JPH09158158A - Filling type concrete dam and construction method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To save the consumption of cement in the construction of a dam body. SOLUTION: A dam body D comprises a rock placed concrete area 1 cast on a foundation bedrock G, a large-sized mass of rock 21 and a core concrete area 2 comprising concrete or mortar 22 filled in a clearance between each mass of rock 21 and outside concrete areas 3 and 4 having a specified thickness, which are provided on a surface layer on the upstream side and the downstream side of this concrete area and whose lower end is joined with the upstream side of the placed rock concrete 1 and the top on the end on the downstream side.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dam construction technique.

[0002]

2. Description of the Related Art Conventionally, in concrete gravity dams, concrete transported in concrete buckets is driven by a cable bucket or jig crane into a columnar block and compacted by an internal vibrator to construct a dam body. Type dam, or a super-hard concrete containing poor mix, and then transporting it with a dump truck, etc., laying it with a bulldozer and leveling it, and creating joints with a vibrating joint cutting machine. There is an RCD dam that is constructed by compacting with rollers.

[0003]

However, in the construction of the concrete dam by the above-mentioned conventional construction method,
A large amount of cement is required because a levee body is constructed by placing concrete in which cement is mixed into aggregates, and moreover, a large amount of cement is required. It is pointed out that there is a large amount of work. In addition, when a large amount of concrete is poured, the amount of heat generated due to the hydration reaction at the time of hardening thereof becomes large, so that there is no choice but to limit the setting amount per time, and there is a problem that the construction period becomes long.

The present invention has been made under the above circumstances, and its technical problem is to reduce the amount of cement used in the construction of a dam and to reduce the work amount. It is to shorten the construction period.

[0005]

The above-mentioned technical problems are as follows.
This can be effectively solved by the present invention. That is, the filling concrete dam according to the present invention includes a core concrete region composed of a group of rocks piled up at a predetermined height and a filling concrete filled in a gap of the group of rocks, and an upstream side of the core concrete region. And an external concrete region made of watertight concrete provided on the surface layer on the downstream side. This space-filling type concrete dam assembles a formwork on the upstream end and the downstream end of the dam body construction area, respectively, and places concrete to form the upstream and downstream external concrete areas. It is constructed by repeating the steps of constructing, injecting a rock mass between these two outer concrete regions, filling the gap between the rock masses with mortar or concrete, and constructing the core concrete region.

In the present invention, the core concrete region stabilizes the dam embankment by its strength and weight. However, since it has a structure in which concrete or mortar is packed in the gaps of the rock masses piled up, the rock mass mutual Sufficient strength is obtained by combining the bite strength of No. 3 and the interlocking force between the rock masses of the stuffed concrete or mortar, and a sufficient weight is obtained by the stuffing. In addition, the use of rock masses significantly reduces the amount of cement used compared to concrete gravity dams, eliminating the work such as leveling and vibration compaction of concrete when placing concrete. The outer concrete area provided on the surface layer on the upstream side and the downstream side of the core concrete area is made of concrete with high watertightness and durability, and is located on both sides of the rock masses piled up during the construction of the core concrete. It has a function as a guide and a weir that prevents the uncured concrete or mortar injected into the gaps of the rock mass from flowing out, and also functions as an impermeable wall against water storage after construction. To do.

Rock fill dams are generally known as dams constructed using rock masses. The rockfill dam is provided with rock regions composed of rock masses on the upstream side and the downstream side of a core region made of a soil material such as cohesive soil having low water permeability through a filter region for preventing the outflow of the core material. The lock area in this case is
Although the whole dam dam body is stabilized by the mutual engagement of the stacked rock masses, the core concrete region in the filling concrete dam of the present invention is such that the stacked rock masses are interlocked with each other and The dam embankment is stabilized by the bonding force and weight of the filling concrete that fills the gap between the dams. Therefore, the cross section of the dam body can be made smaller than that of the rockfill dam, but it is necessary to secure a sufficient space suitable for accumulating large-sized rock masses transported by a large dump truck. It is desirable to make the cross section of the dam body larger than that of the concrete gravity dam. That is, the present invention prioritizes improvement of workability and reduction of construction cost by a large-scale civil engineering machine rather than reduction of bank volume.

[0008]

1 is a cross-sectional view showing a preferred embodiment of a filling concrete dam according to the present invention, in which the left side is the upstream side where water is stored and the right side is the downstream side. The dam levee body generally indicated by the reference symbol D extends on the foundation bedrock G so as to cross in a direction orthogonal to the illustrated cross section that crosses between the upstream side and the downstream side, and the upstream and downstream surfaces. Are formed in a predetermined stable gradient. This dam embankment D is composed of a landing concrete region 1 cast on a foundation bedrock G, a group of large-sized rock masses 21 and concrete or mortar 22 packed in the gaps between the rock masses 21. Core concrete area 2 and an outer concrete of a predetermined layer thickness, the lower end of which is provided on the surface layer on the upstream side and the downstream side of the core concrete area 2 and the lower end of which is joined to the upper surface of the end portion of the rock concrete 1 on the upstream side and the downstream side. It is composed of regions 3 and 4.

The rock-bearing concrete region 1 corresponding to the lower end of the dam body D receives the entire load of the region constructed on it and is required to have sufficient watertightness. Constructed of concrete, it is semi-buried at an appropriate depth of the foundation bedrock G. This prevents horizontal displacement of the dam bank D due to the stored water pressure and leakage of the stored water W downstream along the boundary with the foundation bedrock G. Since the core concrete region 2 maintains the stability of the entire dam embankment D, the large-sized rock mass 21 used here has a biting strength of the rock masses 21 in the stacked state. Fresh, robust, and rock-strength that is not weathered and has sufficient strength is selected so that it can be fully exerted, and the filling consort or mortar 22 completely fills the gaps between the stacked blocks 21. A material having sufficient fluidity necessary to be worked and strength sufficient to consolidate the rock masses 21 is selected. Since the outer concrete regions 3 and 4 are required to have sufficient strength and watertightness, they are formed by pouring the rich mixed concrete as in the landing concrete region 1.

The construction method of the present invention will be described below with reference to the dam body D
The embodiment applied to the construction will be described in the order of steps with reference to FIG.

First, as shown in FIG. 2 (A), the surface layer portion of the foundation rock mass G at the site where the dam is to be constructed is root-cut to an appropriate depth to level the ground, and then the root extending in a direction orthogonal to the cross section shown in the figure. By placing concrete with a rich mixture in the cut part,
The rock-bearing concrete area 1 having the required layer thickness is constructed.

When the concrete in the rock landing concrete area 1 is hardened, as shown in FIG. 2B, the molds 5 and 6 are assembled along the upstream and downstream ends of the rock landing concrete area 1. . These formwork 5 and 6 are outer formwork 51 and 61 in which the lower ends of the weir plates 51a and 61a are in contact with the edges of the concrete of the rock landing concrete area 1, and the weir plates 52a, which are assembled on the concrete. 62a is composed of the barrier plates 51a, 61a of the outer molds 51, 61 and the inner molds 52, 62 facing each other. The formwork 5, 6 has a height Δh corresponding to the construction height of the first layer.
And the weir plates 51a, 52a and 61a, 62
The angle a is inwardly inclined at a predetermined angle corresponding to the slope of both side surfaces of the dam body D to be constructed.

After the molds 5 and 6 are assembled, as shown in FIG. 2C, the placing space defined by the weir plates 51a and 52a and the placing space defined by the weir plates 61a and 62a. First, the concrete with a rich mixture is sprinkled out and compacted by a vibrator or the like to form the outer concrete regions 3 ₁ and 4 ₁ of the first layer on the upstream side and the downstream side.

When a suitable hardness is developed in the concrete of the outer concrete regions 3 ₁ , 4 ₁ over a predetermined time, the molds 5, 6 are removed and sandwiched by the outer concrete regions 3 ₁ , 4 ₁ . In the core forming space,
As shown in (D), a large-sized rock mass 21 group carried in by a large-sized dump truck or the like is thrown in so that the rock masses 11 bite each other, and the outer concrete region of the first layer. The space is piled up in the space at a height almost equal to the upper ends of 3 ₁ and 4 ₁ . At this time, the external concrete area 3
₁ and 4 ₁ play a role of pressing and guiding the stacked rock masses 21 from both sides.

When the group of rock masses 21 has been piled up in the core forming space, high fluidity concrete is formed in the mutually continuous gaps formed between the rock masses 21 as shown in FIG. 2 (E). Alternatively, mortar 22 is injected to fill the space.
This concrete or mortar 22 is carried by a large dump truck or a crane and a concrete bucket, injected from above the rock mass 21 group, and filled in the gap, so that it is compacted by an internal vibrator or by a bulldozer or the like. Since it is not necessary to perform work such as spreading and leveling, both sides of the rock mass 21 group are dammed by the external concrete areas 3 ₁ and 4 ₁ , so that the outflow of the packed concrete or mortar 22 is reliably prevented. It The packed concrete or mortar 22 hardens with the passage of time to consolidate the rock masses 21 and develops a large toughness, whereby the outer concrete regions 3 ₁ and 4 _{1 of} the first layer are formed. The joined first-layer core concrete region 2 ₁ is formed.

The grain size of the rock mass 21 is not particularly limited, but the use of a grain size having a relatively large grain size reduces the injection resistance of the concrete or the mortar 22, so that the rock mass can be reliably packed. It is possible to use, for example, a coarse-grained rock mass generated by cutting the ground or cutting the foundation bedrock G, etc., without using a refining step such as crushing.

Since most of the volume of the core concrete region 2 ₁ thus constructed is occupied by the rock mass 21,
The amount of concrete or mortar 22 used, that is, the amount of cement used, is significantly smaller than that of the concrete gravity dam. For this reason, the amount of heat generated by the hydration reaction during hardening of the concrete or mortar 22 is small, and a large section can be constructed in one step.

When the first layer is constructed by the series of steps described above, the construction is shifted to the upper stage and the steps from FIG. 2B are executed again. That is, as shown in FIG. 3 (A), first, the first outer concrete region 3 ₁ ,
4 ₁ along the opposite side edges of the upper surface Figure 2 (B) and the same mold 5 ', 6' assembled, by pouring concrete into this, the first layer of the external concrete area 3
_1, 4 ₁ second layer outer concrete area 3 continuous with
₂ and 4 ₂ were constructed, then this external concrete area 3
_As shown in FIGS. 3 (B) and 3 (C), a group of rock masses 21 are piled up in the core forming space sandwiched between ₂ and 4 ₂ and concrete or mortar 22 is packed in the gap, whereby the second layer is formed. Construction of eye core concrete area 2 ₂ . Hereinafter, by repeating such a process n times and constructing up to the n-th layer, the construction of the dike D of the filling concrete dam of height h as shown in FIG. 1 is completed.

[0019]

According to the present invention, the following effects are realized. (1) The core concrete area is constructed by filling the gaps of the rock mass with concrete or mortar,
Since the amount of cement used is greatly reduced, the construction cost can be reduced, and the heat generation amount of concrete, which is a problem in the construction of a normal concrete gravity dam, can be reduced. (2) In the construction of the core concrete area, it is possible to reduce the amount of work and save labor, because the work of placing a large amount of concrete, spreading and leveling, and vibration compaction is unnecessary. (3) Sufficient strength of the core concrete area is obtained by the biting strength of the stacked rock masses and the binding force of the rock masses by the packed concrete or mortar.
Moreover, since sufficient weight can be obtained by the space filling, a large levee cross-sectional area such as that of the rockfill dam is not required. (4) There is no limitation on the particle size of the rock mass used, and as long as it is a rocky material with a certain strength, it can be used as it is with a large particle size, so the rock mass can be procured at low cost. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a preferred embodiment of a filling concrete dam according to the present invention.

FIG. 2 is an explanatory view showing a step of constructing a first layer of the filling concrete dam in the order of steps.

FIG. 3 is an explanatory diagram showing a step of constructing a second layer of the filling concrete dam in the order of steps.

[Explanation of symbols]

 1 Landed concrete area 2 Core concrete area 21 Rock mass 22 Filled concrete or mortar 3,4 External concrete area

Claims (2)

[Claims] 1. A core concrete region composed of a group of rocks piled up to a predetermined height and a filling concrete filled in a gap of the group of rocks, and a surface layer on the upstream and downstream sides of the core concrete region. An outer concrete area made of watertight concrete, and a filling concrete dam. 2. The upstream and downstream external concrete areas are constructed by assembling a formwork and placing concrete on the upstream end and the downstream end of the dam embankment construction area, respectively. The required height can be obtained by alternately repeating the steps and the step of constructing the core concrete area by putting rock mass between these two outer concrete areas and filling the space between the rock masses with mortar or concrete. The method for constructing a filling type concrete dam according to claim 1, wherein the dam dam body is constructed.