Centrifuge Modeling and the Analysis of Ancient Landslides Subjected to Reservoir Water Level Fluctuation

Abstract

Landslides are among the most severe natural hazards with significant impacts in human life and infrastructure. The Three Gorges Reservoir Area (TGRA) is vulnerable to landslides because of the geological environment and human activities. A centrifuge model test of a landslide with a planar sliding surface in the TGRA was conducted. Based on the multiple monitoring systems composed of a 3D laser scanner, pore water pressure transducers, particle image velocimetry and earth pressure sensors, multiphysical data were obtained. The work described here had the objective of researching the long-term deformation pattern of this kind of landslide that was subjected to periodic fluctuations in the reservoir water level. The results indicated that the failure processes were characterized by progressive retrogression and cracks caused by the reservoir drawdown. Transverse tensile cracks first appeared in the submerged zone of the slope. The front part of the slope was dominated by horizontal displacement, while the consolidation and compaction deformation in the vertical direction dominated at the mid-rear part of the slope. When the water level dropped again, the front part slid down and fell into the river, but the mid-rear part had no obvious deformation and exhibited a phenomenon of self-stabilization. Moreover, the phreatic line is a concave shape directed into the slope during reservoir filling and converts to a convex shape pointing out of the slope during reservoir drawdown. The earth pressures in the slope vary with the failure process of the landslide. Good agreement is obtained for the deformation characteristics between the experimental results and those of prototype landslides.

Study on the Deformation Mechanism of Reservoir Landslides Considering Rheological Properties of the Slip Zone Soil: A Case Study in the Three Gorges Reservoir Region

“…The evolution and formation mechanism of three large-scale landslides in the Three Gorges Reservoir Area (TGRA) were thoroughly investigated, and it is found that many features associated with landslides were caused by slow, downslope gravitational processes before landslide failure [9]. The long-term deformation pattern of an ancient landslide with a planar sliding surface in the TGRA was found to be deeply connected with periodic fluctuations in the reservoir water level [10]. The failure of these landslides is strictly influenced by the increase in pore water pressure and the consequent reduction in mean effective stress and is considered a complex slope instability phenomenon since the landslides exhibit distinct kinematic characteristics during the failure, post-failure, and propagation stages [11][12][13][14].…”

Influence of permeability on the stability of dual-structure landslide with different deposit-bedding interface morphology: The case of the three Gorges Reservoir area, China

“…6). According to previous studies (Li et al, 2020a;Qian, 2016;, the dip angle of the DBI θ is usually lower than the internal friction angle ϕ in under-dip landslide. Thus, the whole DBI can be considered as the locked segment according to rigid limit equilibrium method.…”

“…The DBI morphology is believed as a dominated factor for slope stability calculation and mitigation measures designs (Hu and Wang, 2010;Stout, 1971;Sun and Hu, 2016). The scientific literature contains many well-documented case histories for the relationship between DBI morphology and failure mechanisms (Tannant et al, 2017;Huang et al, 2015;Li et al, 2020a;Pan et al, 2016;Tang et al, 2020). However, surprisingly, works concerning the statistical analysis of the influence of different kinds of DBI morphology on dual-structure landslide stability in the TGR is rare.…”

Analysis of Susceptibility to Slope Movements in the Environment of Road Infrastructures. Models for Obtaining Predictive Mapping Applied to Roads in the Provinces of Malaga and Granada (Spain)

“…A total of 241 slopes have been selected for the statistical analysis of susceptibility to rockfalls. The selection of predisposing factors has been based on bibliographic criteria ( [58]), and particular attention has been granted when adding to the usual natural causes artificial factors that are characteristic of the anthropized environment of the roads, such as cuts, irrigation, extractive activity or clearing ( [59]; [60]; [61]). No factors related to precipitation or seismicity have been included, as they are not spatially discriminatory when working at large-scale.…”

“…It is a multivariate statistical method that allows to predict the presence or absence of a given event according to the values of a set of starting indicators. The binomial logistic regression allows us to deduce an equation that establishes the underlying mathematical relationship between a dependent dichotomous variable, and a set of independent predictor variables ( [59]). For the analysis, variables of different nature and statistical expression (continuous or categorical, and with or without normal distribution) can be included.…”