Wpływ metody wyznaczania parametrów wytrzymałościowych gruntów na wyniki analiz stateczności skarp i zboczy

Impact of the method of determination of soil strength parameters on the results of slope stability analyses. Prz. Geol., 68: 577–583; doi: 10.7306/2020.22 A b s t r a c t. The basic assumptions determining the methodology for testing soil strength parameters have been known for almost 250 years (Coulomb, 1773). Nevertheless, obtaining reliable and unambiguous parameter values for calculations is still a difficult problem. The main problem results from the fact that soil strength parameters are not a material constant. This means that the values of the angle of internal friction and soil coherence are dependent on the research methodology used. The article presents the impact of the method of determination of soil strength parameters on the assessment of slope stability. The earlier literature recommends adapting the method of testing samples as much as possible to real conditions. This allows the geologist to have some freedom in choosing the research methodology. The PN-EN 1997-2: 2008 standard puts more emphasis on a uniform test methodology. In the interpretation of Eurocode 7, due to the need to determine accurately effective stresses, “only strength tests of soils completely saturated with water or dry soils are considered”. Stability analyses performed for a small, still active landslide in Kojszówka have shown that the use of only effective parameters for slope analyses may not be fully reliable.