فهرست مطالب ناصرحافظی مقدس

Changes in temperature and precipitation are one of the most important debates in the field of environmental sciences. This phenomenon is very important because of its scientific and practical dimensions, because human systems dependent on climate elements such as water, agriculture, industries and the like are designed and operate on the basis of climate stability. Therefore, predicting and knowing about temperature and precipitation changes in the coming years can be a solution to problems such as drought, sudden floods, high evaporation and environmental destruction. The civilization of several thousand years of Sistan has been completely dependent on the flow of water in the Sistan River. Currently, the only source of water supply in the region is the flow of water in the Hirmand River and the water storage sources of Chahnimeh. Considering the dry climate of the region and the rainfall of about 50 mm per year and the presence of 120-day dry winds in Sistan and the lack of suitable underground water resources in the region, the Hirmand River and the Chahnimeh are the only source of water supply in the region. As a result, investigating climate changes and predicting changes in temperature and precipitation within the limits of these devices is very important to save Sistan. In this research, 8 GCM models from CMIP6 were evaluated according to their high resolution and available meteorological data, and after correcting the bias using the LSBC method, the performance of these models was evaluated in simulating the relevant parameters. The study was conducted in the basic period of these models (1990-2014). After receiving the data, the observational and historical parameter values for each of the studied stations were extracted by preparing a in the MATLAB environment using the closest GCMs grid in the base period (1995-2014). Then the bias correction method was used to correct the data. In the following, the difference between the values of observational and historical parameters was evaluated using different indices. After validating and evaluating the accuracy of different GCM models, using the best model, temperature and precipitation changes in the future periods were predicted under three different scenarios and its changes in the future period compared to the historical period (1995-2014) Was investigated. In order to reveal the trend of changes in temperature and precipitation, non-parametric Mann-Kendall test and Sen,s slope estimator were also investigated. The results showed that the rainfall in Zabul and Zahak stations had a decreasing trend and this decreasing trend was not significant in any of the mentioned stations. Based on this, the decreasing trend of precipitation in the studied area is the type of short-term fluctuations of water and It is aerial. The highest decrease in precipitation is related to Zabul station with a gradient of -2.4. The trend of temperature also shows an increasing trend in both meteorological stations and this increasing trend is significant at the level of 5% in Zabul station. Examining the slope of temperature changes also shows that the highest slope of temperature changes is related to Zabul station with a slope of 0.07. After bias correction, the performance and accuracy of the models were evaluated in the simulation of the studied parameters using various indicators at the Zabul syndication station as the selected station of the region. The results showed that based on the RMSE index, BCC_CSM2_MR model and then MPI-ESM1-2-LR have higher accuracy than other models for simulating precipitation. The RMSE of the mentioned models with the observed rainfall data in the studied station on a monthly scale is equal to 0.94 and 0.95, respectively. FGOALS-g3 model also has the weakest performance among the investigated models for simulating precipitation in the study area with RMSE equal to 5.6. In general, based on various indicators of accuracy, the BCC_CSM2_MR model is suitable for simulating rainfall in the study area, so that its coefficient of determination is equal to 0.97, and its MSE and MAE values are lower than other models. The results of projection the rainfall in the future period (2021-2050) based on different scenarios show that based on each scenario, the amount of rainfall will decrease in both stations under study, and its amount is on average For Zabul station it is equal to 4.1% and for Zahak station it is equal to 4.2%. Overall, based on the average scenarios studied, the amount of precipitation in the study area will decrease by 1.4% compared to the observation period. The highest and lowest precipitation changes are estimated based on SSP5-8.5 and SSP1-2.6 scenarios, respectively. According to the average scenarios studied in the future period, the temperature in the study area will increase by 1.4 degrees Celsius compared to the observation period. The most changes in terms of stations are related to the drainage station with 5.9 percent. Also, scenarios SSP5-8.5 and SSP1-2.6 show the highest and lowest temperature changes in the studied area with 1.6 and 1.2 degrees Celsius, respectively. In general, according to the results of the CMIP6 model and the straw scale of the LSBC method, the amount of precipitation in the study area will decrease and the temperature will increase. to follow The totality of these conditions can cause a decrease in the storage and supply of water resources in the Chahnimeh, as a result of which the climatic conditions of the region will also change.

The frequency of limestone has caused to be encountered in different projects of engineering. The Ilam Formation is one of the formations that is widely spread in the Zagros Mountains, and in the sample cutting, it contains 195 meters of cream-colored limestone. Due to the extent of this formation, many projects have been performed on this formation, and they also encounter this formation in oil drilling. Its lower and upper Boundaries are continuous with Surgah Formation and Gurpi Formations, respectively. The aim of this study is to investigate and introduce the engineering geological features of Ilam formation limestones in the type section. The Ilam Formation is a challenge in various projects like other formations with carbonate units. Especially, when the mentioned units are different in terms of lithology, physical, and mechanical. In order to identify the characteristics and engineering behavior of these rocks, 60 blocks were selected from different limestone horizons of the Ilam Formation and were transferred to the laboratory. Then, the physical and mechanical properties and lithology characteristics of limestones are determined. The samples have been used to test the physical properties, durability, point load index, uniaxial compressive strength, Brazilian tensile strength, and wave velocity. The results of the multivariate regression showed that the differences between petrological and physical properties have led to a variation in their mechanical properties. Statistical indices such as R2, , RMSE have been evaluated by Minitab 16 software, and the relationship between physical and mechanical properties was determined. Based on the results, there is a higher reliability coefficient for estimating mechanical properties than other properties in the dry condition compared to the saturated condition. The results of this research showed that lithological and physical characteristics play an important role in the mechanical properties of Ilam limestones.

This study aims to employ supervised Advanced machine learning for the classification of lithological facies from geophysical log data in wells without drilling core samples. For this purpose, a dataset from seven wells in a training set from one of the oil fields in southern Iran has been utilized. This dataset includes natural gamma ray (SGR), corrected gamma ray (CGR), bulk density (RHOB), neutron porosity (NPHI), compressional wave slowness (DTSM), and shear wave slowness (DTCO), which directly influence the classification of geomechanical facies. These parameters are employed as independent variables, while lithological facies serve as the dependent variable for classification. This dataset pertains to depths ranging from 3000 to 4000 meters in the Ilam and Sarvak fractured limestone formations (Bangestan Limestone) of the subsurface. As the title suggests in this article, Initially, through artificial intelligence clustering methods and laboratory studies, these formations were categorized into five distinct lithological facies After this stage, eight supervised machine learning methods were employed, including Regression Logistic, K Neighbors Classifier, Decision Tree Classifier, Random Forest Classifier, Gaussian NB, Gradient Boosting Classifier, Extra Trees Classifier, and Support Vector Machine (SVM), to predict lithological facies in wells without existing classifications. The dataset of these wells underwent training and testing stages with each of these algorithms to construct an appropriate model.As a result, facies labels were predicted. The performance of the models was evaluated using multiple metrics including Accuracy, Precision, F1-Score, and Recall through confusion matrices and ROC curves. The Extra Trees Classifier, Gradient Boosting Classifier, and K Neighbors Classifier showed superior results among these methods. Finally, the model's performance in predicting lithological facies of unseen or out-of-sample wells was presented.

Among the factors and indexes considered for the environmental evaluation of projects mostly the factors with environmental aspects are chosen. Decision making on relative superiority of a project compared to other factors requires going beyond investigation of the exclusive environmental consequences. Environmental Geotechnics is a part of Engineering Geology that considers Environmental and Geotechnical issues concurrently. In this research it has been tried for the first time to investigate environmental factors and issues besides geotechnical viewpoints. For doing so, the water and soil different standards in different scopes including drinking water, agriculture and geotechnics have been investigated and evaluated by the help of Fuzzy Multiple Attribute Decision Making Technique of TOPSIS. Also, their differences and features have been referred while comparison of the mentioned techniques results.As an environment of appropriate decision, 4 networks of irrigation and drainage from Khuzestan province with the name of irrigation and drainage networks of Evan (North- West of Khuzestan), Dasht-e Azadegan (west of Khuzestan), Ramhormoz (east of Khuzestan) and Kheir Abad (South-east of Khuzestan) was used as a platform of necessary information.

In the early 1990s, radar interferometry was introduced and used as a useful tool in the study of all phenomena that cause land surface deformations. If the land surface deforms between two radar images, a surface displacement map can be created with millimeter resolution and accuracy. This paper reports the findings of the Sentinel1 –A data time series results using the SBAS algorithm to detect surface deformation in the Sangan iron ore mine. Sangan Iron Ore Mine is the largest open pit iron ore deposit in the Middle East. Due to mining activities, this mine has undergone many changes in terms of topography and geomorphology, which can intensify geomorphological processes. To detect and obtain the amount of land deformation, 48 SAR images of Sangan iron ore mine obtained by the European Space Agency's Sentinel 1-A satellite were used. The time series (2014-2020) obtained from the deformation in the range of placer mines were analyzed. The results show the average displacement rate of -20 to -35 mm per year and the maximum cumulative rate of deformations of -120 mm. Investigation of the cross-section in the two parts of the apex and the center of the alluvial fan in the placer mines during the period 2014-2017 shows the topographic changes well. To evaluating the reliability of the results, the results derived from SBAS have been compared due to the lack of data in the range of placer mines with the values measured by the total station related to the mountain unit in the years 2020-2014. The results showed that the rate of deformations from radar data using the SBAS algorithm compared to the leveling data has followed a similar pattern. However, there may be some error due to the different nature, ie in the leveling of elevation deformations measured for a point, but in interferometry the average rate is obtained from adjacent points.

It is very important to know the rock creep behavior in the evaporitic cap rocks in order to investigate the convergence in oil wells. In general, among evaporitic rocks, the creep behavior of gypsum and anhydrite has been less investigated compared to halite, which are investigated in this research. Since accessibg to the cores of oil wells drilled in Gachsaran Formation is very difficult and expensive, in this research, sampling was done from the surface outcrops of section 1 of Gachsaran formation. For this purpose, blocks were prepared from gypsum and anhydrite and then cored from them in the laboratory. First, unconfined compressive strength (UCS) tests were performed on cores to determine the amount of initial load for uniaxial multi-stage creep test. Next, based on the UCS results and the approximate temperature conditions of cap rock, creep tests were performed at two temperature conditions of the laboratory and cap rock environment. Then, based on the data obtained from the creep tests, fitting the exponential and Powerlaw creep equations was done on gypsum and anhydrite. The results show the creep yield stress of 12 MPa for gypsum and 20 MPa for anhydrite. Also the creep tests was performed at two levels of initial stress 0.1 yield stress and 0.75 yield stress in UCS test. Based on these tests, the linear viscous limit for creep of gypsum and anhydrite was obtained as 5.5 to 6.7 MPa and 9.8 to 15.15 MPa, respectively. In addition, gypsum shows more uniform plasticity and creep under temperature compared to anhydrite. This is while in the anhydrite, the threshold of accelerated creep is lowered and the creep time is reduced.

Studies show that celestial bodies can be effective in triggering earthquakes from several perspectives by exerting gravitational forces, albeit less than cumulative tectonic forces. These forces in the fluid environment increase the pore pressure and facilitate the rupture and seismicity of the earthquake. Previously, no clear relationship between tidal forces and seismic events with strike-slip faults has been reported.-In this study, the relationship between earthquakes and tidal stress components in the fault area along the sinistral strike-slip of Mosha was investigated. For this purpose, IIEES and NEIC seismic data from 1975 to 2020 have been used.After removing the foreshocks and aftershocks by the Reasenberg method and considering the magnitude of completeness (Mc=2.8), 84 seismic events out of 188, with a magnitude of more than 2 around the fault were studied. -By considering the superficial fault information and the hypocenter of the earthquakes and assuming that the events occurred on the fault plane, the mathematical equation of the fault plane is fitted and modeled.According to the model of the presented fault segments, the main and shear stress components were included and calculated in the frame with the help of the conversion matrix. The results show that the north-south horizontal component of tidal stress has the greatest effect on tectonic forces and facilitates seismic shock. Based on the model of fault segments, the main tidal stress components (two horizontal components and one vertical component) and shear stress are framed into the modeled plane. Events are examined in the frame of modeled planes by Schuster’s test and binomial method, in two conventional modes of 360 and ±180 degrees of tidal phases. -Outcomes of these results are a bit complex. However, the results of the Schuster’s test at the test level of 5% (significance level 95%) do not show the correlation between tidal forces and earthquakes in the general case (in magnitude range 2.8-4.9) and we could not assume a relation between earthquakes and tidal forces, but using the classified magnitudes confirms this relation at specific intervals for different tidal components. For example, the components of tidal shear stress framed in the fault plane (parallel to the rupture of the fault main plane) are associated with a magnitude range of 3-3.9. The binomial test also does not rule out seismic events in some phase cases, where we expect the greatest effect of tidal stress on the dynamic sections of the phase. The study of tidal components shows that the negative values of the north-south horizontal component (towards south) play an important role to decrease the minimum tectonic stress at the beginning of the rupture, which is northward and as a result, the Mohr envelope failure tends to shift to the left. It facilitates fault plane rupture and can cause earthquake triggering.

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.

Many researchers have studied subsurface stratigraphy by approaching three-dimensional geological models in recent decades to overcome the complex nature of the subsurface. In many urban areas, specific three-dimensional spatial models have been developed that are used to predict land conditions, reduce risk, and uncertainty in urban planning. In this study, geological, geotechnical and geophysical analyzes were used based on data collected from 20 geotechnical boreholes and 29 geoelectric soundings around Zarand wide. Having statistically geotechnical and geophysical parameters of the soil estimated (such as liquid limit LL%, plasticity index PI %, moisture content w%, dry density γd, soil shear strength parameters of C and ϕ◦, modified standard penetration resistance N (60) and electrical resistance of the ground Ωm) and using the weighted moving average interpolation method (kriging), two-dimensional maps and three-dimensional spatial distribution of soil properties were prepared by which the problematic soils were identified. The results of spatial distribution and trenches to a depth of 15 meters show that the soils of Zarand are of Cl, CL-ML, SC, SC-SM and ML. According to the classification maps of the dominant soil texture and density as well as ASTM regulation (2002), these soils are in the range of medium collapsibility. In addition, regarding classification map of soil corrosion obtained from moisture content and the same electrical resistance levels of the ground to an average depth of 4 meters, surface soils were mainly located in the range of moderate to high corrosive according to BS-7361 and ASTM STP 1013 standards.

Static parameters are one of the most important parameters in estimating geomechanical properties. Determining these data is very costly in in-house studies, so they are not normally available or limited in scope. Hence, many researchers have tried to provide empirical relationships to estimate these parameters from other characteristics. The aim of the present study is to evaluate the parameters of the Young Static Modulus and the Uniaxial Compressive Strength of Aghchagili limestone based on physical and dynamic properties using multiple regression. For this purpose, ten blocky samples from the surface outcrops of the formation were prepared, and a 18 cores were obtained from them, and various physical, mechanical and wave velocity tests were carried out on the specimens. The results of this study showed that three different variables of density, compressive velocity and dynamic yang modulus have a better relationship with Uniaxial Compressive Strength than different physical and dynamic parameters. Also, for estimating the static Young Modulus, porosity variables and dynamics of Young's Modulus yield more acceptable results.

Oil wells & boreholes logs data are interpreted/processed to identify petrophysical, mechanical, and in-situ geomechanical properties for rocks around oil wells, due to high cost and geological problems, some well logs cannot be measured. For example, sonic logs contain geophysical, and geomechanical information critical to determining the modulus of dynamic elasticity, Young's modulus, the bulk modulus, acoustic resistance/impedance, the shear modulus, and the Poisson's ratio of rocks around the well’s wall. Therefore, in this paper, two random wells were selected from one of the oil fields in southern Iran, one of which was selected as training well to determine the appropriate model and the other to predict the shear and compressional wave slowness. Data analyses were performed using a range of machine learning methods and setting hyperparameter tuning on algorithms, the best models were selected for predicting/estimating sonic logs. In this process, among the regression methods, the K-nearest neighbors algorithm (KNN), and among the combined methods, the Random Forest Regression algorithm and the Extra Tree Regression algorithm show the highest correlation coefficient. As a result, the extra tree algorithm for modeling was performed on the training sets and testing sets data of the well. Then this model was used to predict and synthesize the slowness acoustic compressional and the slowness acoustic shear of the target well. Then, by comparing the actual data of the target well, the root mean square error and the R-squared were obtained. Then, using poroelastic equations, the field stresses were determined and found that Sarvak and Ilam reservoirs are in reverse stress regime and Asmari reservoir is in normal stress regime up to Strike-slip. At the end of this article, using the rock mechanics criteria, the best optimal safe mud weight windows in the studied was presented.

Assessment of seismic strong motion hazards produced by earthquakes originating within causative fault zones allows rather low accuracy of localization of these structures that can be provided by indirect evidence of fault activity. In contrast, the relevant accuracy of localization and characterization of active faults, capable of surface rupturing, can be achieved solely by the use of direct evidence of fault activity. This differentiation requires strict definition of what can be classified as “active fault” and the normalization of methods used for identification and localization of active faults crossing oil and natural gas pipelines.

Machine Learning algorithms have widely been adopted to group well log measurements into distinguished lithological groupings, known as Facies/Geomechanical units. This procedure can be achieved using either unsupervised learning or supervised learning algorithms. Supervised learning is the most common and practical of machine learning tasks and it is designed to learn from the example using input data that has been mapped to the correct output. In this research, we can run the modeling using Unsupervised Learning, where we authorize the algorithms to recognize underlying patterns within the data that may not be easily visible during data exploration. Therefore, an unsupervised learning method has been used to determine geomechanical zones. In this method, we give one's consent/assent to algorithms to identify subsurface patterns using data that may not be easily visible during data exploration. First, the application of practical methods of machine learning algorithms, including the K-mean model, Based Spatial Clustering of Applications with Noise (DBSCAN), Hierarchical Agglomerative Clustering (HAC), and Gaussian mixed model, will be explained, And then in this research, the best method for predicting petrophysical layers will be presented and compared the results with an established Lithofacies curve. The required programming is done in a Python environment. In this regard, after well processing, The XGBoost and Multi-Layer Perceptron Neural Network Algorithms have been used to predict the missing data. The optimal number of clusters is obtained using an ‘elbow’, In this article, as the title suggests, Four methods are used in cluster analysis unsupervised machine learning algorithms, but in petrophysical, geological, and geomechanical realities, data seldom conform to good circle patterns. Whereas if the data clusters are circular, K-Means clustering and Hierarchical Agglomerative Clustering( HAC) work great. Therefore, it is better to use the Gaussian mixed models (GMM) method.

Estimation of resistance parameters of rock mass is one of the most important engineering problems of rock.The study of geomechanical parameters and, finally, the classification of rock masses in the feasibility phase and the initial design of a project, which has very little comprehensive information on the geotechnical properties of rock masses, the amount of stress and the available hydrological characteristics, The main purpose of using a classification system is to classify the parameters and, using their results, provide the nature of the rock mass and its engineering behavior in different conditions. Since rock mass specifications are in the design of drilling, design of retainers, tilt design and other requirements. On this basis, it was considered necessary to obtain the resistance parameters of Khersan 3 Dam site so that, by analyzing these data, the stability of the tunnel, the geomechanical classification of rock mass using the RMR, QI, GSI method can be calculated and the relationship between rock mass resistivity parameters Compare the modulus of elasticity and deformation from different relationships and compare each other.

Mining (especially surface) is one of the major causes of land and environmental degradation globally. Environmental impacts such as deforestation, landscape degradation, alteration of stream and river morphology, widespread environmental pollution, siltation of water bodies, biodiversity loss, etc., have been noted to be associated with mining. Surface deformation is the biggest problem in open cast mines and their surrounding areas due to mining activities.  Surveying engineers study the amount of displacement in open pit mines by using leveling to calculate the amount of displacement and determine it. These methods are expensive and time consuming. Satellite images are considered as an important tool for land resource management due to the wide view that provide of an area and also due to its regular repetitive coverage. Interferometric Synthetic Aperture Radar (InSAR) is a useful tool in the study of surface displacements. The SAR interferometry concept has been introduced in the last 1980s.The objective of this study as an academic research is monitoring deformation using Persistent Scatterer Interferometry Synthetic Aperture Radar (PS-InSAR) method for managing a very rich iron ore resource in the eastern part of Iran named Sangan, near the Afghanistan boundary.

In this paper, surface deformation calculation based on the processing of PS-InSAR technique (Persistent Scatterers SAR Interferometry) have been carried out. For this study, according to the availability of data for study area 47 SLC images of Sentinel-1A covering the study area during the period of October 7, 2014 –July 7, 2020 are downloaded from European Space Agency website. Sentinel-1A acquired images with a swath width of 250 by 180, with revisiting time 12 days within the IW data acquisition mode, it is reduced to six days if the images acquired by the Sentinel-1B satellite are available. Sentinel-1 has launched on 4th April 2014 by ESA. PS includes following steps:Master image selection, Co-registration data, Reflectivity map generation Amplitude stability index, Persistent Scatterers Candidate selection (PSC), PS point selection, Multi-image sparse grid phase unwrapping, Atmospheric phase screen estimation Removal and PS phased reading Displacement estimation. Study area Sangan Iron Ore Complex (SIOC) is located at latitude N 34°24’ to 34°55’   longitude E 60°16’ to 60°55’ in the Khorasan-e-Razavi Province, North-Eastern Iran. The iron ore deposit is about 20 km Northeast of Sangan town at about 1650 meters above sea level. Sangan Iron Ore Mines (SIOM) is one of the largest mineral areas in Iran, and also considered to be one of the Middle East’s richest deposits which are located in a rectangular area with 26km length and 8km width.

In this paper, the 47 scenes of IW SLC Sentinel-1A images, spanning the period from October 7, 2014–July 7, 2020 are accumulated displacement map and the time series of the deformation derived. The PS were selected on the basis of the ASI threshold value of 0.7, which signifies the stability of target points. The LOS displacement was improved by using APS and atmospheric phase delay correction. Later, the LOS displacement velocity on PS locations was estimated. The temporal coherence of all the selected PS was also tested. The PS points having ASI value of 0.7 and above, and temporal coherence of 0.9 and above, gave a relatively stable estimation of LOS velocity. We have identified 215377 Scatterers points. By imposing the standard threshold of 0.7 on ensemble coherence value, this amount decreased dramatically to 52449 PS points.  These factors make the chosen technique suitable for studies of surface deformations. The results showed that the deformation velocity in this area is -4.8 mm/yrs and maximum displacement-30mm. In order to verify the results, we collected the Total Station data and PS data for analysis and comparison. Due to the lack of data in the plain, the Total Station data is related to downslope areas and as a result, uplift of area has been used to validation the results. It has been observed that for the same area the Total Station value shows good agreement with the PS- InSAR result. However, there may be some errors due to the fact that the data are not synchronous and that the nature of the impression is different.

In the present study, PS-InSAR technique and C-band sentinel-1 data have been used for surface deformation monitoring in open cast mines of Sangan-Khaf, Khorasan Razavi. It can be concluded that monitoring the deformation of mined surfaces using traditional monitoring techniques such as field surveys and using Total Station, especially in large study areas, is time consuming. Since in using the interferometry methods in the study of open pit mines, the area covered by SAR images is much larger, so the use of this method will reduce costs. The results were assessed and validated using leavening data has been observed that, for the same area, the levelling value shows good agreement with the PS- InSAR result.

In this study, due to the landslide in schist rocks, in the wall of Mouteh gold mines, including of the eastern wall of ChahKhatoon mine, it is important to identify the effective factors. Therefore, due to the diversity of schists in Chah Khatoon and Sanjadeh gold mines (two active mines in Mouteh Complex), to survey the mineralogy of schist rocks in Moteh gold mine has been done by identifying important factors in changes in rock strength. Cosequently, 10 schist samples from walls of these mines were considered for mineralogical, XRD studies. In the next step, these schists were subjected to uniaxial compressive strength (UCS) and Brazilian tests to estimate the mechanical properties and quality of rock mass in different zones of mineral walls. The results showed that the UCS and Brazilian index in these schists are directly and inversely related to the SiO2 and Al2O3 contents of the rocks, respectively, as well as the secondary structures.Some factors such as the presence of secondary structures, continuous surface area, particle size, and mineralogical composition play an important role in the failure modes of these rocks. UCS and Brazilian strength of schists vary from 10 MPa to 72 MPa and 1.9 to 10.2 MPa, respectively. The lowest UCS occurs in strongly weathered rocks with low silica content. However, the type of clay minerals is effective in the stability of the mineral wall. Considering the presence of montmorillonite clay mineral in the eastern wall of Chahkhatoun mine, the rock resistance is moderate despite the high percentage of silica. UCS values of wet and dry rock samples containing muscovite and montmorillonite clay minerals were more different from those of other rocks. In this regard, the rocks with Illite clay minerals are more resistant than Smectite and montmorillonite minerals. In general, the resistance of schists depends on various factors such as mineralogy, which is of great importance because of its involvement in the formation of secondary structures.

Artificial stone is a mixture of natural aggregate and additives such as industrial gums (resin), cement and other polymer materials. The purpose of this study is to compare the physical and mechanical properties of artificial stones made in different conditions, resins and aggregates. To achieve these goals, synthetic rock samples were made with polyester and vinyl ester resins and granite, lime, silica granules and lime-silica composites, with the existence and lack of vacuum and pressure during the fabrication of artificial stones. To determine the physical and mechanical properties (Brazilian Test, Point Load Test, Uniaxial Compression Test), artificial stones have been tested. Based on experiments, artificial stones made with vacuum and pressure systems have more favorable physical properties and undesirable engineering characteristics than coarse specimens made in completely manual conditions without vacuum and pressure systems. The specimens made with vinyl ester resin have more axial compressive strength than the other specimens and their fracture type is elastic - fracture but the specimens made of polyester resin without paying attention to aggregate type, show the elastic - plastic and creep behevior. Increasing of the resin percentage in artificial stones made of limestone, increases tensile strength but does not have a positive effect on granite. The results show that all the resistive properties of artificial stones are controllable. Also the mixing plan and ratio of mixing percentages are the most important principles in the strength and resistance of the artificial stone and are flexible for any use and taste.

Safety design of structures concerning surface faulting effects such as shear and differential subsidence are very costly and in some cases are impossible. Then the appropriate approach for encountering surface faulting is to determine a suitable fault-avoidance zone. In this study, firstly the theorem of avoidance fault zone is presented, and then the setback area from the fault zone of South Mashhad fault is proposed. Recent studies show that South Mashhad fault is a right-lateral strike-slip fault with a normal component that cut the Quaternary sediments. In this work, the average slip rate and estimated return period for South Mashhad fault are 0.59 mm/yr and 2930 years, respectively.  Accordingly, the proposed avoidance zones in the south (hanging-wall) and north (foot-wall) of the fault are 80 and 70 meters, respectively. Considering the avoidance zones, many residential and other important structures are located in the avoidance zone of the South Mashhad fault.

Having knowledge about geological and engineering properties of marine sediments, is very important to perform stability analysis of offshore structures. In this paper, the geological engineering characteristics of marine sediments (from seabed to a maximum depth about 30 meters below seabed) was investigated in three oil and gas fields located in the northwestern Persian Gulf. In the first step, geotechnical database of study area was developed based on studies carried out by marine geotechnical labs and oil companies in Persian Gulf. Then, the distribution of physical and mechanical properties of marine sediments with depth and also their relation to the other parameters were studied and some graphs and geological/geotechnical profiles were drawn.The results showed that the physical and mechanical characteristics of these sites are influenced by the distance from the Iranian coast, water depth and distance from Arvand Rud river delta. Generally, from siteI to siteIII, the grains size, and liquid limit of fine-grained and strength of subseafloor sediments were increased. The thickness of soft sediments was decreased from siteI to siteIII. By evaluating the percent of carbonate content, it was found that with distance from the coast, the percent of carbonate content in subseafloor sediments were decreased. So, the least amount of carbonate content was observed in site III. According to the result of PI versus PL/LL graph, Illite is the most abundant clay mineral in the study area.

CO2 injection in deep geological formations, such as depleted oil and gas reservoirs, in addition to the environmental benefits, is one of the effective method for enhanced oil recovery (EOR) as tertiary EOR. Presence of reservoirs with a pressure drop which require injection of gas in the southwest of Iran and having the technical and environmental effects of CO2 injection have created a huge potential for CO2 injection to EOR in this region. In the first step, to perform CO2-EOR, the geomechanical assessment is needed to find out pore pressure, in-situ stress magnitudes and orientations and fractures and faults conditions. In this paper, the initial in-situ pore pressure is predicted using modified Eaton method for 47 wells in the length of the study field and calibrated using repeat formation test and mud pressure data. In-situ stress was obtained by the poroelastic method for 47 wells in the length of the study field and calibrated using leak off test and extended leak off test. Then, the orientation of in-situ stresses is obtained based on image logs. Hydraulical and mechanical activities of fractures and faults were performed by critically-stressed-fault hypothesis

In this paper, the initial pore pressure is calculated using modified Eaton method and other corrections that are proposed by Azadpour et al. (2015). The estimated initial pore pressure is validated using mud weight pressure (Pmw) and repeat formation tester (RFT) data. In-situ stresses are composed of three orthogonal principal stresses, vertical stress (SV), maximum horizontal stress (SH), and minimum horizontal stress (Sh) with specific magnitude and orientations. The magnitude of SV is calculated by integration of rock densities from the surface to the depth of interest. The poroelastic horizontal strain model is used to determine the magnitudes of the SH and Sh. Then, the estimated minimum horizontal stress from poroelastic horizontal strain model is validated against direct measurements of LOT and XLOT tests. The orientation of breakouts was determined based on compressively stressed zones observed in the UBI log and using Caliper and Bit Size (BS) logs. The hole elongates perpendicular to the SH and breakouts develop at the azimuth of Sh. Fractures and faults reactivation analyses are very important, they can potentially propagate upwards into the lower caprock and further through the upper caprock due to CO2 injection. Fractures and faults identification were performed based on image logs. Based on performed seismic interpretations by NISOC (National Iranian South Oil Company), 15 faults have been detected in the field. Fractures and faults conductivity and activity in the current stress filed affect on fluid flow and mechanical stability or instability of the CO2 injection site. Critically stressed fault hypothesis, introduced by Barton et al. (1995), states that in a formation with fractures and faults at different angles to the current stress field, the conductivity of fluids through their apertures are controlled by the interplay of principal stress orientations and fracture or fault directions. Hence, conductive and critically stressed fractures and faults in the current stress field were evaluated using critically stressed fault hypothesis. Fractures and faults are plotted in normalized 3D Mohr diagrams (normalized by the vertical stress), therefore conductive and critically stressed fractures and faults were determined.

The maximum distribution of initial pore pressure was 20-25 MPa in the field and the average of initial pore pressure was 25 MPa in the field. Unlike the World Stress Map, the stress regime is normal in the reservoir. Because the Kazeroon fault and Dezful Embayment act as a strike-slip tensional basin, resulting in the subsidence of Dezful compared with other regions. The frequency distribution of calculated in-situ stress in 47 studied wells in the length of the field has been presented. The maximum frequency distribution of SV, SH and Sh were between 60-70, 50-60 and 30-40 MPa, respectively. A large amount of fracturing is observed in 20-25 m below the caprock. Based on the continuity of their low amplitude traces on the acoustic amplitude image of UBI, fractures are classified into 4 classes: discontinuous-open, continuous-open, possible-open and closed fractures. OBMI and UBI image logs processing were performed in 7 wells. As can be seen from the image log, and caliper analysis the most dominant strike of SH around the well is 27◦ and Sh strike is 117◦. These have two dominant orientation, some faults are along the strike of the Zagros fold-thrust belt (NW-SE) and the others are perpendicular to the Zagros fold-thrust belt strike (NE-SW).Based on the normalized 3D Mohr diagrams it is clear that the fractures and faults that are oriented to the SH will be the most permeable, because the faults and fractures experience the least amount of stresses in the direction of SH and they have minimum resistance to flow in this direction, therefore will have relatively high permeability. Also, results showed the faults number 15, 6, 10 and 2 will be the most dangerous faults during CO2 injection.

Landslide is one of the natural disasters which causes the losses of life and property annually all over the world. One of the solution for decreasing the losses of landslides is to determine susceptible zones for landslide and to zoning its risk through preparing risk-based zoning map of landslide. In this paper, the effectiveness of both information value and area density for zoning the risk of landslide have been evaluated in Neka, Gelevard watershed basin. Therefore, at first, we prepared inventory map of landslide in the basin. Then, 9 effective factors in landslide occurrence and related maps have been prepared. The grade of each layers was measured via area density and information value models and then the risk maps of landslide has been prepared by combining these layers in Ar GIS software. The results showed that slope, direction of slope, fault existence, the efficacy of agricultural and lithology are the most important effective factors for landslide occurrence in the studied area. Quality index (Qs) and Preciseness (P) was investigated to compare the methods and evaluate their efficacy. The higher value of these indexes for information value model shows it has more efficacy than area density for zoning landslide.

In the southern margin of the Mashhad plain in Northeastern Iran, there are strips with tens of kilometers length consisting of metamorphic rocks and ophiolite complexes with the NE-SW trend. Ophiolites are fragments of ancient Oceanic crust (Ghaseminejad and Torabi, 2015; Khanchuk et al., 2016; Shirdashtzadeh et al, 2017) most of which consists of ultramafic rocks. Ophiolites are formed during tectonic displacement in the southern part of the Mashhad plain (Alavi, 1991; Karimpour et al., 2010; Sheikholeslami and Kouhpeyma, 2012; Zanchetta et al., 2013; Shafaii Moghadam and Stern, 2014). These undergoing metamorphosed regions ultimately lead to the formation of serpentines complex due to factors of pressure and temperature. Subsequently, tectonic variations create different levels of serpentinization in the region. Different degrees of serpentines have different geotechnical properties that are discussed in this study.

To conduct the lithological studies, 313 samples were collected from surface and trenches in the studied area. Following the preparation of the microscopic cross-section of all specimens, the mineralogical characteristics, texture changes, color changes, degradation and microcrack development were studied. Then, the samples were classified based on the general classification of ultramafic rocks (Streckeisen, 1974). According to this classification, the ultramafics extracted from the studied area were classified in the metaperidotite and metapyroxenite groups. After separating various metaperidotites and metapyroxenites the percentage of serpentinization in all specimens were determined and 60 samples with different serpentinite percentages were selected. Also, the stone blocks were provided for preparing the core samples. Physical tests (such as dry and saturated unit weights, porosity, and water absorption percentage), and mechanical tests (such as uniaxial compressive strength, point load strength, and Brazilian tensile strength) were performed based on the Brown (1981) method in the laboratory of the Ferdowsi University of Mashhad.

The results show that there is a good relationship between the percentage of serpentinization of samples and uniaxial compressive strength (the most important geotechnical parameter in rocks). The ultramafic rocks are divided into three groups based on uniaxial strength and 25 to 40% of serpentine are very strong, 40 to 60% of serpentine are strong and 60 to 75% serpentine are of medium strength. Also, the ultramafics with 75% to 95% of serpentine, are named as serpentinite rocks with weak uniaxial compressive strength.

Although most of the ultramafic rocks have good strength as the foundation for building, the construction of a structure on these rocks has numerous problems due to the formation of minerals such as serpentine and talc with one-directional cleavage. With increasing the degree of serpentinization, some phenomena such as slope instability, sliding, excavation collapse will occur. The results of the present research indicated the priority of serpentinization degree of ultramafic rocks compared to their strength. As it is seen, although in a high degree of serpentinization, the metapyroxenites have higher strength and lower water absorption compared to metaperidotites. Therefore, the mentioned issues demonstrated the importance of the degree of serpentinization compared to strength in ultramafic rocks. 

The authors would like to thank Professor Mohammad Hassan Karimpour for his helpful and effective guidance on the petrography of ultramafics rocks in this paper.

Groundwater resources are the most valuable resources of each country. Development of agricultural activities in Ardabil plain and over-use of fertilizers and pesticides, improper disposal of municipal sewage and industrial areas are responsible for groundwater pollution. Clean-up of groundwater resources is very difficult and expensive. One of suitable method in preventing groundwater contamination is determination of the vulnerable zones of an aquifer to manage water resources and sustainable development. 

In this study for determining of vulnerability of aquifer Ardebil, information of 52 observational wells, 43 pumping tests, average of annual precipitation of 8 stations, 45 logs of exploration wells, land use map, topographic map and geological map have been gathered. Then, data layers of groundwater depth (D), Recharge (R), Aquifer media (A), Soil media (S), topography (T), impact of vadose zone (I) and hydraulic conductivity of aquifer (C) were prepared and overlaid based on DRASTIC method in ArcGIS software.

Zoning map of DRASTIC method showed that DRASTIC index varied between 63 to 195 units. Areas with high vulnerability potential were characteristic with shallow depth groundwater, coarse-texture soil, thin soil and gentle topographic slope. Accuracy of the zoning map was evaluated by nitrate concentration map which showed the increase of DRASTIC index with nitrate concentration.

Northwestern and central parts of the Ardabil plain showed high vulnerability. The results of this study could help to reduce the environmental impact of contaminants on groundwater resources of the study area in future.