Historical survey of using rigid core-wall in designs of embankment dams
Introduction. Diaphragm is a thin-walled seepage control element located in the dam body. Concrete and reinforced concrete core-wall (hereinafter CCW) are referred to rigid elements. Dams with CCW have been constructed for already 50 years. In scientific and technical literature there established an opinion about CCW safety. In order to understand the advantages and disadvantages of CCW the author fulfilled a historical survey of their use. Materials. The publications issued in the period of active using the dams with CCW were used for compilation of the historical survey. Results. The survey describes the history of using the dams with CCW over the period of about one hundred years as well as the designs of the most important dams of this type. There given the information about failures of Eildon, Oued Kebir dams and other dams, which caused distrust of engineers in CCW designs. The survey showed that several dozens of embankment dams with CCW were constructed in America and Europe. In spite of the established opinion most of these dams showed high level of safety and are still successfully operating. Some of the dams with CCW reach the height of 50-70 m. Conclusion. The main disadvantage of CCW is in their inability to perceive high deformations of embankment dams; cracking is possible in them. However, this was not the cause why dams with CCW are no longer used. Using CCW stopped in the middle of the XX-th century, when more simple and safe asphalt concrete diaphragms appeared. At present the dams with concrete diaphragms enjoy a new lease of life, however, their structures are built based on other principles. Clay-cement concrete is used instead of low-slump concrete, and diaphragms themselves are made by methods of cutoff walls.