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This paper presents a new framework for characterizing landslide deformation. Here, the deformation of a landslide is interpreted as a summation of three components: rigid deformation, within-mass deformation, and residual deformation. On the basis of the monitored data of the landslide deformation, these three components may be characterized separately: the rigid deformation is simulated by a summation of a trend term and a periodic term, the within-mass deformation is simulated by a high-order polynomial model, and the residual deformation is simulated by a conditional random field model. In particular, the characterization of the residual deformation, the third component of the landslide deformation, with the random field allows for a probabilistic assessment of the landslide deformation in the face of geological uncertainties. With the proposed framework, the evolution of landslide deformation in both geometric and time domains may be established, which allows for an assessment of the sliding mechanism of the landslide. Further, evolution in the geometric domain may allow for an assessment of the serviceability of infrastructures in the landslide area. To illustrate this new landslide deformation characterization framework, a case study of the Yu-Kai highway landslide in Guizhou, China is presented, through which the effectiveness of the proposed framework is demonstrated. [ABSTRACT FROM AUTHOR]

Several colluvial landslides have developed in the Jurassic strata region of Zigui County, a major landslide-prone region in the Three Gorges Reservoir Region of China. The bedrock in which stabilizing piles are placed in the landslide-prone Zigui region can be generally characterized as upper sandstone and lower silty mudstone. A site investigation of the Majiagou No. 1 landslide indicated that the pile heads were displaced horizontally by approximately 15.0 cm. This paper presents a novel model for determining the reasonable embedded length for stabilizing piles in colluvial landslides with upper hard and lower weak bedrock based on the deformation control principle. A negative power function relationship between the horizontal displacement of the pile head and the reasonable embedded ratio for stabilizing piles is proposed on the basis of the allowable pile deformation according to industrial standards. Furthermore, the lower limit on the horizontal displacement of the pile head is deduced to obtain the maximum reasonable embedded ratio of stabilizing piles. Reasonable embedded length ratio models of stabilizing piles are analyzed based on various influencing factors. The results show that (1) increasing the embedded length of the piles can significantly reduce both the horizontal displacement and the maximum absolute value of the shear force on the piles, (2) the increase in the maximum bending moment of the pile with increasing embedded pile length is insignificant, and (3) increasing the thickness of the upper hard rock and the coefficients of subgrade reaction of the upper hard and lower weak rock and reducing the driving force of the landslide help to reduce the reasonable embedded length of the piles. Consequently, it is suggested that stabilizing piles should be set in stronger and thicker upper hard rock in regions with low landslide driving force in order to minimize the reasonable embedded length of the piles. [ABSTRACT FROM AUTHOR]

The Huangtupo landslide is the volumetrically largest, most complex, and economically most significant landslide in the Three Gorges Reservoir Region. Detailed information about the character and dynamics of this tractive landslide is available because of access provided by a unique, 908-meter in situ research tunnel, augmented by long-term data provided by an extensive monitoring system for ground water levels, rainfall, and in situ deformation. Three major rupture surfaces plus 12 interlayer sliding zones (weak layers) were recognized during tunnel excavation, which also provided access and samples that establish a complex, multistage deformation history. Data from the in situ monitoring system shows that the toe of the landslide is creeping at a steady annual rate of about 25-30 mm, but at a slower rate of about 12 mm/year near the crown. However, the monthly creep rates are variable, being highest during May-August when rainfall is heavy and reservoir levels are low. Displacement-depth curves in the HZ6 borehole inclinometer establish that the creep of Slump Mass I# is most rapid above a depth of 37 m, where a major rupture zone occurs immediately above bedrock. Engineered defense structures along the toe of Huangtupo landslide can improve its stability to some extent. The effect of rapid changes of the reservoir level on landslide stability should be considered in reservoir management. [ABSTRACT FROM AUTHOR]