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Identification of poroelastic constants of deep argillaceous rocks. I: Experimental set up and qualitative analysis
Published in J.-L. Auriault, C. Geindreau, P. Royer, J.-F. Bloch, C. Boutin, J. Lewandowska, Poromechanics II, 2020
Laurent Malinsky, Serge Chanchole, François Coste
Retention curve exhibits a linear relationship between gravimetric water content and suction. This behavior, characteristic of clay material, indicates that the argillite skeleton is not cemented by the carbonates. This fact is confirmed by microscopic observations showing the presence of individuals calcite and quartz grains whose size can be as large as 200 µm.
Characterization of hydromechanical damage of claystones using X-ray tomography
Published in Vladimir Litvinenko, Geomechanics and Geodynamics of Rock Masses: Selected Papers from the 2018 European Rock Mechanics Symposium, 2018
The main driver of self-sealing in argillite is the swelling of clay minerals. A study of selfsealing, or of self-healing, is therefore closely linked to the study of clay shrinkage/swelling. Zhang et al. (2013) describe clay swelling as the sum of crystalline and osmotic swelling, the latter dominating over the former in conditions of high relative humidity (RH).
Characterization of hydromechanical damage of claystones using X-ray tomography
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
The main driver of self-sealing in argillite is the swelling of clay minerals. A study of self-sealing, or of self-healing, is therefore closely linked to the study of clay shrinkage/swelling. Zhang et al. (2013) describe clay swelling as the sum of crystalline and osmotic swelling, the latter dominating over the former in conditions of high relative humidity (RH).
Landslide hazard zoning based on numerical simulation and hazard assessment
Published in Geomatics, Natural Hazards and Risk, 2018
Chia-Ming Lo, Zheng-Yi Feng, Kuang-Tsung Chang
The study used multi-remote sensing images with a heavy reliance on the interpretation of stereo-aerial photography supplemented by field checking to conduct the landslide classification in the study area (Figure 5), that shows 26 landslides, including 7 rockfall (about the total number of 27%; a mass of falling or fallen rocks under gravity condition to form talus), 14 debris slide (about the total number of 54%; when comparatively dry, a mass of predominantly noncontinuously soil and rock fragments that has slid or rolled rapidly down a steep slope under gravity condition to form an irregular hummocky deposit), 2 compound slide (about the total number of 8%; compound slide are those which are composed of several simple landslides; the compound slide belong to muti-storeyed landslides in the study area), and 3 debris flow (about the total number of 11%; debris flows are those which are composed of water-laden masses of soil, fragmented rock, and debris material rush down mountainsides, funnel into stream channels, entrain objects in their paths, and form thick, fan shape deposits on downstream). These types of movement represent the vast majority of the typical landslides recognized in the study area. Although the mechanism of the typical landslides is extremely complicated in the study area, however, the primary cause was the significant quantities of cleavage and joints in the slate and argillite slopes with fragile intact rock strength (Figure 3(ii)). Moreover, the terrain was steep, which created thicker layers of regolith or colluvium that were less stable and prone to forming shallow slides and debris flows in the event of heavy rains. In general, metasandstone is brittle; it easily ruptures under stress and is highly jointed. With the downcutting of the river and decompression, the metasandstone near the ground surface is abnormally fragmented, which facilitates rock falls or slope slides. In the more gently inclined interbedded metamorphic rock, there is a thick layer of the more corrosion-resistant metasandstone, which is less susceptible to weathering. However, some roughly vertical joints (ruptures) are present within the thick layer of sandstone. Water can infiltrate these joints and create a pushing force when it freezes in colder weather, and the pushing force then causes collapses. Another possible cause is the headward erosion of the river. The less corrosion-resistant slate surrounding the metasandstone layer is gradually eroded and cannot support the rock above it, which then causes progressive collapsing along the edges (Figure 3(ii)) and forms the material for the next debris flow. The strata downstream of the study area mainly consist of argillite, which is shale with a mineral composition of soft clay minerals that previously underwent slight metamorphism. Fresh argillite comes in the shape of blocks and is moderately hard and dense. However, weathered fragments are pencil-shaped and fragile. In steep terrain, erosion such as heavy rain can easily cause collapses (Figure 3(iv)) and result in geological disasters.