engleski

Undrained Ring Shear Tests Performed on Samples from Kostanjek and Grohovo Landslide

Kostanjek and Grohovo landslides were chosen for research as pilot areas within Croatia-Japan Joint Research Project. Laboratory soil testing along with monitoring and modelling of landslides are planned for the analyses of these two landslides. For this purpose, new, transportable ring shear apparatus, ICL-1, was designed. Although smaller in dimensions compared with previous versions, it has high capacity ; it can load normal stress and keep undrained condition of pore water pressure up to 1 MPa. Ring shear apparatus has two purposes: it can be used for the basic soil tests (for determination of soil parameters) and for the landslide simulation test. This paper presents the use of the new apparatus for obtaining basic soil parameters on surface samples from two Croatian landslides: shale sample from Kostanjek and clay sample from Grohovo landslide. The aim of the work was to establish testing procedure and obtain preliminary results on surface samples. Speed control tests were conducted under constant shear speed of 0.002 cm/sec and until shear displacement reached 1-3 m, in order to obtain steady state condition. From speed control test results, peak, mobilized and apparent friction angle for both materials are obtained. Test results are in accordance with data obtained by earlier laboratory tests and back analysis. The testing procedure used and preliminary results obtained will be used for planning and conducting of tests on borehole samples.

landslide ; ring shear test ; undrained speed control test

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