A dam is a barrier that stops or restricts the flow of water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect water or for storage of water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees (also known as dikes) are used to manage or prevent water flow into specific land regions.
Dam foundation excavation refers to the removal of ground cover and weathered broken rocks, so that the dam is directly built on a solid and complete rock foundation.
The excavation depth should be determined according to the stress of the dam foundation, the strength of the rock and its integrity, combined with the requirements of the superstructure on the foundation.
High dams should be dug to fresh or slightly weathered bedrock; lower dams should be dug to slightly weathered or weakly weathered bedrock.
Excavation slopes are slopes set up to maintain the stability of the unsettled soil at the edges of the earth excavation area and prevent landslides. Slope stability is the basic guarantee for construction safety.
The slope angle is expressed as the ratio of height to bottom width H: B. The angle is related to factors such as soil quality, excavation depth, excavation method, length of slope indwelling time, drainage, and load on the slope, etc., and a stability check should be performed.
Excavation of slopes shall be carried out in layers from top to bottom along the contour line.
Concrete face rockfill dam is a concrete structure which is arranged around the face plate and sits on the foundation, which is also called pedestal. The toe board is connected with the panel through a peripheral seam with a water stop to form an anti-seepage body above the dam foundation, and at the same time, it is connected to the bedrock after the foundation treatment to seal the leakage channel below the ground, thereby preventing the upper and lower The infiltration structure is connected as a whole. Its main function is not only to prevent seepage, but also to serve as a base for the cover plate and panel of the base grouting.
During the leakage measurement of the concrete faced rockfill dam, it was found that the leakage gradually increased with the rise of the reservoir water level, and the leakage of the joints around the concrete faced rockfill dam was abnormally increased by inspection. Time has proved that the peripheral joint is the main leakage channel of the concrete faced rockfill dam. Therefore, once the peripheral joint water-stop structure is damaged, it will form a leakage channel, which will cause the anti-seepage system to fail. Therefore, it is necessary to choose a reasonable and effective peripheral joint stop Water structure.
Many dams have serious problems such as dam foundation seepage and dam abutment seepage due to the neglect of the treatment of overburden and underlying rock masses. We generally use consolidation grouting and curtain grouting to prevent dam foundation and abutment leakage.
"Technical Specifications for Waterstop of Joints of Concrete Faced Rockfill Dams" was formulated in accordance with the original "Ministry of Education and Industry Science and Technology  No. 28 document" On the Issuance of the 1997 Formulation and Amendment of Power Industry Standard Plan Projects "arrangement.
The joint water-stopping of concrete faced rockfill dams (hereinafter referred to as faced dams) is the main channel for faced dams which is more likely to cause water leakage, and it is also one of the key to faced dam construction technology. The preparation of this standard in the electric power industry standard, summing up the experience of less than 15 years of panel dam construction and scientific research results, is not only a requirement of engineering practice, but also a foundation. Through the implementation of this specification, the efforts are made to make the structure, materials and construction technology of the joints of the face dam meet the standards, which will help to ensure the quality of the joints of the face dam and prevent the occurrence of accidents.
The damage and water-damage of the face of a high-face rockfill dam is a high probability event. The second anti-seepage system formed by the cushion layer and the transition layer is the second line of defense to ensure the safety of the dam when the panel and its waterproof system partially fail, and it is also used as a temporary flood prevention when the panel is not formed during the dam filling process. The infiltration system must be able to maintain its own infiltration stability under the action of infiltration.
Rockfill refers to directly depositing large-diameter blocks into the warehouse, and then pouring special self-compacting concrete without any vibration from the surface of the rockfill, and using the special self-compacting concrete with high fluidity and high penetration. Features, relying on its own weight to completely fill the gap of the rockfill to form a complete, dense, low hydration heat, and meet the strength requirements of large-volume concrete. Rockfill concrete technology has simple construction process, low comprehensive unit price, small hydration temperature rise, easy on-site quality control, high construction efficiency and short construction period.
Face rockfill dams are widely used because they make full use of local materials. The structure of the face rockfill dam from upstream to downstream is generally: face plate, cushion material area, overfill area, main rockfill area, secondary rockfill area, dry rock protection slope behind the dam, and a drainage area is set at the lower part. During construction, in order to prevent rain from eroding the cushion material slope surface, and at the same time to provide a base surface for the subsequent panel construction work, the cushion material slope surface is generally protected with dry hard cement mortar labeled M5, and the thickness of the mortar filling is generally 5cm. The upstream slope mortar is compacted by vibrating rollers.
The protection surface is indicated in the dam roof structure. The protection material can be crushed stone, masonry, asphalt or concrete. Note that turf cannot be used in the downstream of level Ⅳ and above, and it can't be used in the upstream.
The dam top includes pavement, wave wall, side stone, railing, drainage ditch, lamp post, etc. When there is no special requirement such as traffic on the concrete dam roof, the width of the dam roof is generally not less than 2 meters. When passing vehicles at the top of the dam and gate opening and closing machinery, design the road surface according to the requirements of traffic and cranes, door cranes, etc. The road surface is provided with a drainage ditch. The drainage pipe is used to drain water upstream or into the dam body drainage equipment.
The safety of the reservoir dam is related to the interests and safety of the country and the people. Hidden safety hazards in the reservoir dam will cause huge losses to people ’s property. In order to ensure that the reservoir dam can better exert social and economic benefits, the safety of the reservoir dam Management is very important. It is necessary to monitor the safety of the dam in real time, to control the real-time dynamics of the dam at any time, and to provide an effective basis for the maintenance of the dam. To ensure the safe operation of the dam is to ensure the safety of the country and people.
Rolled Cople for pipe