scholarly journals Structure and Mechanical Properties of the Dueñas Clay Formation (Tertiary Duero Basin, Spain): An Overconsolidated Clay of Lacustrine Origin

2021 ◽  
Vol 11 (24) ◽  
pp. 12021
Author(s):  
José Nespereira ◽  
José Antonio Blanco ◽  
Mercedes Suárez ◽  
Emilia García-Romero ◽  
Mariano Yenes ◽  
...  
Keyword(s):  
Swelling Pressure ◽  
Point Load ◽  
Load Test ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Compression Tests ◽  
Durability Test ◽  
Thin Sections ◽  
Direct Shear Tests ◽  
Clay Formation

The Dueñas Clay Formation is considered an example of a deposit of lacustrine continental origin. It is formed mainly by overconsolidated clays and includes feldspathic arenites, and clayey and silty levels; however, in geotechnical projects it is considered a clay unit and treated as a whole. The structure of each level was assessed in the field, in thin sections, and by SEM in the case of the clayey level. In addition, identification, strength, deformation, and durability tests were undertaken according to the nature of the samples (grain size analysis, Atterberg Limits, point load test, direct shear tests, uniaxial compression tests, swelling pressure, and unidimensional consolidation tests). The durability test was used as a criterion for dividing the levels within the formation according to their behavior as soil or rock. It was observed that the proportion and type of carbonate cementation controls the way in which the material behaves, with sparithic cement increasing the strength. The clay levels are expansive due to the presence of smectite, which also influences their behavior under shear stress. In addition, the massive and laminar structure of the layers caused by the continental conditions, in addition to the processes of post-sedimentation, explain their low compressibility.

scholarly journals Geotechnical properties for sediment of Tigris River reach banks within Tikrit town/ Iraq

2019 ◽  
Vol 24 (6) ◽  
pp. 65
Author(s):  
Maha Shaher Badowi ◽  
Mohammad Rashid Abood ◽  
Sabbar Abdullah Saleh
Keyword(s):  
Chemical Properties ◽  
Flood Plain ◽  
Point Load ◽  
Load Test ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Left Bank ◽  
Dominant Component ◽  
River Terraces ◽  
Tigris River

The geotechnical, engineering and chemical properties of the sediments of river terraces on the right bank and flood plain on the left bank of Tigris river. The physical tests include (specific gravity, absorption%, moisture content %, atterberge limits, grain size  analysis) showed that the dominant component of soil is (gravel) with varied amount of fine components, the engineering tests include direct shear test, CBR, and point load test, while the chemical analyses include gypsum%, T.D.S% and O.M% showed increase in gypsum% and  T.S.S% in right bank and increase of O.M%, and decrease of the three ratios in the left bank because the leaching of the sediments. The geotechnical study showed many engineering problems occurs in engineering establishments specially in the river terraces because the high ratios of gypsum and T.S.S.   http://dx.doi.org/10.25130/tjps.24.2019.110

scholarly journals Characterization of Weathered Soft Rock Mass by Index Tests

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Fernandes Leão M
Keyword(s):  
Rock Mass ◽  
Soft Rock ◽  
Point Load ◽  
Load Test ◽  
Rock Properties ◽  
Morphological Description ◽  
Durability Test ◽  
Stability Issues ◽  
Weathering Zone

The understanding of geotechnical and geomechanical rock mass behavior is challenging, mainly regarding weathered parts, since they may trigger stability issues. Soft Rocks, as phyllite, are known to enhance these problems. In this case, a road cut on a highway between the cities of Ouro Preto and Mariana (MG – Brazil) was studied, showing a particular weathering zone with changing conditions. After morphological description and geological fragmentation (using geological hammer, the Schmidt hammer and a switchblade) of the weathering zone, tests were done on rock matrix and rock mass in order to identify the discontinuity features. Physical properties were determined by physical index, using the point load test and slake durability test. The results permit to define the weathering zone, showing some huge anisotropy and heterogeneity in the rock properties.

scholarly journals Silt content approximation of Neogene Surma group mudrocks, Sitakund anticline, Bengal basin

2018 ◽  
Vol 30 (1-2) ◽  
pp. 35-43
Author(s):  
Md Yousuf Gazi ◽  
SM Mainul Kabir ◽  
Md Badrul Imam
Keyword(s):  
Particle Size Analysis ◽  
High Rate ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Bengal Basin ◽  
Geologic History ◽  
Thin Sections ◽  
Silt Content ◽  
Rate Of Sedimentation ◽  
Surma Group

Petrography of the Neogene mudrocks in this study incorporates laser particle size analysis, thin sections and scanning electron microscopy (SEM). Ten representative mudrock samples were collected from outcrops of the Sitakund structure. From the studies, it is evident that mudrocks of Sitakund structure are characteristically silty. The silt content, as estimated by laser grain size analysis, of the mudrocks ranges from 39 to 77% with average of 58%. Significant amount of granular silt with the platy clay minerals is also evident from the SEM micrographs. The silts are mainly quartz, feldspar and micas. The high silt content in the Neogene mudrocks implies an enormous flux of silty sediments with a very high rate of sedimentation allowing little time for a more selective sorting. This supports the geologic history that the uplifting and erosion of Himalaya was at the peak during Miocene and the Ganges mega delta received highest rate of sedimentation and growth rendering shale consistently silty.Bangladesh J. Sci. Res. 30(1&2): 35-43, December-2017

Assessment of the Aggregate in Historical Plasters

2016 ◽  
Vol 865 ◽  
pp. 162-166
Author(s):  
Petr Rezek ◽  
Petr Martinec
Keyword(s):  
Grain Size ◽  
Optical Microscopy ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Petrographic Analysis ◽  
Assessment Methodology ◽  
Thin Sections ◽  
Fine Aggregates

This article deals with the analysis of the aggregates of historical plasters. In the paper there is described the assessment methodology of the aggregates of historical plasters. The assessment of the aggregates is carried out with the example of a set of original and modern-day aggregates taken in the prelature and convent of the Želiv Monastery. Composition of fine aggregates of historical plasters was compared to the composition of the aggregates from resources of nearby watercourses. As well as it was assessed the geological character of nearby vicinity of the Monastery. For the analysis of character of the plaster fine aggregates it is applied the optical microscopy of the plaster thin sections, grain size analysis, mineralogical and petrographic analysis of the aggregates. The presented results document the differences in the origin of the aggregate used in plasters.

scholarly journals A geotechnical Study on the Characteristics of Swell-Shrink Soils in Kibaha, Tanzania

2007 ◽  
Vol 30 (2) ◽  
pp. 92-97
Author(s):  
Charles Lucian ◽  
Staffan Hintze ◽  
Joseph J. Msambichaka
Keyword(s):  
Swelling Pressure ◽  
Linear Shrinkage ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
X Ray Diffraction ◽  
Soil Plasticity ◽  
X Ray ◽  
Undisturbed Samples ◽  
Free Swell ◽  
The Difference

The properties of Swell-shrink of the soils in Kibaha were studied. Geotechnical and mineralogical tests were carried outon disturbed and undisturbed samples recovered from trial pits at different locations. Using empirical relationships, theswelling potential of the soil was established in correlation with the soil plasticity limits and grain size analysis (claycontents). The average values for the plastic, liquid and linear shrinkage limits for soils were 22.2%, 60.7% and 14.5%respectively. The plasticity Index (PI) which is the difference between liquid limits and plastic limits ranges from 27% to47.4% with an average of 38.5%. The natural water content is very small ranging from 7% to 11% with an average of9.6% which is smaller than the corresponding shrinkage limit.Furthermore, the samples were tested for percentage of volume change in free swell tests and swelling pressure in one-dimensional swell tests. The free swell and upward pressure were in the excess of 100% to 150% and 50 kParespectively. In addition, the coefficient of linear extensibility ranged from 0.09 to 0.14 signifying high to very high swell-shrink potential.Finally, the main clay mineral present in the sample was determined by running the X-ray diffraction (XRD) test. The x-ray diffraction scan indicated the presence of high proportion of clay minerals (smectite) in the soils.

scholarly journals Evolution of ice crystal microstructure during creep experiments

2007 ◽  
Vol 53 (182) ◽  
pp. 479-489 ◽  
Author(s):  
Ilka Hamann ◽  
Christian Weikusat ◽  
Nobuhiko Azuma ◽  
Sepp Kipfstuhl
Keyword(s):  
Grain Growth ◽  
Boundary Migration ◽  
Strain Range ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Isotropic Hardening ◽  
Ice Crystal ◽  
Compression Tests ◽  
Subgrain Rotation ◽  
Growth Deceleration

AbstractResults of laboratory uniaxial compression tests over the stress range 0.18–0.52 MPa and the strain range 0.5–8.6% at approximately –5 and –20°C are presented. Grain-size analysis and comparisons with annealing tests confirm that grain-growth reducing processes are active during deformation. Microstructural observations reveal that subgrain-rotation recrystallization and grain-shape changes due to strain-induced grain-boundary migration are the causes of the grain-growth deceleration. Further results from microstructural observations show that obstacle formation by dislocation walls and subgrain boundaries is the reason for isotropic hardening during creep. Subgrainboundary types that are likely to be relevant for studies on the activity of different dislocation types are described.

Dislocations in alumina deformed by prismatic slip

1978 ◽  
Vol 36 (1) ◽  
pp. 606-607
Author(s):  
J. Cadoz ◽  
J. Castaing ◽  
J. Philibert
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Basal Slip ◽  
Prismatic Slip ◽  
Compression Tests ◽  
Thin Sections ◽  
Burgers Vector ◽  
Maximum Deformation ◽  
Transmission Electron ◽  
Mechanical Thinning

Plastic deformation of alumina has been much studied; basal slip occurs and dislocation structures have been investigated by transmission electron microscopy (T.E.M.) (1). Non basal slip has been observed (2); the prismatic glide system <1010> {1210} has been obtained by compression tests between 1400°C and 1800°C (3). Dislocations with <0110> burgers vector were identified using a 100 kV microscope(4).We describe the dislocation structures after prismatic slip, using high voltage T.E.M. which gives much information.Compression tests were performed at constant strainrate (∿10-4s-1); the maximum deformation reached was 0.03. Thin sections were cut from specimens deformed at 1450°C, either parallel to the glide plane or perpendicular to the glide direction. After mechanical thinning, foils were produced by ion bombardment. Details on experimental techniques can be obtained through reference (3).

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