The first problem to be considered is whether or not to continue construction in
winter when constructing concrete dams in cold regions. It is better to stop in winter
when constructing the RCCD in a wide valley because it is hard to insulate
when placing concrete due to the large placing area. It is feasible to place mass concrete in winter as constructing concrete arch dam or gravity dam in narrow valley
when effective measures, such as automatically rising movable tent, may be
taken because the placing area is smaller. If it is decided to place mass concrete in
winter, it is necessary to research carefully the technical measures for freeze protection
and crack prevention.