Abstract
Recently, in Japan, not a few dam sites consist of soft and weak rocks or sand and gravel deposits. Because these dam foundations are low in strength, it is required to evaluate seepage failure potential in the designing stage.
We made dynamical studies on accurate and efficient evaluation of seepage failure potential of dam foundations using laboratory seepage failure test (SFT) for undisturbed specimens and in-situ SFT. However, since dam foundations are usually composed of many kinds of strata and rocks/soils, the evaluation of seepage failure potential is time and money comsuming procedure even with less expensive method, that is, laboratory SFT. If index test for seepage failure potential of soils and soft rocks can be found, rough evaluation by this test makes it possible to perform laboratory and in-situ SFTs efficiently.
Three simple tests, such as needle penetration test, pick penetration test and scour test, unconfined compression test and laboratory SFT were carried out for 32 kinds of soils and soft rocks at the site which was mainly composed of pyroclastic flow deposits and pyroclastic fall deposits of the Pleistocene age. The detailed investigation of test results was made, and the possibility of simplified and indirect evaluation of seepage failure potential was considered.
