Effect of spatially variable shear strength parameters with linearly increasing mean trend on reliability of infinite slopes

This paper studies the reliability of infinite slopes in the presence of spatially variable shear strength parameters that increase linearly with depth. The mean trend of the shear strength parameters increasing with depth is highlighted. The spatial variability in the undrained shear strength and the friction angle is modeled using random field theory. Infinite slope examples are presented to investigate the effect of spatial variability on the depth of critical slip line and the probability of failure. The results indicate that the mean trend of the shear strength parameters has a significant influence on clay slope reliability. The probability of failure will be overestimated if a linearly increasing trend underlying the shear strength parameters is ignored. The possibility of critical slip lines occurring at the bottom of the slope decreases considerably when the mean trend of undrained shear strength is considered. The linearly increasing mean trend of the friction angle has a considerable effect on the distribution of the critical failure depths of sandy slopes. The most likely critical slip line only lies at the bottom of the sandy slope under the special case of a constant mean trend. (C) 2013 Elsevier Ltd. All rights reserved.