Ocena wytrzymałości piaskowców fliszowych przy różnych ścieżkach obciążenia w warunkach konwencjonalnego trójosiowego ściskania

Abstract

Assessment of Flysch sandstones’ strength at various loading paths in conditions of conventional triaxialcompression.S u m m a r y. The paper presents an assessment of Flysch sandstones’ strength at various loading paths in conditions of conventional triaxial compression tests. Three types of tests were conducted: single triaxial failure tests at three various confining pressures, multiple failure tests and continuous failure tests. Much attention was given to a tests’ methodics, the courses of multiple failure tests and the most rare continuous failure tests were described. The highest values of Krosno sandstones strength was observed at the load path up to 90 MPa corresponding with single triaxial failure tests. Samples exposed to either multiple or continuous failure were subjected to “material fatigue” and their strength values are lower — about 30 MPa. Strength loops obtained from conducted tests also show some differences. The higher values of internal friction angle and lower values of cohesion were obtained for triaxial failure tests than for multiple and continuous failure ones. The conducted tests also gave possibility to compare angle of failure (shear) surface depending on the loading path at condition of conventional triaxial test.