Journal of Engineering Geology

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Aggregates are one of the high demand building materials in construction of structures and their characteristics have important effects on durability and permanence of projects. Abrasion resistance is one of the important features of aggregates that their utilization in concrete and asphalt are affected by texture and lithology of them. As rock consisted of harder minerals have higher abrasion resistance like igneous rocks, due to more siliceous minerals. More varieties in mineralogy compound usually lead to increase in aggregate abrasion. Aggregates that are contained of different minerals usually have less abrasion resistance. Porosity usually decreases the resistance abrasion. In addition to lithological properties, the environment where aggregates are deposited is important in determining resistance-related parameters of aggregates.
Rivers, alluvial fans, and taluses are the main environments where aggregates are deposited. Geological processes, such as weathering and particle movement may cause changes in natural aggregates, hence affecting their abrasion and impact resistance. Rock weathering can results in increasing porosity, producing minerals that are weaker in comparison to their original rock.
In the process of particles transport by stream water, weak parts of aggregates will be omitted. The present study is focused on the relationship between geology medium and the weight loss of aggregate in Los Angeles test. 
Methodology
Considering that lithology features in aggregates resistance against abrasion have an important role, in order to examine the effect of various geology environments in abrasion resistance of aggregates, the medium should be chosen having similar lithology. Therefore, the north of Damavand and the south of Daneh Khoshk anticline (north of Dire plain) were firstly chosen by using geology map, satellites images and field study. Damavand zone consists of trachyte and trachy-andesite volcanic rocks. These rocks cover the whole area around the Damavand peak. Also, Daneh Khoshk anticline is covered by thick Asmari formation. The selected environment are in the length of each other. Such that taluses feed alluvial fan and alluvial fans feed rivers. Samples were collected from different area of southern part of anticline. 10 river area, 12 alluvial fan and 6 taluses in the south-west area of Daneh Khoshk anticline (north of Dire plain) were chosen. Los Angeles test has been done according to standard A method ASTM D2216-10, 1990 on samples and the results were analyzed by analogous analyzer.
Results and discussion
Results show that porosity and micro-crack percentage increase, respectively in accumulated aggregate in river, alluvial fans and taluses areas. Also, porosity and micro-crack in various alluvial fans is different and is influenced by the area and length of main channel of alluvial fans’ catchment. The porosity decreases by the increase in the length of channel and area of alluvial fans’ catchment.
The percentages of aggregate weight loss in talus, alluvial fan and river areas decreases, respectively. Based on the obtained results, the lowest rates of weight loss belong to river environments (23.7 % in Daneh Khoshk and 42% in Damavand) whereas the highest rates of weight loss belong to taluses (49.3% in Daneh Khoshk and 48% in Damavand). The alluvial fans have an average state. Another noticeable point is the high weight loss in Los Angeles test in Damavand aggregate. Due to having harder mineral, igneous aggregate have more abrasion resistance, but this research illustrates that the weight loss resulting from Los Angeles test in these aggregates is high. This is because of virtues texture that weakness against the impact as well as their high porosity.
Conclusion
The result of this research indicates that the volume of aggregate weight loss in Los Angeles test is related to aggregate accumulation environment. The extent of aggregate abrasion resistance is lowest in talus medium and increases in alluvial fan and river environment, respectively. The difference in aggregate abrasion resistance in various areas result from geology process differences that applies to aggregates in various environment. The extent of caring particles in talus environment is very low and the type of movement is mass or sliding type in these media, micro-crack and weak parts remains within aggregates. The surface of micro crack is weak such that breaks easily in Los Angeles test due to the pressure results from the impact of aggregate, as well as the impact of steel ball on aggregate leading to aggregate breakages. Aggregates move more distances in alluvial fan and river. Aggregate strike together in riverbed and alluvial fan yielding to aggregates breakages from micro-cracks. As the movement distance increases, aggregates approach more to intact rock. During the particles move, the weathered and weak parts are damaged by aggregate abrasion to riverbeds and alluvial fan, and more resistant and harder aggregates remain. As the water current increases, the aggregates impact each other harder, more resistant micro-crack breakages and this change leads to decrease the weight loss in Los Angeles test.
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Introduction
The standard penetration test (SPT) is one of the most common tests in geotechnical investigations. The results of this test are known as a simple, inexpensive, and tangible criterion in geological and geotechnical engineering. Many computational methods and engineering judgments depend on the results of this test. In this research, estimation of physical and engineering properties of clay soils was carried out using statistical methods based on standard penetration test results. The scope of this case study is related to a variety of clayey soils in Tabriz (the northwest of Iran). The existing relationships were confirmed based on database of this study. After statistical analysis of the database, eight relationships including single and two-variable associations have been proposed to estimate the physical and engineering properties with better performance using nonlinear regression.
Material and Methods
Different types of clayey silt and marl layers spread in Tabriz were included for the purpose of this study. The geological age of these layers dates back to the Miocene and Pliocene era. This research was conducted in two sections of the field and analysis. Two machine boreholes were drilled, and, based on ASTM, a standard penetration test with other laboratory tests were performed on the soil specimens in order to determine the physical and plasticity properties. According to the results of this study and the existing data, a total of 107 series were prepared. Based on the soil properties, 11 variables were selected including the fine grain percentage (FGP), liquid limit (LL), plastic limit (PL), percentage of clay particles (C), plastic index (PI), consistency index (CI), activity (A), dry unit weight (γ_d), natural moisture content (w_n), initial void ratio (e_o), and effective vertical stress (σ'_v). The standard penetration tests were run for each meter in drilled boreholes. The results of this test were corrected according to NCEER method. The correlation between the variables and corrected standardized penetration test results (N₆₀) were studied by Spearman ranking coefficient. Verifications of the existing eight experimental relationships between  standard penetration and other soil properties, proposed by Kayabasi (2015) and Hoshmand et al., (2012), were checked out using the findings and data of the present study. The linear, exponential, logarithmic, and exponential regressions between each variable and N₆₀ were investigated using SPSS software, version 16. The best regression with the highest R² for each variable was selected. Eight new relationships were proposed. Performance of the suggested relationships was compared with the existing relationships.
Results and Discussion
The findings of the current study could be summarized as:
1. The clay soils of the studied area in Tabriz were classified into four categories including CH, MH, CL, and ML according to USCS classification. The range of changes in plastic index and liquid limits of the samples were 9.19 ~ 45% and 29 ~ 77%, respectively. The corrected standard penetration test results (N₆₀) changed from 9 to 28 showing that soil compression was low to high.
2. The highest positive and negative Spearman correlation coefficients were related to the consistency index (+0.772) and moisture content (-0.759), respectively.
3. The existing empirical relationships, based on the database of this study, were found to have better statistical coefficients in terms of consistency index, activity, moisture percentage, and fine grained percentage. In term of sample depth, the experimental relationship, showed the lowest statistical coefficient.
4. Four single-variable and two-variable relationships were proposed by nonlinear regression analysis. Using these relationships, clay soil properties including activity, moisture content, fine grain percentage, and consistency index were estimated based on N_60. In addition, two relations were proposed between sample depth (D) and vertical effective stress (σ'_v) with N₆₀. The statistical coefficients of the suggested relationships were better than the existing empirical relationships. The proposed relationship of estimating the consistency index with coefficient (R²) of 0.673 and regression line slope of about 1 had the best performance.
Conclusion
In general, the main objective of this study was to investigate the correlation between physical and plasticity properties of clay soils and N₆₀ on Tabriz clayey soils. Clay soils of the present study included various silty and marl layers. Sufficient correlation was observed between the physical and engineering properties of clay soils and N₆₀. The validation of the existing experimental relationships based on A, w_n, FGP, and D resulted in weak statistical coefficients (R² <5) employing the database of the current study. Six new experimental relationships were proposed to estimate A, FGP, w_n, and CI as well as two correlations of N₆₀ with effective stress and sample depth. Generally, the results have been revealed that the statistical coefficients of the proposed relationships were improved compared with the existing relationships. The most suitable relationship was the estimation of soil consistency index (R²~70) and root mean square error (RMSE=129). Finally, due to the novelty of this research topic, verification and development of the proposed relationships for the soils has been recommended in other areas.

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Slope stability could be a major concern during the construction of infrastructures. This study is focused to analyze the slope stability of Manjil landslide that was located 41+400 to 42+200 km along Qazvin-Rasht freeway, Iran. The Manjil landslide, which had 168 m long and approximately 214 m wide, was occurred due to inappropriate cutting in June 2013 and led to destructive and closure of freeway. Slope stability analysis was carried out using a finite element shear strength reduction method (FE-SRM). The PHASE^2D program was utilized in order to model the slope cutting and stability of landslide. Slope angle was flatted with 3H:2V geometry and stabilized with piling. The results indicated safety factors of 1.95 and 1.17 in the static and pseudo-static states, respectively, while the maximum bending moment with single pile (SP) in the pseudo-static state was 5.69 MN. Maximum bending moment of the pile around the slip surface was significantly large and more than the bending moment capacity of the pile. Due to the large bending moment on the pile, pile-to-pile cap connections (two pile group: 2PG) should be designed at the toe of the slope. The obtained results showed reduction of this parameter to 2.48 MN. Thus, it can be concluded that 2PG is a suitable stabilization method for the Manjil landslide.

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Introduction
The use of various additives to improve the properties of soils from past years have been studied by different researchers. Such additives are lime, cement, fly ash and fiber which have been used frequently in combination with soil. Lime is one of the oldest additives that it is utilized with different types of soils. Lime has positive impact on geotechnical properties of soil that alter some of the soil characteristics. Adding lime causes to reduce plasticity ranges, enhanced efficiency, strength and shrinkage of the soil. Extensive researches in the field of sustainability of clay with lime indicate that the optimum percentage of lime in the soil modification is between 1 to 3% by weight of the soil. But some researchers believe 8% by weight of lime are effective for soil stabilization. The presence of lime in clay soil yiels to occur some reaction, that it improves the soil properties. Reactions are included cation exchange flocculation, carbonation and pozzolanic reactions. Cation exchange between the clay cations and calcium cations takes place in lime. Cation exchange causes clay particles to get closer to each other creating complex structures in the clay soil and this improves the   clay soil features. In recent years the use of nanoparticles is considered in civil engineering field. The investigations have demonstrated that the use of nanomaterial increases cement reactivity and also improves density because it is filled with particles. Recent research has shown that the use of montmorillonite nano-clay soils to control swelling and to reduce failure potential in the soil. A number of researchers have expressed the use of nanoparticles causes to decrease the hydraulic conductivity of soils. In this paper, the effect of nano-clay and lime on the important soil parameters is evaluated. For this purpose, lime at 2 and 4 percentage and nano-clay at 0.5, 1 and 2 percentages have been added to clay soil and their impact on parameters such as optimized moisture, Atterberg limits, unconfined compressive strength and self-healing properties of soil is evaluated. Self-healing properties is one of the features, to repair damages due to internal erosion in the clay which is very efficient and important.
Materials and experimental methods
In the present research, the effect of lime and montmorillonite nano–clay to soil strength is evaluated. For this purpose, samples of clay soil (CL) has been used. In the experimental study, the percentages of additives mixed with the dry soil and then the optimum moisture and maximum specific weight of soil are determined with different percentages of additives. Soil Atterberg limits based on the ASTM D4318 standard have been determined.   Dry samples have been mixed together and then the water is added and mixed well with each other. Then the sample has been prepared in the form of a steel cylinder (cylindrical specimens) with a diameter of 50 mm and a height of 100 mm. Specimens were molded immediately and the weight and dimensions were carefully measured and then placed in plastic to prevent moisture loss and put them at 20 °c and 90%  moisture curing room.
Results and discussion
In this study, the percentage of lime is between 0, 2, 4 percent by weight and nanomaterials percentage is between 0.5 and 1 and 2 percent that can be varied in order to analyze the effect of various additives on the properties of the soil samples. The results indicate that increasing the nano-clay and lime percentage can enhance the optimum specific gravity of soil. The optimum moisture content of sample without any additive is equal to 19.5%. However, samples contain 2% nano-clay and 4% lime, the optimum moisture content increases to 23.5%. But the presence of lime reduces the maximum dry density of soil while adding nano-clay increases this amount. In samples with 4% lime and with no nano-clay, maximum dry density is 17  but in case of lime with 4% and nano-clay with 2% it is increased to 17.5 . In addition, adding lime without the presence of nano-clay only increases strength of soil. When 2 percent of lime is added, the strength of soil increases about 39 percent. As mentioned before, the effect of lime and nano-clay on increasing of unconfined compressive strength is almost the same which means by adding 2% of lime or nano-clay the strength of the soil increases about 40 percent. Using both lime and clay nanoparticles simultaneously (each 2%), a significant increase in strength of soil occurs in approximately 77 percent.
Conclusion
The use of nano-clay and lime improves soil strength parameters. But economically lime is more affordable than nano-clay. Therefore, if you need to increase only unconfined compressive strength, then the nano-clay is not recommended.
When it comes to self-healing in clay, the nano-clay can improve resistance rupture of the soil. By adding 2% of nano-clay in soil, healing of soil resistance after the break and after 24 hours can reach up to 60% of the ultimate strength of the soil. This property can be used to repair of locations that are subjected to internal erosion and scouring.
 
 

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Introduction
Landslide is known as one of major natural hazards. Landslide susceptibility mapping is known as efficient approach to mitigate the future hazard and reduce the impact of landslide hazards. The main objective of this research is to apply GIS spatial decision making systems for landslide hazard mapping in the 5^th segment of Ardebil-Mianeh railroad. Evaluation of the landslide criteria mapping and their relevancy for landslide hazard can be also considered. To achieve the research objectives, an integrated approach of Fuzzy-Analytic Hierarchy Process (AHP), Fooler Hierarchical Triangle and Fuzzy logic methods were employed in GIS Environment.
Material and methods
Within this research, we also aimed to apply GIS spatial decision making systems and in particular GIS multi criteria decision analysis which are available in Arc GIS and Idrisi softwares. We have identified 8 casual factors (including: density of vegetation, land use, faults desistance, distance from rivers, distance from roads, slope, aspect, geology) based on literature review. Accordingly, these layers were prepared in GIS dataset by means of applying all GIS ready, editing and topology steps. The criterion weighting was established based F-AHP approach. The criteria weights was derived and rank of each criterion was obtained. Accordingly, the landslide susceptible zones were identified using GIS-MCDA approaches.
Results and discussion
Finally the functionality of each method was validated against known landslide locations. This step was applied to identify most efficient method for landslide mapping. According to the results and based on the values derived from Qs, P, and AUC, the accuracy of fuzzy method was accordingly about 0.33, 0.74 and 0.76, respectively. In context of Fuzz-AHP the accuracy of 1.08, 0.88 and 0.94 were obtained. While, the accuracy of Fooler Hierarchical Triangle were obtained 0.78, 0.84 and 0.91, accordingly.
Conclusion
As results indicated integration of Fuzzy-AHP represented more accurate results. Results of this research are great of important for future research in context of methodological issues for GIScience by means of identifying most efficient methods and techniques for variety of applications such landslide mapping, suitability assessment, site selection and in all for any GIS-MCDA application.

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Introduction
"Sulfide-carbonate" deposit is a term, which comprises a series of sulfide minerals such as Zn-Pb ore minerals, mainly considered as related to weathering of Zn-Pb sulfide concentrations and influence in sedimentary hosts (carbonate). There are more than 350 Zn-Pb deposits located in Iran, including world-class deposits such as Angouran, Mehdiabad and Irankouh. Due to the mining activity of these deposits, it creates a significant amount of mine waste that releases of these wastes in the environment causing severe problems. One of the main problems is the formation of Acid Mine Drainage (AMD). AMD is produced by oxidation of sulphide minerals, particularly pyrite (FeS2) in waste dump. Due to low pH and the ability to dissolve metals and other compounds, it can host a number of environmental problems. A phenomenon known as natural or alkaline mine drainage (NAMD) occurs at high pH values ​​when the neutralizing minerals are significantly present in the mine waste or when the oxidation of the sulfide minerals is poor. However, the metals and cationic species, such as Cu, Pb and Cd, are more soluble at low pH. In contrast, elements that form anionic species, such as Se, Cr, V, and Mo, tend to be more soluble at high pH and Ni, Zn, Co, As, and Sb, are soluble at near-neutral pH, and can potentially contaminate mine effluents, even without acidic conditions. Therefore Acid or Neutralization potential (AP&NP) of waste dump is significantly affects on the composition, transfers and fates of contaminations transmitted from waste dump. The aim of this study was to monitoring heavy metals concentrations and assessments of pollution potential of waste dumps in Anguran mine by static method and has been compared by mineralogical approach.
Material and methods
The Angouran Zn-Pb deposit is located in the 135 kilometers southwest part of Zanjan Province, NW Iran. This area belongs to the northwestern part of the Sanandaj-Sirjan Zone, a metamorphic belt related to the Zagros orogeny. Angouran mine is one of the most important carbonate hosted Zn-Pb deposits in Iran that mining activity has been created a significant amount of waste dump in around pit. To achieve the goals, the 47 samples taken from different surficial parts of the waste dump were analyzed by using the ICP-MS method to determine the concentration of elements and heavy metals. These elements and metals includes: Ca, Mg, S and As, Cd, Cr, Cu, Ni, Pb, Zn. The pollution index (PI) were modeled for heavy metal contamination risk zoning then modified Acid Base Accounting (ABA) static method was used to evaluate of acid and neutralization potential (AP&NP) of the waste dump samples and the results were modeled by Kriging method. At the end, mineralogical approach (Mg + Ca concentration) was used to determine the source of neutralization and to better interpret the static results.
Results and discussion
The results of contamination index showed that zinc, arsenic and cadmium had the highest average contamination index (18.89, 12.13 and 5.8, respectively) and the trend of total metal changes in the region as Zn> As> Cd> Pb > Ni> Cr> Cu was rated.
Datas measured in modified ABA method were modeled in 2D maps using the Kiriging method. Due to the low total sulfur content (less than 1%), all of the samples were Net Neutralization Potential (NNP) with a range of 49- 990 kg calcium carbonate per ton, and the study area was classified into three neutralization potential (NP), High (NP) and Very High (NP) levels. The mineralogical approach (Mg + Ca concentration) was used as a useful tool for better interpretation of modified ABA results and determines the neutralizing source. Mineralogical approach results indicate that calcite species are the main source of neutralization and have high correlation coefficient (R = 0.99) with the modified ABA method. In order to validate the results, the presence of mineral calcite was confirmed by XRD analysis on 4 samples.
Assessment of AP and NP of sulfide – carbonate waste dump in this research can be used as a basis model for other similar mines to control environmental problems and to identify the behavior and to transfer heavy metals in mine drainage in the future. Mineralogical approach results show that neutralizing potential and neutralizing source can be obtained without using expensive mineralogy analyses in this type of carbonate-sulfide deposit



 

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Introduction
Loess soil is one of the problematic soils that should be improved its geotechnical properties before the project is implemented. Lack of attention to this issue has caused in many problems for civil projects in Golestan province. This has been more evident in some of the rural areas built on this type of soil. Moreover there are many reports regarding different geological hazard such as subsidence, divergence, erosion and landslide in Golestan loess soil. Among the different types of loess soils found in Golestan province, silty loess should be given more attention due to their large extent and being the bed soil of many villages, and many reports of its hazards.
One of the methods for improving soil mechanical behavior and its geotechnical properties is to use additives to reduce geological hazards. Due to the fine-grained structure of loess soils, the application of nanoparticles is more efficient and could result in solving many of the related problems. Nanotechnology is new scientific field which affects many aspects of engineering and in recent years, many efforts have been made to use this new technology in various geotechnical branches.
So far, research has been carried out on the improvement of various soil types with additives such as cement, bitumen, ash, lime and various types of nanoparticles. Nowadays, the use of nanoparticle additives due to reduction of environmental pollution than other additives has a wider application in improving the physical and chemical properties of problematic soils.
In the present study, the effect of nano-kaolinite on strength properties including uniaxial compressive strength, elasticity modulus, cohesion, and internal friction angle of silty Loess in Kalaleh city of Golestan province have been investigated.
Material and methods
In order to carry out the present research, sample of the silty loess soil from Kaleh city of Golestan province was collected and prepared. Then, 0.5, 1, 1.5, 2, 3 and 4 weight percent of nano-kaolinite were added to soil samples. The soil samples were prepared in a natural state (without additives) and with the additive for uniaxial compressive strength and direct shear tests. Strength properties of soil specimens including uniaxial compressive strength, elastic modulus (based on uniaxial compressive strength test), cohesion and internal friction angle (based on direct shear testing) were determined for native soil and its mixture with different percentage of nano-kaolinite. The data were analyzed and the effect of nano-kaolinite on the strength properties of the silty loess soil sample was investigated.
Results and discussion
Uniaxial compressive strength and modulus of elasticity have been increased with increasing amount of nano-kaolinite, and after 2% nano-kaolinite, increase in nano-kaolinite did not have any significant effect on uniaxial compressive strength and modulus of elasticity. The uniaxial compressive strength and the modulus of soil elasticity in the natural state (without nano-kaolinite) are 1.12 and 15.89 kg/cm² respectively, and when 2% of the nano-kaolinite is added to the soil, the values ​​of these properties are maximal and reached to 1.19 and 18.10 kg/cm², respectively.
For native soil (without nano-kaolinite), the cohesion value is equal to 0.09 kg/cm², and with increasing nano-kaolinite from 0.5 to 2%, the cohesion shows an incremental trend and reached to 0.16 kg/cm². With increasing the additive percent from 2 to 4% the amount of cohesion were constant and equal to 0.16 kg/cm². The increasing of cohesion can be attributed to the fact that nanoparticles enhanced water absorption of soil particles which caused in better cohesion and also they affected chemical actions and surface electrical charge of soil particles.
Conclusion
The results of the uniaxial compressive strength tests show that adding up to 2 weight percent Nano-kaolinite to the dry soil increases the uniaxial compressive strength and modulus of elasticity of silty loess soil in the Golestan province, which can be due to proper locking between the nanoparticles and soil particles and increased cohesion.
The results of direct shear tests showed that adding up to 2% nano-kaolinite to dry soil increased the cohesion of the soil and consequently increased the shear strength of the soil.
On the other hand, adding the different amount of nano-kaolinite has not changed much in the internal friction angle of the silty loess soil in the Golestan province.
 
 

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Introduction
Landslides have an effective role in the destruction of freeways and railroads, which have been caused to many human and financial losses. Understanding this phenomenon and its effective factors can be important in planning for development projects and away from landslide prone areas. Based on extensive field in the Qazvin-Rasht freeway that the authors carried out in various researches in 2014-2017, it was found that the freeway was threatened by the type of instabilities due to variety of lithologies  and tectonic structures exploitation phase and needs to be stabilized. The purpose of this study is to determine of the distribution of landslides in different types of lithologicalunits of the Qazvin-Rasht freewaythat shows the role of geology and differences in geotechnical characteristics and tectonic structures in the creation and distribution of landslides on the road.The role of geology on the difference in geotechnical properties and tectonic structures in the creation and distribution in the road. Geological engineering properties and appropriate stabilization methods is the other goals of this study.
Material and Methods
In the study, the locations and the type of landslides are distinguished and the information were plotted on geological map. Then by the ARC GIS 10.2 program, and the use of area density method, the percentage of landslide events in each geological formation was identified. In order to study the role of lithology (type of rock, texture, mineralogy, weathering, alteration and erosion), sampling were carried out from rocks of Karaj formation, Shemshak formation, Cretaceous orbitalolina limestone and Fajan conglomerate. Geotechnical characteristics of the samples were determined by performing laboratory tests such as dry weight, porosity, uni-axial compressive strength according to ISRM standard (1979). For determining the role of tectonic structures (number of joints, dip and dip direction, length (m), spacing (cm), filling percentage, opening (mm), roughness, weathering, water, friction angle) were performed. Then, the results obtained from relative density and frequency were matched with the geological, geotechnical characteristics and tectonic structures of each formation.
Results
In order to separate different types of landslides on various kinds of rocks, area density and frequencyof  landslides were determined by Eqs 1 and 2. Graph of frequency and area density are presented in Fig. 6 and Table 2, respectively. As can be seen in this figure and table, in Karaj formation, the percentage of rock fall, toppling, avalanche, scree slope and combined slip are the highest. In the rocks belonging to the Shemshak formation, the susceptibility of the debris flow and landslides has been increased. In Fajan conglomerates and limestones of the Ziarat and Cretaceous formations, the rockfalls is more formed.
where L_I: area density, A_L:  area of landslides in each lithological unit, A_T: area of landslides in total area.
where L_F: frequency of landslide, N_L:  number of landslides in each lithological unit, N_T: number of landslides in total area.
Conclusion
Result showed that despite significant heterogeneity in lithology, geotechnics, engineering geology and tectonic structures, there are similarities between the types and distribution of landslides. Four of the identified landslides consist of rock fall, toppling, avalanche in the resistant and medium strength rocks such as andesite, trachy-andesite and basalts of Karaj formation, Cretaceous orbitalolina limestone and Fajan conglomerate with regard to the dominant direction of the joints in relation to the slope, the shear strength of the joints and their weathering, falling and scree slope in thesiliceous zone and composite landslide in the argilite-alounite zone due to the high alteration and groundwater level and water retention by the presence of clay minerals, landslide in the sequence of loose and resistant rocks, debris flow and landslides in the soils of Shemshak formation due to the lepidoblastic texture of the slate and their high erosion potential due to the weather climate along the Manjil-Rudbar freeway../files/site1/files/151/4.pdf

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Introduction
The ring footings are very important and sensitive due to widespread use in various industries such as oil and gas; so finding some ways for improving the behavior of these types of footings can be very valuable. One of these ways, which is very affordable and also can be help in environmental protection, is the use of granulated rubber that made from disposable materials like scrape tires, as the soil reinforcement. In the present study, the behavior of ring footings with outer constant diameter of 300 mm and variable inner diameters (90, 120 and 150 mm with inner to outer diameter ratio of 0.3, 0.4 and 0.5) placed on unreinforced sand bed and also granulated rubber reinforced bed, has been investigated by field test. The effects of important parameters like inner to outer diameter ratio of ring footing and thickness of rubber-soil mixture on the behavior of ring footing in terms of bearing capacity, settlement and inside vertical stresses of footing bed have been studied and the optimum values mentioned parameters have been determined.
Material and methods
In all tests, a sandy soil was used to fill the test trench which was excavated in the natural bed of the earth with a length and width of 2000 mm and a height of 990 mm. It should be noted that the type of this soil is well-graded sand (SW) according to the Unified Classification System (ASTM D 2487-11). This sand had medium grain size, D₅₀, of 2.35 mm, moisture content of 5.4% and friction angle of 41.7^∘. The granulated rubber particles with dimensions between 2-20 mm, a mean particle size, D₅₀, of 14 mm and a specific gravity, Gs, of 1.15, have been used in all tests for using in rubber-soil mixture layer.
The loading system consists of several parts such as loading frame for providing reaction force, hydraulic jack, load cell, load transfer system (including loading shaft which was located below Load cell and footing cap which was located under the loading shaft) and rigid steel loading plates with different inner to outer diameter ratios (d/D=0.3, 0.4 and 0.5 and constant outer diameter of 300 mm). Some devices like load cell, LVDT, pressure cell, data logger and unit control were applied to collect the data and control the system. Both soil and rubber-soil mixture layers were compacted by vibrating plate compactor to gain their maximum densities. After preparing the tests, the static load was applied on the system at a rate of 1 kPa per second until 1000 kPa or until backfill failure.
Results and discussion
The results of tests on both unreinforced and rubber reinforced beds indicated that the ring footing with inner to outer diameter ratio (d/D) of 0.4 had the maximum bearing capacity in all settlement levels. This behavior can be related to the arching phenomenon within the internal spaces of ring footing with optimum inner to outer diameter ratio. In fact, when the ring footing with optimum inner to outer diameter ratio is subjected to a certain level of loading, the soil inside the ring seems to be compacted due to interface effect of the two sides of the ring. However, by increasing the inner to outer diameter ratio more than its optimum value, the ring behaves like two independent strip footings without any interface effect and therefore the bearing capacity decreases.
The results of tests showed that the vertical inside stresses in different depths of footing bed (both unreinforced and rubber reinforced beds) decrease with increasing d/D ratio. This stress reduction process can be due to the transfer of stress concentration from the points close to the center of the ring to the outer point because of turning from the ring mode with interface effect to the two independent strip footings that mentioned earlier.
The results of rubber reinforced cases illustrated that, regardless of the footing settlement level and also irrespective of d/D ratio, the bearing capacity of ring footing increases with increasing the thickness of rubber-soil mixture layer (h_rs) up to the value equals 0.5 times the outer diameter of ring footing and further increase in this thickness more than mentioned optimum value (h_rs/D=0.5) can decrease the bearing capacity. Even in some cases of reinforced base (h_rs/D=1), the bearing capacity can be reduced to the value less than that of unreinforced cases. It can be due to high compressibility of rubber reinforced layers with higher thicknesses than optimum value.
It should be mentioned that the rubber reinforced layer can reduce the vertical inside stresses compared to unreinforced cases. It can be due to this fact that the rubber reinforced layer acts as a wide slab. Such that it can spread the applied loading over a wider area. Also rubber reinforced layer has high capacity of absorbing energy and therefore can decrease the vertical inside stresses.
Conclusion
In the present study the behavior of ring footing placed on rubber reinforced bed have been investigated by field test. The effect of different parameters such as inner to outer diameter ratio of ring footing and the thickness of rubber-soil mixture layer on the bearing capacity, settlement and vertical inside stresses of the footing bed were studied. The result indicates that:
- In both unreinforced and rubber reinforced bed, the ring footing with inner to outer diameter ratio (d/D) of 0.4 had the maximum bearing capacity, regardless of settlement level.
-The vertical inside stresses in different depths of footing bed decrease with increasing d/D ratio.
-The bearing capacity of ring footing increases with increasing the thickness of rubber-soil mixture layer (h_rs) up to the optimum value equals 0.5 times the outer diameter of ring footing.
-The vertical stresses can be reduced by using rubber reinforced layer../files/site1/files/151/5.pdf
 

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The soil of the Arvand free zone in the north of Khorramshahr is fine cohesive and cannot be used in earth works. On the other hand, suitable materials for this purpose (coarse-grained soils) are located at the farther distances which a considerable cost requires. In this regard, it is trying to improve the soil with lime and furnace steel slag. This study is focused on improvement of the fine-grained soil by adding various contents of lime and furnace steel slag. For this purpose, after sampling and performance of compaction tests, different amounts of slag (10, 20 and 30% by weight of dry soil) and lime (2, 4 and 6% by weight of dry soil) were added to the soil and after curing for 28 days, the effect of additives on the physical and mechanical properties of soil was investigated by using several tests such as Atterberg limits, compaction, uniaxial compressive strength (UCS) and CBR as soaked and unsoaked. Based on USCS classification the study soil is CL, its plasticity index is about 25% and sulphate ion content is more than 0.5%. Experimental results show that by adding slag and lime at different contents to soil, mechanical properties of soil improve dramatically, so plastic index of soil decreased and UCS and CBR has been increased. Also, the maximum dry unit weight of soil increases and the optimum moisture content decreases. The test results also indicate that the effect of lime on soil is higher than slag and the effect of slag for less than 35% is not considerable, however the test result of unsoaked CBR show that the bearing of soil increase in the more than slag content 20% is significant. According to the previous studies, due to the relatively high sulphate ion content in the soil, the use of lime alone is inappropriate and the slag can only physically improve soil conditions but also chemically prevent the formation of large volume minerals (like Ettringite) by the reaction of lime with soil sulphate ion../files/site1/files/152/%D8%AD%D8%B3%DB%8C%D9%86_%D8%B2%D8%A7%D8%AF%D9%87.pdf

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Expansive soils contain clay minerals such as compacted kaolin which are widespread in nature. Displacements of this type of soils are associated with matric suction and degree of saturation. To determine the in-situ characteristics, necessary measures may be required to deal with the possible failure related to this type of soil. Different constitutive models of unsaturated soils have been considered the subject of many recent researchers (Sheng et al. 2004; Wheeler et al. 2003; Nuth and Laloui 2008; Zhang and Lytton 2009 a, b 2012). However, those constitutive models are generally complicated that are not properly implemented in computer programs for practical applications. The Barcelona Basic Model (BBM) is one of the geomechanical constitutive models to capture the elastoplastic behavior of unsaturated soils../files/site1/files/152/%D8%B5%D8%A7%D8%AF%D9%82_%D8%A2%D8%A8%D8%A7%D8%AF%DB%8C.pdf

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In this study, it is attempted to analyze sensitivity and reliability in order to evaluate the liquefaction potential in soil layers in Tabriz. 62 boreholes that had possible conditions for liquefaction were selected. Seismic mapping was simulated using finite fault method and then the effect of soil layers on PGA was estimated. In continue, the liquefaction potential index was estimated and the zoning map of liquefaction risk was presented. In final, through sensitivity and reliability analysis of the Monte Carlo method, the rate of density function against safety factor of the soil layers versus to liquefaction was determined.

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Many researches have been currently conducted on the effects of fault distance on structures revealing that their seismic response can differ according to their distance from the fault. Suspension bridges due to their long period and high flexibility can be more sensitive to this phenomenon, especially in vertical vibration. Since the engineers tend to use longer spans, the length factor should be studied more accurately. In this paper, the effects of length factor on the seismic response of the suspension bridge under near and far-fault ground motions were addressed. The Vincent Thomas and Golden Gate suspension bridges as short and long ones, respectively, are selected as the case studies. The seismic responses of two bridges under five main worldwide ground motions contained both near and far-fault ones, with the same peak ground’s acceleration, are evaluated. The results indicated that the response of both bridges to the near and far-fault ground motions are perfectly different. Short span suspension bridges are vulnerable to near-fault ground motions, whereas long span ones are completely susceptible to both near and far-fault ground motions, and by increasing the length of span, the sensitivity of bridge was increased against far-fault low frequency excitations. Also, maximum displacement responses of spans in both bridges did not increase by maximizing peak ground’s acceleration.

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