Showing 245 results for Type of Study: Original Research
Zahra Aghayan, Rouzbeh Dabiri,
Volume 18, Issue 3 (12-2024)
Abstract
Recently, the demand for rapid and cost-effective infrastructure development has led to the has led to the development of various soil improvement techniques, including stabilization. Studies on the incorporation of mineral materials such as lime and coal ash into soil stabilization have been carried out in several countries, and these studies have shown promising results. Given the beneficial properties or properties of coal ash, together with its availability and cost-effectiveness, the combination of coal ash with lime for clay soil stabilization is a viable option. This study evaluates lime and coal ash on the behavior and geotechnical properties of clay soils. The evaluation includes plasticity index (PI), compaction, uniaxial compressive strength, California bearing ratio (CBR) and direct shear tests, and direct shear tests. To achieve this, the process began with the mixing of clay with varying percentages of hydrated lime (4%, 6% and 7%), followed by a 28-day curing period for the samples. Coal ash was then added at different (5%, 15%, 25% and 50%) was incorporated into the clay and also cured for 28 days. In the final stage, the optimum amount of hydrated lime was determined, an amount of hydrated lime, equivalent to the amount of coal ash used, was added to the clay and the mixture was cured for a further 28 days. The results indicate that A mixture of 7% hydrated lime and 50% coal ash, after 28 days of curing, is an optimum combination for stabilizing the clay in the study area. This combination increased the uniaxial compressive strength by 1.87 times, the shear strength by 1.34 times and the CBR value by 6.4 times, making it suitable for use in the for use in the construction of pavement layers.
Dr Sasan Motaghed, Dr Marzieh Shamsizadeh, Dr Nasrolla Eftekhari,
Volume 18, Issue 3 (12-2024)
Abstract
In this study, we present the Seismic Hazard Possibility Space (SHPS) for the city of Ahvaz. To achieve this, we applied the intuitionistic fuzzy method to weigh the logic tree used in the hazard analysis and constructed the SHPS based on expert opinions regarding the degrees of membership and non-membership. Hazard disaggregation was performed by through the concept of intuitionistic fuzzy sets, leading to the development of an intuitionistic fuzzy of an Intuitionistic Fuzzy Logic Tree (IFLT). The SHPS includes both the degree of membership and non-membership for pathways contributing to hazard generation. The SHPS illustrates the acceptance, non-acceptance, and ambiguity associated with potential hazard values from an expert perspective, thus assisting analysts in selecting appropriate hazard values. According to the numerical results of our analysis in the Ahvaz region, the seismic hazard is located in an uncertainty (unacceptability) zone, indicating that experts have low confidence in the results of the probabilistic seismic hazard analysis (PSHA) for Ahvaz. In addition, the hazard is characterized by an "unconfident zone". This finding indicates that experts are fairly confident in the results of the analysis for Ahvaz. This finding implies that the models and parameters used in the PSHA for this region are not accepted by experts, and further efforts are needed to identify or develop appropriate models and accurate parameters specific to the area. In conclusion, this research demonstrates how intuitionistic fuzzy sets can be used to construct SHPS, providing a novel framework for quantifying uncertainty and expert opinion in hazard assessment.
Shaghayegh Samiee-Rad, Giti Forghani, Hadi Jafari,
Volume 18, Issue 3 (12-2024)
Abstract
The Garmabdasht River as the first tributary of the Qarasu River, flows through the city of Gorgan and eventually flows into Gorgan Bay. In order to study the hydrochemistry and to assess the water quality, 10 water samples were collected in June 2022. Physicochemical properties (pH, electrical conductivity, total dissolved solids), major ion concentrations, and microbiological parameters (dissolved oxygen content, biological oxygen demand, chemical oxygen demand, and coliform bacteria) were measured by standard methods. The obtained results show that the pH of the water samples varies between 7.5 and 8.5 and the electrical conductivity of water samples varied between 376 and 665 µs/cm. In terms of hardness, water samples were classified as hard and very hard. The concentrations of the major ions, phosphate and nitrate were within the permissible range for drinking usage. By calculating the ionic ratios and drawing the Durov diagram, it was found that the water chemistry was mainly controlled by the dissolution process. The position of the samples on the Piper diagram shows that the type and facies of the river water samples were calcium bicarbonate, magnesium bicarbonate and calcium sulphate. According to the Wilcox diagram, the Garmabdasht river water was suitable for irrigation. The residual sodium carbonate and sodium percentage values confirm this conclusion; however, based on the magnesium hazard index, the studied samples were not suitable for irrigation. The values of dissolved oxygen in all samples were within the permissible limit. The amounts of biological oxygen demand and chemical oxygen demand in some stations exceeded the permissible limit due to the influx of livestock and agricultural effluents. The obtained results show that the samples were microbially polluted, which may induce the health problem in the local population. The values of NSFWQI also shows that, except for the upstream samples of S1 and S2, the quality of the studied samples for drinking is in the bad to medium class.
Dr Eisa Hajiradkouchak, Dr Behzad Rahnama, Dr Hasan Nasrollahzadeh, Mr Ali Shahbazi, Mr Reza Raeiji, Mr Kazem Babaei,
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.
Mr. Ehsan Pegah, Mr. Behrang Feiz Aghaei,
Volume 18, Issue 3 (12-2024)
Abstract
Random noise reduction has always been one of the most important issues in seismic data processing. This study investigates one of the most effective random noise reduction methods, the 2D multi-stage median filter. This filter is applied to seismic data by applying a series of 1D median filters in different directions and then selecting the output value corresponding to the center of the 2D window. By applying a 2D multi-stage median filter to both synthetic and real data, it is shown that the filter can effectively attenuate random spike-like noise in both pre-stack and post-stack data. Similarly, based on spectral analysis, it is shown that this filter does a good job of reducing the level of high frequency random noise in both synthetic and real data. In this study, a 2D median filter is applied to synthetic data containing random noise with a density of 10%. Since increasing the filter length can damage useful signals in addition to attenuating random noise, it is important to specify an appropriate filter length. For synthetic data, the error ratio plot shows that a filter length of 9 points is appropriate for the first stage. In the second stage, a 2D median filter with a length of 7 points was applied to the output of the first stage filter. The effect of this filter on random noise suppression can then be observed by spectral analysis. In addition, median filters of 7 points and 5 points were applied to the pre-stack and post-stack real data, respectively. The effect and efficiency of this filter is assessed by examining the resulting difference plots, sections and spectral analysis.
Nafiseh Shokri, Dr Aliakbar Momeni,
Volume 18, 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 18, 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.
Akbar Khodavirdizadeh, Hassan Moomivand,
Volume 18, Issue 4 (12-2024)
Abstract
In this study, the stability of the Gougerd landslide of Khoy was investigated with respect to changes in the soil internal friction angle. Statistical analysis of the results of changes in the FS of different methods in analyzing the stability of the Gougerd landslide in 282 analyses showed that: 1) In static conditions, under the influence of groundwater conditions, the results of the stability analysis of various methods showed up to 35.2% changes in the FS, and the largest differences in the FS values were obtained in the conventional Fellenius, Spencer, and Morgenstern-Price methods. 2) In static conditions, the FS of various methods showed changes of up to 35% with respect to the effect of the internal friction angle, and the largest difference in the FS values compared to other methods was obtained in the conventional Fellenius method and the Spencer method. 3) In pseudo-static conditions and in the dry state, up to 5% changes in the FS were obtained in different analysis methods, and under the influence of groundwater conditions, the changes in the FS were up to 39.9%. The largest changes in the FS of the dry state were obtained in the simplified Janbu method, Spencer and Morgenstern-Price methods, and under the influence of groundwater, the largest changes in the FS were obtained in the conventional Fellenius method and Spencer method. In examining the results of this research, the effect of different conditions of groundwater level, soil internal friction angle, and earthquake force on the analytical mechanism of the relationships existing in various methods is recognized as the main cause of the difference in the results of different stability analysis methods.
Mr. Masoud Esmaeilzadeh, Mr. Ebrahim Keshavarz, Mr. Mohammad Golkhandandan,
Volume 18, Issue 4 (12-2024)
Abstract
Estimating tunnel construction costs is one of the critical steps in project management. Several factors influence the total cost of a tunnel project, and the complexity and uncertainty in identifying these factors often lead to inaccurate cost estimates. Various analytical methods have been developed to estimate tunnel construction costs, but all have drawbacks. Utilizing real data from other projects can mitigate these shortcomings. In this research, we first discuss the growth of the tunneling industry and its impact on the development of economic infrastructure. We then review the historical research on tunnel cost estimation and the methodologies that have been developed in this area. The lack of a pricing schedule for tunnel construction in Iran, unlike in developed countries, results in inaccurate cost estimates for tunnel projects. This study examines both definite and probabilistic methods for estimating the cost of mechanized tunneling, based on the price schedule of "Dam Field 1403." We compare the cost of tunneling in Iran with other countries. The results indicate a 30% difference in the ratio of labor costs to the total project cost and a 92% difference in the cost per meter for mechanized tunnels in Iran compared to other countries. This discrepancy discourages private contractors from engaging in tunnel projects in Iran. Therefore, we propose the development of a comprehensive pricing schedule for tunneling to enhance the accuracy of cost estimation for tunnel projects in Iran.
Eng. Mohammad Ijani, Dr. Ebrahim Rahimi, Dr. Vahab Sarfarazi, Dr. Ali Faghih,
Volume 18, Issue 4 (12-2024)
Abstract
Numerical modeling is an essential tool in engineering analysis, particularly within the fields of geoscience and geotechnics. The PFC2D software stands out in this field, using the Distinct Element Method (DEM) to simulate processes related to engineering geology and geotechnical assessment. This study focuses on the analysis and comparison of two common contact models: the Flat Joint Model (FJM) and the Linear Parallel Bond Model (LPBM). The Unconfined Compressive Strength (UCS) test is chosen as a the benchmark for calibrating and validating the PFC models. Sandstone samples for this study are taken from the Aghajari Formation located on the southern limb of the Madar Anticline. The results show that both contact models have a high ability to simulate the UCS in the calibration process. As this test is primarily used to calibrate the failure point (σc) and Young's modulus, the output values for both models are almost identical. However, the post-failure behavior in the stress-strain curves differs between the models, with the FJM demonstrating a more brittle response compared to the LPBM. The ability of the FJM model to simulate rough surfaces and material discontinuities allows for the representation of tensile cracking.
Dr Mohammad Fathollahy, Engineer Habib Rahimi Menbar,
Volume 18, Issue 4 (12-2024)
Abstract
In order to produce strong and durable concrete, it is essential to accurately assess the alkali reactivity potential of aggregates. Alkali reactions occur gradually over time and are therefore often overlooked in the early stages of a project.. This research investigates the alkali-aggregate reaction (AAR) potential of concrete aggregates. Petrographic analysis of aggregates, based on ASTM C295, is a simple and rapid method for identifyingminerals that may react with the alkalis in cement. In this study, susceptible aggregates were identified through petrography, and then the accuracy of the results and the importance of petrographic analysis were verified using laboratory methods (ASTM C586 and ASTM C1260) to select suitable materials with minimal cost and time before designing the concrete mix. The results indicate that carbonate aggregates may contain silica and have alkali reactivity potential, necessitating the use of ASR testing methods as well. In addition, the results demonstrate that petrographic analysis is an effective and valuable method for identifying minerals with alkali reactivity potential.
Dr Emad Namavar,
Volume 18, Issue 5 (12-2024)
Abstract
A considerable part of Golestan Province is covered by loess soils, most of which are of the silty loess type, which is one of the most problematic soils. The proximity of the Caspian Sea leads to salinity of the groundwater in some areas of the province. Due to high evaporation, salts reach the surface and cause salinization of the silty loess soils at the surface. The presence of soluble salts can lead to changes in the engineering properties of silty loess soils at the site of construction projects. It is therefore necessary to investigate the influence of salts on the geotechnical properties of silty loess soils. The aim of this study was to investigate the effect of sodium chloride or halite (NaCl) and calcium sulphate or gypsum (CaSO4.2H2O) salts, as the two most abundant natural salts, on the engineering properties of silty loess soils. For this purpose, silty loess soil samples were collected from Maraveh Tappeh city, Golestan province, Iran. Geotechnical tests including uniaxial compressive strength, shear strength and standard compaction tests were then carried out on soil samples in the natural state and with 3, 5, 7, and 9% NaCl and CaSO4.2H2O. Based on these tests, the variation in optimum water content (ωopt), maximum dry density (ρdmax), uniaxial compressive strength (UCS), cohesion (C), internal friction angle (φ) were evaluated. The results showed that these parameters increased with increasing both natural salts concentration. Finally, the reason for the changes in the engineering properties of the soil samples due to the presence of these two natural salts was discussed.
Mr Mohammadreza Harirsaz, Dr Ali Ghanbari, Dr Gholamhosien Tavakoli Mehrjardi,
Volume 18, Issue 5 (12-2024)
Abstract
A series of reduced scale plate load tests was conducted to evaluate the bearing capacity of a strip footing resting on granular slopes. The effect of three factors including geocell burial depth, geocell length and spacing of geocell layers were discussed and evaluated. In this regard, 18 tests were performed to investigate the behavior of one and two layered geocell-reinforced slopes as well as the unreinforced slope and plain conditions. The results suggest that in single-layered geocell-reinforced slope, the optimum burial depth of the first layer of geocell reinforcement is 0.1 times of the strip footing width, whereas at greater depth beneficial effect of the geocell will reduce. In addition, expanding the reinforcement length up to approximately three times the foundation width could effectively increase the bearing capacity, whereas extending the length beyond that does not lead to any significant improvement. Furthermore, it was observed that use of two geocell layers by considering an optimum geocell space of 0.2 times of the foundation width could enhance the bearing capacity up to 226% in comparison with the unreinforced slope, and up to 79% of the plane condition for settlement ratio of 15%. Finally, the results indicate that the efficiency of the geocell reinforcements in lessening the gap between slope and plane conditions increases as the settlement of the footing rises due to better mobilization of dilation characteristics of granular backfill material and better lateral confinement of coarse aggregates in greater strains.
Dr. Ali Misaghi, Dr. Mohammd Raeesi,
Volume 18, Issue 5 (12-2024)
Abstract
In this study, we investigate the spatial distribution of landslides, strong motion data, and seismic intensity patterns associated with the June 20, 1990, earthquake, with a moment magnitude (Mw) of 7.4. Our primary objective is to elucidate the rupture status of the southeastern segment, Zard Geli, of the coseismic rupture by integrating geological and seismological data, Our findings indicate that the southeastern segment experienced only a partial rupture during the 1990 earthquake. This partial rupture is evidenced by the disproportionate distribution and density of landslides along the surface rupture. The incomplete rupture of this segment suggests that it retains a considerable amount of accumulated strain energy that was not fully released during the 1990 event. Consequently, this segment remains a potential source for future seismic activity. These findings have implications for seismic hazard assessment and risk mitigation in the region. This study highlights the need for continued monitoring and detailed geological and seismological investigations to better anticipate and mitigate the effects of future earthquakes.
Soroush Mahdavian, Navid Rashidi, Ali Raeesi, Jamal Abdullahi,
Volume 19, Issue 1 (6-2025)
Abstract
Clay soils typically have low strength and a high swelling percentage. They are considered as problematic soils in Civil Engineering projects. This research study examined the effects of magnesium chloride (MgCl2) solution on the clay soil improvement through conducting laboratory experiments. The experimental program included Atterberg limits, compaction, swelling, unconfined compression strength (UCS) and Scanning Electron Microscopy (SEM) tests. Available clay soil in the Lab was mixed with MgCl2 solution at weight percentages of 3%, 5%, 7% and 10% Samples for the swelling and strength tests were made using thestatic compaction method. The moisture and dry unit weight of the prepared samples were the same as those of thecorresponding compaction curves. The strength test results showed that the final strengths of the samples with 3% MgCl₂ at 7-, 14-, and 28-day curing times were 1401, 2018, and 1848 kPa, respectively. The results also showed that a reduction in strength of the samples occurred with more than a 3% solution of MgCl₂. For samples with 10% MgCl2 solution, the strength decreased until 14 days of curing time, but increased thereafter. Additionally, the results indicated that the reduction in swelling percentage compared to natural soil was 4.95%, 3.98%, 2.8%, and 3.9% for samples with 3%, 5%, 7%, and 10% MgCl₂, respectively, showing that the reduction in swelling depends on the MgCl₂ percentage. Additionally, the SEM results showed that the improvement in the soil was due to chemical reactions between the soil and MgCl₂.
Mr. Mehdi Abbasi, Prof. Gholamreza Lashkaripour, Prof. Naser Hafezi Moghaddas, Dr. Hossein Sadeghi,
Volume 19, Issue 1 (6-2025)
Abstract
The elastic modulus is considered one of the most essential parameters in the analysing and designing deep foundations and underground structures. Accurate determination of this parameter usually requires expensive and time-consuming in-situ testing, and validating its accuracy poses significant challenges. Therefore, researchers have consistently focused on developing empirical models based on geotechnical parameters. In the present study, multiple linear regression models, including general, coarse-grained soil, and fine-grained soil models, were developed to predict the elastic modulus using data obtained from 180 boreholes totaling 5,783 meters in the Mashhad Metro Line 3 project.. Out of 489 pressuremeter tests, 160 datasets were selected based on the availability of complete geotechnical parameters at the same depth. The analysis incorporated the influence of various parameters, including the percentage of sand, silt, and fine particles; grain size characteristics (D10, D30, D60, uniformity coefficient, and coefficient of curvature); Atterberg limits; moisture content; natural and dry density; specific gravity; and cementation indicators (gypsum, carbonate, and organic matter), as well as depth and in-situ stress. The final regression models were developed using a backward stepwise method, implemented through Python programming. The resulting regression equations were derived, and comparative plots between predicted and actual elastic modulus values were presented. The findings demonstrate that the proposed model offers reliable accuracy in estimating the elastic modulus. To evaluate the accuracy of the proposed models in predicting soil elastic modulus, an independent dataset of 39 pressuremeter test results, including both fine- and coarse-grained soils, was used. Statistical indicators demonstrated that the overall model performed best (R²=0.79, MAPE=9.86%). Additionally, the low values of normalized RMSE confirmed the stability and acceptable accuracy of all models.
Mrs Roya Masoumipour, Dr. Saeed Mahdavi,
Volume 19, Issue 1 (6-2025)
Abstract
The Chador-Malu open-pit mine is faces complex challenges regarding the long-term stability of its slopes. These are directly influenced by time, environmental changes, and stresses induced by mining activities. Considering the existing evidence of potential future instability, displacement changes along the northern to eastern pit walls were analyzed over an 18-month period. Long-term wall displacements were measured using radar. Through back-analysis and three-dimensional numerical simulations, the equivalent creep behavior of the slopes was evaluated using the Maxwell creep model. After assessing the geomechanical parameters, the impact of three scenarios passage of time, bench widening, and pit deepening on slope stability was investigated under three horizontal-to-vertical stress ratios of 0.5, 1, and 1.5. The analysis results indicated that a horizontal-to-vertical stress ratio of 1.5 better matched the field observations. In the first scenario, a 50% increase in time led to over a 100% increase in displacement rates, indicating a rise in instability potential over time. In the second scenario, unloading the first two benches reduces the instability potential, due to an 18% reduction in uplift while unloading up to the eighth bench increased instability potential due to the reduction of weight at the slide’s toe and an increase in the average uplift. In the third scenario, pit deepening formed another sliding zone between the tenth and seventeenth benches.
Ehsan Pegah,
Volume 19, Issue 1 (6-2025)
Abstract
Accurately quantifying the anisotropic elastic parameters of in situ soils is essential for many geotechnical and geological engineering studies. This research introduces an innovative geophysical field technique for assessing these parameters in situ by utilizing the directional variations of P-wave and S-wave velocities. Assuming cross-anisotropy in the soil layers at the test location, it was shown that P- and S-wave propagation velocities along different orientations and planes can be effectively measured through a combination of seismic refraction and downhole surveys. The refraction data were analyzed using Seismic Refraction Tomography (SRT), Multichannel Analysis of Surface Rayleigh Waves (MASW), and Multichannel Analysis of Love Waves (MALW) to estimate the horizontal P-wave velocity (VPH), vertical S-wave velocity (VSV), and horizontal S-wave velocity (VSH), respectively.Moreover, the vertical and oblique P-wave velocities (VPV and VPθ) were identified by evaluating the travel times and distances of wave signals obtained from downhole tests. These velocity measurements were then incorporated into advanced equations formulated from elastic wave propagation theory, facilitating the computation of elastic parameters at the site. To evaluate the accuracy and efficiency of the proposed approach, the obtained results were compared with corresponding laboratory measurements, revealing a satisfactory level of agreement between the two datasets. The proposed methodology offers a practical means for in situ assessment of cross-anisotropic elastic properties in near-surface geomaterials using field-based seismic techniques.
Nazila Dadashzadeh, Morteza Hashemi, Ebrahim Asghari-Kaljahi, Akbar Ghazi-Fard,
Volume 19, Issue 1 (6-2025)
Abstract
The urban development of Tabriz faces numerous geological and engineering challenges due to the presence of Neogene argillaceous-marly rocks. These rocks exhibit low mechanical strength and bearing capacity, as well as high deformability. This study aims to analyze these rocks and establish practical correlations among their petrographic, physical, and mechanical properties, alongside ultrasonic test results. These correlationscan help estimate uniaxial compressive strength (UCS), compression wave velocity (Vp), and elastic modulus (E). The findings indicate that argillaceous-marly samples, classified as very weak to weak rocks or hard soils with significant deformability, exhibit low compression and shear wave velocities. These samples are predominantly found in yellow, olive green, gray to dark gray, and brown colors throughout the city. The study reveals significant linear relationships between physical properties, mineralogical composition, UCS, and E with seismic wave velocity. Notably, there is a strong correlation exists between compression wave velocity and uniaxial compressive strength, shear strength parameters, cement content, and mineralogical composition in these rocks. These relationships suggest that mineralogy, porosity, density, and slake durability index are key factors influencing seismic wave velocity. Additionally, the variations in textural and microstructural diversity of argillaceous-marly-marly samples contribute to unpredictable mechanical behavior, which can pose potential hazards. Furthermore, a qualitative fissure index (IQ) was developed usingthe P-wave velocity of the samples to classify them into categories of high fissurability.
Tahereh Azari,
Volume 19, Issue 1 (6-2025)
Abstract
Accurately determining hydraulic parameter values is the first step in sustainably developing an aquifer. Since Theis (1935) introduced the type curve matching technique (TCMT), it has been used to estimate aquifer parameters from pumping test data. However, the TCMT is subject to graphical error. To eliminate this error, a multi-layer perceptron (MLP) artificial neural network (ANN) was developed as an alternative to the conventional TCMT. This MLP ANN models the Bourdet-Gringaten well function to determine fractured double porosity aquifer parameters. The MLP model was developed using a four-step protocol and trained using the backpropagation method and the Levenberg-Marquardt optimization algorithm for the well function of double-porosity aquifers. Through a trial-and-error procedure and by applying principal component analysis (PCA) to the training input data, the optimal network structure with the topology [3×6×3] is determined. We evaluated the validity of the developed network with synthetic and real field data. The network receives pumping test data and provides the user with aquifer parameter values. This network provides an automatic, fast procedure for determining double-porosity aquifer parameters, eliminating the graphical errors inherent in the conventional TCMT.
