نشریه مهندسی عمران و محیط زیست دانشگاه تبریز
سال پنجاه و سوم شماره 4 (پیاپی 113، زمستان 1402)

Bentonite is commonly used as a liner in landfills to prevent the leaching of the waste leachate to the groundwater (Yong et al., 1992; Abollino et al., 2003; Zhan et al., 2022). Sodium-bentonite and calcium-bentonite are among the useful materials for this purpose. On the other hand, in several cases clayey soils are exposed to high temperature in engineering and geo-environmental engineering projects (Tan et al., 2004). Dehydration and de-hydroxylation are the two major phenomena during heating process of clayey soils (El Warid et al., 2022). In spite of several researches on the interaction of heavy metals and clayey soils, there are lack of research on the subject of mutual effect of temperature and double layer cation type on the adsorption of heavy metals in clayey soil. Therefore, the main objective of this paper is to investigate on the impact of temperature and type of double layer cation on adsorption of copper heavy metal by the clayey soils with high plasticity index. To achieve the above mentioned objective, calcium chloride salt was used to make homo-ionic bentonite. Several types of geo-environmental engineering experiments were performed to address and to achieve the above mentioned objective.

In designing a geotechnical structure, two factors of resistance and deformation should be considered, so in this study, the effects of melting and freezing cycles on the deformation parameters of biologically stabilized sand are evaluated and various factors such as all-round pressure, number Melting and freezing cycles Temperature changes in each cycle and the duration of each cycle are evaluated. For this purpose, non-drained reinforced static triaxial tests are performed and the deviation-axis-strain stress curves, chord stiffness (Esec), tangential stiffness (Etan), stiffness equal to 50% of maximum resistance (E50) and absorbed energy (EA) are performed). Is evaluated. The Taguchi method is used to design experiments and provide a relationship to predict some deformation parameters. The results of this study show that the application of melting and freezing cycles reduces the deformation parameters of stabilized samples. The destructive effect of melting and freezing cycles on hardness is greater than the absorbed energy.

Marl or marl clays are named for carbonated soils with the amount of carbonate in varying proportions from 20 to 55% (Elert et al., 2017). Marls are one of the most important problematic soils that not only the problem of volume changes but also their bearing capacity is lower than coarse-grained beds, so not meet the load-bearing goals of engineering structures. Different improvement methods are proposed to improve the engineering characteristics of problematic soils, the most common is using of lime for this purpose in clayey soils (Al-Mukhtar et al., 2012 and Obuzor et al., 2012) But this substance is less effective in marls (Ghobadi et al., 2014 and Ureña et al., 2015). According to the history of soil modification, the geopolymerization method can be introduced as the third generation of cementation methods after lime and cement (Li et al., 2010). Geopolymers are alkaline activated bonds with low calcium and medium to high aluminum produced by the reaction between alkaline hydroxide solution and materials containing alumina silicate (Provis et al., 2009 and Yung-Ming et al., 2016).The purpose of this research is using the geopolymerization technique to stabilize Tabriz carbonate clay with the approach of controlling deformations and increasing strength. To achieve this outcome, laboratory studies have been carried out on Tabriz green marl with alkali activated zeolite and metaclay as sources of alumina silicate to form cemented bonds. The alkali activator used in this study is sodium hydroxide with different concentrations to achieve optimal results. For this purpose, multiple tests of uniaxial compressive strength have been used to evaluate the strength of stabilized soil. The effective parameters studied in the current research can be referred to the weight percentages of materials containing alumina silicate (zeolite and metaclay), curing time and molarity of the alkaline solution (NaOH).

For the seismic evaluation of structures, it is required to determine the inelastic displacement ratio. Indeed, the inelastic displacement ratio is one of the most important coefficients in codes which is used in force-based design method as well as in performance-based seismic engineering (Miranda, 2000a, b). This study attempts to evaluate the inelastic displacement ratio,  for single-degree-of-freedom (SDOF) systems that is defined as follows:

There have been many studies regarding the health monitoring and detection of transmission towers, among which we can refer to the article by Yen et al. in 2009, who investigated damage detection in transmission towers with a limited number of sensors those modal parameters were obtained from the measured environmental vibration data. In their research, mode shape and frequency were used to identify the system. Also, stiffness reduction was also suggested to damage detection. Structural health monitoring by using features such as natural frequencies and mode shapes has attracted the attention of a number of researchers. Damage detection in power transmission towers using these features and using soft computing methods was also considered by Skarbek et al. in 2014. They have investigated frequency damage indicators by simple processing and using neural network for power transmission tower. In 2019, Zhao et al obtained the natural frequency of the 110 kV power transmission tower using the sub-random space method and found that the detected natural frequency is dependent on the wind speed. However, the current article tries to damage detection in the connections due to the lack of access to real data and experimental data and based on numerical modeling of a limited number of possible damages that occurred in the legs of the splice connection of power transmission tower.

In urban environments, due to the existence of structures in the city such as buildings and, more importantly, the presence of people in them, as well as existing underground structures such as service spaces including sewage tunnels, aqueducts, and adjacent tunnels, there have been always concerned about damages to these structures and their interactions existed as a result of tunneling. Significant interaction effects can occur when a new tunnel is dug in the vicinity of an existing tunnel. For example, the construction of a new tunnel could impose unauthorized deformations or bending moments on the existing structural support system. This interaction depends on parameters such as the distance of the tunnels, the size of both tunnels, the rigidity of the support system and the method used to locate the second tunnel, and the geotechnical characteristics of the excavation site.Aqueducts are underground structures and excavating new tunnels can have special interaction effects on these structures. An aqueduct is a subterranean canal with a gentle slope, which connects water-rich zones at high altitudes to the fields where cultivation takes place.According to studies, the interaction between underground structures is one of the critical factors that affect ground displacement and subsidence. The effect of the interaction between the tunnels as well as the amount of face pressure on the ground subsidence has been investigated using methods such as physical modelling, numerical modelling, and local measurements. In this paper, the effect of face pressure has been investigated in excavating the 2nd tunnel Line of Tabriz Metro on existing aqueducts. It is worth noting that for 3D modelling, FLAC3D software is used in this paper.

The presence of dispersion in clays affects the behavior of these types of soils. Experience has shown that not paying attention to this issue has created many problems for civil projects and even led to their destruction in some cases. In the past, it was recommended not to use divergent soils, but today, due to the expansion of civil projects and the possibility of dealing with these types of soils, it is very important to investigate their behavior and find appropriate methods of improvement. Ibrahim et al. (2021) conducted a laboratory study on clay with different percentages of glass powder. They concluded that the maximum dry density and unconfined compression strength of modified soils increase with the increase in glass powder ratio. Different combinations of glass powder and cement were evaluated for silt stabilization according to different curing times. The results have shown that the durability and compressive strength of the modified soil increases with increasing curing time period (Baldovino et al., 2020). Using recycled glass powder can be an effective way to improve the geotechnical properties of soils due to its economic nature and its role as a recycled material in reducing environmental problems. Even though the effect of using glass powder in improving the resistance properties of soils has been investigated by researchers, the use of glass powder and its effect in improving problematic soils, especially dispersive clays, have not been specifically studied. Therefore, the purpose of this research is to investigate the effect of adding recycled glass powder on reducing the dispersivity potential of clay soils and improving their geotechnical properties.

To study the dynamics of embankment models, which is the basis for the construction of many engineering structures, physical modeling with different scales can be performed. The pre-seismic behavior of physical models has a great impact on the subsequent results of their seismic modeling. Appropriate experiments in this field can be used for pre-seismic examination of physical models. Free vibration and impact tests are among these tests (Dezi et al., 2012; Capatti et al., 2018; Kramer, 1996). Impact pulse tests (IPT) can be used to determine the natural frequency characteristics of physical models. Interpretation of frequency responses provides researchers with appropriate pre-seismic parameters. According to the evaluation of these findings in the first step, a suitable geometric scale can be selected for physical modeling. In addition, the relationship between soil conditions in terms of density and particle size and frequency response quantities of physical models is also determined. In this paper pre-seismic simulations of a small-scale physical model of a granular soil layer inside a rigid physical modeling box are developed.

The purpose of this study is to analyze the environmental risks of soil erosion in the runoff of the Shahid Rajaei Dam in Sari based on GIS and remote sensing approach. In this study, soil erodibility was assessed based on the global model of soil loss called RUSLE with rainfall erosion input parameters, soil erodibility, topographic factors: length and slope, land cover management, conservation operations. For this purpose, before producing the results of these factors, first the input data such as DEM, slope, geological layer, land use layer, precipitation, soil and vegetation index was prepared and their spatial distribution pattern in the study area was described and analyzed. In the next step, the potential for flooding and runoff production was measured using the criteria of distance from waterways, drainage density, slope, slope direction, land use, rainfall, geology, soil type. In this regard, while fuzzy the layers, different variables were applied in order to integrate the mentioned layers in the final step on the production of flood potential map and runoff production. After producing the main layers, namely flood potential and runoff production, soil erodibility was studied using Pearson correlation test and regression model of the relationship between these factors and the results were discussed. The results of this study showed that remote sensing and GIS techniques in combination with field measurement values of the studied parameters can have many applications in the field of environmental studies in the field of civil engineering and in modeling and estimating environmental parameters. Be very beneficial bio.

For the gas and oil pipelines in marine environment, the forces exerted on these structres are regarded to be of the important parameters in designing them. These pipelines are usually installed with twin arrangements as tandom or side by side. The diameters of the two pipelines may also be identical or different. Neverthless, a number of them may also be configured as piggyback, an special case of side by side arrangements when their diameters are not equal. The parameters around this special arrangement have already been studied both experimentally and numerically by a few number of researchers, namely, Zhao et al. (2007), Zang et al. (2012), Hakimzadeh and Mosahebi Mohammadi (2016), Kardan and Hakimzadeh (2018). However, for this research study, the momentary hydrodynamic forces acting on the piggyback pipelines due to steady currents have been investigated using numerical simulation. All simulations were performed in 3D using ANSYS FLUENT 16 software environment. First, the capability of the software for the current study was investigated. The number of cells and various turbulence models were considered to find the proper mesh size and model, respectively. Then, considering that for flows around a single pipe, the conventional turbulence models may not provide accurate results, therefore, by examining different cell types and turbulence models, an attempt was made to select the appropriate type that can provide more accurate results by spending a reasonable computational cost. Then, it was found that a structured cell formation together with LES turbulence model reproduced the flow patterns around the pipe with a reasonable accuracy when compared with the experimental data. For the numerical simulation results, first, the effects of the inlet flow velocity and main pipe diameter (i.e., the Reynolds number) variations on the coefficients of instantaneous hydrodynamic forces (i.e., drag and lift) exerted on piggyback pipelines were determined. Further, effects of the distance between pipes (G/D), the proximity to the bed (e/D) and the relative diameter (d/D) variations on the drag and lift coefficients were considered through computer simulations.

With the expansion of oil industries, the leakage of oil materials increases. In addition to the negative effects of the environment, the oil leakage causes changes in the physical and geotechnical properties of the soil. These changes in granular soils are in the form of changes in the physical properties and structure of the soil, which leads to a decrease in the bearing capacity and an increase in the settlement of the soil under the foundation. In order to investigate the geotechnical behavior of fine-grained soils due to oil infiltration, a soil sample was taken from the Shazand Arak Refinery area and mixed with 0-5-10-15-20 percent crude oil by weight and remolded with a density of 90 percent of the maximum density (Proctor method) has been subjected to various physical and mechanical tests. Of course, the plastic index has a decreasing trend with the increase of the amount of crude oil. In the compaction test, the maximum dry unit weight of the soil increases with the addition of crude oil and the optimum moisture content decreases with the increase of the amount of crude oil up to 10% and then increases. In addition, the addition of oil generally reduces the permeability coefficient of the soil. Increasing the amount of oil has a different effect on soil consolidation, and the coefficient of soil consolidation increases with increasing the amount of oil. In addition, the uniaxial compressive strength of the soil decreases with the increase of the oil content.

A control room is a place where, as a center of operations in the petrochemical industry, production processes are monitored and controlled. Two main factors must be considered in the design of control rooms. The first factor is the protection of the control room building against possible hazards and the second factor is the location of the control room and the arrangement of the panels, to ensure the effective and ergonomic operation of the control room in normal and emergency conditions, which must be designed in such a way that the danger to the residents of the control room is acceptable and be suitable for the maintenance and protection of the unit (ASCE, 2010; Association, 2014). One of the regulations for the design of blast-resistant structures is the Swedish shelter regulations, which are derived from the examination of structures destroyed in the second world war (Ekengren and räddningsverk, 1994). The Swedish Shelter Regulations regulate the design of civil defense shelters in Sweden and include the requirements specified for these protection structures. Civilian defense shelters are designed not only to withstand the effects of conventional weapons, but also to withstand radioactive radiation, chemical and biological warfare, and gases explosion. By considering these requirements, shelters should be designed with minimal risk of death or injury to those in need of shelter, and be able to withstand the effects of the shockwave generated by a 250-kg bomb at a distance of 10 meters. Also, the requirements of proper design and retrofitting of existing structures against explosion can significantly reduce costs. In view of the above, the analysis and design of refinery structures against explosion loads and the strengthening of their members has great importance. Long-distance explosions and loading of structural elements also include phenomena that are not yet well understood. In order to increase knowledge in this field, a numerical study is currently presented. For this purpose, in this study, four types of concrete columns and four models of exterior wall for the control room were designed according to Swedish regulations to withstand the pressure of an explosion of a 250kg TNT at a distance of 10 meters and then against explosions of 6000, 4000 and 8000 kilograms at a safety distance of 40 meters is evaluated by the Eulerian-Lagrangian coupling method in Autodyn software. Response limit-state are selected according to the ASCE standard (ASCE, 2010).

One of the most important issues in the design of earth dams is the analysis of dam body and foundation seepages. Seepage problems may be caused by the characteristics of the foundation, support, floor and walls of the reservoir or dam body materials. Therefore, one of the determining parameter in the stability evaluations of earth dams is seepage analysis. In this study, seepage analysis of Sattarkhan dam is located in East Azarbaijan province, has been done by using the finite difference method, Flac3D software. The behavior of the seepage analysis model has been investigated and compared in two and three-dimensional case. The results of the analysis have been compared and validated with the pore water pressure measured by piezometers installed in the core and have been in good agreement. The main variable in the seepage analysis of dam is the permeability coefficient of the material. The role of this coefficient in the results of the seepage analysis of the dam body has been investigated by sensitivity analysis.In general, it can be said that in the mentioned dam, the water flow vector parallel to the dam axis is not decisive, and the pore water pressure production process complies the two-dimensional model approach. Also, the results show that the permeability ratio of the shell related to the core is effective in its seepage behavior, and in the design of the earth dam body s, it will be necessary to check this ratio according to the property of the borrow mines located in the dam construction area.

Human being has been faced with destructive phenomenon specially earthquake for a long time. Knowing about the time and area of major earthquake and aftershocks is so necessary to mitigate the damage of financial and life by warning the earthquake or aftershocks happen before it really happened. Maybe this day we can't predict the earthquake exactly but the study about the information of previous earthquakes can identify the potential land that have Earthquake Bloodbath and with this knowing in building construction we can mitigate the damage due to the earthquake.     The tendency of rocks to fail in a brittle manner is thought to be a function of both shear and confining stresses, commonly formulated as the Coulomb failure criterion. Here we explore how changes in Coulomb conditions associated with one or more earthquakes may trigger subsequent events.      Study of Stress changes in earth's crust is useful for the predicting earthquakes. Analysis of Coulomb stress changes has been used in many seismic areas. These researches showed that the area and the speed of next earthquake will affect by the static stress changes which are the result of historical earthquake in this area.

In the present era, environmental pollution is a global crisis, increasing population growth and urban development, industrial expansion and unlimited use of natural resources, are among the increasingly important factors of pollutants (Reilley, 1996). Vocciante (2021) found in the study of stability in electrokinetic modification processes that the electrokinetic method is suitable for cleaning inorganic pollutants from clay. Zhou (2021) found that using the electrokinetic method is effective in removing heavy metals zinc, cadmium, and manganese from the soil and leads to the removal of about 72% of the pollutant from the soil sample. Vaishnavi (2021) in the study of bio-electrokinetic modification of diesel-contaminated environment with biosurfactant found that this method is an effective method for cleaning and cleaning soils contaminated with diesel hydrocarbons. Hanaei et al. (2021) found that the direct shear test showed that the adhesion of the soil sample increased and the friction angle decreased after oil contamination, and the permeability test showed that the contamination of the soil sample decreased the permeability of sandy soil and this change It is a function of the amount of oil and the viscosity of oils.

In this study, the effect of the unreinforced and geogrid-reinforced granular blankets, end-bearing stone columns and the combination of these techniques on the behaviour of loose sand soil models have been investigated through laboratory and numerical simulations. In the models, a stone column from a large group of them with a triangular pattern was simulated in a unit cell. Since the rupture of the geosynthetic reinforcement within the reinforced granular blanket has never been experimentally investigated, a novel method of installing the geogrid reinforcement was used, allowing it to mobilize and ultimately fail under loading. The optimal thickness of the unreinforced and geogrid-reinforced blanket, the optimum layout of the reinforcement within the blanket and the changes in the stress concentration ratio of the stone column in different modelling conditions have been determined. Another objective of the present study is to discover the relationship between the failure of the geogrid layers and the characteristics of load-carrying capacity and settlement of the model tests.

Long-time Settlements or creep means the gradual increase in deformation of the soil over time, which is subjected to a constant load. The phenomenon of creep is very important in geotechnics and it is carefully investigated in cases where time and factors affecting it are involved, because when settlement occurs in the structure, many problems such as creating cracks, increase in deformation and stress are created, which , reduces the efficiency, utilization and useful life of the structure. Modifying the behavior of soil by using different additives is one of the important issues for the progress of researchers in civil engineering. Common additives such as lime, cement, bitumen, fly ash, wood ash, copper slag, iron slag, etc. have been investigated in previous studies, and nano and polymer materials, whose use in other branches of engineering science has led to fundamental changes and have unique characteristics, have been more interested in geotechnical engineering in recent years.

Modification of equivalent acceleration relation of horizontal and vertical earthquakes in ground elliptical tanks was done in the current study. The seismic analysis of the tank is highly important because by investigating the results obtained from this analysis, a useful recognition of the tank behavior quality can be obtained at the time of a real earthquake. The results of the seismic analysis include the impulsive pressure and the wave height of fluid on different points of the tank. In Housner theory, earthquake equivalent acceleration is a key parameter in calculation of impulsive vibration mode parameters such as impulsive pressure and impulsive force. US nuclear reactors and earthquakes code presented a simple relation to calculate earthquake equivalent acceleration. To obtain more calculation accuracy in the ground elliptical tanks, a suitable equation was provided in the current study for the earthquake equivalent acceleration, by the use of principles of statistical regression. Because of less average error, the use of the equation proposed by this study instead of the equation presented by US nuclear reactors and earthquakes code, provides more accuracy in the tank design applications. By the study of the conclusions of this research, it was revealed that the accuracy index of horizontal and vertical earthquake equivalent acceleration relations developed by this research is 16% and 26% more than that of the corresponding relations of US nuclear reactors and earthquakes code, respectively.