Effect of Fast Shearing on the Residual Shear Strengths Measured Along Pre-Existing Shear Surfaces in Kaolinite

Shear‐Rate‐Dependent Behavior of Clayey Bimaterial Interfaces at Landslide Stress Levels

“…Wang et al (), through laser and scanning electron microscopy (SEM) observations, showed a possible change from sliding to turbulent mode that could account for the observed rate effect with implications on landslide behavior (Saito et al, , ; Wang et al, ). In our tests, the persistence of a polished, slickensided regular surface after fast shearing (Figure e) appears to exclude a transition toward turbulent shearing—consistently with SEM observations by Khosravi et al ()—even at low σ n , possibly due to the high clay fraction (Tika et al, ). On the other hand, the resistance peaks observed with rate changes in the range v ≥ 3 mm/min (Figure ) may suggest a temporary disruption of the shear surface or transient negative pore pressures due to dilative behavior.…”

Total Stress Analysis of Soft Clay Ground Response in Centrifuge Models

“…Lefebvre and LeBoeuf (1987) investigated four Canadian clays under normally and overconsolidated conditions and found a 7 to 14% increase in undrained strength per log cycle of strain rate for a ̇ range of 10 -5 %/s to 1%/s. Fully softened and residual strengths have also been shown to increase at rapid (vs slow) loading rates in ring shear and sliding block studies (Khosravi et al, 2013;Meehan et al, 2008). Given this prior work, two knowledge gaps are especially pertinent for this study: (1) rate effects on undrained strength have been investigated for relatively few soil materials, and the applicability of the prior results for Bay Mud are unknown, and (2) the trend in strength increase with rate of cyclic loading has not been adequately investigated at strain rates higher than 1%/s, which are believed to be important for highly nonlinear soil response during seismic loading.…”

Yüksek Plasti̇si̇teli̇ Ki̇lleri̇n Kalici Kayma Mukavemeti̇ne Plasti̇si̇teni̇n Etki̇si̇

“…Yapılan araştırmaların sonuçlarında, kalıcı kayma mukavemetinin en çok zeminin mineralojik yapısı [6], jeolojik yük [2] ve kesme hızından [7,8] etkilendiği ortaya konulmuştur. Bunun dışında mineralojik yapıyı dolaylı olarak temsil edebilen kıvam limitleri [9,10] ve plastisite [11,12] , özgül yüzey alanı [6] , aşırı konsolidasyon oranı [13], kil yüzdesi [14], kesme modu [14], boşluk suyu kimyası [15,16] ve sıcaklık [17] kalıcı kayma mukavemetine etki eden diğer faktörler olarak sayılabilir.…”