EP4116497A1 - Dam relief - Google Patents

Abstract

In a method for relieving a main dam wall (1) of a dam arrangement (13), the dam arrangement (13) comprising a main dam wall (1) for damming up a reservoir, a relief wall (5) is built downstream of the main dam wall (1), which has a lower height than the main dam (1), a relief lake (6) being formed between the main dam (1) and the relief wall (5) in such a way that resulting hydrostatic pressure forces on the main dam (1) are reduced.

Description

technical field

The invention relates to a method for relieving an existing or new dam wall by integrating it into a dam structure arrangement. The invention further relates to a dam structure arrangement comprising a main dam and a relief wall.

State of the art

The invention relates to a method for relieving a main dam wall of a dam structure arrangement. Dam structures are also known as dams, retaining walls or dams and are often, but not only, part of the dam of a hydroelectric power station.

A dam can have different construction methods such as gravity dam, arch dam and pier dam. Such designs are known to those skilled in the art.

Due to long periods of use of decades up to a hundred years, dam structures need to be renovated or even have to be replaced. A complete renovation often requires shutting down the power plant for months or even years. During this time it is not possible to produce electricity, which causes large operating losses. The emptying of the reservoirs and the resulting lack of capacity for water can cause further problems in water management in the area.

Various methods are known with which a rehabilitation of an existing dam structure can be achieved. For example, especially in the case of leaks in the Floor area concrete capsules are connected to the dam structure, the capsule being connected via a line to the interior of the reservoir in such a way that a back pressure is generated in the capsule.

In another variant, a new dam is built downstream as a replacement dam, with the old dam being flooded after the new dam is completed. Other techniques for rehabilitating or constructing new dam structures are known to those skilled in the art.

The disadvantage of the known methods for new construction and complete renovation is that they are very complex and therefore expensive.

Presentation of the invention

The object of the invention is to provide a method for relieving existing dam structures or new dam structures, which belongs to the technical field mentioned at the outset, and which can be carried out particularly cost-effectively. In particular, the method makes it possible to discharge the reservoir without emptying it.

The solution to the problem is defined by the features of claim 1. According to the invention, a discharge wall is built downstream of the main dam, which has a lower height than the main dam, wherein a discharge lake is formed between the main dam and the discharge wall such that resulting hydrostatic pressure forces on the main dam are reduced.

In the process of relieving an existing dam, a relieving wall is built downstream of the main dam, which is lower in height than the main dam. A relief lake is then formed between the relief wall and the main dam.

The invention further relates to a dam structure comprising a main dam wall, the dam structure comprising a spillway wall downstream of the main dam wall having a lower height than the main dam wall has, wherein between the main dam and the relief wall a relief lake is formed such that resulting hydrostatic pressure forces are reduced to the main dam.

The relief lake is preferably designed in such a way that the level of the water in the relief lake is within a height between the low point of the main dam wall on the reservoir side and the level of the water in the reservoir. While the water in the reservoir exerts a pressure against the main dam, this pressure is at least partially compensated by a counter-pressure in the discharge lake, so that the main dam is subjected to a lower resultant pressure. This relieves the pressure on the main dam wall. Instead of refurbishment, a main dam wall in need of refurbishment can be relieved by this structural measure. Depending on the configuration of the main dam, a reinforcement of the main dam can also be achieved. If it is a gravity dam whose cross-section decreases towards the top, a weight force can act on the main dam with the discharge lake, which strengthens the main dam or presses it downwards.

The effects of the relief wall and the relief lake can be calculated as follows:
A constant width B from bottom to top is assumed for both walls for a quantitative assessment of the relief of the main dam wall. The static pressures in each of the upper reservoir and lower relief lake increase linearly with the depth of the water.

): $$F=\bar{p}\mathit{BH}=\frac{1}{2}{\mathit{\rho gBH}}^2\left(\mathrm{N}\right)$$

The load on the main dam wall at the (theoretically) maximum filling level H of the reservoir is given by the resulting force (mean pressure $\bar{p}=\frac{1}{2}\mathit{\rho gH}$

): $$f=\bar{p}\mathit{bra}=\frac{1}{2}{\mathit{\rho gBH}}^2\left(\mathrm{N}\right)$$

The relief of the main dam depends only on the level of the relief lake. At the (theoretically) maximum filling level h, which is equal to the height of the relief wall, the relief force is calculated $$\mathit{\Delta F}=\frac{1}{2}{\mathit{\rho gBh}}^2\left(\mathrm{N}\right)$$

The resultant force acting on the main dam is reduced to $$f-\mathit{\Delta F}=\frac{1}{2}\mathit{<figure-callout\; id="2"\; label="\rho gB\; H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">\rho gB</figure-callout>}\left(H^{}\right)\left({}^2-H^2\right)\left(\mathrm{N}\right)$$

The degree of relief is then calculated $$\frac{\mathit{\Delta F}}{f}={\left(\frac{\mathrm{<figure-callout\; id="2"\; label="H\; H"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">H</figure-callout>}}{H}\right)}^2$$

For h / H = 0.5 a relief of 25% can be expected. For a dam wall that is still operational, such a relief is considerable and therefore of great importance. For h / H = 0.7, the main dam wall is relieved by about 50%. In the case of 2 with the replacement dam, the relief of the main dam is 100%.

Preferably, the relief lake has a free surface. This achieves a particularly simple design, with which the manufacturing process in particular can be kept cost-effective. In variants, the relief lake can also be closed - but care must be taken that no force-transmitting connection is formed between the relief wall and the main dam. These should be force-technically independent.

The height of the relief wall is preferably between 30% and 95% of the height of the main dam, in particular between 35% and 60%. In variants, the height can also be less than 30%.

A height of the relief wall is particularly preferably between 30% and 95% of the height of the main dam, measured from a lowest point in the terrain of the main dam, in particular from a lowest point in the terrain on the reservoir side of the main dam. In variants, the height can also be less than 30%.

The crown of the relief wall is preferably at least 5% of the height of the main dam below the crown of the main dam.

The above method is preferably used to relieve an existing main dam wall instead of renovating it. This can relieve an older, overloaded main dam wall, thus significantly increasing its service life. Depending on the condition of the main dam wall in need of rehabilitation, the main dam wall can only be partially renovated, whereby the main dam wall can also be additionally raised if necessary.

In another preferred method, both the main dam and the relief wall are rebuilt. The process is therefore also suitable for new construction projects where there was no main dam wall. This means that the main dam can be built more cost-effectively from the outset, since the load on the main dam during operation is lower. Furthermore, more than one relief wall can also be built, in particular a cascade of relief walls can theoretically be provided, with each subsequent downstream wall having a lower height than the previous one. It is irrelevant whether the main dam or the spillway wall is designed as a gravity dam, as an arch dam or as a pillar dam - the process works with any type of main dam or spillway wall.

The main dam and the spillway wall preferably each include at least one reference point, with which a change in shape of the main dam and/or the spillway wall and a displacement of the main dam and/or the spillway wall relative to one another can be monitored or regularly checked. In variants, the reference point can also be omitted.

The relief lake preferably comprises at least one intermediate floor. A swimming pool or the like can thus be formed, for example. The intermediate floor is preferably only firmly anchored on one side, for example in the main dam, so that neither tensile nor compressive forces act between the main dam and the relief wall.

The relief lake between the main dam and the relief wall can be used in many different ways. For example, the relief lake can be used as a leisure facility, in particular as a water sports facility, as a swimming pool and/or for fish farming or fishing. In other variants, the relief lake can also be used as a stilling basin. Other applications are known to those skilled in the art. On the other hand, the relief lake can also remain unused.

Further advantageous embodiments and combinations of features of the invention result from the following detailed description and the entirety of the patent claims.

Brief description of the drawings

Fig. 1

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer;

Fig. 2

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer, welche gemäss Stand der Technik durch eine Bogenstaumauer ersetzt wird;

Fig. 3

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer, eine Entlastungsmauer und den Entlastungssee;

Fig. 4

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer mit den aufgrund des Entlastungssees resultierenden Druckkräften;

Fig. 5

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer mit den aufgrund des Entlastungssees erreichten Verstärkungskräften;

Fig. 6

eine schematische Darstellung einer Frontansicht der Entlastungsmauer;

Fig. 7

eine schematische Darstellung eines Querschnitts durch eine Gewichtsstaumauer, bei welcher das Baumaterial statt für eine Entlastungsmauer zur Verstärkung der Hauptstaumauer eingesetzt ist; sowie

Fig. 8

eine schematische Darstellung gemäss Fig. 3, wobei im Entlastungssee Zwischenböden eingelegt sind und an den beiden Mauern Referenzstellen montiert sind.

The drawings used to explain the embodiment show:

1

a schematic representation of a cross section through a gravity dam;

2

a schematic representation of a cross section through a gravity dam, which is replaced according to the prior art by an arch dam;

3

a schematic representation of a cross section through a gravity dam, a discharge wall and the discharge lake;

4

a schematic representation of a cross section through a gravity dam with the pressure forces resulting from the discharge lake;

figure 5

a schematic representation of a cross-section through a gravity dam with the reinforcement forces achieved due to the overflow lake;

6

a schematic representation of a front view of the relief wall;

7

a schematic representation of a cross-section through a gravity dam, in which the building material is used instead of a relief wall to reinforce the main dam; such as

8

a schematic representation according to 3 , whereby intermediate floors are inserted in the relief lake and reference points are mounted on the two walls.

In principle, the same parts are provided with the same reference symbols in the figures.

Ways to carry out the invention

In the known 1 a gravity dam (1) is shown, which is in need of rehabilitation due to its long service life of decades to hundreds of years. Because the renovation requires the emptying of the reservoir (2) and the shutting down of the power plant for the production of electricity for months to years and will therefore cause large operating losses, after 2 a replacement dam (4) planned and built in certain cases. In this case, the replacement dam wall (4) at the same level as the main dam wall (1) completely replaces the old dam wall (1), which mostly remains and is flooded later. In the case of the dam (1) under monument protection, there would be discussions.

In the case of the main dam wall (1), which is in need of rehabilitation, the replacement dam wall (4) will incur high costs, depending on its size. The construction work will also take several years.

In order to save costs and time and, in particular, not to cause an interruption in electricity production, the existing dam wall (1), which is in need of renovation and is referred to here as the main dam wall, is simultaneously strengthened and relieved through low construction costs. Instead of building the replacement dam (4) at at least the same height as the main dam (1), a relief wall (5) of lower height is used according to 3 built. The relief wall (5) is located down the valley (downstream) from the main dam (1). The minimum distance between the relief wall (5) and the main dam (1) can be as small as you like (e.g. down to 0.1 m). The maximum distance is generally unlimited, but essentially depends on the geographic location of the valley and the construction costs.

The space between the two dams (1, 5) is filled with water, creating a relief lake (6) with an open surface to the atmosphere. The filling level of the relief lake (6) can be changed. In general, the level set remains constant. Temporal or continuous inflow and outflow from the spillway lake (6) in certain quantities are permitted for specific purpose.

The main dam (1), the spillway wall (5) and the spillway lake (6) form a dam arrangement (13, 14) with a spillway effect. The main dam (1) can be a gravity dam, an arch dam and a wall with other designs. In particular, the main dam (1) can be a new development.

The level of the discharge lake (6) determines the degree of discharge of the main dam (1) (see above). The hydrostatic pressure forces (7) in the discharge lake (6) are set against the pressure forces (3) on the main dam wall (1) in the corresponding area. This reduces the overall compressive forces (8) in the main dam (1), see 4 . This is most effective, since with a dam wall (1) the greatest load is always in the lower part of the wall.

The water in the relief lake (6) also ensures that the gravity dam (1) under consideration is additionally strengthened by an additional mass of water (9) pressing the wall down ( figure 5 ). Both the strengthening and the relief of the main dam (1) depend on the level of the relief lake (6). The reinforcement of a gravity dam (1), for example, is done by additional mass (9) of the water figure 5 . This also depends on the inclination of the outer wall of the dam (1).

For a dam wall that is still operational, a relief of e.g. B. 20%-30% (degree of relief) is expected to be considerable and therefore of great importance. Even a complete renovation of the old dam wall (1) would not or only with difficulty achieve a comparable result.

The reinforcement and relief of the main dam wall (1) achieved by the relief wall (5) and the water-filled relief lake (6) only depend on the fill level of the relief lake (6). They are of the amount of water in the relief lake (6) and therefore independent of the distance between the two walls (1, 5). In theory, the relief wall (5) can be built as close to the main dam (1) as you like, as long as the two walls are separated from the water in the relief lake (6).

Since the relief wall (5) is relatively low, it is only subjected to relatively little stress from the water in the relief lake (6), so that the dam wall thickness can be kept small ( Figures 3 and 4 ). Because of the additionally small width of the valley ( 6 ) in the lower area of the valley, a lot of building materials (stones, concrete) can be saved overall. The construction volume of the relief wall (5), depending on the height of the relief wall (5), z. B. be reduced to 1/2 to 1/8 of the construction volume of the replacement dam (4),

It should be noted that the reinforcement and relief of the main dam (1) achieved by the spillway dam (5) and spillway (6) are much greater than the effect of simply adding building materials (5a) to an existing gravity dam ( 7 ). The case in 7 corresponds to a type of mechanical support or reinforcement instead of hydraulic relief of the main dam (1).

In the case of an old dam wall that has been classified as "worth preserving" by the monument preservation authorities, the dam wall remains visible and thus enjoys a certain monument protection.

In the case of a new development of the main dam (1) in all possible construction methods (gravity dam, arch dams, etc.), the dam (1) can be built correspondingly thin if the relief wall (5) is also built. The overall building materials decrease accordingly. The construction of the relief wall (5) based on the latest technology also creates a feeling of increased security among the population.

The free surface relief lake (6) can be made into a recreational facility such as a free swimming pool. To ensure security, an intermediate floor (10) z. B. be laid out of plates ( 8 ).

For the production of electricity, the water is still to be drawn from the upper reservoir (2). In the case of the old dam wall (1), which is in need of rehabilitation, the previous one remains received piping system. The water in the lower relief lake (6) is typically not used for electricity production.

The importance of the relief lake (6) in connection with the relief wall (5) lies in the fact that a relief degree of e.g. 25% to 90% (see above) can be achieved.

In special variants, a dam arrangement (13) consists of a main dam (1), a relief wall (5) and a relief lake (6) with an open surface, the main dam (1) often being an old wall and therefore in need of renovation.

More preferably, the spillway wall (5) is installed at low height, any shape and thickness (wall thickness) downstream of the main dam wall (1), including dam wall, dam and dam.

The height of the relief wall (5) is preferably 30% to a maximum of 95% of the height of the main dam (1), both walls being measured from the same altitude (12) of the lowest point in the terrain of the main dam (1) ( 3 ).

The crest (upper edge) of the spillway wall is preferably at least 5% below the crest of the main dam wall (1) from the height of the main dam wall (1).

The discharge lake (6) preferably has a free surface, the free space between the main dam (1) and the discharge wall (5) being completely or partially filled with water.

In the process of strengthening and relieving the main dam wall (1), the hydrostatic pressure forces in the discharge lake (6) counteract those in the reservoir (2).

The relief lake (6) is preferably used in whole or in part for special applications such as leisure facilities, swimming pools, water sports, fish farming and fishing, and as a water source for other experiments with specific objectives.

One or more intermediate floors (10) are preferably built in the relief lake (6).

Several reference points (11) are preferably attached to the main dam wall (1) and the relief wall (5) in a dam structure arrangement (14) in order to regularly check the deformation of and relative displacements between the two walls.

As part of the dam structure arrangement (13) and method for relieving the main dam (1), the spillway wall (5) and the spillway lake (6) are preferably also used when the main dam (1) is new or is being built.

In summary, it can be stated that, according to the invention, a method for relieving existing dam walls is created in which emptying of the reservoir can be avoided and at the same time construction volume (stones and concrete) can be saved.

Claims (9)

Method for relieving a main dam wall (1) of a dam arrangement (14), the dam arrangement (14) comprising a main dam wall (1) for damming up a reservoir and a spillway wall (5), characterized in that downstream of the main dam wall (1) a spillway wall ( 5) is built, which has a lower height than the main dam (1), wherein a relief lake (6) is formed between the main dam (1) and the relief wall (5) in such a way that resulting hydrostatic pressure forces on the main dam (1) are reduced will. Method according to Claim 1, characterized in that the relief lake (6) has a free surface. Method according to Claim 1 or 2, characterized in that the structural height of the relief wall (5) is between 30% and 95% of the structural height of the main dam (1). Method according to one of Claims 1 to 3, characterized in that the crown of the relief wall (5) is at least 5% of the building height of the main dam (1) below the crown of the main dam (1) and a water level in the relief lake (6) is around at least 5% of the building height of the main dam (1) below a water level of the reservoir (2). Use of the method according to one of Claims 1 to 4 for relieving an existing main dam wall (1) in need of rehabilitation instead of its complete rehabilitation. Dam structure arrangement comprising a main dam wall (1), characterized in that downstream of the main dam wall (1), the dam structure arrangement comprises a relief wall (5) which has a lower height than the main dam wall (1), wherein between the main dam wall (1) and the Relief wall (5) a relief lake (6) is formed such that resulting hydrostatic pressure forces on the main dam (1) are reduced. Storage structure arrangement according to Claim 6, characterized in that the main dam wall (1) which is in need of renovation can be partially renovated, with the main dam wall (1) also being able to be additionally raised if required. Storage structure arrangement according to Claim 6 or 7, characterized in that the main dam (1) and the discharge wall (5) each comprise at least one reference point, with which a change in shape of the main dam (1) and/or the discharge wall (5) and a displacement of the main dam ( 1) and/or the relief wall (5) can be monitored relative to one another. Dam structure arrangement according to Claim 6 or 7, characterized in that the relief lake (6) comprises at least one intermediate floor.

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