Shear strength testing of consolidated claystones: breakpoint detection of shear stress versus shear displacement curves, a statistical approach

Abstract The evaluation of shear stress versus displacement curves is in the main focus geotechnical engineering. Such curves, depending on rock assessed, consist a quasi-linear section, followed by “kick” representing peak strength, and residual part, mostly parallel to abscissa. aim present study facilitate future automatic detection these crucial characteristics take step towards replacing their visual/analogue determination via modern statistical tools. Breakpoint methods (Cross-Entropy, Change Point Model) were applied obtained from laboratory tests describing shearing along discontinuities nine Mont Terri Opalinus Claystone samples. Smooth moderately rough claystone surfaces studied. Results indicated that end rising section kick observed strength was effectively approximated with Model framework. An additional practical advantage applying tools such as breakpoint it ensures comparability results.