtained from the vicinity of a construction site. CSG material contains coarse aggregate, such as crushed stone and coarse gravel, with a maximum aggregate size of approximately 80 mm to 120 mm, which is larger than the maximum aggregate size (40 mm) for general ready-mixed concrete. Although the excavated soil materials may be processed to remove oversized pieces or to crush them, classification, particle size adjustment, and washing are not generally performed. In other words, CSG material, which uses excavated soil materials (unclassified soil) as its main raw material, can be manufactured continuously with simpler equipment than that used for manufacturing concrete, and when constructing a dam body, equipment such as aggregate manufacturing equipment required for the construction of a general concrete dam is unnecessary. As for cement, there are Portland cement, blended cement, and special cement, but Portland cement and blended cement (such as blast furnace cement and fly ash cement) are used for CSG and the CSG method. In particular, moderate-heat Portland cement, blast furnace cement (Type B), Portland cement mixed with fly ash, or moderate-heat Portland cement mixed with fly ash cement can be used.

[0027] Figure 2(B) shows the specific composition of the internal CSG in this embodiment. As shown in Figure 2(B), in the internal CSG, the maximum aggregate size is 80 mm or more and 200 mm or less, and the mass of cement per unit volume (unit cement content C) [kg / m³] 3 ] is 40 kg / m 3 More than 160kg / m 3 The following is the mass of water per unit volume (unit water volume W) [kg / m³]. 3 ] is 80 kg / m 3 More than 140kg / m 3 The following applies. Furthermore, a hardening retarder may be added to the internal CSG to delay the cement hardening reaction. The water-cement ratio (W / C) of the internal CSG is set to 50% or more and 350% or less. More preferably, the water-cement ratio (W / C) of the internal CSG is 60% or more and 120% or less.

[0028] Internal concrete and internal CSG with this type of mix have a lower unit cement content C compared to slump concrete materials. Therefore, when constructing the internal structure 2 of the dam body 1, using internal concrete and internal CSG with this mix can reduce raw material costs. In addition, internal concrete and internal CSG have a lower unit water content W compared to slump concrete materials and have low fluidity in the unhardened state, so they can be poured into the desired shape without the need for formwork. This shortens the construction period for the internal structure 2. Furthermore, because internal concrete and internal CSG have lower unit cement content C and unit water content W compared to slump concrete materials, the temperature rise due to hydration heat can be suppressed, and cracks caused by hydration heat can be reduced.

[0029] Next, we will describe the external concrete used to construct the outer shell 3 of the dam body 1.

[0030] The exterior concrete is composed of cement-based materials manufactured by mixing cement and water with aggregates selected according to size, and is specified to have a slump value of 4.0 cm ± 1.0 cm or less (center value), i.e., a stiff concrete with a slump value of 5.0 cm or less. More preferably, the exterior concrete is specified to have a slump value of 3.0 cm ± 1.0 cm or less (center value), i.e., a stiff concrete with a slump value of 4.0 cm or less. An example of the mix design for the exterior concrete in this embodiment is shown in Figure 2(A). As shown in Figure 2(A), the exterior concrete has a unit cement content C [kg / m³] compared to the interior concrete and interior CSG used to construct the interior structure 2. 3The ] is large, and the water-cement ratio (W / C) is small. Specifically, the water-cement ratio (W / C) of the exterior concrete is set to 40% or more and 60% or less (less than 65%). The water-cement ratio (W / C) of the interior concrete is set to 65% or more and 95% or less. As a result, the outer shell 3 constructed of exterior concrete has higher strength and durability compared to the interior structure 2 constructed of interior concrete or interior CSG. As shown in Figure 2(A), in the exterior concrete, the maximum aggregate size is less than 80 mm, and the mass of cement per unit volume (unit cement content C) [kg / m 3 ] is 180 kg / m 3 More than 230kg / m 3 The following is the mass of water per unit volume (unit water volume W) [kg / m³]. 3 ] is 80 kg / m 3 More than 140kg / m 3 The following is preferred: Preferably, the mass of water per unit volume (unit water volume W) [kg / m³] 3 ] is 100-120 kg / m 3 That is the case.

[0031] Furthermore, as shown in Figure 2(A), an AE (Air Entraining) additive is mixed into the exterior concrete of this embodiment. Examples of AE additives include anionic types such as resin-based, alkylbenzene sulfonic acid-based, and higher alcohol ester-based additives, as well as nonionic types. By mixing an AE additive into the exterior concrete, numerous microbubbles (entrained air) with a diameter of approximately 25 μm to 250 μm are generated within the exterior concrete after hardening. This improves the durability, freeze-thaw resistance, and workability of the exterior concrete. The amount of air contained in the fresh exterior concrete is measured according to JIS A 1128 "Test method for the amount of air in fresh concrete by pressure," and is measured in a fresh state. The amount of air contained in the fresh exterior concrete excludes the amount of air due to hollow microspheres, which will be described later. The amount of air in the exterior concrete is preferably about 4.0 ± 1.0 volume%. Furthermore, it is preferable that the amount of air contained in the exterior concrete is greater than the amount of air contained in the interior concrete.

[0032] Furthermore, as shown in Figure 2(A), an AE water-reducing agent is mixed into the exterior concrete of this embodiment. Examples of AE water-reducing agents include polycarboxylic acid-based, naphthalene-based, aminosulfonic acid-based, and melamine-based agents. By mixing an AE water-reducing agent into the exterior concrete, the ability to entrain air bubbles is improved, and the unit water content W and unit cement content C can be reduced.

[0033] Furthermore, as shown in Figure 2(A), hollow microspheres are mixed into the outer concrete of this embodiment. The hollow microspheres are, for example, hollow beads made of resin. The hollow beads are preferably hollow bodies (shells with space inside) made of resin with a diameter of about 0.01 mm to 0.3 mm. The space secured by the hollow beads when they are mixed into the outer concrete, i.e., the voids, are preferably 0.5% to 2.0% of the volume of the outer concrete. More preferably, they are 0.5% to 1.5% of the volume of the outer concrete.

[0034] When the dam body 1 is constructed in a cold region, the moisture contained within the outer concrete may repeatedly freeze (expand) and thaw (contract). Under such conditions, the pressure changes caused by the freezing (expanding) and thawing (contracting) of moisture can put a load on the outer concrete, which can lead to concrete failure such as cracking (this phenomenon is called "frost damage"). Therefore, in this embodiment, the frost damage resistance is improved by mixing the above-mentioned AE additive, AE damping agent, and hollow beads into the outer concrete.

[0035] Next, with reference to Figures 3 to 5, we will outline the procedure for constructing the dam body 1. First, we will explain the internal structure construction process for constructing the internal structure 2.

[0036] The internal structure 2 is constructed by stacking internal layers 20, each equivalent to one lift, from bottom to top, formed by pouring internal concrete or internal CSG as described above. The height of each internal layer 20, i.e., the lift height H, is approximately 75 cm to 100 cm.

[0037] Figure 3 shows the internal structure 2 in the process of construction. As shown in Figure 3, the internal layer 20 is constructed by stacking multiple layers (first internal layer 21, second internal layer 22, third internal layer 23) formed by internal concrete or internal CSG. The first internal layer 21, second internal layer 22, and third internal layer 23 become shorter in length in the upstream / downstream direction (horizontal length in the drawing) as they are formed higher up.

[0038] First, the internal concrete or internal CSG, which has been transported using dump trucks or conveyors (not shown), is unloaded and spread evenly using heavy machinery such as bulldozers (not shown). Next, the spread internal concrete or internal CSG is compacted to form the lowest layer, the first internal layer 21.

[0039] Next, internal concrete or internal CSG is transported onto the top surface of the leveled first internal layer 21, and the transported internal concrete or internal CSG is leveled using heavy machinery such as a bulldozer (not shown). Then, the leveled internal concrete or internal CSG is compacted to form the second internal layer 22 on the top surface of the first internal layer 21.

[0040] Furthermore, internal concrete or internal CSG is transported onto the upper surface of the leveled second internal layer 22, and the transported internal concrete or internal CSG is leveled using heavy machinery such as a bulldozer (not shown). Then, the leveled internal concrete or internal CSG is compacted to form the third internal layer 23 on the upper surface of the second internal layer 22.

[0041] Then, after the third internal layer 23 is formed, as shown in Figure 3, the first internal layer 21, the second internal layer 22, and the third internal layer 23 are compacted by applying vibration from the outside to the layer formed by the internal concrete or internal CSG using construction machinery equipped with a vibration plate or heavy machinery 4 such as a vibratory roller. In other words, of the three layers 21, 22, and 23 that make up the internal layer 20, at least the uppermost layer (third internal layer 23) is laid down and then compacted by heavy machinery 4. However, the first internal layer 21 and the second internal layer 22 may also be laid down by heavy machinery such as a bulldozer and then compacted by heavy machinery 4.

[0042] As described above, heavy machinery 4 such as construction machinery equipped with a vibrating plate or a vibratory roller is used for compaction from the upper surface 2a side of the inner layer 20 (third inner layer 23). However, the internal concrete and internal CSG near the slope shoulder 2c, which is the end of the upper surface 2a of the inner layer 20, may not be able to withstand the weight of the heavy machinery 4, and there is a risk that the area near the slope shoulder 2c may collapse. Therefore, in this embodiment, a predetermined range (region R1) from the slope shoulder 2c of the upper surface 2a is compacted by construction machinery 5 such as a power shovel with a compaction attachment device 6 attached to the tip of the arm 5a (see Figure 3). The construction machinery 5 applies vibration to the inner layer 20 from the upper surface 2a via a vibrating plate 6a provided on the compaction attachment device 6, thereby compacting the inner layer 20 in region R1. Region R1 is, for example, a range of about 1 to 1.5 m from the slope shoulder 2c.

[0043] Furthermore, since it is difficult for the heavy machinery 4 to move along the slope 2b, the construction machine 5 is used for compaction of the internal structure 2 (first internal layer 21, second internal layer 22, and third internal layer 23) from the slope 2b side, similar to the compaction of area R1. Specifically, vibrations are applied to the slope 2b via the vibrating plate 6a of the compaction attachment device 6 attached to the construction machine 5 to compact the internal layers 20 (first internal layer 21, second internal layer 22, and third internal layer 23).

[0044] Thus, in the internal structure construction process, the unhardened internal concrete or internal CSG is compacted by applying vibration from the outside (top surface 2a and slope 2b). This removes air from the internal concrete or internal CSG, increasing its density and creating a smooth surface. Furthermore, this compaction ensures the structural strength. The air removed by this vibration compaction is air bubbles that are mixed into the concrete during mixing or spreading, even without the use of admixtures such as AE agents or AE water-reducing agents. These bubbles have a larger diameter and irregular shape compared to entrained air, and therefore contribute less to improving freeze resistance and workability.

[0045] Next, the outer shell construction process for constructing the outer shell 3 will be explained with reference to Figures 4 and 5.

[0046] The outer shell 3 is constructed by stacking outer layers 30, each equivalent to one lift, from bottom to top, formed by pouring the outer concrete as described above. The height of each outer layer 30, i.e., the lift height H, is equivalent to that of the inner layer 20, specifically, about 75 cm to 100 cm.

[0047] Figures 4 and 5 show the outer shell 3 in the process of construction, illustrating the state in which three outer layers 30 are stacked. The outer layers 30 are composed of multiple layers (first outer layer 31, second outer layer 32, third outer layer 33) formed from outer concrete. Each stacked layer (first outer layer 31, second outer layer 32, third outer layer 33) is formed to have a nearly constant length in the upstream-downstream direction (horizontal length in the drawing). Note that Figures 4 and 5 partially show the internal structure 2 and outer shell 3; in reality, the outer layers 30 (outer shell 3) are constructed on both the upstream and downstream sides of the internal structure 2. The width W of the outer layers 30 (outer shell 3) is set to approximately 1.5m to 3m.

[0048] First, the external concrete, transported using dump trucks or the like (not shown), is unloaded and then spread and leveled using heavy machinery such as bulldozers (not shown). This forms the lower first external layer 31.

[0049] Next, outer concrete is transported onto the top surface of the leveled first outer layer 31, and the transported outer concrete is leveled using heavy machinery such as a bulldozer (not shown). This forms the second outer layer 32 on the top surface of the first outer layer 31.

[0050] Furthermore, outer concrete is transported onto the top surface of the leveled second outer layer 32, and the transported outer concrete is leveled using heavy machinery such as a bulldozer (not shown). As a result, the third outer layer 33 is formed on the top surface of the second outer layer 32.

[0051] Then, after the third outer layer 33 is formed, as shown in Figure 4, the upper surface 3a of the third outer layer 33 is compacted by the heavy machinery 4, thereby compacting the first outer layer 31, the second outer layer 32, and the third outer layer 33. In other words, of the three layers 31, 32, and 33 that make up the outer layer 30, at least the uppermost layer (the third outer layer 33) is laid down and then compacted by the heavy machinery 4.

[0052] As described above, heavy machinery 4 is used for compaction performed from the upper surface 3a side of the outer shell 3 (third outer layer 33). However, the outer concrete near the shoulder 3c, which is the end of the upper surface 3a of the outer shell 3, cannot withstand the weight of the heavy machinery 4, and there is a risk that the area near the shoulder 3c may collapse. Therefore, the compaction performed from the upper surface 3a side of the outer shell 3 is performed by compacting a predetermined area R2, which is the area obtained by removing a predetermined range (area R3) from the shoulder 3c of the upper surface 3a, in other words, a predetermined range (area R2) that extends from the boundary portion B between the upper surface 2a of the inner layer 20 and the upper surface 3a of the outer layer 30 toward the shoulder 3c (outside), with the heavy machinery 4 (see Figure 4). At this time, it is preferable to compact the material so as to overlap a predetermined range near the boundary portion B on the upper surface 2a of the inner layer 20 (third inner layer 23), more specifically, up to region R1, that is, to cross the boundary between the upper surface 3a of the outer shell 3 (third outer layer 33) and the upper surface 2a of the inner layer 20 (third inner layer 23). By compacting in this manner, it is possible to prevent a step from occurring at the boundary portion B between the upper surface 2a of the inner layer 20 (third inner layer 23) and the upper surface 3a of the outer layer 30 (third outer layer 33). In this embodiment, "region R2" and "region R3" on the upper surface 3a correspond to "first upper surface" and "second upper surface" in the claims, respectively. Furthermore, the steps of compacting region R2 and region R3 correspond to "first outer concrete compaction step" and "second outer concrete compaction step" in the claims, respectively.

[0053] Furthermore, the area (region R3) from the shoulder 3c on the upper surface 3a of the outer layer 30 and the slope 3b of the outer layer 30 are compacted by applying vibration from the outside via a vibrating plate 6a provided on the compaction attachment device 6 using construction machinery 5, similar to the inner layer 20. Region R3 is, for example, an area of ​​about 1 to 1.5 m from the shoulder 3c on the upper surface 3a.

[0054] In this outer shell construction method, the unhardened outer concrete is compacted by applying rolling or vibration from the outside (top surface 3a and slope surface 3b). This removes air from the outer concrete, increasing its density and creating a smooth surface. Furthermore, this compaction ensures the structural strength.

[0055] In the construction method of the dam body 1 of this embodiment, three layers of internal concrete or internal CSG (Compressed Solid Gum) are stacked and compacted, and then three layers of external concrete 30 are stacked and compacted. Subsequently, three layers of internal concrete or internal CSG are stacked on top of these layers, and three layers of external concrete 30 are stacked. This process is repeated thereafter to complete the internal structure 2. Finally, the outer shell 3 is completed by pouring external concrete to cover the upper surface 2a of the internal structure 2, and the dam body 1 is completed.

[0056] As described above, in this embodiment, stiff concrete is used as the internal concrete for constructing the internal structure 2 and the external concrete for constructing the outer shell 3. Furthermore, in this embodiment, CSG material is used as the material for constructing the internal structure 2. As a result, there is no need to use formwork when constructing the internal structure 2 and the outer shell 3. This eliminates the need for the process of setting up and removing formwork, thus streamlining the process.

[0057] According to the above embodiments, the following effects and advantages are achieved.

[0058] In the construction method of the dam body 1 of this embodiment, stiff concrete is used as the external concrete for constructing the outer shell 3. Conventionally, so-called slump concrete was used as the concrete, so it was necessary to set up formwork when constructing the outer shell 3. In contrast, since the external concrete is stiff concrete with a slump value of 5.0 cm or less, it is not necessary to use formwork. As a result, the process of setting up and removing formwork is eliminated, thus streamlining the process.

[0059] Furthermore, the exterior concrete of this embodiment has a smaller maximum aggregate size, a larger unit cement content C, and a smaller water-cement ratio (water-binder ratio) W / C compared to interior concrete or interior CSG. As a result, the outer shell 3 constructed with the exterior concrete of this embodiment can ensure higher strength and weather resistance than the interior structure 2 constructed with interior concrete or interior CSG.

[0060] In this embodiment, an air-entraining (AE) additive is mixed into the exterior concrete. By mixing the AE additive into the exterior concrete, the durability, freeze-thaw resistance, and workability of the exterior concrete can be improved.

[0061] Furthermore, an AE water-reducing agent is mixed into the exterior concrete of this embodiment. By mixing the AE water-reducing agent into the exterior concrete, the ability to entrain air bubbles is improved, and the unit water content W and unit cement content C can be reduced.

[0062] In this embodiment, hollow beads are mixed into the exterior concrete. When hollow beads are mixed in, physically stable microbubbles can be formed in a desired manner, compared to air bubbles caused by chemical admixtures such as AE enhancers and AE dampers. In other words, when hollow beads are mixed into the exterior concrete, the size and amount of microbubbles can be controlled more precisely. This improves the reliability of the durability and freeze-thaw resistance of the exterior concrete.

[0063] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0064] Furthermore, fly ash may be mixed into the exterior concrete. In this case, for example, 30% by weight of the cement could be replaced with fly ash. By replacing a portion of the cement with fly ash cement in this way, the long-term strength of the exterior concrete can be increased, and the amount of heat generated during the concrete hydration reaction can be reduced.

[0065] The numerical range ○○ to △△ in the formulation tables in Figures 2(A) and (B) represents a range of ○○ to △△. [Explanation of symbols]

[0066] 1...Dam body, 2...Internal structure, 2a...Top surface, 2b...Slope, 2c...Slope shoulder, 3...Outer shell, 3a...Top surface, 3b...Slope, 3c...Slope shoulder, 4...Heavy machinery, 5...Construction machinery, 6...Compaction attachment device,...Internal layer, 21...First internal layer, 22...Second internal layer, 23...Third internal layer, 30...Outer layer, 31...First external layer, 32...Second external layer, 33...Third external layer

Claims

1. A method for constructing a dam body, An internal structure construction step involves laying and leveling internal concrete mixed with binder, water and aggregate, and compacting the internal concrete by applying vibration from the outside to construct the internal structure of the dam body, The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body, The aforementioned internal concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior concrete. The aggregate included in the aforementioned exterior concrete is selected according to its size, including at least coarse aggregate and fine aggregate. Methods for constructing dam bodies.

2. A method for constructing a dam body, An internal structure construction step involves laying and leveling internal concrete mixed with binder, water and aggregate, and compacting the internal concrete by applying vibration from the outside to construct the internal structure of the dam body, The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body, The aforementioned internal concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior concrete. The aggregate included in the aforementioned exterior concrete is selected according to its size, including at least coarse aggregate and fine aggregate. Methods for constructing dam bodies.

3. A method for constructing a dam body, An internal structure construction process involves spreading and leveling an internal CSG (Compressed Solid Grain) containing a binder, water, and unclassified soil, and compacting the internal CSG by applying vibration from the outside to construct the internal structure of the dam body. The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body. The aforementioned internal CSG has a unit cement content of 40 to 160 kg / m³. ３ The unit water volume is 80-140 kg / m³. ３ The maximum size of the aggregate is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior CSG. The aggregate included in the aforementioned exterior concrete is selected according to its size, including at least coarse aggregate and fine aggregate. Methods for constructing dam bodies.

4. A method for constructing a dam body, An internal structure construction process involves spreading and leveling an internal CSG (Compressed Solid Grain) containing a binder, water, and unclassified soil, and compacting the internal CSG by applying vibration from the outside to construct the internal structure of the dam body. The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body. The aforementioned internal CSG has a unit cement content of 40 to 160 kg / m³. ３ The unit water volume is 80-140 kg / m³. ３ The maximum size of the aggregate is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior CSG. The aggregate included in the aforementioned exterior concrete is selected according to its size, including at least coarse aggregate and fine aggregate. Methods for constructing dam bodies.

5. A method for constructing a dam according to any one of Claims 1 to 4, The ratio of the mass of the fine aggregate to the total mass of the coarse aggregate and the fine aggregate per unit volume contained in the external concrete is 25% or more and 45% or less. Methods for constructing dam bodies.

6. A method for constructing a dam body, An internal structure construction step involves laying and leveling internal concrete mixed with binder, water and aggregate, and compacting the internal concrete by applying vibration from the outside to construct the internal structure of the dam body, The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body, The aforementioned internal concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior concrete. The aggregate contained in the aforementioned external concrete is washed aggregate. Methods for constructing dam bodies.

7. A method for constructing a dam body, An internal structure construction step involves laying and leveling internal concrete mixed with binder, water and aggregate, and compacting the internal concrete by applying vibration from the outside to construct the internal structure of the dam body, The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body, The aforementioned internal concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior concrete. The aggregate contained in the aforementioned external concrete is washed aggregate. Methods for constructing dam bodies.

8. A method for constructing a dam body, An internal structure construction process involves spreading and leveling an internal CSG (Compressed Solid Grain) containing a binder, water, and unclassified soil, and compacting the internal CSG by applying vibration from the outside to construct the internal structure of the dam body. The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body. The aforementioned internal CSG has a unit cement content of 40 to 160 kg / m³, a unit water content of 80 to 140 kg / m³, and a maximum aggregate size of 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value of 5.0 cm or less, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior CSG. The aggregate contained in the aforementioned external concrete is washed aggregate. Methods for constructing dam bodies.

9. A method for constructing a dam body, An internal structure construction process involves spreading and leveling an internal CSG (Compressed Solid Grain) containing a binder, water, and unclassified soil, and compacting the internal CSG by applying vibration from the outside to construct the internal structure of the dam body. The process includes laying and leveling external concrete, which is a mixture containing a binder, water, and aggregate, on the outside of the internal structure, and compacting the external concrete by applying vibration from the outside to construct the outer shell of the dam body. The aforementioned internal CSG has a unit cement content of 40 to 160 kg / m³, a unit water content of 80 to 140 kg / m³, and a maximum aggregate size of 80 mm or more and 200 mm or less. The aforementioned exterior concrete is a stiff concrete with a slump value less than the specified slump value of 4.0 cm ± 1.0 cm, and the maximum aggregate size is less than 80 mm. The aforementioned exterior concrete has a larger unit cement content and a smaller water-binder ratio compared to the aforementioned interior CSG. The aggregate contained in the aforementioned external concrete is washed aggregate. Methods for constructing dam bodies.

10. A method for constructing a dam according to any one of claims 1 to 4 and claims 6 to 9, The aforementioned exterior concrete has an AE additive added to it. A method for constructing an embankment, wherein the air content of the external concrete, according to JIS A 1128 "Test method for air content of fresh concrete by pressure", is 4.0 ± 1.0 volume percent of the external concrete.

11. A method for constructing a dam according to any one of claims 1 to 4 and claims 6 to 9, The upper surface of the aforementioned exterior concrete is A first upper surface extending outward from the boundary portion with the upper surface of the compacted internal concrete or internal CSG, It has a second upper surface which is formed in continuity with the first upper surface and extends to the crest of the slope, In the aforementioned internal structure construction process, The upper surface of the internal concrete or the internal CSG, within a predetermined range from the slope crest and the slope itself, is compacted using a vibrating plate. Except for the predetermined area on the upper surface of the internal concrete or the internal CSG, compaction is performed using a vibratory roller. In the aforementioned outer shell construction process, A first compaction step involves compacting the first upper surface and a predetermined area including the boundary portion on the upper surface of the internal concrete or internal CSG using a vibratory roller so that they overlap, A method for constructing an embankment, comprising: a second compaction step of compacting the second upper surface with a vibrating plate and compacting the slope of the external concrete.

12. A method for constructing a dam according to any one of claims 1 to 4 and claims 6 to 9, The aforementioned exterior concrete has hollow beads added to it. A method for constructing an embankment, wherein the voids created by the hollow beads are 0.5% to 2.0% by volume of the external concrete.

Images