Reconstruction of pressure soil dams and dikes of reservoirs in terms of critical filtration

Abstract

A great number of water reservoirs is situated in the influence zone of the inhabited and developed downstream areas. The ability to resist the filtration flow through the dam is dramatically changing in time due to their long term stay under the permanent pressure. Continuous physical and chemical diffusion causes the creation of the micro-channels in the dikes which increase the amount of the filtration flow. It has been observed that the the speed and the amount of filtration has been increasing in geometric progression. It brings a danger of the critical moment and erosion of the dike  body. It is essential that the dikes are constructed of the finely dispersed soils, which can easily be washed away from the body of the dike. As a result of the studying the interaction of different types of wetted soils with a pressure of water mass showed the inevitability of washing dusty particles with pressure in the period after the arrangement of the dam. In order to replace the space from the washed particles, it is necessary to carry out the mass sealing.

Two options are offered. The first method is based on research, in laboratory conditions, changes in the structure of soil moistened to the limit of fluidity under the influence of its own weight at the release of excess, except for capillary moisture. The second method is based on research with using vibration effects on soil mass with an additional gravitational load to the mass of the test specimen. Researches simulate the proposed method of eliminating the over-normative filtration of the soil dam body in natural conditions.

In the first case, the filtration is reduced by an average of 24 percent. The disadvantage, however, is the considerable amount of time caused by the slow effect of gravity due to the molecular adhesion of the soil.

In the second option of the research the effect of reducing the filtration flow through the dam model is an average of 82 percent and manifests itself during the time of the experiment, that is, instantly. This method confirms its effectiveness in conditions that prevent long-term emptying of the reservoir, which is present in most cases.

The suggested method allows for the stabilization of the filtration stability of the soil dikes.