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Prediction of shear strength parameters of Bandar Abbas soils using artificial neural network
Dr Mohammad Fathollahy, Mr. Habib Rahimi Menbar, Dr. Gholamreza Shoaei,
Volume 16, Issue 3 (12-2022)
Abstract
Shear strength parameters are important for assessing the stability of structures, and are costly to calculate using conventional methods. In this research, simple geotechnical techniques and artificial intelligence were used to calculate the angle of internal friction and soil cohesion without the need for more complex testing. To this end, intact samples from 14 boreholes in Bandar Abbas, which had undergone primary geotechnical testing and direct cutting, were selected and used to train neural networks.  195 networks were trained in in this research. To achieve the best performance, feedforward neural networks were first trained in single and double layer modes with a low number of neurons in the middle layer, and the TRAIN BR function was selected due to the high ratio of R (0.97). Then, by incorporating additional layers, the Median model was trained using configurations of 3, 4, and 5 layers, each with varying numbers of neurons in the intermediate layer (50, 40, 30, 20, and 10). The results show that the four-layer MLP network gives the best results, for this mode R training 1, the test R is 0.90 and the total R is 0.98. Finally, to validate the neural network, 15 samples were selected and the input parameters of the network were trained in the optimal states of 2, 3, and 4 layers, then the output of the network was evaluated. For cohesion prediction, the neural network in 4-layer mode (R2=0.99) and 2, 3 and 4-layer networks (R2=0.99) have the best output for the friction angle.

The Elastic Anisotropy Ratios in Cohesionless Soils and Corresponding Bilateral Correlations
Ehsan Pegah,
Volume 17, Issue 2 (9-2023)
Abstract
The ratios of elastic anisotropy in cohesionless soils are always of substantial importance in respective analyses to the geotechnical and geological engineering projects. These ratios are raising from the available discrepancies in anisotropic elastic parameters ascribed to the different directions and planes of soil mass. The major objective of this study is to recognize the variations range of anisotropy ratios resulting from anisotropic shear and Young’s moduli for a variety of cohesionless soils followed by assessing the potential relations among these two anisotropies. To this end, by assuming the transversely isotropy in cohesionless soils, the anisotropic elastic constants from 266 conducted laboratory tests on 37 various soil specimens relating to 10 different sands were derived from conventional triaxial and seismic waves laboratory tests coupled with the numerical testing results in literature. By sorting the collected data and subsequently their analyses, at the first stage, the values of shear and Young’s moduli anisotropy ratios were calculated for the studied soils. Furthermore, by plotting the anisotropy ratios in several joint panels and performing a series of regression analyses on the resulting values, the possible dependencies were inspected between these two anisotropies. At last, the indicative equations among shear and Young’s moduli anisotropies were developed with insistence on use of which instead of the former similar relations in literature. 

Effect of Tunnel Excavation of Tehran Metro Line 6 on Groundwater and Ali Spring in Shahr-e-Rey
Professor Hamidreza Nassery, Koosha Tamimi, Dr Farshad Alijani, Dr Sadegh Tarigh Azali,
Volume 17, Issue 3 (12-2023)
Abstract
The development of underground transportation activities in cities, such as tunnel boring, may exert short-term or long-term effects on the groundwater and springs of such areas. The construction of the tunnel of Tehran Metro Line 6 (TML6) through alluvium and carbonate rocks of Ali Spring has aroused concern due to the caused fluctuations in discharge and temporary dryness of the spring. The hydrochemical properties of the groundwater and catchment area were investigated to find a connection between the aquifers around the spring and determine the major aquifer feeding it. The estimated volume of water penetrated to the tunnel and the most greatly affected area by the water leakage into the tunnel was determined using analytical methods of water leakage into the tunnel and the DHI method. The statistics for precipitation with the changes in the discharge of the spring before and after the excavation of the metro tunnel were compared to evaluate the changes in the discharge of the spring with the precipitation in the area. The results showed that the metro tunnel excavation has dramatically affected the hydrological system of the area and discharge of the Ali Spring. Moreover, continuing the extraction may produce adverse effects on the discharge of other springs and wells and alter the flow system of the area temporarily or forever.

Evaluation of permeability, karst development potential and karst conceptual model of Ghareikan dam construction – Razavi Khorasan
Hossein Mohammadzadeh, Vahid Naseri Hesar, Hamid Ghalibaf Mohammadabadi,
Volume 17, Issue 4 (12-2023)
Abstract
Due to the complex hydrogeology of karst areas, the sealing of dams in such areas is more difficult, time-consuming and expensive, and the possibility of water leaksge is higher. After the dewatering of the Gharetikan dam and appearance of downstream springs and the leakage of water from the abutment of the Tirgan limestone formation, the possibility of karst development is considered to be the most important problem of this dam. In this article, the potential of karst development in the area and supports of the Gharetikan Dam has been studied by carrying out geological studies, structural geology and joint studies, geotechnical permeability and analysis hierarchy method (AHP).. The results show that about 14.6% of the ​​Gharetikan dam area has a high potential for karst development. The area of ​​Gharetikan dam area is affected by the Sarroud fault zone system, which has caused the collapse of the left side of the dam axis. The joint studies in the abutment of Gharetikan dam show three main types of joints. Two groups of joints are located at the intersection with the dam axis and the slope of the other group of joints is towards the dam basin. The investigating of Lugeon permeability tests in the dam construction shows that the highest permeability can be seen in the left abutment with turbulent flow, and then under the river bed with linear and turbulent flow, but there is no permeability in the right abutment. And the flow is mostly linear. According to the structural-conceptual model prepared from the location of the Gharetikan dam, to the location of the dam axis in the Sarroud fault system, and the amount opening and the slope direction of the joints in each station, it is expected that the amount of water leakage and escape and the possibility of karst development from the left side and the bed of the dam will be more than the right side of the dam.

Hydrogeological and hydrogeochemical investigation of Vorskharan karsitic spring in Firoozkooh county
Hossein Ebrahimi, Farzad Akbari, Soroor Mazrae Asl, Babak Biglari,
Volume 17, Issue 4 (12-2023)
Abstract
The Vorskharan karst spring with a catchment area of 50 square kilometers and an average discharge of about 1.35 m2/s is one of the most important springs in the city of Firouzkouh. In order to asses the hydrogeological and hydrogeochemical charachteristics of the spring, the physical and chemical properties of the spring water were measured and analyzed for several months. The results showed that the recession curve of the spring has a slope and the value of its coefficient is about 0.003. The low coefficienof the discharge variation t, electrical conductivity and major ions, as well as the single slope of the spring’s recession curve , are mainly due to the elongated shape of the aquifer and the long-term presence of snow in the catchment basin of the spring. Considering the relatively high water level of the spring and the existence of a sinkhole and a polje in the spring’s catchment area, as well as the coefficient of small changes in the physical and chemical parameters of the spring, it can be said that the dominant flow system in the aquifer which recharges Vorskharan spring,is  conduit-diffusive. According to the field studies and the evaluation of the percentage of soil cover, the development of dissolved spaces and other morphological effects of karst, the percentage of annual recharge in the catchment area was estimated  at 56%. With the amount of precipitation, the percentage of annual recharge, the annual recharge volume of the preliminary water catchment basin equal to 19.2 MCM and the annual discharge volume of the spring through the annual hydrograph of the spring was calculated to be equal to 20.1 MCM. It was also observed that the type of water is Ca-HCO3, and the lithology of the aquifer is calcareous and dolomite.

Evaluation of rock burst phenomena in tunnel sites using experimental and semi-experimental methods – A case study: Haji-Abad tunnel in Hormozgan province
M.sc. Behrooz Margan, Dr. Davood Fereidooni,
Volume 18, Issue 1 (5-2024)
Abstract
In this research, various aspects of the rock burst phenomenon in the Haji-Abad tunnel site in the Hormozgan province have been discussed. Considering that the tunnel site is located in an active tectonized environment in terms of geological conditions and the depth of the tunnel in some parts reaches more than 100 to 253 m, and also considering the variety of rocks in the tunnel site, which are massive rocks with high strength up to broken fault zones, the importance of studying and investigating the phenomenon of rock burst is very important for the safety of the labor force and equipment and the stability of the underground space. For this purpose, the Haji-Abad tunnel site has been divided into ten units of engineering geological conditions using the BGD method, which includes eight units T1 to T8 and two crashed zones Tf1 and Tf2. Then, using common experimental and semi-experimental methods, the phenomenon of rock burst in the tunnel site has been evaluated. In the experimental procedure, Goel et al.'s criterion was used, according to which the rock burst phenomenon does not occur in any of the tunnel units. Using semi-empirical methods, including the criterion of linear elastic energy of the tunnel site units in the range of very low to moderate rock burst phenomena and using the tangential stress criterion, the site units in the medium to very high range and based on the stress criteria of these units in the moderate to high range and finally, using the fragility criterion, all site units are placed in the range of high rock burst.

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