Loess area is the region that geohazards happened most frequently, accounting for 1/3 of the geohazards in China. Cutting slope has become the most prominent products in human engineering activities and slope failure induced by rainfall has become the main form in recent years. Well-instrumented centrifuge model tests have been introduced to investigate the failure process and failure pattern, including pore water pressure, progressive deformation-failure process and characteristic of the high cutting slope by rainfall. The results show that rainfall induced loess slope failure is characterized by shallow slide to flow and two deeper creepage sliding-tension surfaces. All the sliding faces are characterized by planar surfaces parallel to slope surface. The planar sliding surface differs a lot to the circular sliding surface in the gravitational soil landslide. The accumulative deformation especially the abrupt displacement before failure induced the excess pore water pressure, after which flow failure with high-speed happened. The pore-water transducers on both sides of the shallow sliding surface have distinct response to slope deformation. The quantitative monitoring data indicates that the liquefaction is not the reason but the result of the deformation accumulation and big transient deformation.

We modeled the sensitivity of six ice-cemented slope deposits from the western McMurdo Dry Valleys, Antarctica to failure by shallow, thaw-induced planar sliding. The deposits examined have purportedly remained physically stable, without morphologic evidence for downslope movement, for millions of years. Could they fail in the near future from greenhouse-induced warming? To address this question, we first prescribed various increases in mean summertime soil surface temperature (MSSST) and modeled numerically the resultant changes in soil thaw depths using a one-dimensional heat diffusion equation (including the effects of latent heat of fusion). Second, we calculated the minimum thaw depths required to facilitate failure by shallow planar sliding for each deposit, for all numerical simulations, we maintained present soil-moisture conditions and used a Mohr-Coulomb-based equation of safety factor. Third, we calculated the rate of subsurface meltwater flow assuming Darcy's Law. Our results show that although most deposits contain sufficient subsurface ice to induce sliding upon thawing, lateral rates of water flow of as much as similar to 40 m/day for some colluvial deposits prohibit the build-up of requisite pore pressures for failure. On the other hand, silty deposits, that contain gravimetric water >= 15%, occur on slopes > 20 degrees, and possess low hydraulic conductivities (similar to 30-60 cm/day), common in the Dry Valleys region, could fail if MSSST, and by inference mean summertime atmospheric temperatures, increase by 4 to 9 degrees C. This temperature increase is similar to that predicted to occur from greenhouse-induced wart-ning in Antarctica over the next century. (c) 2007 Elsevier B.V. All rights reserved.