Research On The Region Of High Plastic Clay Of High Rockfill Dam

Rockfill dam composed of soil, concrete and asphalt concrete is supported by the rockfill body. As one of the earth-rock dam, it has many advantages, such as making full use of the local rock materials, adapting to various geological conditions, having well construction methods and seismic performance, and so on. With development of soil mechanics theory and appearance of the large scale vibrating machines, the construction of core rockfill dam come into high speed development time in the sixties of the twentieth century. Core rockfill dam has gradually become one of the mainstream dam types for high dam construction in the world through the development of several decades.The dam foundation seepage is an outstanding problem of construction of high rockfill dam on the overburden. Each two the region of the connection is weak section at the traditional three dimensions impervious system composed of core wall, concrete cutoff wall and anti-seepage curtain, especially the connection of core wall and concrete cutoff wall. Unsuitable connection makes some unfavorable effects, for example, concrete cutoff wall is in state of high stress level and cracks appear in the core wall, these will seriously imperil the security of impervious system of the dam. In order to avoid unfavorable effects, generally, high plastic clay is set up in the place of connection, but at present how to set up high plastic clay is not well known.Some helpful conclusions and rules were summarized based on the Changhe-dam, according to two dimensional and three dimensional nonlinear finite element calculation of the linking position of core wall and concrete cutoff wall. These are helpful to design and construction of practical project and the main research work of this paper are as follows:1. Development process of the core rockfill dam at home and abroad was introduced, also the loading characteristics of the concrete cutoff wall and the gallery in rockfill dam and constitutive models of rockfill materials was stated.2. Main program was debugged and calculation models of all kinds of schemes was established in finite element software ANSYS, in addition, preprocessing program used in generating input file was compiled.3. Post-processing program used in linking with the drawing software TECPLOT10.0 and analyzing calculation results was compiled.4. Influence of the region of high plastic clay on the stress-strain of its peri-region and concrete cutoff wall was studied in detail at completion stage and water stage, according to two dimensional and three dimensional nonlinear finite element calculation of Changhe-dam in the Dadu River. It was summarized that the appropriate size of the region obviously decrease the major principal stress of concrete cutoff wall and the gallery, improve working state of the concrete structure, assure the safety of impervious system of the dam when the dam settlement was not increased remarkably.