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Saeed Mojeddifar, Nastaran Ostadmahdi Eragh,
Volume 13, Issue 2 (8-2019)
Volume 13, Issue 2 (8-2019)
Abstract
Introduction
This work intends to apply ASTER images to discriminate hydrothermal alteration zones in Kerman Cenozoiic Magmatic Belt (KCMB). Band ratio, principal component analysis, Crosta and color composite images are important methods to analyze satellite images. Previous researches showed that these techniques are not able to discriminate hydrothermal alteration zones and they usually detect vegetation covering as alteration zones. The reason is found in the spectral signature of vegetation and alteration minerals. It means that they present the same interaction when face with electromagnetic energy in different wavelengths. Hydroxyl-bearing minerals are the important products of hydrothermal alteration. Clays, which contain Al-OH- and Mg-OH-bearing minerals and hydroxides in alteration zones, are distinguished by absorption bands in the 2.1–2.4 µm range of ASTER data. Solving these problems is difficult when using standard image-processing techniques such as band rationing, principal component analysis, or spectral angle mapper. In recent years, several attempts were made to extract altered regions in the areas covered with vegetation. To overcome this problem, this research uses ASTER data by applying support vector machine (SVM) algorithmn. SVM is a new technique for data classification in remote sensing application. This paper aims to investigate the potential of SVM algorithm in mapping of hydrothermally altered areas. In many applications, SVM has been shown to provide higher performance than traditional learning machines and has been introduced as powerful tools for solving classification problems. The adopted dataset contains three ASTER scenes using SWIR and VNIR bands, covering the Meiduk porphyry copper deposit, Kader, Abdar and Iju occurrences located in Kerman Province, southeast Iran.
Material and methods
This work has been prepared on three ASTER level 1B scenes. Two scenes were acquired on 18th April 2000 and another scenes on 15th June 2007. These scenes were georeferenced by using an orthorectified ETM + image, in UTM projection and WGS-84 ellipsoid as a datum. The first two data sets were corrected for Crosstalk. Atmospheric corrections were also performed by using Fast Line of Sight Atmospheric Analysis of Spectral Hypercubes (FLAASH). The data sets were then mosaicked. Internal Average Relative Reflectance (IARR) correction was also applied. In this part, the training and test samples of the ASTER data are presented. The adopted image is a multispectral satellite image that contains 2204 training pixels which 516 pixels are related to arjillic zone, 1278 pixels are related to phyllic zone and 500 pixels are pertinent to propylitic zone (Fig. 1).
Fig. 1. Training pixels for learning SVM algorithm; Red pixels: arjillic; Green pixels: phyllic; Blue pixels: propylitic
Results and discussion
ASTER bands 4, 6, 7 and 8 were applied for determination of phyllic and arjilic zones and 9 bands of ASTER for propylitic alteration. In order to evaluate the developed algorirhm, confusion matrix was used and validation showed that discrimination of phylic and arjilic is not possible but propylitic zone could be identified by SVM. Also, the present research introduced a new error function, so called blind error, which is calculated using confusion matrix. Based on blind error, SVM did not classify 73.6 percent of the alteration pixels. But the remained pixels were classified with accuracy of 66.06%. Honarmand et al. (2011) and Mojedifar et al. (2013) studied the field samples of the present study area. Their studies showed that sericitization is the most widespread form of hydrothermal alteration at the Iju, Serenu, Chahfiroozeh, Meiduk, Parkam, Kader and Abdar porphyry copper deposits. Two types of phyllic alteration could be found in the study area including ferric-iron-rich and iron-oxide poor phyllic alteration. ASTER images were also analyzed by band rationing and principal component analysis (PCA) in order to compare their results with the SVM classified image. A comparison of the field data with altered areas mapped by PCA reveals errors in the classified map. Vegetation cover and sedimentary rocks are enhanced, which are erroneously identified as areas of alteration. The band ratio approach yields similar errors to those produced by the PCA method. These problems are less evident in the classified image obtained by SVM. The qualitative assessment of the accuracy of these methods indicates that SVM algorithm could be a reliable technique for alteration mapping, provided that the nature of the training areas is well known.
Conclusion
A comparison of the results obtained from traditional classification methods and support vector machine algorithm was performed in order to map hydrothermal alteration. Since the known occurrence of mineralization in the study area is consistent with the mapped distribution of hydrothermal alteration using SVM, this method is suggested to apply in exploring for hydrothermal alteration in other parts of the Iranian Cenozoic magmatic belt../files/site1/files/132/6Extended_Abstracts.pdf
S. M. Ali Sadreddini, Navid Hadiani,
Volume 13, Issue 3 (11-2019)
Volume 13, Issue 3 (11-2019)
Abstract
Introduction
Past research studies have demonstrated that seismic ground motion can vary significantly over distances comparable to the dimensions of long span engineering structures. The accurate determination of earthquake ground motion at the base of long span structures such as dams and bridges whose piers are located on the valleys surface is one of the most important issues in earthquake engineering. In this paper, the spatially variable earthquake ground motions are generated at stations located on the valley slopes, considering the topography effect of a triangular valley. To this end, the simplified geometry of the valley of Masjed Soleyman embankment dam has been used for numerical modeling. The spatially varying ground motions are simulated by using spectral representation method. According to this methodology, the generated time histories are compatible with prescribed response spectra reflecting the wave passage and loss of coherence effects. This method assumes that the response spectrum is identical for all stations i.e., they have the same amplitudes and frequency content. This assumption is not valid for stations located on valley surface in which the amplitude and frequency content of the seismic waves are changed considerably by topography features. It is concluded that the proposed method in this study can lead to artificial spatially variable earthquake ground motions which can be readily reflect the amplification pattern of 2D triangular valleys.
Material and methods
In the first part of this paper, seismic response of a triangular valley is investigated through time history analysis conducted by using FLAC2D computer program. The geometry of the valley analyzed in this paper is chosen close to the valley of the Masjed Soleyman embankment dam. Dynamic analysis is conducted using an artificial earthquake generated by spectral representation method. The material properties are obtained based on the results of a comprehensive study carried out to identify the dynamic characteristics of two large embankment dams in Iran. Spectral amplification functions of seismic waves are calculated by dividing the response spectra of stations located on the slope of the valley to that in base of the valley. These functions are then used as target quantity for generation of spatially variable ground motions at points located on the valley. In this study, spectral representation method, the most widely accepted method for generation of spatially variable ground motions, is developed to take into account the topography effect. According to this methodology, the generated time histories are compatible with prescribed spectral amplification functions reflecting the wave passage and loss of coherence effects. The Harichandran-Vanmarcke coherency model is used to simulate spatially variable seismic ground motions.
Results and discussion
Based on the obtained results the maximum and minimum values of peak acceleration are yielded at the base and at the edge of the valley, respectively. The results indicate considerable increase of the acceleration RMS at points near the edge of the valley. Maximum spectral amplification is also observed at the edge of the valley. For all points located on the valley, the first peak spectral amplification occurred at frequency of 1.15Hz, which can be readily interpreted as the natural frequency of the valley. In order to evaluate the accuracy of the proposed method, the RMS and spectral amplification functions of artificial earthquakes are compared to target quantities. A very good consistency between the spectral amplification of artificial earthquakes and target spectral amplifications was observed in terms of both amplitude and frequency content.
Conclusion
The following conclusions were drawn from this paper.
- Artificial earthquakes generated using proposed method of this paper are in a very good agreement with the amplification pattern of the valley.
- The results of this study can be readily used to investigate the influence of spatial variability of earthquake ground motion on structures like bridges and dams whose supports are located inside the valley and are subjected to multi-support earthquake excitation.
- The proposed method of this paper is not limited only to the valley topography, but it can be effectively used in the generation process of non - uniform artificial earthquakes for stations located on other topography features. The latter can be carried out by establishing the spectral amplification functions of other topography features such as slopes and hills resulted from field or numerical studies.
Mohammad Hossein Ghobadi, Mehrdad Amiri, Farhad Aliani,
Volume 14, Issue 1 (5-2020)
Volume 14, Issue 1 (5-2020)
Abstract
Because of the diversity in petrography, peridotites have variable physical and mechanical properties. For this reason, knowledge of resistance properties and their deformation will help with the prediction of engineering behavior of these rocks. Due to the large spread of igneous rocks, especially peridotite, in Zagros, northeastern and central Iran, special attention has been paid to their petrographic, physical and mechanical characteristics. The construction of the structure within or on the peridotites and the choice for the purpose of the stone borrow depends on the recognition of its engineering geology characteristics. In this paper, in addition to the field and laboratory study, the geological characteristics of peridotite engineering has been investigated.
Material and methods
In order to study the geological characteristics of the peridotites of Harsin region, 15 suitable blocks were selected and transferred to the laboratory. Accordingly, from collected rock samples, 150 cylindrical cores of diameter 54 mm were prepared and physical and mechanical tests were performed according to (ISRM, 2007) and (ASTM, 2001) guidelines. In this research, after sampling of the study area and preparing the core for the lithological characteristics of the samples by providing thin sections of them with polarizing microscopy was studied.
Results and discussion
By considering the results of laboratory tests and analysis from Harsin peridotites in Kermanshah province, we can acclaim that with increasing the percentage of minerals in olivine and pyroxene in rock, the strength was decreased and the levels weaknesses, which is due to the weak structure of the mineral-olivine and pyroxene. According to the physical properties test and Anon classification, the porosity percentage in porosity percentage is low and as a result the amount of water absorption index is low. Based on the Gamble classification, all peridotites are very resistant to durability and based on the Franklin and Chandra classification, all samples are extremely resistant. The results of this study showed that the single axial compressive strength, elasticity modulus, point load index and tensile strength were decreased with an increase in humidity content of peridotite samples. This is due to the fact that with the increase of humidity pore pressure of water increases. According to the Anon classification, the peridotites are very high in terms of the length of the longitudinal passage through the rock. The highest compliance between the Brazilian Tensile strength test (BTS) and Schmidt hammer (SHV) was achieved in the dry condition and the determination coefficient (R2) equals to 0.95 was obtained. Also there is an acceptable relation between the Brazilian Tensile Strength Test (BTS) and the dry volume unit weight (γd) with the determination coefficient (R2) of 0.93. In addition, there is an admissible relationship between durability test and single-axial compressive strength, with a coefficient determination (R2) of 0.94. Regarding the obtained regressions in this study, the physical and mechanical properties show good agreement and most of the equations have an acceptable coefficient determination.
Bakhtiar Fezizadeh, Meysam Soltani ,
Volume 14, Issue 2 (8-2020)
Volume 14, Issue 2 (8-2020)
Abstract
Introduction
Landslide is known as one of major natural hazards. Landslide susceptibility mapping is known as efficient approach to mitigate the future hazard and reduce the impact of landslide hazards. The main objective of this research is to apply GIS spatial decision making systems for landslide hazard mapping in the 5th segment of Ardebil-Mianeh railroad. Evaluation of the landslide criteria mapping and their relevancy for landslide hazard can be also considered. To achieve the research objectives, an integrated approach of Fuzzy-Analytic Hierarchy Process (AHP), Fooler Hierarchical Triangle and Fuzzy logic methods were employed in GIS Environment.
Material and methods
Within this research, we also aimed to apply GIS spatial decision making systems and in particular GIS multi criteria decision analysis which are available in Arc GIS and Idrisi softwares. We have identified 8 casual factors (including: density of vegetation, land use, faults desistance, distance from rivers, distance from roads, slope, aspect, geology) based on literature review. Accordingly, these layers were prepared in GIS dataset by means of applying all GIS ready, editing and topology steps. The criterion weighting was established based F-AHP approach. The criteria weights was derived and rank of each criterion was obtained. Accordingly, the landslide susceptible zones were identified using GIS-MCDA approaches.
Results and discussion
Finally the functionality of each method was validated against known landslide locations. This step was applied to identify most efficient method for landslide mapping. According to the results and based on the values derived from Qs, P, and AUC, the accuracy of fuzzy method was accordingly about 0.33, 0.74 and 0.76, respectively. In context of Fuzz-AHP the accuracy of 1.08, 0.88 and 0.94 were obtained. While, the accuracy of Fooler Hierarchical Triangle were obtained 0.78, 0.84 and 0.91, accordingly.
Conclusion
As results indicated integration of Fuzzy-AHP represented more accurate results. Results of this research are great of important for future research in context of methodological issues for GIScience by means of identifying most efficient methods and techniques for variety of applications such landslide mapping, suitability assessment, site selection and in all for any GIS-MCDA application.
Reza Ahmadi, Zahra Baharloueie,
Volume 15, Issue 1 (5-2021)
Volume 15, Issue 1 (5-2021)
Abstract
In Yazd Darreh-Zereshk copper deposit geophysical data containing magnetic, resistivity and induced polarization have been surveyed and 25 boreholes have been drilled in the area. In the present research, inversion and processing of geophysical data as well as their qualitative and quantitative accordance with boreholes assay data have been carried out. To achieve the goal first, total magnetic intensity map after applying necessary filters and processing, was mapped to identify surface and deep expansion of anomalies on it. Drawing the anomaly profile of magnetic stations surveyed along 4 geoelectric profiles shows that most of the magnetic anomaly zones have high chargeability and low resistivity that indicates the qualitative compatibility of magnetic and geoelectric data, as a result increasing the probability of mineralization in the area. Afterward on the basis of qualitative interpretation of geoelectrical sections, optimal locations of drilling on the each profile were proposed. Plotting mineral deposit cross-section along the geoelectrical profiles using the boreholes assay data, revealed that drilling of some boreholes located on the geophysical profiles haven’t been based on the results of geophysical operation, carried out without any right logic, purpose and design. In general, the qualitative accordance of the results of geoelectrical operation with the boreholes assay data showed a pretty good qualitative accordance. Also investigation of linear correlation coefficient value between inverted geophysical data and borehole assay in a specific same range after a same definite gridding and interpolation of their values, overall indicated a relatively good quantitative accordance (between 0.4 and 0.7)../files/site1/files/151/1.pdf
Mohadeseh Sadeghi, Naser Hafezi Moghads, Mohammad Ghafoori, Mehrdad Amiri, Ali Bashari,
Volume 16, Issue 2 (9-2022)
Volume 16, Issue 2 (9-2022)
Abstract
The design of underground or terrestrial structures on the rock bed depends on the physical and mechanical properties. Considering the mining method in Tabas coal mine extraction method is long and destructive, the evaluation of the geomechanical properties of the rocks is more necessary. In this research, the characteristics of the rock units of the eastern tunnel No. 3 of Tabas coal Pervadeh mine were investigated. In this study, 3 samples of shale, sandstone and mudstone were examined. Considering the importance of the subject in this research, new experimental relations have been proposed, and their application shows desirable results. In order to obtain geomechanical characteristics and empirical relationships, physical tests such as porosity, water absorption percentage, unit volume weight, and mechanical properties such as uniaxial compressive strength, point load index, Brazilian tensile strength, direct cutting test, durability and brittleness index were carried out. To achieve the desired objective, the most appropriate relationships are presented using the regression method. Statistical analysis shows good correlation between different parameters in shale, sandstone and mudstone samples.
Dr. Davood Fereidooni, Dr. Sajeddin Mousavi, Dr. Esmaeil Najafi, Dr. Gholam Reza Khanlari,
Volume 16, Issue 4 (12-2022)
Volume 16, Issue 4 (12-2022)
Abstract
Assessing and understanding the hydromorphological characteristics are necessary to understand the behavior of a river and its active processes. This is useful for understanding the erosion and sedimentation regime and changing the river path, for making correct engineering and human activities in the river's catchment area. The Gian River, with an average annual discharge of 2.3 m3/s, is one of the tributaries of the Gamasiab River in the Hamedan province. From a geological and hydrogeomorphological point of view, the Gian is a small river. It is fully compatible with the geological structures of the region. The calculation of the sinusoidal coefficient has shown that this river is a meandering river whose wavelength, the amplitude of the oscillation and the width of the meander belt are smaller in the mountainous area than in the plain area The gradient of the river bed is relatively low and it is classified as an erosion and sedimentation river in its different sections. The Gian River has a rocky bed in the mountainous part and an alluvial bed in the plain. The Gian River has a small catchment area, and, according to theGravelius' coefficient, its shape is almost elongated. The catchment elevation of the Gian River is between 1455 and 2700 with a weighted average of 1715.20 m.a.s.l. and its area decreases with the increase in the elevation. The concentration time of the catchment is 4.204 hours. The application of the data and results of the research can be very effective in land use planning, engineering and executive applications to predict river changes and protect engineering structures such as roads, bridges, coastal structures and railways, protect agricultural lands in the region and develop tourism.
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Volume 17, Issue 1 (3-2023)
Volume 17, Issue 1 (3-2023)
Abstract
Waste management is a cornerstone of societal needs. The volume and composition of waste dictate the available disposal options, with landfill being a primary method. The selection of landfill sites is critically dependent on site characteristics and requires thorough and ongoing evaluation, particularly in the areas of water and soil contamination. This study started with geoelectrical and geochemical investigations in the vicinity of the landfill in the city of Damavand. It included 24 geoelectric soundings using the Schlumberger array, organized into 4 profiles covering three intervals. In parallel, three water samples, five soil samples and one leachate sample from two intervals were collected for laboratory analysis. Analyses revealed soil contamination at the waste accumulation site to a depth of two meters with a southerly extent. In particular, a cementitious layer prevents leachate from penetrating deeper into the soil. This, together with a very deep groundwater table, ensures that groundwater contamination is currently and in the foreseeable future prevented. Additional factors such as the depth of the groundwater table, the thickness of the unsaturated zone, the short life of the landfill, reduced rainfall and increased evaporation limit the volume of leachate. The pH of the leachate tends to be alkaline during dry periods and acidic during wet periods. Currently, parameters such as EC, TDS and various ionic and metallic concentrations remain within acceptable limits, ensuring minimal environmental impact.
Dr Asghar Milan, Mehran Shafiei,
Volume 17, Issue 2 (9-2023)
Volume 17, Issue 2 (9-2023)
Abstract
Calculating the volume of earthworks in mines is one of the challenging, costly, and time-consuming issues in the field. In mining projects, it is necessary to calculate the volume of excavation to estimate the volume of extraction in order to plan the sale of the produced products and to calculate the cost performance of the contractors. The calculation of excavation volumes presents many challenges, such as the selection of the best measurement tool and technique, the need to adjust maps produced in different time periods, the existence of inflation coefficients and the volume to weight conversion factor. Today, tools such as laser scanners, total stations and metric cameras are used to calculate earthwork volumes. However, they are expensive to use and require an experienced operator. Therefore, there is a need to investigate methods to calculate volumes in less time with acceptable accuracy. This research evaluated the use of smartphones for optimal volume estimation of earthworks. In this research, the image data obtained from the smartphone was processed with a technique based on structure from motion (SFM) and the results were used to create a digital terrain model to estimate the volume of earthworks. The calculated volume differences for the earthworks volume compared to ground methods for a soil mass and the studied excavation are 3.86% and 1.84% respectively, which shows that the method used in this research has the necessary accuracy to calculate earthworks volumes and considering the many advantages it has over traditional methods in terms of cost and time, it can replace them.
Dr Mehran Esfahanizadeha, Dr Mohamad Davoodi, Dr Ebrahim Haghshenas, Dr Mohamad Kazem Jafari,
Volume 18, Issue 2 (9-2024)
Volume 18, Issue 2 (9-2024)
Abstract
The determination ofgeological subsurface strata and shear wave velocity profiles is one of the most important engineering measures for seismic design and site effects studies. Recently, the use of seismic geophysical methods in engineering geological studies for this purpose has become widespread. In this paper, the accuracy and efficiency of seismic geophysical methods with active and passive seismic source in determining the subsurface geological structure of a selected site in the city of Abasabad in northern Iran have been studied. To this end, first, by conducting several exploratory boreholes, the subsurface geological structure of the study site up to a depth of 70 meters was carefully determined using engineering geological experiments. The results of this section showed that the shallow sediments of Abasabad site are mainly composed of sandy soils with four separate geological layers. In the next step, in two other separate boreholes, seismic geophysical experiments with active source of down-hole test were performed in order to accurately determine the shear wave velocity profile in different layers. In addition, in the next phase, using the array microtremor recording method, which is a new seismic geophysical method of passive-source type, to determine the subsurface geological structure of the study site in the form of shear wave velocity profiles. It should be noted that the array microtremor recording was performed using fifteen different arrangements of receptors (with different numbers and distances of receptors) and by two analyzing methods including F-K and SPAC. The results of these studies showed that both active and passive seismic geophysical methods had acceptable performance in determining the subsurface geological stratification of the site. It also could be inferred that the down-hole test with high accuracy determines the shear wave velocity in each layer compared to the array microtremor method but requires artificial production of seismic waves and borehole drilling. Array microtremor method without the need for drilling and production of artificial seismic waves has high efficiency in determining the subsurface layering and estimating the shear wave velocity of each layer and in general the results of this paper showed that in estimating the shear wave velocity compared to down-hole method shows up to 10% error.
Mr. Farhad Mollaei, Dr. Reza Mohebian, Dr. Ali Moradzadeh,
Volume 18, Issue 3 (12-2024)
Volume 18, Issue 3 (12-2024)
Abstract
The brittlenessindex is one of the most important parameters in geomechanical analysis and modeling. Many methods have been proposed to estimate the brittleness index. One of the recently used methods is the intelligent method. In this paper, firstly the aim is to introduce a new algorithm using deep learning algorithms to predict the brittleness index in one of the wells of the hydrocarbon field in southwest Iran. In this article, first, the effective features for the input of the algorithms were determined using Pearson's correlation coefficient, and then using (recurrent neural network + multi-layer perceptron neural network) (LSTM + MLP) and (convolutional neural network + recurrent neural network) (CNN+ LSTM) brittleness index was estimated and the mean error value (MSE) and coefficient of determination (R2) were calculated for the training and test data. For both training and test data, both algorithms have a coefficient of determination close to 1 and a very low error. Also, in order to ensure the results of the algorithms, a part of the data was set aside as blind data, and the error and coefficient of determination were calculated for this data, and the error was
Dr Eisa Hajiradkouchak, Dr Behzad Rahnama, Dr Hasan Nasrollahzadeh, Mr Ali Shahbazi, Mr Reza Raeiji, Mr Kazem Babaei,
Volume 18, Issue 3 (12-2024)
Volume 18, Issue 3 (12-2024)
Abstract
Many researchers believe that providing safe water, sanitary disposal and optimal management are the three axes of health, and in all these cases, while paying attention to the process of doing work, continuous control should also be done. This study was designed and implemented with the aim of seasonally investigating the physicochemical and microbial water quality of Qarasu River in Golestan province using the IRWQIsc index. 6 sampling stations were identified for Qarasu River and sampling was done once every month in four seasons of 1400. The measured parameters include pH, BOD, COD, dissolved oxygen (DO), electrical conductivity (EC), ammonium (NH4), nitrate (NO3), phosphate (PO4), total hardness (TH), turbidity and total suspended solids. It was a stool form. According to the measured parameters, Iran's surface water quality index IRWQISC was calculated. The results of the study based on the index showed that the quality of this index for all stations in all seasons was between 70.5 and 14.7 and according to the IRWQISC index, it was in five good categories (70-1.85), relatively good. (55-1/70), relatively bad (30-44-9), bad (15-29-9) and very bad (less than 15). The influencing parameters were total suspended solids, turbidity, nitrate, temperature and fecal coliform. It can be concluded that the amount of 70.5 with good quality is related to (Tuskestan village) in winter and the amount of 7.14 with very bad quality is related to (Pol Qara Tepe) in summer that the quality of the river water in The Gorgan to Aqqla road bridge station (Qorban Abad) is in bad condition in all seasons due to the entry of urban and industrial pollutants into this station, and Tuskestan village station has good and relatively good quality in most seasons because Tuskestan is in It is located in high altitudeand the entrance of clean running water into thisarea is more and it is far from industrial and urban pollutants.
Nafiseh Shokri, Dr Aliakbar Momeni,
Volume 19, Issue 4 (12-2024)
Volume 19, Issue 4 (12-2024)
Abstract
The purpose of this study is to create a map of landslide hazard potential along the Tuskestan road using Analytical Hierarchy Process (AHP) model. The effective parameters on landslides that were used in this study are lithology, slope, slope aspect, vegetation, distance from the road, distance from the stream, and distance from the fault. At the first, a map of each of these parameters is prepared and divided into three or four subgroups based on their changes. Then, using hierarchical analysis, for each of these subgroups based on the degree of superiority , a weight was assigned to compare them together, so that qualitative maps are converted into quantitative maps. The result of this weighting showed that lithology and slope had the greatest effect, while the distance from the fault had the least effect in landslide hazard zoning. The final weight of each layer was obtained by multiplying the weight of each parameter by the weight of its sub-group. Finally, these quantitative maps were integrated into the Geographic Information System (GIS) environment to obtain the final landslide hazard zonation map. Assessment of the location of the previous landslides showed that among the 7 old landslides, 6 landslides were in the range of high hazard potential and 1 landslide was in the relatively high hazard category, which indicates the accuracy of the landslide hazard map. The obtained hazard zoning map showed that 9.3% of this area with an area of 355 hectares is located in the category of high hazard potential of landslides.
Dr Ali Ghanbari, Fatemeh Mirdar,
Volume 19, Issue 4 (12-2024)
Volume 19, Issue 4 (12-2024)
Abstract
Examining the seismic response of the ground surface and its impact on structures due to topographic effects and soil-structure interaction (TSSI) is highly significant. If the site has sloping topography, the importance of this study is further amplified, and the slope effect on soil-structure interaction must be considered. This research uses Loma Prieta (1989) earthquake records to analyze the seismic response of a 5-story concrete building located 5 meters from the crest of the slope for four angles: 15, 30, 45, and zero degrees (SSI), using 3D numerical analysis. Modeling was conducted with MIDAS GTS NX software for both TSSI and SSI systems. An elastic model and an HSS model were used for the building and soil, respectively. The seismic response of the building was evaluated by comparing maximum lateral displacements, base shear forces, inter-story drifts, and horizontal accelerations in TSSI and SSI analyses. As the slope angle increased from zero degrees (SSI) to 15, 30, and 45 degrees (TSSI), the average lateral displacement of the floors increased by 44%, and the average maximum horizontal acceleration increased by 21%. Additionally, with the slope angle increasing from zero degrees (SSI) to 15, 30, and 45 degrees (TSSI), the average ratios of inter-story drift and maximum base shear force increased by 14% and 21%, respectively.
Dr. Amin Jamshidi,
Volume 19, Issue 4 (12-2024)
Volume 19, Issue 4 (12-2024)
Abstract
The durability of a building stone is its resistance to deterioration processes under the climatic conditions of a given geographical area. This parameter plays an important role in the selection of a suitable building stone, as ignoring it can lead to premature deterioration of the stone during the life of a building. Therefore, before selecting a building stone, it is necessary to pay special attention to its durability and to select a stone that has a suitable resistance to environmental degradation processes. The physical and strength characteristics are among the factors that influence the durability of a building stone. The evaluation of these characteristics can provide valuable information about the durability of stone subjected to deterioration processes. In this work, the effects of physical and strength characteristics on the durability of building stones were investigated. The results indicate that porosity, water content, degree of saturation and pore size distribution are the most important physical characteristics determining the durability of a building stone. In addition, strength properties, including uniaxial compressive strength, tensile strength, flexural strength and abrasion resistance, also play an important role in the durability of a building stone. The results of the present study can be used as a simple, quick, inexpensive and practical tool to indirectly evaluate the durability of building stone against environmental degradation processes.
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