Journal of Engineering Geology

Identification of groundwater flow anomalous in the area of Neyriz Rizab Plain and determination of its probable cause

somayeh zarei doudeji

Groundwater resources in Iran are of particular importance due to the lack of surface water resources, lack of precipitation, high evaporation volume and recent droughts. The first step in identifying and exploiting groundwater resources is its quantitative and qualitative investigation. Neyriz watershed, located in the study area of Qatroiye desert, has 17 piezometers, whose groundwater level has been recorded monthly during the statistical period of more than 12 years. Investigations of the groundwater level and the map of the flow lines show the anomaly of the flow in the south and southwest part of the aquifer, which shows the direction of the groundwater flow contrary to the direction of the topography of the area. In this research, an attempt was made to investigate the cause of this anomaly based on the available information, including piezometer drilling logs, aquifer quality data, and national statistical data. Based on the qualitative information of the aquifer, the electrical conductivity and chlorine values of the groundwater increase in the direction of the topographic slope, which indicates the flow in the direction of the topographic slope. Qualitative charts of Piper, Schuler and Durov also confirm this issue. The level of groundwater in selected exploitation wells for qualitative sampling based on the information of the depth of groundwater in national statistics also indicates the flow in the direction of the topographic slope. Finally, a clay layer with a thickness of 10 to 30 meters was observed in the drilling log of the piezometers in the south and southwest of the aquifer. Examining all the results shows that the existing aquifer is probably a double-layered aquifer, where the flow direction in the upper layer is in the direction of the topographic slope and in the lower layer is against it, and the piezometers of the south and southwest parts penetrated the lower aquifer. In order to confirm the desired hypothesis, it is suggested to carry out geophysical studies in the area or to dig exploratory wells.

Comparison of hydrodynamic coefficients of Dalon- Meydavood plain by grain size analysis, geophysics and pumping test methods

elahe iraniasl

Groundwater is one of the main sources of water supply for agriculture, drinking and industry in Iran, especially in areas with arid and semi-arid climates. Therefore, due to the high importance of groundwater resources, it is necessary to know the hydrodynamic parameters in order to determine the natural flow of water and manage the optimal utilization of groundwater resources. Considering the role of the Daloon-Meydavood aquifer in providing part of the water needed in the study area, especially for agricultural purposes, the hydrodynamic parameters of this aquifer were estimated using the methods of grain size analysis, geophysics and pumping test. The parameters were calculated by all three methods and validated using the flow rate of the exploitation wells. In all three methods, the hydrodynamic parameters (Hydraulic conductivity, Specific yeild, transmissivity coefficient) are the highest in the north and northeast and the lowest in the south and northwest. The results showed that 2 methods including grain size analysisand pumping test had the most similarity with the discharge map of the exploitationwells.

Evaluation of the effectiveness of adding nanominerals to improve the engineering characteristics of concrete

Ebrahim Rahimi

This article deals with the strength evaluation of concrete obtained by adding different percentages of three types of nanominerals, including nanocalcite, nanobarite and nanofluorite. To measure the velocity of ultrasonic waves and compressive strength of concrete, 15×15×15 cm cube samples were prepared with 7-, 28- and 90-days curing. 10 types of mix designs with 0.39 water-cement ratio, including the control sample (without additives) and the samples with 0.5, 0.75 and 1% nanominerals were subjected to the mentioned tests. The results showed that the addition of nanocalcite, nanofluorite, and nanobarite with values of 0.75%, 1%, and 0.75%, respectively, have the highest compressive strength compared to the control sample. Although these do not have pozzolanic properties, they play a positive role in increasing the concrete strength by filling concrete voids and due to their high specific gravity, increasing concrete density.

Evaluation of rock burst phenomena in tunnel sites using experimental and semi-experimental methods – A case study: Haji-Abad tunnel in Hormozgan province

Davood Fereidooni

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.

Influence of well physical parameters on the cone of depression in the zone of influence of water wells in unconfined alluvial aquifers

Amin Ahmadi

The zone of influence is the area where water withdrawal from the well causes the water level to fall. The drawdown cone is a conical shape of the water level in the zone of influence, and it is necessary to know the effect of the factors influencing it. Previous studies have mainly investigated aquifers with horizontal water levels and less realistic conditions. The purpose of this study is to investigate the effect of well physical parameters on the drawdown cone in one of the unconfined aquifers with a sloping water surface. In this aquifer, a normal discharge well was simulated using the Modflow program and the effect of the target parameters was studied. The results showed that: the drawdown cone is symmetrical up to long pumping and relatively long distances; the zone of influence will eventually extend to the entire aquifer and significant drawdown will occur at long distances. A significant part of the drawdown in the well is recovered in the first moments of pump shutdown, but at long distances, the drawdown continues to increase for a long time. An inflection point can be extracted from the drawdown cone which represents the minimum drawdown that does not increase after the pump is stopped and can be introduced as a unique value. By increasing the flow several times, the depth of the cone increases, but the width of the cone increases only slightly. If the pump is turned on and off successively, the general shape of the cone does not depend on the nominal discharge of the well, but mainly on the average discharge of the aquifer. Relative infiltration increases the depth of the cone only near the well and has no significant effect on its shape further away.

Investigating the method of calculating the allocable underground water in Iran and providing corrections for it

kamal ganjalipour

In determining the water that can be allocated for different uses, including agriculture (as the main consumer), the most important step in this era is the proper management of groundwater resources. The observance of water consumption within the limit of allocated water ensures that the consequences of the exploitation of groundwater resources and the sustainability of development are guaranteed, and operators use technological methods to increase the efficiency of using water resources for more production in proportion to the amount tend to available water. In this article, first, the method of calculating the water allocated to the agricultural sector in the country has been studied and criticized. In this study, it was found that in the formula for calculating the current allocated water, the component of agricultural return water as an effective parameter causes a huge error in the calculation of allocated water. Then, a new formula for the calculation of allocated water was proposed, and an attempt was made to correct and apply the effect of the input component of agricultural return water on the amount of allocated water based on the calculation of allocated water in the new proposed method, taking into account the aquifer capacity based on the parameters of the water resources balance.

Engineering Geological Analysis and Modeling of Excavations in the medium depth, Venarch Manganese Mine (Qom)

Mohammad Reza Asef

This paper investigates the application of geomechanical and geological engineering methods to determine the optimum working face width for the safe and efficient extraction of manganese ore extraction at the Venarch Mine (Qom Province, Central part of Iran). The underground workings on the west face (240m depth) present significant geotechnical challenges due to the presence of faults, clay seams, and loose rock layers. These features require careful careful stability analysis to ensure the safety and economic viability of the underground mining operation. This study uses three established methods for rock mass classification and stability assessment. The Rock Mass Rating (RMR) classification system, the Q-system (Barton), and the numerical analysis using Plaxis 3D software. A robust and data-driven approach to determining the optimum workshop width was achieved by employing a synergistic combination of these three methods, together with meticulous ground observations and expert engineering judgement. This framework offers a powerful tool for determining the optimal and safe workshop width for this sector of the mine. By capitalizing on the strengths of each methodology, this research aims to establish a data-driven and informed decision-making process to ensure a stable and economically viable approach.

Determining separate resistance factors for base and shaft in driven pile foundations

Sayed Ali Asghari Pari

Pile design is subject to a number of uncertainties that must be addressed to ensure the reliability and safety of the foundation. A common approach to reduce uncertainties in pile design is to calibrate the resistance factor in the Load and Resistance Factor Design (LRFD) method through reliability analysis. However, it is important to recognize that the LRFD method may not fully account for uncertainties associated with soil and pile resistances. The results of this study show that the separate consideration of base and wave resistance can lead to a more accurate and reliable design of piles. The proposed method can help engineers make more informed decisions and reduce uncertainties in pile design. In addition, the study highlights the importance of considering different factors such as the ratio of dead to live load and the ratio of base to shaft resistance when calculating the resistance factor.