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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.

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.

Mohammad Reza Haddad Tehrani, Mehdi Talkhablou, Mohammad Reza Asef, Mehdi Ostad Hasan,
Volume 19, Issue 2 (10-2025)
Abstract

Complex carbonate reservoirs, such as the Asmari Formation, present challenges to the accurate determination of geomechanical parameters and effective stresses due to high lithological and structural heterogeneity. The objective of this study is to develop a comprehensive three-dimensional model of geomechanical parameters and effective stresses in the Kupal oil field. Well log, core, and seismic data were used, and three-dimensional modeling was performed using the Sequential Gaussian Simulation (SGS) method based on variogram analysis. The prevailing stress regime was validated using FMI logs and wellbore breakout analysis. Additionally, a one-at-a-time sensitivity analysis was conducted on key parameters, including static Young’s modulus, Poisson’s ratio, cohesion, internal friction angle, and pore pressure. Results indicate that the maximum vertical effective stress (σv) is 87 MPa and the maximum horizontal effective stress (σHmax) is 127 MPa. Analysis of wellbore imaging data confirms a normal faulting stress regime (σv>σHmax>σhmin) in the field. Stress concentration around minor faults was also identified. The model was validated against one-dimensional models achieving 88% agreement. The findings of this study can be applied to well design, gas injection, and reservoir stability assessment in the Kupal field.

Dr Seyed Ali Asghari Pari,
Volume 19, Issue 6 (12-2025)
Abstract

Various factors influence earth dams' stability and flow rate, including geometric characteristics, material permeability, and upstream water height. Understanding unsaturated soil behavior in earth dams is crucial, necessitating the application of unsaturated soil mechanics principles due to the complexities involved. 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. The findings reveal that SWCC parameters significantly influence water flow and slope stability. Additionally, considering unsaturated unit weight can improve slope stability under varying conditions.
 


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