A pilot study of the method choice about the blanket length over earth-rock dam on the infinite deep pervious foundation

At present, how to select the length of the blanket on infinite deep pervious foundation has not been resolved, this paper mainly discuss the options of effective length for impervious blanket by set an mathematics model to calculate it, using a model experimentation to validate it, and the theory and the experiment get fine mutual verification. Moreover, considering the environments issue about pickle and swampy soil in practice, we put forward the conception of eco-length and method to calculate it about the blanket, the method is simple and useful.