Arabian Journal of Geosciences

Metang, Victor; Tassongwa, Bernard; Emmanuel, Nomo Negue; Kenzo, Henri Appolinaire; Franck Bamou-Wandji, Steve; Domkam, Brigitte; Mboutchouang, Dior-Christelle; Mbakam, Diane Marilyn Nkamga; Kengne, Léa Grace Tene; Mouafo, Lucas

doi: 10.1007/s12517-022-10244-wpmid: N/A

The Mewoulou-Nkolbisson (Western Yaoundé-Cameroon) fault has been mapped in previous works from aerial images only. This paper aims at better describing this fault using satellite images and petrographic and structural features. The satellite images used are SRTM images, imported into ArcGIS 10.3.1. After processing, the shaded relief was extracted and the images filtered to better appreciate the morphology and the constituent elements of the relief. Four main secondary fault corridors characterized by cataclasites were investigated along the scarps of the main fault. These cataclasites crop out in sub-lozengic shape in subvertical corridors. Microscopic observations of these rocks show that they are protocataclasites since the percentage of the fine matrix is less than 50%. From the structural analysis, the main fault is a ductile left lateral strike-slip fault–oriented NNW-SSE. The stresses that induced fractures are oriented NW–SE for σ1 and SW-NE for σ3. Regionally, the Mewoulou-Nkolsisson fault makes an angle of about 80° with the direction of the Sanaga fault. According to the Riedel model, this geometric arrangement suggests that the Mewoulou-Nkolbisson fault is an antithetic satellite fault to the dextral kinematic Sanaga fault. The study area presents steep slopes, rock blocks from fractures, and valleys along the fault. All these features constitute a risk of accident, burial, and flooding for the surrounding populations.

Abbasi, Akbar; Mirekhtiary, Fatemeh; Turhan, Şeref; Kurnaz, Asli; Rammah, Y. S.; Abdel-Hafez, Shams H.; Zakaly, Hesham M. H.

doi: 10.1007/s12517-022-10249-5pmid: N/A

Soil pollution with heavy metals (HMs) has become an increasingly serious environmental concern and needs assessment of ecological and human health risks, especially in an urban area. For this purpose, the contents of eight HMs (As, Mn, Cr, Cu, Hg, Ni, Pb, and Zn) in surface (0–5 cm) soil samples from 32 urban sites in the North area of Cyprus were examined using EDXRF spectrometer analysis. The average concentrations for As, Mn, Ni, Pb Cr, Cu, Hg, and Zn in soil samples were 4.7, 950.6, 230.5, 48.2, 1.8, 186.8, 15.1, and 87.5 mg/kg, respectively. The results showed that the mean concentrations of the HMs in the soil samples followed the order Mn > Cr > Ni > Zn > Cu > Pb > As > Hg, respectively. The mean geo-accumulation index (Igeo) of Hg was found in strong/extreme contamination. The potential ecological risk index (PERI) mean value was calculated in moderate ecological risk. Also, health risks assessment through three exposures pathways in adults and children showed that the total hazard index (HI) values for children were higher than for adults.

Sedara, Samuel Omosule; Ray, Labani; Alabi, Olusegun Olalekan

doi: 10.1007/s12517-022-10192-5pmid: N/A

The southwestern part of Nigeria is one of the known regions in Nigeria for exploration and development potential, where manifestations of geothermal resources are present. Some geophysical studies and geochemical analysis were undertaken in this region, but the thermal properties of the rocks are devoid and these parameters are valuable for geothermal exploration. In the present study, thermal conductivity is determined by an indirect method from the mineralogy of rocks using various mathematical mean models and the thermal conductivity (TC) of those minerals. The igneous and metamorphic rocks available in this region exhibit a wide range (2.1 to 5.1 Wm−1 K−1) in thermal conductivity. TC of granitic rocks, as well as phyllite and amphibolite (2.41 to 3.15 Wm−1 K−1 and 2.9 to 3.4 Wm−1 K−1, respectively), show a narrower range, whereas different types of gneisses (banded gneiss, granite gneiss, and migmatize gneiss) and schists (quartz-mica schist, mylonitize schist) exhibit wide variations (2.7 to 4.3 Wm−1 K−1 and 2.8 to 4.1 Wm−1 K−1, respectively). The quartzite represents the highest thermal conductivity (3.6 to 5.1 Wm−1 K−1) among all the rock types in the present study. These datasets constitute the first methodical estimations of the thermal conductivity of rocks due to the lack of direct measurements in the region. The study also brings out the need for systematic characterization of thermal and physical properties of major rock types in the region for thermal modeling, assessment of geothermal energy and geo-engineering applications in the region as there are wide variations in thermal conductivity.

Xu, Junlong; Wen, Xingping; Luo, Dayou; He, Ping

doi: 10.1007/s12517-022-10258-4pmid: N/A

In this study, the potentialities of optical images in different spectral ranges for automatic lineament extraction were compared by Landsat-8 OLI, Sentinel-2, and GF-1. First, the correlation coefficients between illumination coefficient images that are capable of depicting topographic relief and OLI B5, Sentinel-2 B6, B7, B8, B8A, B9, and GF-1 B4 images were higher than 0.6. In addition, the correlations between illumination coefficient images and the above band images before and after topographic correction changed significantly, thus revealing that the gray values of the above bands were affected most significantly by the topography. Subsequently, the differences in three-dimensional (3D) morphology between the fault zones and the no-fault zones should be the most intense. Second, the differences in gray values between different objects were insignificant in the above band images, thus leading to the less significant natural and artificial linear traces that did not belong to geological structure elements or geomorphic elements. Furthermore, there were a certain degree of correspondences between the NE-strike linear traces heightened on the basis of image filtering and the NE-strike main Faults. Lastly, the geological lineaments exhibiting fairly good correspondences with the tectonic geomorphology and river valley geomorphology were extracted effectively from the above band images by using a set of technical methods with wavelet transformation as its core. As indicated by the results, the near infrared (NIR) bands, consisting of OLI B5, Sentinel-2 B8, B8A, and GF-1 B4, as well as Sentinel-2 B6 (red edge 2) B7 (red edge 3) and B9 (water vapor), of which the spectral characteristics were similar to NIR, were found as the optimal bands for automatic lineaments extraction.

Zhang, Jinpeng; Liu, Limin; Shao, Jun

doi: 10.1007/s12517-022-10251-xpmid: N/A

Concrete carriers are stronger and cheaper than coal pillars. The gangues in the coal mine gob to produce concrete can not only achieve the utilization of abandoned gangues, but also achieve the purpose of protecting roadways and saving resource. This paper presented a new non-coal pillar mining method by concrete carrier replacing coal pillar. The feasibility of the concrete carrier was analyzed by the key block theory. The optimum proportion of gangue concrete and the width of concrete carrier were investigated through laboratory tests and numerical simulations. Then, the innovative method was applied to a coal mine. The results indicated that the optimum proportion of concrete carrier was water-cement ratio of 0.5, cement content of 255 kg/m3, fly ash content of 45 kg/m3, river sand content of 200 kg/m3, and gangue content of 600 kg/m3. The most reasonable width of the concrete carrier between two adjacent roadways was 2 m. The overall deformations of the roadways were not large. And the maximum bolt stress was less than 4.5 MPa, indicating that the bolt can work normally. So, the concrete carrier replacing coal pillar was successful.

Mahfoudhi, Sélim; Mansour, Aida Ben; Hammouda, Sofiane Ben; Hafiane, Amor; Trabelsi, Ismail

doi: 10.1007/s12517-022-10202-6pmid: N/A

The adsorption of humic acid (HA) onto granular-activated carbon (GAC) was studied. The effect of four experimental parameters (GAC dose, pH, ionic strength, and temperature) on HA adsorption and evaluation of optimum levels of process variables were evaluated in a batch system using central composite design (CCD). The principal component analysis (PCA) and dendrogram were performed to study the possible correlation between different parameters. Pseudo-first-order, pseudo-second-order (Types 1 and 2), Elovich, Weber–Morris intraparticle diffusion, and Boyd models were used to find out the kinetic data and mechanism of adsorption process. The pseudo-second-order model type 2 described well the kinetic data, while the rate limiting the process in the beginning was external mass transfer and intra-particle diffusion is not the only rate limiting step. The statistical analysis proves the suitability of the model in representing the adsorption process with an R2 value of 0.9898. Operating conditions of GAC weight: 3 g L−1, pH 6, NaCl concentration: 0.57 g L−1, and temperature 40 °C allow reaching an adsorption of 98.10%. Temkin isotherm model and pseudo-second-order kinetic model type 2 were found to be statically in accordance with the adsorption data. In conclusion, understanding of HA removal is well described by the optimization of the GAC dose, pH, ionic strength, and temperature parameters. Comparison of different GACs in full-scale studies is also important due to differences in the TOC removals of GACs with similar product specifications.Graphical abstract[graphic not available: see fulltext]

Ayad, Abderrahim

doi: 10.1007/s12517-022-10181-8pmid: N/A

Ezati, Maryam; Gholami, Ebrahim

doi: 10.1007/s12517-022-10280-6pmid: N/A

In the Central part of the Kopeh Dagh, there are a set of active right-lateral strike-slip faults that obliquely intersect the range and cause displacement in geomorphological and geological structures. In order to evaluate the rate of tectonic activities in the Central Kopeh Dagh, T, SL, Vf, HI, and RIAT morphometric indices were evaluated. The average value of T index is equal to 0.25, and the main rivers are tilted toward the south. So, the E-W trending folds and thrusts, which are parallel to the basins, have caused the main river to tilt to the south. The highest value of the SL index is related to the intersection of the strike-slip faults which cut the sixth and seventh order rivers. The lowest values of the Vf index are related to the northern part of the studied region; hence, the V-shape valleys and high incision rates are associated with the high degree of tectonic uplift in the Shirinrood basin. Moreover, high values of the SL index and low values of the Vf index are related to the intense tectonic activities in the northern part of the Central Kopeh Dagh. The hypsometric integral (HI) indicates that the highest rock uplifts rate happened in the Shirinrood basin. Neotectonic analysis of the Central Kopeh Dagh shows that the northern part of the study area has the highest tectonic activity and earthquake risk.

Wang, Hai-Ping; Gao, Meng; Wang, Ying; Chen, Qing-Sheng

doi: 10.1007/s12517-022-10284-2pmid: N/A

Seismic liquefaction of sand is an important research topic in geotechnical engineering. Most of the previous researchers have simulated liquefaction process under earthquake by sinusoidal load dynamic test, that is, the actual seismic wave is simplified to equivalent sinusoidal wave through Seed’s method of equivalent cycle number. However, it cannot reflect the actual situation of soil seismic performance. To overcome this issue, in this paper, a method for applying the actual seismic wave to test is proposed, which is used for conducting the dynamic triaxial test to study the liquefaction properties of calcareous sand under actual seismic loading. Based on the equivalent cycle number method, the actual seismic waves are equivalent to sinusoidal waves, and the liquefaction properties of calcareous sand under equivalent sinusoidal loads are compared with that of actual earthquake loads. After that, the earthquake performance of calcareous sand under different loading modes is analyzed to obtain the equivalent reduction coefficient conforming to calcareous sand. The results demonstrate that the pore water pressure development of calcareous sand under actual seismic loading has the characteristic of “stepped.” The strain failure type is a tensile failure, and there is a threshold cyclic stress ratio of liquefaction failure. Compared with the actual seismic load, the pore water pressure and strain accumulation of calcareous sand under sinusoidal load have more regular shapes. When studying the dynamic liquefaction properties of calcareous sand, the pore water pressure failure criterion is preferred for actual seismic load, while the strain failure criterion is preferred for the sinusoidal load. The equivalent reduction coefficient of calcareous sand under seismic loading is slightly less than 65%, and it is supposed to be selected according to different loading periods.

Pan, Weidong; Jiang, Hao; Chen, Jian

doi: 10.1007/s12517-022-10235-xpmid: N/A

In the process of heat conduction between thermo-active ground structures and the ground, the change of the temperature field will lead to the change of the soil stress field and the change of mechanical properties of soil and soil-structure interface. Based on the quadruple shear strain-controlled direct shear apparatus, a temperature-controlled system was added and converted into a temperature-controlled direct shear apparatus. A series of temperature-controlled interface direct shear tests were carried out between sand and concrete with different contents of fine-grained soil to investigate the effect of the fine-grained soil content and temperature on the interface shear strength parameters. Based on the shear strength theory of unsaturated soil, the interface friction mechanism was summarized, and the micro mechanism of temperature effect of the interface shear characteristics was analyzed. It is found that the temperature has little effect on the type of the interface shear stress versus shear displacement curve (τ-l curve), but has a slight effect on the peak point. When the content of fine-grained soil β≤11%, the interface shear strength index first decreases and then increases with the increase of temperature, and the minimum value appears at the temperature of 40°C (T=40°C). The interface shear strength indexes all increase with the increase of temperature when β >11%. With the increase of the fine-grained soil content, the interface internal friction angle is negatively correlated, and the interface cohesion force is positively correlated.