نشریه زمین شناسی مهندسی ایران
سال شانزدهم شماره 1 (بهار 1402)

The construction site of Masjed Soleyman Dam is of considerable importance due to the presence of impermeable clay layers and the conditions for the formation of suspended water aquifers. First, engineering geological studies of the site including office studies, field visits, discontinuities, detailed studies were performed, then using UDEC software, stability analysis and groundwater flow modeling were performed and the results obtained from numerical modeling were in good agreement with the reading. Stretching devices that confirm the accuracy and validity of numerical modeling. According to the results of numerical modeling, the hydrogeological conditions of the site have formed suspended aquifers within the conglomerate and sandstone layers, the lower boundary of which is impermeable clay layers. Because the slope of the stratification is oblique and its direction is inward, the water does not drain easily. Increase in volume), produce and increase pressure on the retaining walls and eventually cause it to crack and fall. In these cases, the use of vertical gravity drains at the top of the slope with greater depth so that it has cut all impermeable layers (clay) and the use of horizontal gravity drains at the bottom of the slope with longer length can reach at least up to the layering boundary to stabilize the structure. Be effective.

Determining the lateral bearing capacity of piles is one of the important issues that due to factors such as heterogeneity of soil environment in the pile and its geometric characteristics, the correct estimation of lateral bearing capacity of a pile is a problem. Although pile loading testing can be used as a reliable method at various stages of design despite its high accuracy, it incurs high costs and long execution times for construction and mining projects. In this paper, in order to apply new intelligent methods to estimate the lateral bearing capacity of piles in soft clay soils, two bee colony optimization and invasive weed optimization algorithms have been used.Finally, in order to evaluate the accuracy of the models, the indices of square correlation coefficient (R2), variance inclusion (VAF), mean absolute error percentage (MAPE), root mean square error (RMSE) and mean square error (MSE) were used. The evaluation results showed that for the bee colony algorithm, the estimation accuracy using R2 and VAF indices was about 0.98-0.99 and using MAPE, RMSE and MSE indices between 0.000032-0.0056 and also for the algorithm. For invasive weed optimization algorithm, estimation accuracy using R2 and VAF indices was about 0.97-0.98 and using MAPE, RMSE and MSE indices was between 0.0005-0.023. In addition, the results of sensitivity analysis showed that the non-drained shear strength of soil (Su), among other input parameters, has the greatest impact on the lateral bearing capacity of piles and change in it will have the greatest impact on the output.

In hydrocarbon reservoirs of hard formations, hydrocarbon extraction and field development are strongly dependent on the geomechanical conditions of the reservoir, such as fractures and faults status and in-situ stress conditions. Image logs are powerful tools used to evaluate geomechanical conditions of hydrocarbon reservoirs in recent decades. In this study, using the FMI image log, which has a high resolution, coverage percentage and accuracy, the status of fractures, faults, and in-situ stress conditions of the upper Arab Formation in one of the Persian Gulf oil fields were investigated. Accordingly, 206 open fractures in 10 crashed zone with N60E-S60W domain trend and 96 closed fractures with two N45W-S45E and N50E-S50W trends in the Upper Arab Formation of well A were detected and based on the orientation, they mainly were categorized in longitudinal tensile fracture. Also, based on the observed induced fractures and breakouts, maximum and minimum horizontal stresses are oriented in N50E-S50W and N40W-S40E directions, respectively

Cement-based solidification/stabilization is one of the common methods for increasing the stability of heavy metals in contaminated soils. However, the presence of some of the heavy metals such as lead ions causes a delay and prevention in cement hydration which makes this method as an inapplicable. Enhancement of contaminated clayey soils by NaOH can remove the problems associated with cement hydration delay in presence of heavy metal ions. The main objective of this paper is to determine the impact of enhancement on solidification/stabilization of contaminated soils in extreme acidic and alkaline environment. To achieve the above mentioned objective, samples of contaminated bentonite by 50 and 100 cmol/kg-soil of lead nitrate at two different conditions of enhancement by NaOH and without enhancement were solidified/stabilized by 10 and 50 percentages of cement. The extreme acidic and alkaline conditions simulated by performing of equilibrium soil washing, endorsed TCLP test in solidified/stabilized cured samples. In addition, series of XRD experiments were performed to address the rate and quantity of CSH formation. The achieved results indicate that at extreme alkaline conditions the enhancement of contaminated bentonite has decreased the leach-ability of lead ions around 96%. With a decrease in pH of samples to the quantities less than 5, the use of enhanced samples has reduced the quantity of leachate in enhanced samples in comparison to unenhanced samples around 90%. This is attributed to the contaminant retention by clay fraction of bentonite and contaminant solidification by CSH gels.

Today, dipole shear sonic imager measurement is widely used in the oil industry and provides valuable data for seismic interpretation, structural evaluation, and mechanical applications of rock. The data used in this research are taken from SefidZakhour in Fars area. In this study, different applications of shear sonic imager processing modes and image log as a complement, was examined for geomechanical evaluation. To achieve the goal, the shear wave was first divided into two components, fast and slow and then the reservoir anisotropy was determined based on the energy difference. The results showed that at the depth bottom of the well, the minimum energy at minimum and the maximum energy at large. The areas of the well that are falling have more intense peak waves. Factors affecting the reflection of stoneley waves and the presence of Chevron pattern indicated that well wall falling are the most important factor influencing. By evaluating the results DSI and FMI in the field of in situ stresses, the maximum direction of maximum stress along NE-SW10 was determined. Also, the two maximum stress NE-SW45 and SE-NW45 were in accordance with the maximum stress in Zagros.

Due to the enhancement of urbanization, industry, and agriculture, increasing temperature, and decreasing rainfall, the demand for water supply has increased. Excessive extraction of groundwater for consumption imposes a decline in the groundwater level and the occurrence of subsidence as a consequence. In this study, a support vector machine approach is applied to model the subsidence. Groundwater level drop, the thickness of alluvial sediments, the transmissivity of alluvial sediments, and elasticity modulus have been used as independent parameters of subsidence modeling by a support vector machine. The results indicate that the support vector machine model can model the subsidence with reasonable accuracy. To verify the performance of the support vector machine, the model's results have been evaluated with the measured values of the InSAR method obtained from the satellite images of some parts of Aliabad Plain. In addition, to examine the impact of model input parameters on subsidence, a sensitivity analysis has been conducted, and the results illustrate that the occurrence of subsidence is distinctly dependent on the drop in the underground water level in the region. The generalizability of the model has been investigated by using a new dataset, and the results indicate the generalizability of the subsidence support vector machine model.

Central Alborz Zone (CAZ) comprises a range of industries and a high concentration population (about one-fourth of the country's population), essential to provide material resources and create the necessary infrastructure for this massive population. The CAZ has a large variety of rock formations and facies, which causes extensive expansion in rock materials and resources. One of the major materials in the CAZ is the existence of a wide variety of carbonate rocks (Elika, Dalichai, Lar, Tizkuh, Ziarat, and Kond formations). This study aims to investigate the geological and engineering geological characteristics of six carbonate formations in the CAZ and to classify carbonate rocks based on their material and their performance in asphalt mixtures. Therefore, by sampling these formations and performing various lithological and engineering geological experiments, six studied formations have been classified, and have been used to evaluate their performance in asphalt mixtures. Selected formations include Elika, Dalichai, Lar, Tizkuh, Ziarat, and Kond. The studied carbonate rocks were classified based on the lithology and performance of their asphalt mixtures in fatigue and cracking test. This classification includes the best performance to the weakest performance, respectively, including Mudstone (Elika Formation), Bioclast Grainstone (Kond Formation), Bioclast Packstone (Dalichai Formation), Bioclast Packstone (Tizkuh), Packstone-wackestone (Ziarat Formation) and Dolostone (Lar Formation).

Topographic and geological features have a significant impact on ground movements. Some topography is distributed intermittently in nature. Topographic alternation can be one of the reasons for the significant intensification of earth's seismic motion. However, most studies have focused on the amplification caused by a single topography. Limited research has been conducted on intermittent topography. In this paper, the intensification of seismic motion of the earth in heterogeneous semi-sin hills that hill materials, layers with angles of 15 to 75 degrees relative to the horizon, have been investigate. At all angles of layering, with the increase in the number of hills, the displacement intensification also increases, for example, for the ridge, at an angle of 45 degrees, the maximum magnification in the presence of a roughness is 1.63, but the same amount reaches to 1.66 when the three roughness is topographical. At smaller angles, the increase in the amplification of three-layer hills is more noticeable than the two-layer hills, and the larger the inter layer angle, the closer the amplification of the two and three-layer hills to the other. Therefore, each of the parameters of changing the angle of materials of the layers in the hill, as well as the increase in the number of layers in the hill, have an impact on the amount of seismic amplifications and each of these parameters should be considered in seismic designs.