Journal of Engineering Geology

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Awareness of orphological features of rivers is necessary for recognition of river behavior and optimum application of rivers. Overall catchment physiografy have important role for determination factors such as floods, erodible and sediment mutagenicity. In this study in order to understand the behavior of Gamasiab River in the east of Kermanshah province, geomorphologic features of this river has been considered. Study of engineering geomorphologic properties is done by using existing data from previous studies, site visit and field perceptions, study of geology and topography maps. Physiographic properties of catchment, channels morphologic properties and geology conditions in this region have been studied. In this research, several parameters such as average width, environment, area, hydrogeologic coefficient, catchment form, maximum, minimum and mean high, and longitudinal slope has calculated. Also status of drainage density of this river has been investigated and time to focus calculated. Finally this river review and classified according to various classifications for rivers

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Comprehensive laboratory tests were performed to assess fatigue behavior of Alvand monzogranite rock subjected to uniaxial cyclic loading. A series of static loading tests was done to obtain the required data for the fatigue tests. Three maximum load levels (85, 90, 95% uniaxial compressive strength (&sigmac)) at amplitudes 70% were used with 1Hz cyclic loading frequency. The results indicated that maximum stress level significantly influenced fatigue behavior of this rock. It was found that fatigue life decreases in a power function with increasing maximum stress level. Accumulative fatigue damage process shows three stages of behavior including crack initiation phase, uniform velocity phase and acceleration phase. Fatigue damage process were analyzed according to axial and lateral maximum and minimum strain, tangent and second modulus, toughness and hysteresis energy in both loading and unloading conditions. Among these parameters, lateral strain, axial strain and second modulus show the best three-stage fatigue damage behavior. Also, it should be noted that most of the cracks generated in parallel to loading direction and lateral strain are affected by more than axial strain.  

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 Knowing the engineering geological characteristics of carbonate formations is necessary for database. In this research, using petrological study and mechanical tests on 5 types of Ilam-Sarvak formations limestones in Khorramabad city, their engineering geological characteristics were determined and the relationship between physical and mechanical properties have been analyzed. IBM SPSS Statistics (version 19.0) software was used to determine the required relations. The relations have high correlations. Based on the studies on this of thin sections, rocks are characterszed as biomicrite. Limestones of Ilam-Sarvak formations have high hardening and low porosity. These rocks are in medium to high density, very resistant durability index, medium to high UCS and high point load strength category. The rocks are also impermeable. Based on the UCS, modulus ratio of the intact rock, the limestones are CM and CL. According to solubility test, the solution velocity constant was 1.39×10^-6 m/s.

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The main objective of this research is to investigate the mechanism of cement-clay-heavy metal contaminant interaction from micro-structural point of view. To achieve this objective series of batch equilibrium and XRD experiments were performed. The results indicate that the addition of 10% cement not only stabilizes the soil, but also at 250 cmol/kg-soil of heavy metals causes 130% increase in heavy metal retention. Furthermore, the XRD analysis shows that in solidified samples with less than 10% cement, the main reason for reduction in peak intensity of clay fraction is due to the presence of heavy metals. However, as the percentage of cement increases, the clay solubility is the main reason for reduction in peak intensity of montmorillonite in XRD test

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In order to assess mineralogical composition influence on durability and strength of rocks, four samples of hornfelsic rocks were selected from southern and western parts of the city of Hamedan, west of Iran. These rock samples were subjected to mineralogical, physical and mechanical tests in the laboratory. Also, they were evaluated in 15 cycles of slake-durability testing in different pH of sulfuric acid solutions and XRD analysis. Based on the results, the type and amount of minerals, their density and hardness had an influence on the uniaxial compressive strength and the slake durability index of tested rocks. That means, presence of non-dissolved minerals such as graphite in studied rocks, decreases Unconfined Compressing Strength (UCS) but increases the slake durability index. The results of slake-durability test indicated that weight loss of the samples at initial cycles was found to be higher than the end cycles. Also, in these samples, initial minerals in the fresh samples were not exchanged by secondary minerals such as clay minerals. Therefore Hamedan hornfelsic rocks are approximately resistant when were put under accelerated chemical weathering and degradation in the laboratory and natural chemical weathering.

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One of the best approaches to reduce transportation problem is to use the underground tunnels. Therefore, Niayesh highway tunnel was performed by the New Austrian Tunnelling Method (NATM) in the northern part of Tehran and it includes north and south tunnels. The excavation of tunnels and other underground structures cause considerable changes in local stress conditions around structures that lead to surface settlement. In this research, surface settlement has been studied for five sections (CS-1 to CS-5) by empirical methods, numerical analysis and actual settlements. For the empirical and numerical methods, O’Reilly and New (1982) method and also finite element method (PLAXIS_2D software) have been used, respectively. On the basis of the obtained results, the numerical method in all sections (except section 3) is in agreement with the actual settlements. While, empirical methods have estimated the settlements more than actual values in those sections.  Also, the achieved results from the aforementioned methods show that the maximum settlement due to tunnel excavation is more than allowable settlement and it is in risk condition

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In tunnelling in soil mass, in groundwater existing mode, liquefaction, elastic displacements and settlement in soils upon the tunnel, are the risks may attack the excavated underground space stability. In this case study that were performed on second line of Mashhad city subway route, information catched from Standard Penetration Test, in situ and laboratorial tests, were used to optimum numerical values search for soil engineering parameters that could optimize the TBM stationing level. In order to this goal attaining, intelligent, numerical and probabilistic methods were used and the reliability of intelligent and numerical methods with the Safety Factors of tunnel stability, investigated simultaneously. The results were denoting the accordance of intelligent models such as Genetic Algorithm (GA) and Multi objective Genetic Algorithm with Finite Element model's output. So these models could be complement of each others in planning and designing of tunnels and using of them advised in tunneling and excavations.

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This research focuses on the identification and description of various features of pseudokarst in different parts of Alvand granitic batholith, Hamedan, west of Iran. In the literature, karst features have been presented as specific types of terrain or landscapes with particular characteristics suites of well-known surface and subsurface dissolutional forms. Whereas, pseudokarst refers to non-dissolutional surface or subsurface features and landforms created in different areas such as slopes, coastal lines crushed stone areas, lava tubes and permafrost regions. In this research, a comprehensive field investigation program has been carried out. During the field investigations, the most important features of pseudokarst in Alvand granitic batholith have been recognized and classified. Results show a wide range of pseudokarst features in the Alvand granitic rock masses. These landforms are created by erosion, weathering processes and some holes caused by rock block movements along the rock slopes. Some of the most important forms and features of the pseudokarst in the studied area are consist of tafoni, genama, pseudokarren, talus caves, caves associated with the residual blocks and erosional forms along joints and fractures within the granitic rock masses

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./files/site1/files/7Extended_Abstract.pdfExtended Abstract
 (Paper pages 135-156)
Introduction
Many civil structures (e.g. tunnel walls, bridge pillars, dam abutments and road foundations) are subjected to both static and dynamic loads. Cyclic loading leads to occurring fatigue phenomenon. Fatigue is the tendency of materials to break, or the process of damage accumulation, under cyclic loading. It was found that the dynamic fatigue strength can be reduced by 30-70 percent on average compared to uniaxial compression strength. Different materials show different response when they are subjected to cyclic loading. Some materials become stronger and more ductile, while others become weaker and more brittle. Although it is clear that the mechanical properties of rock under dynamic loads varied dramatically from those under static loads, the nature of dynamic failure in rock remains unclear, especially in cyclic loading condition. Fatigue behavior of rocks was rarely studied in respect to other materials such as steel and soil. The performed researches on fatigue behavior of rocks indicated that fatigue life will be decreased by increasing load amplitude in logarithmic and exponentially pattern. Also, strain softening is the dominated behavior of rocks against cyclic loading. Furthermore, some parameters such as maximum load level, confining pressures, amplitude, and loading frequency have considerable effects on fatigue behavior of rocks. However, available data on fatigue behavior remain insufficient for solving the practical tasks of predicting rock bursts and earthquakes. Obtained results are inconclusive and sometimes discordant. The aim of the current work was to assess tonalite rock fatigue behaviour under different loading conditions to describe the fatigue damage process of the granitic rock.
Material and methods
Several core samples were prepared to perform this research. The core samples were prepared with a L/D ratio of 2.5 with an average diameter of 54 mm. Before the fatigue tests, the physical and mechanical properties of the rocks were measured. Uniaxial compressive strength test (UCS) has been done on 5 core samples. The tests were performed in the load-control mode with a 1.6 kN/s loading rate. The tests were conducted to obtain the physico-mechanical parameters of the rocks in static loading condition, and provided a reference for subsequent dynamic tests. The cyclic tests were performed in both load and displacement control modes. To record axial and lateral strains during the fatigue tests, four strain gauges have been employed with arrangement of two axial and two laterals. Also, three acoustic emission sensors were installed on top, mean and bottom of the core samples to record cracking sound. In order to doing the tests a servocontrol Instron machine with 500 kN capacity was employed. The fatigue tests were conducted with three different maximum loads, 1 Hz frequency, and constant amplitude (0.82 of uniaxial compressive strength). The maximum stress level (the ratio of maximum cyclic stress to static strength) was varied 0.80, 0.85, and 0.90. The amplitude level (the ratio of amplitude stress to static strength) ranged from 0.50 to 0.70 and 0.90. Finally, Multi stages loading with increasing amplitude were applied for the displacement control tests. The results of fatigue tests have been evaluated by fatigue damage parameters including maximum and minimum axial strain, maximum and minimum lateral strain, tangent and secant modulus, toughness and hysteresis energy.
Results and discussion
The obtained results indicated that during fatigue process failure occurs below the maximum strength loading condition as a result of accumulative damage. Analysis of the fatigue test results showed that the fatigue failure consisted of three stages: fatigue crack formation (initiation phase I), stable crack propagation (uniform velocity phase II), and unstable crack propagation resulting in a sudden breakdown (accelerated phase III). By comparing the axial and lateral deformation, it was found that lateral deformation is more sensitive to fatigue. At higher stress levels, considerable part of fatigue life is response to crake development, whereas at lower stress levels, crack acceleration phase of fatigue life is distinguishable. Descending trend of loading and unloading tangent modulus shows a scatter pattern. This behavior may be related to the calculation method and loading condition, as well as microstructure and behavior of the rock mass. In spite of tangent modulus results, the three-stages of damage process (especially phase I and II) for secant modulus in both loading and unloading conditions are clear. The result is due to the method of calculation and increase in axial strain with increasing number of cycles. Brittle behavior of this type of rock leads acceleration phase to be hidden and unclear in most of fatigue damage parameters. A dramatic decrease of toughness and hysteresis energy in the first few cycles is due to the closing of pre-existing micro fractures. In fact, during the initial cycle, the rock behaves in a more ductile fashion than in the next few cycles. Thereafter, toughness begins to increase slowly, then steadily, and finally rapidly. A similar behavior was found for hysteresis energy as well. This fact indicated that cracks generated in parallel to loading direction. Fatigue displacement control tests show a strain softening behavior for the granitic rocks. This behavior is highlighted in variation of maximum stress during the tests. This parameter, especially in final step of loading, shows distinguishable decreasing trend.
Conclusion
The tonalite rocks were subjected to uniaxial cyclic loading in both load and displacement control mode. The following conclusions were drawn from this research.
-Accumulated fatigue damage occurs in an obvious three-stage process. This is the result of the micro-fracturing mechanism in the fatigue process.
-By comparing axial and lateral strain damages, it was found that crack propagation occurred in the loading direction and crack opening occurred in the lateral direction. So, among fatigue damage parameters, lateral strain shows the best three-stage fatigue damage behavior.
- Strain softening was found as rock response to cyclic displacement control loading.

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Geotechnical engineers, in many cases face with low strength or high swelling potential of clayey soils. Stabilization methods are used to improve the mechanical properties of this type of soils. Lime and cement are the most popular materials used in chemical stabilization of clayey soils. If sulphate exists in the stabilized clayey soil with lime, or if soil is exposed to sulphates, problems such as strength reduction and swelling increase will occur. Reuse of industrial residual such as Rice Husk Ash (RHA) can be beneficial from the economy point of view. RHA includes a proper amount of silica with high specific surface area which is very suitable for activating the reaction between the soil and lime. In this paper, chemical stabilization of gypsum clays using lime and RHA is addressed Sulphates exist in the constitution of the soil. Unconfined compression strength and swelling potentials of the stabilized soil are evaluated. The results of this study indicate that RHA has positive impacts on improving mechanical properties of the gypsum clays stabilized with lime. From the view point of strength and swelling characteristics, and economy, addition of 6–8% lime and 8-10% RHA as an optimum amount is recommended.

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Rock anisotropy plays an important role in engineering behavior of rocks. Slates are anisotropic rocks which have long been used for gable roof, floor tiles, borrow materials, and other purposes. The slates studied in this research are calcareous and have a porphyro-lepidoblastic texture. To determine the role of the anisotropy on the tensile strength and fracture pattern, two variables including ψ (the core axis angle to foliation) and β (the angle between the axis of loading and foliation) in the Brazilian tests were used. The angles were selected at 15^° intervals. Thus, for both ψ and β, seven angles of 0˚, 15˚, 30˚, 45˚, 60˚, 75˚, and 90˚ were selected (i.e., there are 43 possible modes). In order to name and examine the failure pattern, 11 models were proposed. The average value of the failure strength for the three stations varies from 3.21 MPa to 20.94 MPa. Based on the obtained results, there is a direct relation between the average tensile strength and density. A comparison between Brazilian test data under dry and saturation conditions shows that the saturated Brazilian tensile strength is 30.8% less than the dry Brazilian tensile strength. Moreover, the changes in fracture length with the changes in ψ and β indicate an inverse relation. Eventually, the average of tensile strength (σt) and strength anisotropy index (Ia) demonstrates that the influence of orientation angle (ψ) is much larger than that of foliation-loading angle (β).
 

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Introduction
The selection of the best subsurface exploration methods corresponding to geotechnical, topographical and economic circumstances of the project is one of the most effective factors in the success of a tunneling project. On the other hand, the development of a decision model and consequently choosing the most suitable alternatives are complex tasks. Therefore, prioritizing and selecting the best subsurface exploration methods, as the main aim of this study, can reduce the economic and social costs associated with the execution of a tunneling project. For this purpose, ten experts from tunneling community have been asked to weigh the chosen criteria of the problem in this research. A methodology utilized in this study is the Analytical Hierarchy Process (AHP) which proved useful in engineering decision-making problems. The other method is TOPSIS, one that has continuously been used in decision making in the recent decades. These two techniques have been combined and utilized in this work to rank the aforementioned exploration methods.
 
 
Material and methods
The study area is located about 109 km far from Shahrekord city amid the Zagros mountains. The Sabzkooh tunnel development plan has been under evaluation in the time that this research was being done. The geology of the area majorly encompasses sedimentary rocks which have been outcropped as folds, faults, and fractured and altered zones. However, the variety of the lithological units in the tunnel route is high, and units of limestone and shales also exist over the path.
In the first step, geological and topographic maps were produced for the study area, and general information from the tunnel path was collected and examined. Suitable exploration methods were evaluated, and six main methods were chosen to be considered as the alternatives of the study including (a) discontinuities study, (b) Lugeon tests, (c) RQD, (d) Geo-electric, (e) Gravimetry, and (f) Seismic methods. Moreover, nine criteria ranging from “volume of the available information” and “environmental impact” to “cost” and “accuracy” of the employed methods were taken into account. A pairwise comparison matrix was then developed, and the experts were asked to fill it out. The importance of each criterion was then simply calculated through this matrix. Alternatives pairwise comparison matrices were also filled out and, in this manner, the alternatives could be ranked using the AHP technique. Next, the TOPSIS technique was employed for the same purpose using a rather different process.
Results and discussion
Both AHP and TOPSIS techniques show very close results for ranking of the alternatives in this study. They rank the three Seismic, Geo-electric and Discontinuities studies methods as the best ones for the considered tunneling project. The only difference between these two techniques is how they determine the worst method. The AHP ranks the Lugeon as the last rank among the six methods whereas the TOPSIS determines the RQD as the least reliable method of exploration for the Sabzkooh tunnel project.
 
 
Conclusion
The prioritization and the subsequent selection of the most reliable exploration methods for an underground excavation project is a crucial task amid technical decisions. In this research, two major multi-criteria decision-making methods including AHP and TOPSIS were considered and applied for the Sabzkooh tunnel in Iran. The results indicate a high agreement between the two methodologies even though these two approaches decide differently on the least reliable methods to be applied.

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Introduction
In regard to consumptions of oil materials by human, soil contamination causes worriness in environment and geotechnics areas in previous years, such that studying of soils lead to soil refine, soil bearing capacity and soil changing by infiltration of contamination. The rates of problems on environment are different and it depends on soil types and its structure, organic materials values, soil permeability, climate and type of contamination. In viewpoint of geotechnics, many investigations have been done on various contaminated soils that their result leads to optimum application of those as road construction and decrease of costs. In this research, with adding of different percentages of gasoil into the soil, engineering properties of contaminated soils were investigated and its effect on the erodibility of soils was studied. Regarding to the Hamedan oil storages complex extension and lateral installations, the study of contaminated soils are essential. Also, because the location of that complex is at urban area, the environmental risk of leaking of oil materials is available. Thus, the goal of this research is to investigate the erodibility of contaminated soils at the studied area.     
Material and methods
Hamedan oil storages complex is located about 17.7 km far from Hamedan city. In order to study engineering geological properties and erodibility of three layers of soils in studied area, the soil samplings were done from three soil layers. Based on the field and laboratory results, all of three soil layers were classified into SM class and had too much lime (Table 1). Testing program is divided into engineering geological tests and erodibility tests. All of the engineering geological tests on the uncontaminated and contaminated soils were undertaken according to ASTM (2000) (Table 2). In order to prepare the contaminated soils and to determine the maximum absorbable gasoil, the soil samples were contaminated by gasoil and some standard compaction tests were undertaken on the soils. According to the test results, upper and lower layers were saturated by 19% of gasoil and middle layer was saturated by 15% of gasoil. After determination of gasoil saturations percentages for studied soil layers, the 7, 13 and 19 percentages of gasoil were added into the upper and lower layers and the 5, 10 and 15 percentages of gasoil were added into the middle layer. Thus, for engineering geological tests, 9 samples of contaminated soils were prepared.   
Table 1. Soil properties of studied area

Lime percentage	Soil type	PI%	PL%	LL%	Sample	Layer
85.15	SM	8.99	40.65	49.64	L1	Upper
62.16	SM	15.49	32.12	47.61	L2	Middle
88.72	SM	15.46	27.14	42.60	L3	Lower

Table 2. Engineering geological tests according to ASTM (2000)

Standard No.	Test type
ASTM-D422 (2000)	Soil classification
ASTM-D4318-87 (2000)	Atterberg limits
ASTM-D698 (2000)	Standard Compaction
ASTM-D3080 (2000)	ِDirect shear
ASTM-D2166-87 (2000)	Uniaxial Compressive Strength

To prepare the sample for direct shear test, a mould with dimension of 10 cm *10 cm *2 cm was used. Then, the prepared sample was set inside the shear box and vertical stress was applied. All of direct shear tests were done in unconsolidated-undrained condition (UU), in maximum dry unit weight _dmax) and in optimum water content _{( opt})of soil samples.
All of the soil samples for uniaxial compressive strength tests were prepared in maximum dry unit weight and optimum water content. To prepare the soil samples, a split tube mould with 5*10 cm of dimensions was used. Based on that test, the soil samples are set under axial load and failure occurred at the end of the test.
To investigate the effect of gasoil on soil erodibility, first the erodibility tests by using rainfall simulator were done on uncontaminated soils and then, on contaminated soil with different percentages of gasoil. All of soil samples for erodibility test were prepared into the pans with 30*30*15 cm of dimensions and in maximum dry unit weight and optimum water content. The thickness of soil samples were 5 cm and the gravelly drainage layers were 10 cm. The rainfall intensity was equal to rainfall intensity of sampling area (29 mm/hours) and the steepness of soil samples were equals to sampling area steepness (10 to 40 degrees). After catching of runoff and drained water, the eroded soils were weighted and the weight loss of soil samples was calculated.   
Results and discussion
All of the engineering geological tests results are shown in Table 3. With increasing of the gasoil percentages, dry maximum unit weights of all three layers have decrease trends while the optimum water contents have increase trends. Surrounding of the soil grains by gasoil and water causes the easy sliding of grains and more compaction. The Atterberg test results shows that liquid and plasticity limits of soil had increase trend with increasing the gasoil. In the middle layer its trend is more than the others. Because the viscosity of gasoil is more than the water viscosity, the adhesion of contaminated soil would be more than the uncontaminated soil and then, the liquid and plasticity limits of contaminated soils are more than the others. The uniaxial compressive strength results show that the undrained strength of contaminated soils would be decrease with increasing the gasoil content. This behavior is the result of sliding of the contaminated soil grains on each other.
The results of erodibility tests results are shown in Table 4. The erodibility would be increase with increasing the gasoil percentages. Also, it would be increase with steepness dips degrees. In compare to the uncontaminated soils, the maximum weight loss of the contaminated soil is 608.3 kg/m².hr in 15% of gasoil and 40 degrees of steepness in L2 layer. The minimum weight loss of the contaminated soil is 13.33 kg/m².hr in 0% of gasoil and 10 degrees of steepness in L3 layer. Thus, the assessment of gasoil effect on erodibility of soils is very important.
Table 3. Results of the engineering geological tests on the uncontaminated and contaminated soil samples

Layers	Gasoil percentage	Liquid limit (%)	Plasticity limit (%)	Plasticity Index (%)	Maximum  dry unit  weight  (g/cm3)	Optimum water content (%)	Internal friction angle (ɸ)	Cohesion (kPa)	Uniaxial compressive strength (kPa)
L1	0%	49.64	40.65	8.99	1.65	22	4.6	7.4	18.4
	7%	54	40.13	13.87	1.87	10.5	4.04	6.6	8.7
	13%	55.67	43.71	11.95	1.88	8.5	3.26	3.7	7.8
	19%	55	40.65	14.34	1.96	3	2.3	2.75	3.5
L2	0%	47.61	32.12	15.49	1.87	14	6.97	6	9.6
	5%	64	40.39	23.61	2.08	9	5.73	5.5	7
	10%	66	46.63	19.37	2.11	6	5.15	4	6.1
	15%	68	49.09	18.91	2.14	3.5	4	2	1.25
L3	0%	42.6	27.14	15.46	1.62	22.3	2.6	10.7	22.6
	7%	56	39.27	16.72	1.92	9.5	2.41	8.5	10.5
	13%	57.18	41.66	15.51	2.01	6	2.17	7/3	7.8
	19%	63	42	20.99	2.03	3	1.45	6.9	4.4

 
Table 4. Results of the uncontaminated and contaminated soils in different steepness*

Layer	Gasoil percentage	Dip of 10◦	Dip of 20◦	Dip of 30◦	Dip of 40◦
L1	0%	56.4	70.4	73.2	111.06
	7%	149.6	178.8	248.4	202.53
	13%	166.53	227.2	241.6	278.93
	19%	227.86	256.66	419.86	334.66
L2	0%	30.8	102.53	156.53	317.73
	5%	58.66	142.66	151.2	324.8
	10%	74.93	168.66	244.53	365.73
	15%	105.73	283.73	359.86	608.13
L3	0%	13.33	75.06	79.46	86.26
	7%	55.2	98.53	78.13	81.06
	13%	124.13	176.8	145.73	140.06
	19%	196.4	279.46	200.93	210

Conclusion
1. According to the grain size analysis test results, all of three layers of soils around the Hamedan oil storage are SM with too much lime.
2. With increasing the gasoil, liquid and plasticity limits of three soil layers had increase trend. its trend in the middle layer is more than the others.
3. According to the erodibility results of contaminated soils, the weight loss of middle layer was more than the other layers because of the middle soil layer had lower percentages of lime.   
4. The gasoil causes decrease of soil strength and increase of weight losing. Thus, the uniaxial compressive strength and weight losing have reverse correlation.  
5. With increasing of the contamination, the cohesion and internal friction angle of soils would be decrease and then, the erodibility would be increase.
6. Maximum of erosion of contaminated soils was in 15 and 19 percentages of gasoil and it was three times more than that of uncontaminated soils.
7. The critical steepness of uncontaminated soil layers was 40 degrees for all three layers, but it was different for contaminated soils, 
8. Regarding to the location of Hamedan oil storages, the environmental risk of oil leakages and erodibility of contaminated soils are certain.  
./files/site1/files/132/5Extended_Abstracts.pdf

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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
Studying the effect of slope angle on bearing capacity of foundations on the slope in urban areas is a challenging problem that has been investigated by researchers for years. In general, the analytical approaches for solving this problem can be categorized into limit equilibrium, characteristics and limit analysis methods. In recent years, there have been studies for using the limit analysis within the framework of finite element method for geomaterials. In these studies, the soil mass is not considered as rigid and there is no need to predefine a failure surface for the slope. In the performed research, using the upper bound finite element limit analysis, bearing capacity of strip foundation on slope have been studied. This analytical method enables the use of the advantages of both methods of limit analysis and finite element analysis. In this method, the slip between the two elements is considered. In order to find the critical state of the failure, the rate of power internally dissipated is linearly optimized, by using the interior points method. The advantages of this method are the high convergence rate in comparison with other analytical optimization methods. The effect of different upstream and downstream slopes and foundation depths and also the influence of various mesh discretizations have been evaluated. Finally, the results are compared with those obtained from previous methods available in the literature.
Methods
The finite element limit analysis method is based on nodal velocities. Considering the principals of the finite element method and having the nodal velocities, the velocity at each node of the element can be obtained from corresponding shape functions. The rate of power internally dissipated in each element is defined by multiplying the strain rate on stress in each element. In this method, the slip between the two elements and the rate of internal power dissipated at each discontinuity of two adjacent elements is considered. For this purpose, in each node, four new unknowns’ velocities are defined. To remove the stress from the equations, and provide a linear relationship for linear optimization, a linear approximation to the yield function has been used. For this purpose, the Mohr-Coulomb yield criterion is estimated with a polygon in the stress space. Also, using the reduced strength parameter, the effect of the dilation angle is considered. According to the principles of upper bound limit analysis, the value of plastic strain rate is calculated from the flow rule. The velocity field in elements and discontinuities must satisfy the set of constraints imposed by an associated flow rule. In order to have an acceptable kinematics field, the velocity vectors have to satisfy the boundary conditions. These conditions include zero kinematics velocities along the vertical and horizontal boundaries of the geometry as well as negative vertical unit velocities and zero horizontal velocities at points underneath the rigid foundation.
Results and discussion
In order to calculate the bearing capacity of foundation, a set of different uniform and non-uniform mesh has been examined. The results obtained from different uniform mesh sizes indicate a certain divergence in the course of analysis. However, the results between the fine and very fine non-uniform mesh are closely related to each other and are converged. The obtained results show that, by increasing the internal friction angle, the bearing capacity has been increased. At high angles of modified friction, the effect of increasing the internal friction angle on the increase in bearing capacity is more in slopes with lower angles. By increasing the downstream foundation depth, the bearing capacity has been increased. This increase is more important in the case of slopes with lower angles. However, the upstream depth variations didn't present a significant effete on bearing capacity. In order to investigate the effect of upstream angle on the bearing capacity, the upstream mesh is also refined similar to the downstream. The obtained results indicate that variations of the upstream angle have a minor effect on the bearing capacity. This is of course true if the upstream slope is fully stable. The results of the proposed method in this study are an upper bound for the results reported by the limit equilibrium and displacement finite element methods. As seen in Figure 1, the suggested method predicts lower bearing capacities compared to rigid block limit analysis method and is indeed a lower bound for the classical limit analysis method. The finite element limit analysis with linear optimization has resulted in more bearing capacity than cone optimization. The bearing capacities, obtained from characteristic lines method depending to the slope angles, in some cases is more and in some cases less than those explored by the proposed method.
In this paper, the bearing capacity of foundation located on slope was evaluated by finite element limit analysis method. In this regard, the effects of different downstream and upstream angles of slope and foundation depths and also, the effect of various mesh discretizations on the bearing capacity were studied. It is shown that an increase in the downstream angle causes a decrease in the bearing capacity and an increase in the downstream foundation depth leads to an increase in the bearing capacity.  However, the upstream angle and upstream foundation depth were not much effective on the bearing capacity.
 

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Because of the diversity in petrography, peridotites have variable physical and mechanical properties. For this reason, knowledge of resistance properties and their deformation will help with the prediction of engineering behavior of these rocks. Due to the large spread of igneous rocks, especially peridotite, in Zagros, northeastern and central Iran, special attention has been paid to their petrographic, physical and mechanical characteristics. The construction of the structure within or on the peridotites and the choice for the purpose of the stone borrow depends on the recognition of its engineering geology characteristics. In this paper, in addition to the field and laboratory study, the geological characteristics of peridotite engineering has been investigated.                                    
Material and methods                    
In order to study the geological characteristics of the peridotites of Harsin region, 15 suitable blocks were selected and transferred to the laboratory. Accordingly, from collected rock samples, 150 cylindrical cores of diameter 54 mm were prepared and physical and mechanical tests were performed according to (ISRM, 2007) and (ASTM, 2001) guidelines. In this research, after sampling of the study area and preparing the core for the lithological characteristics of the samples by providing thin sections of them with polarizing microscopy was studied.
Results and discussion
By considering the results of laboratory tests and analysis from Harsin peridotites in Kermanshah province, we can acclaim that with increasing the percentage of minerals in olivine and pyroxene in rock, the strength was decreased and the levels weaknesses, which is due to the weak structure of the mineral-olivine and pyroxene. According to the physical properties test and Anon classification, the porosity percentage in porosity percentage is low and as a result the amount of water absorption index is low. Based on the Gamble classification, all peridotites are very resistant to durability and based on the Franklin and Chandra classification, all samples are extremely resistant. The results of this study showed that the single axial compressive strength, elasticity modulus, point load index and tensile strength were decreased with an increase in humidity content of peridotite samples. This is due to the fact that with the increase of humidity pore pressure of water increases. According to the Anon classification, the peridotites are very high in terms of the length of the longitudinal passage through the rock. The highest compliance between the Brazilian Tensile strength test (BTS) and Schmidt hammer (SHV) was achieved in the dry condition and the determination coefficient (R²) equals to 0.95 was obtained. Also there is an acceptable relation between the Brazilian Tensile Strength Test (BTS) and the dry volume unit weight (γ_d) with the determination coefficient (R²) of 0.93. In addition, there is an admissible relationship between durability test and single-axial compressive strength, with a coefficient determination (R²) of 0.94. Regarding the obtained regressions in this study, the physical and mechanical properties show good agreement and most of the equations have an acceptable coefficient determination.

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Introduction
Series A of coarse-grained alluvial deposits of Tehran are extended in eastern and north-eastern areas of Tehran. Analyzing and studying of these alluvial deposits from a geological point of view as well as their creation time and general characteristics such as the deposits’ mineral types, their source, and formation conditions, gives a better point of view to geotechnical engineers about exploring their characteristics as well as geotechnical aspects in underground structure design, excavations, and foundation design processes. On the other hand, in order to analyze stability, estimating the factor of safety and the seismic design of these structures, considering their location, which is in Tehran with a high seismic hazard area, the necessity of knowing the exact mechanical and dynamic properties of Tehran's alluvium is felt more than ever.
Material and methods
Due to the grain size of Tehran’s coarse-grained alluviums (series A) as well as high level of cementation of them, it is impossible (or maybe so difficult) to make undisturbed samples in order to do experiments. Such that it is excavated 23 boreholes with 30 to 140 meters depth as well as 17 test wells with 20 meters depth in an area which was extended in 10 kilometers in long which were located in Tehran’s No. 13 and No. 14 districts (as it can be seen in Figure 1). During the excavation of the entrance ramp and tunnel of eastern highway of Tehran, in-situ tests have been done in different sequences. Since it was important to investigate real behavior of these alluviums, different in-situ tests such as plate load test, in-situ shear test, pressuremeter test, and downhole test have been done as well as many laboratory and field tests. Furthermore, (1) X-Ray Diffraction (XRD) and (2) X-ray Fluorescence (XRF) as well as (3) Scanning Electron Microscopy (SEM) methods, have been used to explore the type of minerals and those used in cementation.
 
 
 
 

(ب)
 
 
 
Figure 1. a) Geological plan and the location of boreholes and test wells in the alignment of East Tehran Freeway
Results and discussion
Based on the results of XRD tests, it is quite clear that the largest weight percentages of tested samples are lime and silica.
Calcium and magnesium levels-as the high-power cations in flocculation process-in soil sample No. 1 (soil with high cementation level) are much more than soil sample No. 2 (soil with moderate cementation level).
This is the cause of high cementation level of soil sample No. 1 comparing with soils sample No. 2. A rapid increase in stress level can be seen in in-situ shear test results, in low shear displacements, up to reaching a maximum of τ_p (peak point) and afterwards reduction in shear stress with softening behavior.  
Cohesion and shear strength levels also increase by increasing the depth. According to the plate load tests results, an increase in soil modules changes can be seen in different depths by depth increasing.
Large tendencies to increase in volume and dilation can be seen in under shear load cemented soils, after applying a primary compression on them. A brittle behavior with the occurrence of a certain peak can be seen in cemented samples. The significant increase in strength is directly related to the severe dilation rate, which can be seen in cemented samples results.  The shear strength would be decreased, if this cement is broken during the particles’ displacements.
The results of downhole tests are shown in Figure 2. According to this figure, it has been explored that V_s,30 is about 600 m/s in moderate cemented soils while it is about 850 m/s in highly cemented soils.  Because of the homogeneity and uniformity of sedimentary deposits, shear wave velocity is increasing due to the higher density of the layers and high level of cementation in both of the soil types. However, this increase is not significant at depths above 25 meters.
Conclusion
Based on the results, cementation level of the eastern coarse-grain-alluvium of Tehran is moderate to high and minerals used in cementation of this type of soil are generally carbonated and especially calcite.
Investigating the level of cementation of soil as well as the results of chemical analysis and in-situ tests, it can be found that the strength and deformation parameters of the soil are directly related to the degree of its cementation.
Based on the obtained results, the deformation modulus increases by about 25%, the cohesion by about 55% and the shear wave velocity by about 30% with increasing the degree of cementation (Table 1).
Increases of these parameters are directly related to depth. However, the cementation level does not significantly affect the internal friction angle of the soil.
Table 1. Average results of in-situ shear tests

Deformation Modulus (MPa)	Peak Friction Angle (deg.)	Cohesion (kPa)	USCS	Depth (m)	Sample
50-60	39	30-35	GW-GM	5	Moderately Cemented Soil (M.C. Soil)
75-85	41	50-60	SP-SC	10
85-90	41	50-60	GW-GC	15
95-105	41	50-60	GW-GC	20
60-70	39	35-40	GW-GM	5	Highly Cemented Soil (H.C. Soil)
75-85	39	50-60	GW-GC	10
110-120	42	65-75	GW-GC	15
125-140	41	110-120	GC	20

 
 

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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
Grouting is one of the most widely used methods of soils improvement in which pressurized grout penetrates in the voids, of the soil. In the grouting method, in addition to reducing the permeability, shear strength and stiffness of the soil increase significantly. However, application of this method in projects such as dam construction and soil improvement requires the use of a large volume of grouting materials in order to satisfy the design criteria. In more recent years, due to the economic and environmental issues, in the case of cement-based grouts, replacing the whole or a portion of Portland cement with other materials has been experimentally investigated. A special type of kaolinite clay called metakaolin has recently been used in concrete, which has yielded interesting results. However, few studies has been conducted on the use of metakaolin in cement-based grouts. Such that, its effect on the mechanical behavior of the grouted soil are not well understood. Accordingly, in the present study, the mechanical behavior of a type of sandy soil grouted with different combinations of Portland cement and metakaolin was experimentally investigated in laboratory scale.
Material and methods
Different materials used in the present study including sand, cement, metakaolin, bentonite and water were selected based on the standard criteria and with the aim of better interpreting the test  result and their differences due to considered influencing factors. Sand was obtained from Malayer Shushab river bed. According to the Unified Soil Classification System (USCS), it is classified as SP. Ordinary Portland cement was used in this study regarding to its widespread application in the practical works. The metakolin is classified as class N pozzolan according to the ASTM C618. Another constituent material of grout is bentonite which is produced by Iran Barit factory as sodium-calcium bentonite. Its liquid limit and plastic index are 296 and 262 percent, respectively. The water used to prepare the grouts was provided from Hamedan drinking water, which according to ASTM C94 has the required quality for grouting operations in laboratory.
The device for grouting specimens was developed at the Soil Mechanics Laboratory of Bu-Ali Sina University during the present study. It equipped with grouting pressure control system and tool for keeping grout in homogeneous conditions during the grouting operation into specimen. The samples were prepared with 0, 5, 10, 15, 20 and 25 percent substitution of cement with metakaolin. Curing time of grouted samples was considered as14 and 28 days.
In order to investigate the factor affecting stress-strain behavior of the grouted sand, the samples were sheared using advanced triaxial apparatus. After passing considered curing time, the samples were sheared considering three levels of confining pressures of 50, 100 and 200 kPa and by applying axial strain rate of 1 mm per minute. For each test, the maximum deviator stress and its corresponding axial strain were recorded. In addition, for studying post peak behavior of grouted soil, for every one of tests, average ratio of deviator stress to the axial strain as softening modulus, was calculated from the deviator stress-axial strain curves.  The moisture content of the samples was also measured according to ASTM D2216 at the end of tests. In the following, the role of different factors influencing stress-stain behavior of grouted sand including; confining pressure, ratio of water to the mix of cement and metakaolin, percentage of metakaolin, curing time and moisture content were investigated.
Results and discussion
Figure 1 shows the effect of metakaolin as alternative of a portion of cement on maximum confined compressive strength and its corresponding axial strain.
For the samples confined by pressure of 50 kPa the maximum confined compressive strength is almost constant by replacing cement with metakaolin up to 10%. However, the amount of axial strain corresponding to the maximum compressive strength of the specimens increases by 6% (Figure 2). For 25% replacement, the maximum confined compressive strength of the samples decreases by 17% compared to the initial state (pure cement). In contrast, the axial strain value related to peak state of most samples has been increased by 4% in comparison to the initial state.
 
In the case of confining pressure of 100 kPa, by replacing up to 10%, the mean confined compressive strength of the specimens was almost constant. However, the amount of axial strain corresponding to the peak state of the specimens has been increased by a maximum value of 18%. For 20% replacement percentage the compressive strength of the specimens has been decreased by about 15% compared to the initial state. However, in the range of 20 to 25 percent, the reduction process has slowed down, which can be due to various factors such as the effects of sample densification during further increase of metakaolin. According to Figure 1, it can be seen that in the range of 20 to 25% substitution, the amount of strain at failure state increased by an average of 40%, which indicates that the sample is more deformable.
In the case of confining stress of 200 kPa, by replacing 10% of the cement with metakaolin, maximum confined compressive strength and its corresponding axial strain, has been increased by approximately 5 and 14%, respectively. With increasing cement substitution up to 25%, the resistance of the specimens decreased by 8% compared to the result of sample grouted with pure cement. Although, axial strain at peak state has been increased by 28%. From the Figure 1, it is obvious that increasing in confining pressure yeilds a considerable increase in the maximum compressive strength of grouted soil. Besides, post peak behavior of grouted soil is also affected significantly by confining pressure. Such that an increase in confining pressure leads to decrease in softening modulus. On the other word, grouted soil displays a more deformable behavior. It should be noted that these aspects of grouted sand cannot be described by unconfined test. However compressive strength of the grouted soils in the majority of case, has been evaluated based on the unconfined test results. 
Conclusion
The aim of this study was to investigate, in laboratory scale, the mechanical behavior of sand grouted with cement-based grout and considering different percentage of metakaolin as an alternative for a portion of cement. The soil samples were grouted using a specific device developed during present study. After passing curing time the samples were sheared using triaxial apparatus by considering three levels of confining pressures. The main findings of this experimental research are as follows:
- Replacing 10% of cement with metakaolin, increases deformability of grouted soil, without reducing compressive strength. Deformability of grouted soil increases with adding more percentage of metakaolin however, in this case compressive strength decreases.
- By increasing confining pressures, more values of metakaolin can be used instead of cement in the grout.
- Increasing confining pressure, increases compressive strength, increases deformability and deceases softening modulus at post peak behavior.
- Shear strength parameters of grouted sand is affected by adding metakaolin into the grout. Increasing the percentage of metakaolin results in small changes in the internal friction angle of the grouted sand, however, the amount of cohesion decreases.

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