PROCESS
(Available only in Japanese)
PROCESS.1
Preparation work
Before the start of construction, a ground survey is conducted as preparatory work to check for any discrepancies between the design and the actual site.
To build a dam body, the river stream is changed temporarily. A “temporary drainage channel” for diverting river water, an “upstream temporary cofferdam” to intercept the river, and a “downstream temporary cofferdam” to prevent the backflow of water are built.
The impact on the surrounding environment caused by dam construction is reduced.
We are also tackling environmental conservation in the construction of the Kawakami Dam, which is currently under construction.
(Link to Japan Water Agency Kawakami Dam website.)
Japanese giant salamander 
Scarce birds of prey
Plants
PROCESS.2
Foundation excavation work
To construct the dam on firm bedrock, excavate soil and sand and weak bedrock to expose the firm bedrock.
To increase the strength and water tightness of the foundation ground of the dam, the foundation bedrock is filled with cement milk.
PROCESS.3
Dam concrete placing works
The tower cranes, concrete batching plant, and belt conveyors for material transportation, necessary to construct the dam body, are installed.
Concrete is placed for the dam body. There are two types of casting methods: the “columnar block method,” where each block is stepped and divided into pillars, and the “RCD method” and “extended layer method,” where the blocks are placed without creating a height difference.
Vehicle management system using an infrared camera
Expert in the concrete manufacturing
Automatic concrete transportation system of dam
Automatic concrete transportation system of dam using tower crane.
Dam concrete compaction judgment system
Aqua Thermo®, a wet curing method with high thermal insulation properties for concrete
Obayashi Corporation uses the latest technology to focus on the safety management of people working on-site.
PROCESS.3
Embankment work for dam body
PROCESS.4
Completion・maintenance
After the dam is completed, water is stored to check if there are any problems, and the safety of the dam is confirmed.
After the completion of the dam, maintenance to achieve the objectives such as flood control, water utilization, normal function maintenance of running water, and keeping functionality over the long term is conducted.
