Showing 174 results for gh
Mojtaba Rahimi Shahid, Gholam Reza Lashkaripour, Naser Hafezi Moghaddas,
Volume 19, Issue 2 (Summer 2025)
Abstract
The Sanandaj–Sirjan Structural-Sedimentary Zone is one of the most important geological regions in Iran. The limestone formations in this area play a key role in civil engineering and mining projects. Knowing the precise mechanical properties of these rocks, especially the uniaxial compressive strength (UCS dry) and dry point load index (Is₅₀-dry), is essential for safely and economically designing structures. Because direct testing methods are costly and time-consuming, this study uses indirect modeling techniques, such as regression and neural networks, to predict these properties. First, a comprehensive database was compiled by collecting the physical, mechanical, dynamic, and chemical data of limestone samples from the region. Then, univariate, bivariate, and multivariate regression analyses were conducted to extract statistical relationships among the variables. Finally, multilayer perceptron neural network models with various architectures based on the Levenberg–Marquardt learning algorithm were developed. The comparison results of the model performance indicated that neural networks, due to their ability to identify complex and nonlinear relationships between parameters, provide more accurate predictions of the limestone mechanical properties compared to statistical models. A comparison of the correlation coefficients of multivariate regression equations and neural network models showed that, overall, using neural network models improves the accuracy of UCS Dry predictions by 14.89% and the Is ₅₀-Dry predictions by 4.70%. The results show that predicting UCS Dry in the presence of Is ₅₀-Dry among the input parameters has a significant impact on improving the accuracy of the models. For example, the model with the inputs Is ₅₀-Dry, SH, γ Dry and n showed very good performance. For predicting Is ₅₀-Dry, the models that included the parameters SDI1 and BI Dry as inputs also performed very well. The application of these models can contribute to cost reduction, increased speed of rock engineering studies, and improved safety in civil projects.
Soroush Mahdavian, Ali Raeesi Estabragh, Shima Azadeh Ranjbar,
Volume 19, Issue 3 (Autumn 2025)
Abstract
This research study investigated the impact of dimethyl phthalate (DMP) on the physical and mechanical properties of clay soil through experimental testing. Additionally, the impact of hydrated lime and magnesium oxide on improving the properties of clay soil was investigated. The contaminated soil was artificially produced in the laboratory. Natural and contaminated soils were mixed with the above agents at percentages of 5.0%, 10.0% and 15.0%, respectively. The experimental test programme for this study comprised: Atterberg limits, compaction, uniaxial compression tests (UCS) and scanning electron microscopy (SEM). Samples for the UCS tests, both with and without additives, were prepared using the static compaction method and tested at curing times of 7, 14 and 28 days. The results showed that, in general, the Atterberg limit, compaction parameter (maximum dry unit weight) and UCS values for the contaminated soil were lower than for the natural soil. The results also indicated a reduction in UCS values for a mixture of contaminated soil and 10% hydrated lime or magnesium oxide. A comparison of the final strength values of samples made from a mixture of contaminated soil and 10% hydrated lime or magnesium oxide showed that the strength was 34.4% and 63.8% lower than that of a mixture with 5% of these additives at the same curing time. The E50 values were calculated from the stress-strain curves of the different tests. Additionally, the SEM results showed that changes in the properties of the mixture prepared from these agents and natural or contaminated soil were due to a chemical reaction between the soil and the additives.
Eng. Mohammad Hossein Jowlar, Dr. Mashalah Khamehchiyan, Dr. Mohammad Reza Nikudel, Dr. Asghar Azadi,
Volume 19, Issue 3 (Autumn 2025)
Abstract
Over the past three decades, research into the factors influencing the development of gypsum karsts has become an active and growing area of study. The mechanically weak nature of gypsum, along with its rapid dissolution and deformability, contributes to the formation of gypsum karsts, voids, and caverns in regions where gypsum deposits are present. This process can significantly undermine geotechnical stability by reducing bearing capacity and increasing settlement. This issue is particularly critical in heavy industrial settings such as petrochemical facilities, where large storage tanks and other infrastructure are founded directly on the ground surface. Consequently, identifying and assessing these processes is essential for the design, construction, and maintenance of engineering projects. This study assesses subsurface gypsum karsts within the Masjed Soleyman Petrochemical site using an integrated geophysical and geotechnical approach. Ground Penetrating Radar (GPR) was employed across 24 profiles totaling 2,307 meters, also geotechnical data were obtained from 113 boreholes drilled to depths of 20–40 meters. Following data analysis, 32 occurrences of subsurface gypsum karsts were identified at depths ranging from 4 to 36 meters. Subsequently, surface water drainage patterns were analyzed and digitized from historical Corona satellite imagery (1968). In parallel, groundwater levels and flow direction maps were generated using data from electric probe depth finder measurements in boreholes. The integration of these datasets revealed that most gypsum karsts are concentrated in areas where groundwater tends to accumulate and flow. Finally, groundwater sampling and chemical analysis revealed an average sulfate concentration of approximately 1,480 ppm, indicative of a severe sulfate exposure environment.
Ms Haniye Yaghoubi, Dr. Reza Jahanshahi, Dr. Morteza Mozafari,
Volume 19, Issue 3 (Autumn 2025)
Abstract
This study examines the hydrochemistry and contamination levels of groundwater resources in the urban area of Birjand in eastern Iran. Water quality was assessed and pollution sources were identified through sampling 22 wells, 12 qanats and 4 springs. The results showed that electrical conductivity varied from 300 to 8,000 µS/cm, while pH ranged from 7.23 to 8.71. According to the Piper diagram, the dominant hydrochemical facies were chloride, sulphate and bicarbonate types. In some of the samples, the nitrate concentration exceeded the permissible limit of 50 mg/L set by the World Health Organization, indicating the influence of urban wastewater and agricultural effluents. The ionic ratios reveal the influence of halite and gypsum dissolution processes, as well as ion exchange reactions, on the chemical composition of the water. A health risk assessment showed that, while most sources are within the safe range for adults, some wells and qanats pose a higher risk to infants and children. This study aims to provide a scientific framework for understanding the geochemical processes that control water quality, and to identify high-risk areas for the sustainable planning and management of groundwater resources in the Birjand plain.
Seyedeh Aida Mirshafiey, Asghar Milan,
Volume 19, Issue 4 (Winter 2025)
Abstract
As one of the key factors causing changes in the Earth's altitude, earthquakes can lead to subsidence or uplift in different areas. These changes are mainly caused by the displacement of tectonic plates, movement along faults and changes in pressure deep within the Earth. The type of fault and the conditions of the earthquake determine whether uplift or subsidence occurs. Monitoring and examining these changes is of great importance for crisis management and relief, improving urban planning, and reducing environmental damage. To study changes in the Earth's surface, various methods are used, including accurate alignment, global positioning systems, laser scanning, and remote sensing, each of which has a specific accuracy and characteristic. Nowadays, satellite data and remote sensing methods are an efficient tool for calculating the vertical displacement of the Earth's surface. This study investigated the potential of Sentinel-1 satellite data and images to study land surface changes due to the 5.6-magnitude Khoy earthquake using the radar differential interferometry technique. Processing the radar images before and after the earthquake allowed us to extract the vertical displacements of the phase changes. The results show uplift and subsidence occurring in some areas close to the epicentre and in more distant places. The maximum uplift was 0.08 metres and the maximum subsidence was -0.156 metres. These results demonstrate the non-uniform pattern of land surface elevation changes caused by this earthquake.
Younes Mousavi, Mohammad Nakhaei, Gholamhossein Karami,
Volume 19, Issue 4 (Winter 2025)
Abstract
Planning the management and optimized consumption of groundwater resources is a critical infrastructural necessity, as these resources supply a significant portion of the country's drinking water. A key component of this planning is accurately calculating the water balance, which requires determining the aquifer's hydrodynamic parameters, including transmissivity (T) and hydraulic conductivity (K). This study calculated these parameters using step-drawdown pumping test data from a single-well system across various locations in the 411-square-kilometer Hashtgerd Plain aquifer (an unconfined aquifer) with AquiferWin32 software. The results indicate that transmissivity is distributed unevenly across the plain. The lowest transmissivity values were observed in the southern (Kourosh Town) and southwestern (Najmabad) sectors, while the highest values were associated with the Kordan alluvial fan and its downstream lands. Based on these findings, maximum transmissivity was estimated at 3,682 square meters per day, with an average of 440 square meters per day. Hydraulic conductivity was determined by integrating saturated thickness data from geoelectrical studies with the previously calculated transmissivity values. The final results showed that hydraulic conductivity ranges from a minimum of 0.2 meters per day in the southern regions to a maximum of 9.7 meters per day in the central aquifer.
Mohammad Sadegh Sharifi, Saeed Zarei, Seyed Reza Mansouri, Abdullah Hussaini,
Volume 19, Issue 4 (Winter 2025)
Abstract
The active tectonics of eastern Iran, resulting from the convergence of the Arabian and Eurasian plates and numerous active faults, has caused high stress concentration, as evidenced by major historical earthquakes such as those in Tabas (1978) and Bam (2003). This study aims to conduct a fractal analysis of seismicity parameters and investigate crustal stress heterogeneity in eastern Iran. To this end, an earthquake dataset of historical and instrumental events with Mw ≥ 4 (1900–2024) was compiled from the ISC and NEIC databases. After filtering and declustering, the data were analyzed using ZMAP and ArcGIS. The b-value (an indicator of stress level and the probability of large earthquakes), the D-value (the geometrical complexity of faulting), and the D/b ratio were calculated simultaneously and mapped spatially. The results show that the b-value ranges from 0.8 to 1.1, and the D-value ranges from approximately 1.6 to 2.3. Regions with low b-values and high D-values, especially along the Nehbandan and Dasht-e Bayaz faults, indicate high stress concentrations and an elevated likelihood of larger earthquakes. The total seismic moment of the cataloged earthquakes is estimated at 3.5×10²³ N·m, yielding an average annual seismic moment rate of 2.7×10¹⁶ N·m/yr (calculated by averaging over the available catalog years). The D/b ratio, regarded as an index of stored energy and stress heterogeneity, exceeds two in these zones and exhibits a strong correlation with areas of a high rate of seismic moment release. This pattern implies that an increase in fault geometrical complexity coupled with a decrease in the b-value signals the crust’s approach to the rupture threshold. Thus, by emphasizing the significance of the D/b ratio, the present findings offer a quantitative approach to mapping stress states, fault structures, and the potential for significant earthquakes in eastern Iran.
Dr Seyed Ali Asghari Pari,
Volume 19, Issue 5 (English articles 2025)
Abstract
This study investigates the effect of Soil-Water Characteristic Curve (SWCC) parameters on the slope stability of an earth dam under steady-state and rapid drawdown conditions. Given the importance of unsaturated soil behavior in earth dams, this research employs principles of unsaturated soil mechanics to analyze the influence of SWCC parameters on water flow rate and slope stability.The results indicate that parameters a and n positively enhance the flow rate, while an increase in parameter m reduces it. In slope stability analysis, parameters of SWCC showed negligible effects on the downstream slope stability, whereas an increase in m caused a slight reduction in the safety factor. Under rapid drawdown conditions, all parameters initially led to a decrease in the safety factor, but stability was restored after 10 days. Additionally, accounting for the unsaturated unit weight of the soil improved the safety factor in both steady-state and rapid drawdown scenarios. These findings highlight the critical role of unsaturated soil conditions in the design and stability analysis of earth dams.
Prof Seyyed Mahmoud Fatemi Aghda, Dr Asieh Hamidi, Ms Fatemeh Amiri,
Volume 19, Issue 5 (English articles 2025)
Abstract
The evaluation of mechanical strength, particularly the uniaxial compressive strength (UCS) of rocks, plays a critical role in the design and performance prediction of surface and underground structures, significantly impacting project costs and safety in engineering applications. Traditional laboratory testing methods for UCS assessment are destructive, time-consuming, and expensive, while indirect methods often lack reliability due to rock heterogeneity. This study addresses these limitations by developing advanced machine learning frameworks that integrate petrographic features with conventional rock properties to predict UCS and quantify associated uncertainties. The research utilized a comprehensive dataset from sedimentary rocks collected along Iran's southern coastlines (Persian Gulf and Gulf of Oman), encompassing mechanical properties (UCS, Brazilian tensile strength, point load index, porosity, ultrasonic pulse velocity), durability indices (Los Angeles abrasion, slake durability, aggregate impact value), and detailed petrographic characteristics derived from thin-section analysis. Three complementary approaches were implemented: (1) hybrid Neural Network-Gradient Boosting regression (ANN-GBR), (2) AutoML-optimized Random Forest, and (3) Monte Carlo simulation-based uncertainty quantification. Key petrographic features including immature and mature clastic textures, the mineral composition (quartz, chert) were used as input parameters alongside alongside laboratory testing to improve the prediction of UCS.The influence of these petrographic features on the rock’s microstructure and microcrack propagation contributes to reducing model uncertainty and enhances the reliability of predictions in complex and heterogeneous rock conditions. The AutoML-optimized Random Forest model demonstrated exceptional predictive performance with R² = 0.9884, RMSE = 0.5732 MPa, and MAPE = 3.6%, significantly outperforming traditional empirical methods. The ANN-GBR hybrid approach achieved R² = 0.9412 with RMSE = 1.385 MPa, while Monte Carlo simulations provided robust probabilistic assessments through 95% confidence intervals and systematic bias identification. Feature importance analysis revealed that soundness parameters and mineralogical composition are the most influentialpredictors, emphasizing the critical role of micro-scale petrographic properties in determining macroscopic mechanical behavior.
Dr Seyed Mahmoud Fatemi Aghda, Dr Mehdi Talkhablou, Habibolah Heidari,
Volume 19, Issue 5 (English articles 2025)
Abstract
Reliable assessment methods are required for designing initial support for tunnels in complex geological conditions. This study provides a thorough comparison of the Rock Mass Rating (RMR) and Rock Engineering System (RES) frameworks, examining a substantial dataset comprising 38 tunnels situated in various lithological and tectonic zones across Iran. While the RMR framework offers empirical simplicity, the RES framework provides a systems-based approach that quantifies parameter interdependencies. Analysis of field data, including shotcrete thickness and bolt density, revealed that the RES framework captures hydro-mechanical coupling more effectively, particularly in intermediate rock masses. To reconcile discrepancies between the two systems, we explored an integrated statistical formulation combining normalized RMR ratings with RES stability indices. This approach demonstrated a significantly higher correlation with field performance (R² ≈ 0.99) than the individual methods. The results emphasise the importance of integrating empirical and systems-based approaches to improve the reliability of predictions in tunnel support design and provide a solid foundation for engineering decisions in heterogeneous rock masses.
Dr Ali Ghanbari, Dr Mohammad Nakhaee, Dr Saeed Kalani, Dr Hamidreza Azizi,
Volume 19, Issue 6 (Accepted Articles 2025)
Abstract
Land subsidence represents a multifaceted geotechnical hazard that exerts profound impacts on environmental stability, infrastructure resilience, and socio-economic security. This research presents a systematic field-based assessment of subsidence manifestations across the Hashtgerd, Eshtehard, and Karaj plains in Alborz Province, derived from extensive surveys conducted during the spring and summer of 2025. Diagnostic indicators—including extensional and compressional ground fissures, localized structural deformations, wellhead displacements, large-scale surface cracks, and variations in groundwater levels—were systematically documented. The Hashtgerd plain, particularly the Saeidabad, Sepehr, and Najmabad areas, exhibited the highest density of subsidence evidence, encompassing progressive surface settlements, widespread fissuring, and instability of near-surface strata. In the Eshtehard plain, structural cracking in school buildings, ground ruptures adjacent to transmission towers, and failures in retaining walls were frequently observed. Deep surface fissures were also identified in the Fathabad region, situated between Eshtehard and Buin Zahra. Conversely, despite significant groundwater withdrawal, field surveys in parts of the Karaj plain revealed no pronounced subsidence indicators. The findings highlight a strong spatial correlation between the severity of subsidence and geological heterogeneity, unregulated groundwater exploitation, and the absence of smart metering systems in wells. This study underscores the urgent need for integrated monitoring frameworks, adaptive management strategies, and the application of advanced remote sensing technologies to mitigate and control the expansion of land subsidence in Alborz Province.
Akramalsadad Ghadami, Houshang Khairy, Ebrahim Rahimi,
Volume 19, Issue 6 (Accepted Articles 2025)
Abstract
Land subsidence is a major geomorphological hazard in arid and semi-arid regions, primarily driven by excessive groundwater extraction. In such areas, declining water tables can cause irreversible compaction of fine-grained sediments, reduced aquifer storage capacity, and damage to critical infrastructure. This study aims to monitor subsidence rates in the Damghan aquifer and analyze their relationship with groundwater level decline using satellite imagery and ground-based data. The study area covers approximately 1,522 km² of the Damghan aquifer in Semnan Province, characterized by a layered and heterogeneous alluvial structure. Data sources include Sentinel-1A radar images (2017–2021), groundwater level records from 38 observation wells (2012–2019), and drilling logs from 13 production wells. Radar data were processed using SNAP software, and spatial-temporal analyses were conducted in ArcGIS and GMS environments. Results indicate that groundwater levels in central and southeastern parts of the aquifer have declined by over 7 meters, with an average annual drop of 0.46 meters. Radar interferometry maps revealed subsidence rates of up to 32 cm in these zones. Soil texture and saturated layer thickness analyses showed that areas with high clay and silt content are more sensitive to water level decline and subsidence. Zoning results indicate that 44% of the aquifer surface is affected, with the highest rates observed in zones with alluvial thickness exceeding 230 meters. Field evidence—including surface fissures, well damage, sinkholes, and structural failures—highlights the practical implications of this phenomenon. Findings underscore the urgent need for continuous groundwater monitoring and targeted management to mitigate infrastructure risks and ensure environmental sustainability.
Salman Shamsoddini Motlagh, Saeed Mahdavi,
Volume 19, Issue 6 (Accepted Articles 2025)
Abstract
Due to the deepening of open-pit mines and the associated environmental considerations, the current era has been called the "return to underground mining period." One of the fundamental considerations in the transition from open-pit to underground mining is the design of crown pillars based on economic and technical considerations. As result of uncertainties in this research topic, the present study employs three-dimensional numerical simulation to investigate the interactive effects of geometric and geomechanical parameters on crown pillar behavior during the transition to underground mining. The pillar behavior was evaluated based on displacement magnitude and plastic zone volume of the pillar. The results of the numerical simulation showed that geometric parameters play a much more significant role than rock mechanical properties. Among geometric parameters, the pillar dimension index (product of pillar thickness and span) and crown pillar span have a decisive role in controlling pillar behavior. From a geomechanical perspective, within the range of variations considered in this research, rock elastic modulus was identified as the influential parameter on crown pillar behavior, which controls crown pillar behavior with a critical value of 7 GPa. The crown pillar span, as the second most influential parameter, can predict crown pillar displacement with a correlation coefficient of 0.83, and the pillar dimension index can estimate the plastic zone volume in the pillar with 20% accuracy.
Dr Seyed Ali Asghari Pari,
Volume 19, Issue 6 (Accepted Articles 2025)
Abstract
The present study systematically compares probabilistic slope stability analysis using three widely used geotechnical engineering software packages: PLAXIS LE V21, GeoStudio 2024 (SLOPE/W module), and Slide2. Given the critical importance of risk assessment and the inherent uncertainty in soil parameters, probabilistic analysis has emerged as an essential approach for quantifying uncertainties and calculating key metrics such as probability of failure and reliability index. This research evaluates the capabilities, accuracy, efficiency, and limitations of each software by performing identical analyses on three distinct scenarios (homogeneous soil, three-layered soil, and pseudo-static conditions) while employing ten common limit equilibrium methods. The results demonstrate that all three software packages are capable of conducting probabilistic analyses with acceptable accuracy; however, each offers distinct strengths: Slide2 is ideal for complex risk analyses due to its specialized tools and advanced graphical visualizations; GeoStudio is better suited for routine projects owing to its intuitive user interface and seamless integration with other modules; and PLAXIS LE excels in computationally demanding problems through its high numerical accuracy and hybrid finite element limit equilibrium (FELA) approach. This study provides practical guidance for engineers in selecting the most appropriate software based on project complexity, required accuracy, and available resources. It also emphasizes the advantages of probabilistic approaches over traditional deterministic analyses in effective risk management.
