| "In constructing a rockfill dam with an impervious core in Japan, it often happens that it is difficult to obtain a sufficient quantity of core materials near the dam site or that the construction of a core affects the critical path of an entire execution schedule in rainy as well as cold regions. To address these problems, many studies have been made on enhancing the construction efficiency by reducing the core width of a rockfill dam with a central impervious core. In Japan, a gradient of 1:02 is conventionally applied to the upstream and downstream slopes of a central impervious core for a rockfill dam. However, because there is no firm basis for justifying such a practice, it is not possible to reduce the width of a core without appropriate engineering evaluation methods. Previous research results, recognize that the hydraulic fracturing of a core is an important element in investigating the reduction of core width.In this paper, banking and seepage analyses were carried out with various combinations of core and filter widths to examine their effects on the safety of a core against hydraulic fracturing. As a result, it was found out that the minor principal stress in the total stress in the core reduces as the gradient of both the core and the filter becomes steeper, lessening the safety factor against hydraulic fracturing. Based on the analytical results, a design of a core width for rockfill dams with central impervious cores was examined. " |
