scholarly journals Quantitative Geomorphological Parameters Analysis for the Aynalem- Illala Streams, Tigray, Northern Ethiopia

2021 ◽  
Vol 13 (1) ◽  
pp. 67-88
Author(s):  
Fethangest Woldemariyam Tesema ◽  
Gebrerufael Hailu Kahsay ◽  
Berihu Abadi Berhe
Keyword(s):  
Morphometric Analysis ◽  
Rock Material ◽  
Parameter Analysis ◽  
Surface Shape ◽  
Morphometric Parameter ◽  
Maturity Stage ◽  
Northern Ethiopia ◽  
Hypsometric Integral ◽  
Heterogeneous Rock ◽  
Relief Ratio

Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge.  The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.

scholarly journals Determination of Mechanical Properties of Altered Dacite by Laboratory Methods

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 813
Author(s):  
Veljko Rupar ◽  
Vladimir Čebašek ◽  
Vladimir Milisavljević ◽  
Dejan Stevanović ◽  
Nikola Živanović
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Rock Mass ◽  
Uniaxial Compressive Strength ◽  
Rock Material ◽  
Strength Parameter ◽  
Gradual Transition ◽  
Strength Parameters ◽  
Triaxial Compressive Strength ◽  
Heterogeneous Rock

This paper presents a methodology for determining the uniaxial and triaxial compressive strength of heterogeneous material composed of dacite (D) and altered dacite (AD). A zone of gradual transition from altered dacite to dacite was observed in the rock mass. The mechanical properties of the rock material in that zone were determined by laboratory tests of composite samples that consisted of rock material discs. However, the functional dependence on the strength parameter alteration of the rock material (UCS, intact UCS of the rock material, and mi) with an increase in the participation of “weaker” rock material was determined based on the test results of uniaxial and triaxial compressive strength. The participation of altered dacite directly affects the mode and mechanism of failure during testing. Uniaxial compressive strength (σciUCS) and intact uniaxial compressive strength (σciTX) decrease exponentially with increased AD volumetric participation. The critical ratio at which the uniaxial compressive strength of the composite sample equals the strength of the uniform AD sample was at a percentage of 30% AD. Comparison of the obtained exponential equation with practical suggestions shows a good correspondence. The suggested methodology for determining heterogeneous rock mass strength parameters allows us to determine the influence of rock material heterogeneity on the values σciUCS, σciTX, and constant mi. Obtained σciTX and constant mi dependences define more reliable rock material strength parameter values, which can be used, along with rock mass classification systems, as a basis for assessing rock mass parameters. Therefore, it is possible to predict the strength parameters of the heterogeneous rock mass at the transition of hard (D) and weak rock (AD) based on all calculated strength parameters for different participation of AD.

scholarly journals Numerical Studies on the Failure Process of Heterogeneous Rock Material with Preexisting Fracture under Uniaxial Compression

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Qi Zhang ◽  
Dan Ma ◽  
Jiangfeng Liu ◽  
Kai Zhang ◽  
Zhiqiang Fan
Keyword(s):  
Shear Failure ◽  
Failure Process ◽  
Damage Model ◽  
Rock Material ◽  
Tensile Failure ◽  
Underground Engineering ◽  
Intact Specimen ◽  
Numerical Studies ◽  
Heterogeneous Rock ◽  
Reduced Parameters

It is of vital importance to understand the failure processes of the heterogeneous rock material with different kinds of preexisting fractures in underground engineering. A damage model was introduced to describe the initiation and propagation behaviors of the fractures in rock. Reduced parameters were applied in this work because the microcracks in the rock were neglected. Then, the numerical model was validated through comparing the simulation results with the laboratory observations. Finally, a number of numerical uniaxial compressive tests were performed on heterogeneous rock specimens with preexisting fracture, and the influence of the heterogeneity of the rock and the angle and length of the preexisting fractures was fully discussed. The results showed that the brittleness of the rock increased with the increase of the homogeneity index, and tensile failure was the main failure form for relatively heterogeneous rock, whilst shear failure was the main failure form for relatively homogeneous rock. The uniaxial compressive strengths of the specimens with the angles of 0, 30, 45, and 60 of the preexisting fracture dropped 62.7%, 54.7%, 46.6%, and 38.2% compared with that of the intact specimen; the tensile cracks were more difficult to form, and the required load was increasing with the increase of the angle of the preexisting fracture; besides, antiwing cracks were difficult to form than wing cracks because the tensile stress in wing cracks’ area was greater than that in antiwing cracks’ area. The uniaxial compressive strengths of the specimens with the lengths of 20 mm, 25 mm, 30 mm, and 35 mm of preexisting fracture dropped 38.6%, 46.6%, 53.4%, and 56.6% compared with that of the intact specimen, and the damage conditions of the samples with different lengths of preexisting fracture were similar.

scholarly journals MORPHOMETRIC ANALYSIS OF BAUR CATCHMENT IN LESSER HIMALAYA: USING GEO-SPATIALTECHNIQUES

2021 ◽  
Vol 9 (4) ◽  
pp. 83-100
Author(s):  
Neelesh Singh ◽  
◽  
Manisha Tripathi ◽  
Sunil Kumar ◽  
◽  
...  
Keyword(s):  
Morphometric Analysis ◽  
Geographical Area ◽  
Quantitative Description ◽  
Drainage System ◽  
Outer Part ◽  
Drainage Density ◽  
Morphometric Parameter ◽  
Lesser Himalaya ◽  
Drainage Pattern ◽  
Siwalik Group

The current assessment is an undertaking to evaluateand compare variousmorphometric parameters of the Baur catchment. Morphometric analysis of the river basin provides a quantitative description of the drainage system, which is an important aspect of the categorization of the basin (Strahler, 1964).The Baur catchment is located in the outer part of the Lesser Himalaya in the Kumaun region, which is a major part of Western Himalaya.The geographical area of Baur Catchment is 106.233Km2.Morphometric analysis of Baur Catchment includes linear, areal, and relief aspects.The calculation of the morphometric parameter, along with map preparation, was performed with the help of GIS techniques and ancillary material.Most of the area of Baur Catchment is occupied by Siwalik Group (sandstone and clay intercalation with pseudo-conglomerate) of rocks.The entire Baur Catchment has found 6th order drainage, which reveals sub-dendritic to a dendritic type of drainage pattern. It is observed that the drainage density of the Baur Catchment is 3.525 km/halfkm2.

Mechanical Parameter Analysis of Rock Material via PLSR Model

2011 ◽  
Vol 467-469 ◽  
pp. 1826-1831 ◽  
Author(s):  
Zao Bao Liu ◽  
Wei Ya Xu ◽  
Fei Xu ◽  
Lin Wei Wang
Keyword(s):  
Regression Model ◽  
Principal Component ◽  
Partial Least Square ◽  
Rock Material ◽  
Least Square ◽  
Parameter Analysis ◽  
Partial Least Square Regression ◽  
Mechanical Parameter ◽  
Least Square Regression

Mechanical parameter analysis is a complicated issue since it is influenced by many factors. Closely related with the influencing factors of compressibility coefficients of rock material (sandstone), this article first introduces the way to process partial least square regression (PLSR) analysis. The process of carrying out PLSR is divided into six steps as for analysis and prediction of the regression model, which are data preparation, principle collection, regression model for first principle component, secondary principle analysis, establishment of final regression model and number determination of principal component l. And then introduces PLSR for application of analysis and prediction of compressibility coefficients with 30 experiment samples. Seven prediction samples are carried out by PLSR with the training process of 30 samples. The result shows PLSR has good accuracy in prediction under the condition that the model is properly deprived based on certain experimental samples. Finally, some conclusions are made for further study on both mechanical parameters and partial least square regression method.

scholarly journals Linking Soil Erosion Modeling to Landscape Patterns and Geomorphometry: An Application in Crete, Greece

2021 ◽  
Vol 11 (12) ◽  
pp. 5684
Author(s):  
Imen Brini ◽  
Dimitrios D. Alexakis ◽  
Chariton Kalaitzidis
Keyword(s):  
Soil Erosion ◽  
Soil Loss ◽  
Anthropogenic Activities ◽  
Landscape Patterns ◽  
Parameter Analysis ◽  
Morphometric Parameter ◽  
Erosion Modeling ◽  
Soil Erosion Modeling ◽  
Erosion Rates ◽  
Soil Erosion Rates

Soil erosion is a severe and continuous environmental problem caused mainly by natural factors, which can be enhanced by anthropogenic activities. The morphological relief with relatively steep slopes, the dense drainage network, and the Mediterranean climate are some of the factors that render the Paleochora region (South Chania, Crete, Greece) particularly prone to soil erosion in cases of intense rainfall events. In this study, we aimed to assess the correlation between soil erosion rates estimated from the Revised Universal Soil Loss Equation (RUSLE) and the landscape patterns and to detect the most erosion-prone sub-basins based on an analysis of morphometric parameters, using geographic information system (GIS) and remote sensing technologies. The assessment of soil erosion rates was conducted using the RUSLE model. The landscape metrics analysis was carried out to correlate soil erosion and landscape patterns. The morphometric analysis helped us to prioritize erosion-prone areas at the sub-basin level. The estimated soil erosion rates were mapped, showing the spatial distribution of the soil loss for the study area in 2020. For instance, the landscape patterns seemed to highly impact the soil erosion rates. The morphometric parameter analysis is considered as a useful tool for delineating areas that are highly vulnerable to soil erosion. The integration of three approaches showed that there is are robust relationships between soil erosion modeling, landscape patterns, and morphometry.

scholarly journals Morphometric analysis of Capitella capitata (Polychaeta, Capitellidae)

2010 ◽  
Vol 100 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Erica Veronica Pardo ◽  
Laura Laund S. Teixeira ◽  
Antônia Cecília Z. Amaral
Keyword(s):  
Morphometric Analysis ◽  
Linear Regression Analysis ◽  
Allometric Equation ◽  
Morphometric Parameter ◽  
Northern Coast ◽  
Intertidal Zones ◽  
Straight Line ◽  
Capitella Capitata ◽  
Best Parameters ◽  
Area And Volume

Accurate size measurements are fundamental in characterizing the population structure and secondary production of a species. The purpose of this study was to determine the best morphometric parameter to estimate the size of individuals of Capitella capitata (Fabricius, 1780). The morphometric analysis was applied to individuals collected in the intertidal zones of two beaches on the northern coast of the state of São Paulo, Brazil: São Francisco and Araçá. The following measurements were taken: the width and length (height) of the 4th, 5th and 7th setigers, and the length of the thoracic region (first nine setigers). The area and volume of these setigers were calculated and a linear regression analysis was applied to the data. The data were log-transformed to fit the allometric equation y = ax b into a straight line (log y = log a + b * log x). The measurements which best correlated with the thoracic length in individuals from both beaches were the length of setiger 5 (r² = 0.722; p<0.05 in São Francisco and r² = 0.795; p<0.05 in Araçá) and the area of setiger 7 (r² = 0.705; p<0.05 in São Francisco and r² = 0.634; p<0.05 in Araçá). According to these analyses, the length of setiger 5 and/or the area of setiger 7 are the best parameters to evaluate the growth of individuals of C. capitata.

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