China
Africa
Explore chapters and articles related to this topic
Stability and stabilization of natural slopes
Published in Manuel Matos Fernandes, Analysis and design of geotechnical structures, 2020
Figure 9.23 shows a photograph of the shear surface of the slope from the previous figure. The destabilization occurred after digging part of the passive block for building a new road. The polished surface of the clay results from the phenomenon previously discussed. The visible grooves, a result of the landslide, are known in the literature as slickensides. In the case presented, the residual angle of shearing resistance, ϕ′r, mobilized in the slip surface ranged between 11° and 14° (with an almost null residual effective cohesion, c′r).
Site investigation, instrumentation, assessment and control
Published in Bujang B. K. Huat, Arun Prasad, Sina Kazemian, Vivi Anggraini, Ground Improvement Techniques, 2019
Bujang B. K. Huat, Arun Prasad, Sina Kazemian, Vivi Anggraini
Structures in this context mean the presence or absent of discontinuity inside the soil mass and not arrangement of particles in soil skeleton. Structure in soil mass plays an important role in controlling soil behavior, especially its shear strength and permeability. Description which refers to its properties are: Bedding: This refer to visible bedding plane, such as thin layers, thick layers or alternate layers.Discontinuity: Usually refers to joints or fissures. Undisturbed means no discontinuity. For fissures, record has to be made of the surface and intensity of its discontinuities.Shearing: The presence of the shear surface is normally indicated by the presence of slickenside (polished surface due to shearing).
Analysis of the landslide mechanism of Iwakura creep in Saga, Japan
Published in Jan Rybář, Josef Stemberk, Peter Wagner, Landslides, 2018
J. Gunatilake, Y. Iwao, T. Yamasaki
Deeper shear zones identified as slip surfaces have been formed at depths of 15–28m. They are characterized by the presence of slickensides, fault gauge and thin clay seams. Rocks at these shear zones have progressively crushed and oxidized. Slickensided fault plains are very common along the surface through out the rock slope. Existence of the slickensides and fault gauges provide evidence for the complex movements occurred in the area over the past. The faults at N 40–45° E and N 10–15° W directions are the dominant as seen in the stereographic projection. Regional geomorphologic evidence also suggests the existence of NE-SW and NW-SE lineaments, which could be well identified in topographical maps and aerial photographs.
Fractures characterization of carbonate reservoir using core analyses and borehole image logs
Published in Petroleum Science and Technology, 2023
In the examined cored intervals, naturally occurring fractures are described as those characterized by stylolitic structures and being empty or partially filled with the associating secondary mineralization (Aguilera 1995; Ameen 2003; Bratton et al. 2006; Lavenu et al. 2014). The observed naturally occurring fractures had dips ranging from 17° to 74° (Figure 10a–e). They may be detectable over the whole core diameter or restricted to the core edges. Some of the naturally occurring fractures were eventually filled by the authigenic calcite, which was most likely derived from the dissolved bioclasts (Figure 10f and g); these fractures developed during the early diagenetic alteration of the Judea Formation sediments (Yousef et al. 2021a; Yousef, Morozov, and Sudakov 2021). Some of the naturally occurring fracture surfaces showed polishing and/or formation of the linear slickensides (Figure 10h and k). These characteristics demonstrate considerable differential mobility between the fracture surfaces. The slickensides' linear shape suggests that they are a natural feature rather than the result of torque generated by coring (Thompson 2000; Tingay, Reinecker, and Müller 2008). Microphotographs of slickensides taken with a scanning electron microscope (SEM) (Figure 10h and k) show polished, hummocky surfaces with a sequence of linear grooves and ridges. The slickenside surfaces are covered in brecciated host rock debris and remnant bitumen spots. The brecciated host rock most likely formed as a result of the fault movement (Thompson 2000; Tingay, Reinecker, and Müller 2008).
K-Ar fault-gouge dating in the Lower Buller gorge constrains the formation of the Paparoa Trough, West Coast, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2021
Uwe Ring, Ibrahim Tonguc Uysal, Kui Tong, Andrew Todd
The brittle fault zones observed in outcrops are commonly penetratively fractured into arrays of blocks whose surfaces have different orientations. The cataclastic rocks associated with the faults have a rubbly to fragmental appearance and show numerous mesoscopic brittle faults, which are characterised by anastomosing clayey gouge layers with thin (∼1 mm to 10 cm) zones of cataclasite, breccia and hematite-clay-coated fractured rock. Weakly oriented phacoid-shaped tectonic slivers of country rock in the fault zone are in the centimetre to decimetre range. Individual blocks are separated by thin, striated surfaces, which provide the direction of slip on fault planes (e.g. Hancock 1985; Petit 1987; Doblas 1998). We distinguish slickensides, striations, and slickenfibres. Slickensides is the planar, polished, surface of a fault plane. Striations (or slickenlines) are linear grooves scratched into fault surfaces by brittle wear and are the most common type of striae observed in the Lower Buller gorge. Slickenfibres comprise new minerals (mainly quartz, chlorite and epidote) precipitated on a fault surface as fibres elongated parallel to the slip vector.