WO2019197402A1

WO2019197402A1 - Water-dam-wall support-structure for a dam and method for upgrading and/or repairing a dam including stoppage of water leakages

Info

Publication number: WO2019197402A1
Application number: PCT/EP2019/058953
Authority: WO
Inventors: Niko Kleuters
Original assignee: Nk Trading And Engineering Gmbh
Priority date: 2018-04-09
Filing date: 2019-04-09
Publication date: 2019-10-17
Also published as: CN111936704A; EP3762549A1; BR112020019220A2

Abstract

A method for upgrading and/or repairing a dam (1, 30), the dam (1, 30) being provided for damming a reservoir of water (2) and having a dam wall (3) the bottom (4) thereof being founded on a ground (5); whereby said method comprises the following steps: Formation of a support structure (6) on a side (7) of the dam wall (3) facing away from the reservoir of water (2); whereby the support structure (6) defines at least one pressure-tight space (8) being bounded by the dam wall (3); Applying pressure above atmospheric pressure to the pressure-tight space (8), so that the penetration of water into the pressure-tight space (8) through the dam wall (3) is at least minimized. At complete pressure- balance the water-leakages are being stopped. Furthermore, a dam (1, 30) for damming a reservoir of water (2), comprising: a dam wall (3), the bottom (4) thereof being founded on a ground (5); and a support structure (6) being arranged on a side (7) of the dam wall (3) facing away from the reservoir of water (2); whereby the support structure (2) is configured to define at least one pressure-tight space (8) being bounded by the dam wall (3), and wherein pressure above atmospheric pressure is applied to the pressure-tight space (8), so that the penetration of water into the pressure-tight space (8) through the dam wall (3) is minimized, preferably stopped. Any pressure above atmospheric pressure in the pressure-tight space (8) will result in hydraulic support/reduction of forces of the dam-wall (3). The support structure (6) further provides mechanical support and can be combined with a spill-water run-off chute (33) which prevents the near dam downstream river-bed from being eroded in form e.g. of a deep "Plunge-Pool" which may cause structural damage to the dam-wall (3).

Description

Water-Dam-Wall Support-Structure for a dam and method for upgrading and/or repairing a dam including stoppage of water leakages

The present invention relates in general to a dam for damming a reservoir of water. More in particular, the present invention relates to a method for upgrading and/or repairing and/or supporting existing dam walls using a support structure, and to a dam having a support structure.

Dam walls which are subject to fatigue etc. and/or which suffer from erosion from water leakages through the foundation of the dam wail etc. pose a risk of a potential collapse of the dam wall. Eliminating the risk of an eroded/vulnerable etc. dam-structure for damage to people and assets by a respective failure of a dam-wall may result in:

- Need to reduce water-level in dam resulting in reduced water storage capacity.

- If the reservoir of water is used to drive turbines for electrical power generation, reduced hydro-power generation capacity due to reduced water-level.

- Reduced power generation in order to reduce vibrations from turbines etc. which may affect stability of a vulnerable dam-wall.

The present invention has the objective to overcome the afore-mentioned disadvantages, such as e.g. reducing the water level in the reservoir of water being dammed by a dam wall which is subject to fatigue etc. and/or which suffers from erosion from water leakages through a foundation of the dam wall, reducing power generation in order to reduce vibrations from turbines etc. and avoid even complete shut-down of hydro-power-generation.

Furthermore, the present invention has the objective to reliably eliminate the risk of potential collapse of a dam wall being subject to fatigue etc. and/or which suffers from erosion from water leakages through a foundation of the dam wall. These objectives are achieved by a method for the upgrading and/or repairing a dam having the features of claim 1, and by a dam for damming a reservoir of water having the features of claim 18.

Further, particularly advantageous embodiments of the invention are disclosed in the respective dependent claims.

It should be noted that the individual features listed in the description below can be combined in any technically meaningful way with each other and show further embodiments of the invention. The description of the invention is additionally characterized and specified particularly in connection with the accompanying figures.

In an advantageous embodiment, the present invention discloses a method for upgrading and/or repairing a dam, the dam being provided for damming a reservoir of water and having a dam wall the bottom thereof being founded on a ground; whereby said method comprises the following steps: Formation of a support structure on a side of the dam wall facing away from the reservoir of water; whereby the support structure defines at least one pressure-tight space being bounded by the dam wall; Applying pressure above atmospheric pressure to the pressure-tight space, so that the penetration of water into the pressure-tight space through the dam wall/dam foundation is at least minimized. At complete pressure-balance the water-leakages are being stopped.

According to a further aspect of the present invention, an advantageous embodiment discloses a dam for damming a reservoir of water comprising: a dam wall, the bottom thereof being founded on a ground; and a support structure being arranged on a side of the dam wall facing away from the reservoir of water; whereby the support structure is configured to define at least one pressure-tight space being bounded by the dam wall, and wherein pressure above atmospheric pressure is applied to the pressure-tight space, so that the penetration of water into the pressure-tight space through the dam wall is minimized, preferably stopped. Any pressure above atmospheric pressure in the pressure-tight space will result in hydraulic support/reduction of forces of the dam-wall. The present invention basically proposes a new structure which is being constructed in very short distance downstream of the dam-wall.

The invention does not require any structural changes on the existing dam wall to be executed.

According to an embodiment, the new support structure will preferably be made of reinforced concrete.

The new support structure is based on a "state of the art" new foundation which will not allow for water-leakages through or underneath the foundation.

The support structure reaches upwards from the foundation and closes towards the existing dam wall structure, thus forming a chamber between the existing dam wall, the new support structure and the ground, the so called "Pressure Chamber" or "pressure-tight space".

According to a further embodiment, the "Pressure Chamber'Ypressure-tight space along the dam-wall can be divided in a number of separate, shorter " Press u re - Chambers'Ypressure-tight spaces (hereinafter also called "sectional pressure chambers" or "sectional pressure-tight spaces") which can be sealed off against each other.

Further features and advantages of the present invention will become apparent from the following description of non-limiting embodiments of the invention which will be explained below with reference to the drawing, wherein :

FIG. 1 shows a sectional side view of an exemplary embodiment of a dam according to the invention.

FIG. 2 shows a detailed view of the dam designated with "X" in FIG. 1.

FIG. 3 shows the dam of FIG. 1 in a further sectional side view.

FIG. 4 shows the dam of FIG. 1 in still another sectional side view. FIG. 5 shows a perspective view of an exemplary dam being subject to fatigue and/or suffering from erosion from water leakages through the foundation of a dam wall.

FIG. 6 shows a top view of the dam of FIG. 5.

FIG. 7 shows a sectional side view of a further exemplary embodiment of a dam according to the invention.

FIG. 8 shows a sectional partial side view of yet a further exemplary embodiment of a dam according to the invention.

In the various figures, equivalent elements with respect to their function are always provided with the same reference numerals so that these elements are usually described only once.

In the following description of an exemplary embodiment of the invention, reference will be made to FIGs. 1, 2, 3, and 4.

On its left-hand side, FIG. 1 shows a sectional side view of an exemplary embodiment of a dam 1 according to the invention. On the right-hand side of FIG. 1 a more detailed view of a section indicated with "X" inside a dotted circle on the left-hand side view of FIG. 1 is shown. FIG. 2 shows a detailed view of the dam designated with "X" in FIG. 1, FIG. 3 shows the dam of FIG. 1 in a further sectional side view, and FIG. 4 shows the dam of FIG. 1 in still another sectional side view.

As is clearly shown in FIG. 1, the dam 1 dams a reservoir of water 2 and comprises: a dam wall 3, the bottom 4 thereof being founded on a ground 5; and a support structure 6 being arranged on a side 7 of the dam wall 3 facing away from the reservoir of water 2; whereby the support structure 2 is configured to define a pressure-tight space 8 (herein also named as a "pressure chamber") being bounded by the dam wall 3, and wherein pressure above atmospheric pressure is applied to the pressure-tight space 8, so that the penetration of water into the pressure-tight space 8 through the dam wall 3 is minimized, preferably stopped. Any pressure above atmospheric pressure in the pressure-tight space 8 wii! result in hydraulic support/reduction of forces of the dam-wall 3.

Furthermore, FIG. 1 shows the support structure 6 comprising a foundation 10 extending on the ground 5 and along the bottom 4 of the dam wall 3 and defining the pressure-tight space 8 such that the pressure-tight space 8 is further bounded by the soil 11 at the ground 5 adjacent to the bottom 4 of the dam wall 3, in order to at least minimize the penetration of water from the soil 11 into the pressure- tight space 8, while there is pressure applied to the pressure-tight space 8.

Moreover, the exemplary dam 1 shown in FIG. 1 comprises at least one pressure balancing pipe 12 for establishing a fluid-conducting and pressure-tight connection between the water reservoir 2 and the pressure-tight space 8 in order to flood the pressure-tight space 8 with water from the reservoir of water 2 and to apply water pressure from the water reservoir 2 to the water in the pressure-tight space 8 as pressure and to balance the pressure with a hydrostatic pressure resulting from a water level 9 of the reservoir of water (2).

Furthermore, FIG. 1 shows a valve 13 (also shut-off valve) for selectively applying pressure to the pressure-tight space 8 and/or release pressure from the pressure- tight space 8. The valve 13 is arranged in the pressure balancing pipe 12.

As can be seen for example in FIG. 2, the pressure balancing pipe 12 comprises an inlet 14 for entering of water on the side of the reservoir of water 2, while the inlet 14 is arranged below the water level 9 of the reservoir of water 2.

The inlet 14 can be arranged below an imaginary line that is parallel to the top of the dam wall 3 at half height of the dam wall 3. Additionally, or alternatively, the inlet 14 can be arranged below a predetermined minimum water level of the reservoir of water 2.

In the embodiment of the present invention shown in the present figures, the support structure 6 is at least partially made of concrete, preferably reinforced concrete. As is further shown in FIGs. 1-4, according to the illustrated exemplary embodiment, sealing means 16, 17, 18, 19, and 20 are provided between the support structure 6 and the dam wall 3. The sealing means can be a sealing surface 16, exchangeable seals 17, a seal chamber 19 having arranged thereon a seal chamber cover 18, and a chamber 20 for a sealant.

A force-locking connection and/or form-fitting connection can be provided between the support structure 6 and the dam wall 3.

Additionally, as can be seen for example in FIG. 4, the foundation 10 of the support structure 6 can be arranged deeper than the dam bottom 4.

Preferably, the foundation 10 of the support structure 6 can be seated on solid ground. Furthermore, the foundation 10 of the support structure 6 can comprise means for providing a watertight sealing within the ground 5.

According to yet another exemplary embodiment of a dam 30 according to the present invention, a sectional partial side view of which is shown in FIG. 8, the support structure 6 comprises one or more injection pipes 15 running from outside the support structure 6 through the body 23 of the support structure 6 aside or through the pressure chamber 8 into the foundation 4 (not visible in FIG. 8) of the dam wall 3.

Preferably, the injection pipes 15 facilitate the injection of media into the foundation 4 of the dam wall 3 for consolidation purposes and/or stoppage of leakages while counter-pressure is applied in the pressure-chamber 8 or, if the pressure-chamber 8 is divided in a number of separate pressure-chambers 8 (not shown), in each of the multiple pressure-chambers 8. To this end, the pipes 15 are solidly anchored and sealed in the foundation and serve to inject media deeper into the foundation 4 of the dam wall 3 for consolidation purposes and/or for sealing off water-leakages. This way of consolidation and/or sealing is of high efficiency as any disturbing water flow though leakage holes, cracks etc. is stopped or at least essentially reduced by means of the created/applied counter-pressure in the pressure chamber 8. Due to the provision of the above-mentioned injection pipe(s) 15, any application of consolidation of the dam wall foundation 4 and/or closure of leakages can be executed through these pipes 15 with the pressure chamber 8 being filled with water.

Furthermore, such injection pipe(s) 15 can be installed/pre-installed from inside the pressure chamber 8 into the dam wall foundation 4. Thus, foundation consolidation work can be executed from inside the pressure chamber 8 (man- entry) either under atmospheric pressure or increased air-pressure. Man-entry into the pressure chamber 8 can be executed under pressure if so required.

A method for upgrading and/or repairing the dam 1 or 30 according to the present invention, wherein the dam 1, 30 is provided for damming the reservoir of water 2 and comprises the dam wall 3 the bottom 4 thereof is founded on the ground 5, comprises the following steps: Formation of the support structure 6 on the side 7 of the dam wall 3 facing away from the reservoir of water 2, whereby the support structure 6 defines the pressure-tight space 8 being bounded by the dam wall 3; and applying pressure above atmospheric pressure to the pressure-tight space 8, so that the penetration of water into the pressure-tight space 8 through the dam wall 3 is at least minimized or even entirely stopped. At complete pressure-balance the water- leakages are being stopped.

Applying the overpressure to the pressure-tight space 8 is preferably carried out while the dam 1 is damming a reservoir of water 2, i.e. while the reservoir of water 2 is at least partially filled with water.

The pressure is selected such to stop leakage of water into the pressure-tight space 8. Preferably, the pressure is related to a hydrostatic pressure resulting from the water level 9 of the reservoir of water 2 creating a pressure-balance with the consequential stoppage of damaging leakage water flow, thus allowing for efficient, higher quality permanent sealing-off of water-leakages. Furthermore, the pressure can be related to the hydrostatic pressure being present at a position below the water level 9 of the reservoir of water 2, which corresponds in height to the position of the pressure-tight space 8. Preferable, the support structure 6 comprises a foundation 10 extending on the ground 5 and a!ong the bottom 4 of the dam wall 3 defining the pressure-tight space 8 such that the pressure-tight space 8 is further bounded by the soil 11 at the ground 5 adjacent to the bottom 4 of the dam wall 3, in order to at least minimize the penetration of water from the soil 11 into the pressure-tight space 8, while there is pressure applied to the pressure-tight space 8,

A fluid-conducting and pressure-tight connection 12, in particular the pressure balancing pipe 12 between the water reservoir 2 and the pressure-tight space 8 can be provided, in order to flood the pressure-tight space 8 with water from the reservoir of water 2 and to apply water pressure from the water reservoir 2 to the water in the pressure-tight space 8 as pressure and to balance the pressure with a hydrostatic pressure resulting from the water level 9 of the reservoir of water 2,

The fluid-conducting and pressure-tight connection 12 can further comprise at least one valve 13 for selectively applying pressure to the pressure-tight space 8 and/or release pressure from the pressure-tight space 8.

Moreover, the fluid-conducting and pressure-tight connection 12 can comprise at least one inlet 14 for entering of water on the side of the reservoir of water 8, while the inlet 14 is arranged below the water level 9 of the reservoir of water 2.

The inlet 14 can be arranged below an imaginary line being parallel to the top of the dam wall 3 at half height of the dam wall 3. Additionally, or alternatively, the inlet 14 can be arranged below a predetermined minimum water-level of the reservoir of water 2.

Preferably, the support structure 6 is at least partially made of concrete, preferably reinforced concrete.

Moreover, the sealing means 16, 17, 18, 19, 20 mentioned above can be provided between the support structure 6 and the dam wall 3.

A force-locking connection and/or form -fitting connection can be provided between the support structure 6 and the dam wall 3. According to yet another preferred embodiment of the invention, the foundation 10 of the support structure 6 can be arranged deeper than the bottom 4 of the dam wall 3.

Furthermore, the foundation 10 of the support structure 6 can be seated on solid ground 5.

Still further, the foundation 10 of the support structure 6 can comprise means for providing a watertight sealing within the ground 5.

FIG. 5 shows a perspective view of an exemplary dam 31 being subject to fatigue and/or suffering from erosion from water leakages through the foundation of a dam wall 3. In particular, part (a) of FIG. 5 shows a photographic view of the dam 31 and part (b) of FIG. 5 shows an outline view of part (a).

FIG. 6 shows a top view of the dam 31 of FIG. 5. Again, part (a) of FIG. 6 is a photographic illustration of the dam 31, whereas part (b) is an outline view of part (a). In FIG. 6 it is schematically shown where the support structure 6 (hatched area) can be arranged close to the dam wall 3 on the side 7 facing away from the reservoir of water 2.

It is to be understood, that the layout and/or size of the "Pressure Chamber" 8 can be such, that man-entry is possible for purpose of inspection, injection drilling and/or leakage repair etc. The "Pressure-Chamber" can be divided in separate smaller "Pressure-Chambers" with same function.

The height of the support-structure 6 shall be determined in accordance with the specifically calculated support requirements.

The pressure chamber 8 is sealed-off to the dam wall 3 by a multi-purpose sealing system/arrangement which is preferably made up by multiple seals. Also, the seals can be of inflatable design. The chamber 8 is connected to the water in the water reservoir 2 on the up-stream dam-wall side by means of a communicating pipe 12 (pressure balance pipe 12).

The new "Support- Structure" 6 shall be designed to and its structural weight shall be sufficient to withstand the created pressure-forces created from inside the "Pressure-Chamber" 8 and to provide sufficient resistance to additionally provide mechanical support to the dam wall 3 if so required.

Any resulting forces from the pressure in the pressure chamber 8 and/or by mechanical support are being transferred into the foundation 10 of the support structure 6.

The water pressure in the "Pressure Chamber" 8 neutralizes the forces deriving from the water pressure on the water reservoir side of the dam wall 3 according to the sealed off wall area in the pressure chamber 8. As a result, any water- leakage comes to a stand-still. Moreover, the optional division of the "Pressure- Chamber" 8 in separate smaller "Pressure-Chambers" 8 would allow for sectional treatment/repair of the dam-wall 3 and/or the wall foundation 4; this way the uplift force created by the water-pressure under the dam-wall 3 can be controlled and kept in acceptable ranges.

In still a further advantageous embodiment, which is illustrated in FIG. 7 showing a sectional side view of yet a further exemplary embodiment of a dam 32 according to the invention, the support structure 6 can at its upper end be constructed in such a way that an appropriate run-off chute 33 or a spill-water run-off chute 33 is provided for overflow water 34 being released from the dam 32 via flood-control gates 35 in the crown of the dam wall 3. The run-off chute 33 has the function to smoothly divert the water 34 into the down-stream river bed without the risk of damaging/affecting the foundation 4 of the dam wall 3 and/or creating a damaging "plunge-pool". Hence, the support structure 6 further provides mechanical support which prevents the near dam down-stream river-bed from being eroded in form e.g. of a deep "Plunge-Pool" which may in turn cause structural damage to the dam-wall 3. Regarding the Pressure-Balance in "Pressure Chamber" 8, the "Pressure-Balance- Pipe" 12 ensures that the water pressure on the up-stream side and inside the "Pressure-Chamber" 8 are equal and thus stopping any water-leakages through or from underneath the existing dam-wall 3 (the "Pressure-Chamber" 8 is then filled with water). For inspection purposes and/or facilitating "active leakage prevention measures" the pressure-chamber 8 can be filled with pressurized air.

The sealing system, i.e. the sealing means 16, 17, 18, 19, 20 mentioned above, allows for any desired pressure to be build-up in the pressure chamber 8 ranging from atmospheric pressure to even above the static head water-pressure from the water reservoir 2 etc. Also, the seals can be of inflatable design to be able to actively increase contact pressure of the seals and increase tightness.

Regarding the Sealing-Arrangement, the "Sealing-Arrangement" is a multi purpose design. The "upper-seal chamber" 19 is preferably equipped with a multiple of seals or multiple-lip seals; the seals are held in position, e.g. by means of the "Seal Chamber Cover" 18. The seals can be exchanged if so needed, even without drop of pressure in the pressure chamber 8. The system is fail-safe. For additional precaution purposes, the additional "Chamber for Sealant" 20 can be filled (pressure filled) with special sealant as support to the upper seals and/or as temporary seal in case that the upper seals need to be exchanged; thus the "Pressure-Balance" can be maintained.

The respective ends of the seals shall be tightly held by "seal-caps" which form part of the support-structure 6.

Regarding the Sealing-Surface/Pressure-Chamber Wall Surface, for best sealing effect, safe and long-life application a special "Sealing-Surface" 16 is preferably applied (e.g. glued or bolted etc.) to the existing dam-wall 3. The wall-Surface of the existing dam-wall 3 inside the Pressure-Chamber 8 shall be treated and renovated from weathering to ensure water tightness.

Regarding the Pressure Balance connection, the "Pressure-Balance-Pipe(s)" 15 is/are preferably routed from the "Pressure-Chamber" 8 to the outside and then through the existing dam-wall 3 below water level 9 on the water-reservoir side. In the out-side routing of the "Pressure-Balance-Pipe" 15 "shut-off valves" may be installed with No, 1 valve allowing to shut the connection to the water-reservoir 2. No, 2 valve allows for controlling/testing of water-leakage volumes. During normal operation the No. 1 valve is opened and No, 2 valve is closed; during controlling/testing of water-leakages No. 1 valve is closed and No. 2 valve is open.

Regarding the "Repair of water-leakages", during initial commissioning of the "Support Structure" 6 and/or at any time during operation, the "Pressure Chamber" 8 can be used to facilitate closure/repair of water-leakages. For purpose of general shallow leakage-closure and/or repair, the "Pressure-Chamber" 8 shall preferably not be flooded with water. For this purpose, a respective liquid sealant/cement-mixture or other shall be filled in the Chamber covering the "floor" of the chamber with amount/volume of applied sealant be determined according to expected requirements. The sealant shall then be pressurized above the prevailing static pressure in the water-reservoir and thus pushed into any voids etc. which allow for water-leakages.

Any deeper consolidation of the dam foundation and/or sealing off of leakages shall be executed as explained above.

Reference signs:

1 Dam

2 Reservoir of water

3 Dam wall

4 Bottom/foundation of 3

5 Ground / Solid ground

6 Support structure

7 Side of 3 facing away from 2

8 Pressure-tight space /Pressure chamber

9 Water level of 2

10 Foundation of 6 / Watertight foundation of 6

11 Soil

12 Fluid-conducting and pressure-tight connection / Pressure balancing pipe

13 Valve / shut-off valve

14 Inlet of 12

15 Injection pipe

16 Sealing surface

17 Seal arrangement / Exchangeable seals

18 Seal chamber cover

19 Seal chamber

20 Chamber for sealant

21 Water leakage

22 Bottom of 1

23 Concrete wall of 6

30 Dam

31 Dam

32 Dam

33 Run-off chute

34 Overflow water

35 Flood-control gates

Claims

Claims:

1. A method for upgrading and/or repairing a dam (1, 30), the dam (1, 30) being provided for damming a reservoir of water (2) and having a dam wall (3) the bottom (4) thereof being founded on a ground (5); whereby said method comprises the following steps:

Formation of a support structure (6) on a side (7) of the dam wall (3) facing away from the reservoir of water (2); whereby the support structure (6) defines at least one pressure-tight space (8) being bounded by the dam wail (3);

Applying pressure above atmospheric pressure to the pressure-tight space (8), so that the penetration of water and/or damaging water-leakages into the pressure-tight space (8) through the dam wall (3) is at least minimized.

2. The method according to claim 1, whereby the step of applying overpressure to the pressure-tight space (8) is applied while the dam (1) is damming a reservoir of water (2).

3. The method according to any one of the foregoing claims, whereby the pressure is selected to stop leakage of water into the pressure-tight space (8).

4. The method according to any one of the foregoing claims, whereby the pressure is related to a hydrostatic pressure resulting from a water level (9) of the reservoir of water (2) creating a pressure-balance with the consequential stoppage of damaging leakage water flow, thus allowing for efficient, higher quality permanent sealing-off of water-leakages.

5. The method according to the foregoing claim, whereby the pressure is related to the hydrostatic pressure being present at a position below the water level (9) of the reservoir of water (2), which corresponds in height to the position of the pressure-tight space (8).

6. The method according to any one of the foregoing claims, whereby the support structure (6) comprises a foundation (10) extending on the ground (5) and along the bottom (4) of the dam wall (3) and defining the pressure-tight space (8) such that the pressure-tight space (8) is further bounded by the material (11) at the ground (5) adjacent to the bottom (4) of the dam wall (3), in order to at least minimize the penetration of water from the soil (11) into the pressure-tight space (8), while there is pressure applied to the pressure-tight space (8).

7. The method according to any one of the foregoing claims, whereby a fluid conducting and pressure-tight connection (12), especially a pressure balancing pipe (12), between the water reservoir (2) and the pressure-tight space (8) is provided, in order to flood the pressure-tight space (8) with water from the reservoir of water (2) and to apply water pressure from the water reservoir (2) to the water in the pressure-tight space (8) as pressure and to balance the pressure with a hydrostatic pressure resulting from the water level (9) of the reservoir of water (2).

8. The method according to the foregoing claim, whereby the fluid-conducting and pressure-tight connection (12) comprises at least one valve (13) for selectively applying pressure to the pressure-tight space (8) and/or release pressure from the pressure-tight space (8).

9. The method according to any one of the foregoing claims 7 or 8, whereby the fluid-conducting and pressure-tight connection (12) comprises at least one inlet (14) for entering of water on the side of the reservoir of water (8), while the inlet (14) being arranged below the water level (9) of the reservoir of water (2).

10. The method according to the foregoing claim, whereby the inlet (14) is arranged below an imaginary line being parallel to the top of the dam wall (3) at half height of the dam wall (3).

11.The method according to one of the foregoing claims 9 or 10, whereby the inlet (14) is arranged below a predetermined minimum water-level of the reservoir of water (2).

2.The method according to any one of the foregoing claims, whereby the support structure (6) is at least partially made of concrete, preferably reinforced concrete. 3.The method according to any one of the foregoing claims, with sealing means (16, 17, 18, 19, 20) being provided between the support structure (6) and the dam wall (3). 4.The method according to any one of the foregoing claims, with a force-locking connection and/or form -fitting connection being provided between the support structure (6) and the dam wall (3).

15.The method according to any one of the foregoing claims 6 to 14, whereby the foundation (10) of the support structure (6) is arranged deeper than the dam bottom (4).

16.The method according to any one of the foregoing claims 6 to 15, whereby the foundation (10) of the support structure (6) is seated on solid ground (5).

17.The method according to any of the foregoing claims 6 to 16, whereby the foundation (10) of the support structure (6) comprises means for providing a watertight sealing within the ground (5).

18. A dam for damming a reservoir of water (2), comprising: a dam wall (3), the bottom (4) thereof being founded on a ground (5); and a support structure (6) being arranged on a side (7) of the dam wall (3) facing away from the reservoir of water (2); whereby the support structure (2) is configured to define at least one pressure-tight space (8) being bounded by the dam wall (3), and wherein pressure above atmospheric pressure is applied to the pressure-tight space (8), so that the penetration of water into the pressure-tight space (8) through the dam wall (3) is minimized, preferably stopped.

9.The dam according to the foregoing claim, whereby the support structure (6) comprises a foundation (10) extending on the ground (5) and along the bottom (4) of the dam wall (3) and defining the pressure-tight space (8) such that the pressure-tight space (8) is further bounded by the soil (11) at the ground (5) adjacent to the bottom (4) of the dam wall (3), in order to at least minimize the penetration of water from the soil (11) into the pressure-tight space (8), while there is pressure applied to the pressure-tight space (8).

20.The dam according to any one of the foregoing claims 18 or 19, comprising at least one pressure balancing pipe (12) for establishing a fluid-conducting and pressure-tight connection between the water reservoir (2) and the pressure- tight space (8) in order to flood the pressure-tight space (8) with water from the reservoir of water (2) and to apply water pressure from the water reservoir (2) to the water in the pressure-tight space (8) as pressure and to balance the pressure with a hydrostatic pressure resulting from a water level (9) of the reservoir of water (2).

21. The dam according to the foregoing claim, whereby the pressure balancing pipe (12) comprises at least one valve (13) for selectively applying pressure to the pressure-tight space (8) and/or release pressure from the pressure-tight space (8).

22.The dam according to any one of the foregoing claims 20 or 21, whereby the pressure balancing pipe (12) comprises at least one inlet (14) for entering of water on the side of the reservoir of water (2), while the inlet (14) being arranged below the water level (9) of the reservoir of water (2).

23.The dam according to the foregoing claim, whereby the inlet (14) is arranged below an imaginary line being parallel to the top of the dam wall (3) at half height of the dam wall (3).

24. The dam according to one of the foregoing claims 22 or 23, whereby the inlet (14) is arranged below a predetermined minimum water-level of the reservoir of water (2). The dam according to any one of the foregoing claims 18 to 24, whereby the support structure (6) is at least partially made of concrete, preferably reinforced concrete. The dam according to any one of the foregoing claims 18 to 25, with sealing means (16, 17, 18, 19, 20) being provided between the support structure (6) and the dam wall (3). The dam according to any one of the foregoing claims 18 to 26, with a force locking connection and/or form-fitting connection being provided between the support structure (6) and the dam wall (3). The dam according to any one of the foregoing claims 19 to 27, whereby the foundation (10) of the support structure (6) is arranged deeper than the dam bottom (4). The dam according to any one of the foregoing claims 19 to 28, whereby the foundation (10) of the support structure (6) is seated on solid ground. The dam according to any of the foregoing claims 19 to 29, whereby the foundation (10) of the support structure (6) comprises means for providing a watertight sealing within the ground (5). The dam according to any of the foregoing claims 18 to 30, whereby the support structure (6) comprises at least one injection pipe (15) which runs from outside the support structure (6) aside or through the pressure-chamber (8) into the foundation (4) of the dam wall (3). .The dam according to the foregoing claim, the injection pipe (15) allowing for media to be injected into the foundation (4) of the dam wall (3) for consolidation purposes and/or stoppage of leakages while counter- pressure is applied in the pressure-chamber (8).