Structural features and the evolutionary mechanisms of the basal shear zone of a rockslide

Furuki, Hirokazu; Chigira, Masahiro

doi:10.1016/j.enggeo.2019.105214

Cited by 10 publications

(6 citation statements)

References 14 publications

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“…Large natural slopes are sub-critically stressed (i.e., subjected to stress condition slightly lower than their instantaneous strength) and respond to major geomorphic perturbations (e.g., river incision in uplifting settings, glaciation/deglaciation) by progressive rock failure processes 8,9 . Over time, these processes lead to rock damage accumulation and permeability enhancement, until strain localizes along basal shear zones similar to tectonic faults [10][11][12] . As rockslide shear zones accumulate strain, they become thicker and richer in fine-grained gouge, causing permeability reduction and favoring the development of perched aquifers systems 9,[13][14][15][16] (Fig.…”

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confidence: 99%

Slow-to-fast transition of giant creeping rockslides modulated by undrained loading in basal shear zones

et al. 2020

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Giant rockslides are widespread and sensitive to hydrological forcing, especially in climate change scenarios. They creep slowly for centuries and then can fail catastrophically posing major threats to society. However, the mechanisms regulating the slow-to-fast transition toward their catastrophic collapse remain elusive. We couple laboratory experiments on natural rockslide shear zone material and in situ observations to provide a scale-independent demonstration that short-term pore fluid pressure variations originate a full spectrum of creep styles, modulated by slip-induced undrained conditions. Shear zones respond to pore pressure increments by impulsive acceleration and dilatancy, causing spontaneous deceleration followed by sustained steady-rate creep. Increasing pore pressure results in high creep rates and eventual collapse. Laboratory experiments quantitatively capture the in situ behavior of giant rockslides and lay physically-based foundations to understand the collapse of giant rockslides.

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confidence: 99%

Slow-to-fast transition of giant creeping rockslides modulated by undrained loading in basal shear zones

et al. 2020

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“…Particle Displacement. At macroscale level, the shear band is the significant characterization of the slope slip [32][33][34]. Correspondingly, the analysis of particle displacement field of discrete domain, at microscale level, can improve the understanding of the movement of granular materials and allow better judgment in relation to the trends associated with displacements [35].…”

Section: Correlation Analysis Of Shear Strain Increment Andmentioning

confidence: 99%

The Instability of High-Steep Road Cutting Slope: A 3D Continuum-Discrete Coupling Method

et al. 2022

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In this paper, the 3D continuum-discrete coupling analysis method combined with the strength reduction theory is used to study the macrodeformation, stress law, and microfracture mechanism of a high and steep cutting slope of Zhongkai Expressway in Guangdong Province. The 3D continuum-discrete coupling slope model is established based on the finite difference software FLAC and the discrete element program PFC. Then, based on the correlations between stress tensor and force chain, displacement and shear strain increment, plastic deformation, and microfracture, the mechanism of slope instability is analyzed from macro- and microscales. The research shows the following: (1) the continuum-discrete coupling model is reasonable and effective in the three-dimensional slope stability analysis. (2) The coupling domain was penetrated by the shear band, and the upper part displacement of the coupling domain was large, whose direction was basically consistent with the shear band direction; thus, the slope slip surface was formed. (3) The microfracture can represent the macroscopic failure phenomenon, and the slope landslide can be interpreted as the result of shear fracture in slip direction, accompanied by the extension and penetration of tension crack.

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“…These materials can have a different origin or formation process. In most cases, clay materials within basal rupture zones have a mechanical origin and occur as a result of strong rock comminution and pulverization caused by shear stresses [7][8][9][10][11][12] or are caused by weathering and alteration of the rock [4,[13][14][15][16][17], even if a combination of both rock disruption and weathering is also possible. In addition to the aforementioned processes, in sedimentary rock masses, clay materials can occur as interbeds within the lithostratigraphic sequence involved in the basal rupture [6,18].…”

Section: Introductionmentioning

confidence: 99%

“…Clay materials occurring within basal shear zones were identified thanks to detailed field surveys of failure scars of some rockslides [3,10,14,20] or by means of drilling or exploration adits performed on large unstable rock slopes [7,9,11,12,15]. Mineralogical investigations on clay materials collected from basal shear zones revealed the occurrence of clay minerals that, in most cases, derived from the parent rock involved in the basal disruption [7,[9][10][11][12]17]. In these cases, typical clay minerals found in the soil mixtures are illite and chlorite deriving from gneissic rocks [7,17], greenstones [12], sandstones, and mudstones [10].…”

Section: Introductionmentioning

confidence: 99%

“…Mineralogical investigations on clay materials collected from basal shear zones revealed the occurrence of clay minerals that, in most cases, derived from the parent rock involved in the basal disruption [7,[9][10][11][12]17]. In these cases, typical clay minerals found in the soil mixtures are illite and chlorite deriving from gneissic rocks [7,17], greenstones [12], sandstones, and mudstones [10]. Smectite was identified in clay materials resulting from crushing of tuff [2] and shale [11,12], or can derive from physical and chemical alteration under saturated conditions of the primary rocks [4,[14][15][16][17], even as a result of circulation of sulfuric acid [13].…”

Section: Introductionmentioning

confidence: 99%

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Mineralogical and Geotechnical Characterization of the Clay Layers within the Basal Shear Zone of the 1963 Vajont Landslide

et al. 2020

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The 1963 Vajont landslide is a reference example of large rockslides involving clay interbeds emplaced in sedimentary rock masses in correspondence with the basal rupture zone (thinly stratified cherty limestone of the Fonzaso Formation dated to Middle–Upper Jurassic). The basal shear zone of the 1963 Vajont landslide was made up of a chaotic assemblage of displaced rock masses, limestone angular gravel, and spread clay lenses. The mineralogical investigations showed that the clays are characterized by complex assemblages of illite/smectite mixed layers (36–96%) admixed with variable amounts of calcite (4–64%) and quartz (0–6%). The clay layers show highly variable plasticity properties and shear strength characteristics. The samples with a large prevalence of clay mineral content (CM) (CM > 79%) are characterized by low values of the residual friction angle (6.7–14.9°), whereas clay materials characterized by a higher content of granular minerals (calcite and quartz) clearly show greater friction angle values (19.5–26.7°). The high permeability of the limestone angular gravel, which caused a rapid reservoir-induced inflow (1960–1963), together with the low friction angle of the clay layers were responsible for the overall shear strength reduction in correspondence with the basal rupture zone, thus favoring the huge sliding on 9 October 1963.

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Structural features and the evolutionary mechanisms of the basal shear zone of a rockslide

Cited by 10 publications

References 14 publications

Slow-to-fast transition of giant creeping rockslides modulated by undrained loading in basal shear zones

Slow-to-fast transition of giant creeping rockslides modulated by undrained loading in basal shear zones

The Instability of High-Steep Road Cutting Slope: A 3D Continuum-Discrete Coupling Method

Mineralogical and Geotechnical Characterization of the Clay Layers within the Basal Shear Zone of the 1963 Vajont Landslide

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