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Paying little attention to the identity of Iranian architecture is one of the problems of contemporary architecture of Iran which has caused the absence of a precise definition of Identifying criteria in contemporary architecture of Iran; so that diversity of selected views is one of the main features of this architecture. Perhaps it can be said that many Iranian architects design without codified principles and even without theoretical knowledge and precise understanding of mental concepts in different styles. However, the lack of attention to values of Iranian traditional architecture is followed by eclecticism crisis in contemporary architecture. The questions raised in this context is whether a new definition of architecture can be given by examining the thoughts and opinions of Iranian philosophers like Mulla Sadra gave a new definition of architecture and whether according to their theories outlined principles Can be codified for contemporary architecture? The general approach in this research which intends to paraphrase the ideas of Mulla Sadra in contemporary architecture is Interpretative - historical and descriptive. The research data are derived mainly through observation and documentary studies. The results indicate that by using Mulla Sadra's definitions of being (al-wujud) and essence (mahiyyat) we can have a new defined view at architecture. As Sadra considers all phenomena in two dimensions, architecture also has both being and essence aspects. The essence of architecture responds to material needs and its being is a truth which architecture maintains and brings it to presence. Indeed, the Physics of architecture is the essence of architecture (mahiyyat) and the valuable concepts underlying the architectural Physics are the being of architecture (al-wujud). Considering Mulla Sadra's primary of being (asalat al-wujud) we can conclude that there is also primary of being in architecture. Of course this does not mean that the architect who cares about the being of architecture pays no attention to the essence of architecture. It means that the architect who cares about the being of architecture tries to discover and understand the being of traditional architecture and to present it in a new body which is appropriate for today's architecture. Therefore by regarding the Principles of Mulla Sadra's thought and practice used to achieve the roots of his philosophy, principles can be formulated for architectural design. The principles are formed in order to achieve the lofty goal of traditional Iranian architecture and they attend guide and direct the audience attention toward the pure being (God). Using concepts as inspiration and metaphor and manifestation of the light can be useful to achieve this goal. These concepts are the essential to make the basis clear for contemporary architecture and shows that we can achieve our goals for contemporary architecture of Iran in the same way that Mulla Sadra was able to resurrect the underlying concepts of traditional philosophy. From the perspective of al- wujud ontology, the first target of architecture is to show the truth of being essences; to show the being within the essences without them there is no sense of architecture. If we consider the context of architecture as an activity consisting of a combination of emotion and symbolic meanings, according to Mulla Sadra's method, architecture must accommodate itself to life as a significant whole. In this case the main task for architects will be to shape living spaces and to create necessary content for human presence (al-hozur) and to provide features for human identification. So there is no doubt that one of the main goals for architecture is to create the perfect place and to promote the human presence (al-hozur). Architecture is the genuine sense of human presence (al-hozur), and it may be understood by the human presence (al-hozur). Creation of art is a kind of creation that its nature is extracted from god. According to Mulla Sadra's principles, man unites with his artwork and then the truth would emerge. Architecture is a part of the whole art that tends to reveal the being (al-wojud). From the perspective of being and essence (al-mahiyyat) architecture itself is consisted from two sides; one side is being and the other is essence. And the perception of its essence is possible because of its being: but the being of architecture obtains its existence from the creator and so architecture is always in compliance with its creator's rank of being (mrateb al-wojud). In this theory the origin of architecture is the being of architecture (al-wojud) and the essence of architecture (al-mahiyyat) is manifested through its being. If the architect is higher in the rank of being his designs will also be higher and more spiritual. Therefore as mentioned, there is no doubt that one of the main goals for architecture is to create the perfect place and to promote the human presence (al-hozur). To improve the rank of human being by the effect of space is among the most sublime objectives of architecture. According to al-wojud Philosophy and Mulla Sadra, when an architect designs the different parts and details of a building it is necessary to emphasize the overall structure of notion and so the overall structure of space and of the geometry which is known as the architecture generator. The two mentioned elements are such abstractions in architecture and to emphasize them is to help us accept the concepts and principles of the being (al-wojud) for the prospective architecture considering the variables that influence it. This structure is basically a coded architecture. Since al-hikmat al-mota'alie is based on alhikmat al-eshragh and in alhikmat al-eshragh god or al-wajeb al-wojud is equal to the absolute light, therefore the light manifested in architecture, is an allegory of al-wajeb al-wojud or god. The sublime architecture upgrades man to the level of meaning and wisdom and leads him toward the perception of al-wajeb al-wojud. Architecture answers to this character of perception by metaphor. According to Sadra's point of view Subscription between the human spirit and architecture is required so that the presence of pure meaning in human perception is based on the human presence (al-hozur) itself.

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A large number of beliefs and old credences of Turkmen people inhabiting in Turkmen Sahra can be categorized based on the cultural reflections appeared in rituals like Porkhani or Daggers Dance. These rituals and costumes reflect the beliefs and ideas borrowed from neighboring societies or ancient religions dating back to the pre islamic era as well as Islamic ideology.

From a different angle studying the superstitious beliefs such as believing in evil creatures, harmful ghosts, demons,fairies are indications of vicissitude history of Turkmen people.

In this research we endeavoured to re estate information gathered from field work research as well as presenting credible research resources utilising comprehensive analysis from phenomenology of symbols of religious-tribal turkmen rituals.

The anthropological study of Shamanism as the main religious idea among ancient turkmens and synthesis of iranian elements along with Sufism with it is the dominant content of this research paper that depicts the belief system turkmens. This phenomena is called “folk religion” that is an amalgamation of beliefs, primitive perceptions, legends, myths, ancient religions, subordinate and tribal ideologies along with manipulated and false images and lastly the official religion of the territory.

Folk religion is an absorbing subject for folklorists, anthropologists and ethnologists so that they can record and recognise the consisting elements and worldview, mood, mentality of people in general.

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Plant growth promoting bacteria produce ACC deaminase (EC4.1.99.4) which regulates the biosynthesis of ethylene through cleavage of ACC (immediate precursor of Ethylene) into -ketobutyarate and ammonia. Therefore, it has an important role in plant growth promotion via lowering indigenous ethylene levels especially when the plants are exposed to an environmental stress. Therefore, this study aimed to investigate the cloning, expression, purification and determination of biochemical properties of ACC deaminase from Pseudomonas fluorescense. In this regard, the ACC deaminase encoding gene of Pseudomonas fluoresense FY32 was isolated and cloned in pET28 a (+) and the resultant pET28/acdS construct then was transformed into E. coli BL21(DE3). The expressed enzyme was purified by metal-affinity chromatography on Ni(2+)-TED-Sepharose column and then the optimum conditions and biochemical properties of the purified enzyme was examined. This enzyme showed the highest activity at 28 °C, pH 7 in the presence of 30 mM MgSO4. Also, the significant reduction of ACC deaminase activity was observed in 160 ppm of NaCl. The Km and Vmax of enzyme were calculated to be 9.66 mM and 0.11 nM mg-1 h-1, respectively (determined by the concentration of the produced α-ketobutyrate), which were relatively higher than those previously reported.

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Introduction
In simple terms, land-use planning means what form of development is placed in a region to achieve its primary goal in a long-term sustainable manner. Additionally, passive defense is one of the basic approaches that should be taken into consideration so that military centers have the lowest level of vulnerability during military attacks and wars.
Methodology
In this research, 18 parameters were identified and selected from the educational, research and operational resources of the armed forces of the Islamic Republic of Iran for the construction of military centers in Golestan province, and then the weight of each indicator was determined using the AHP approach in the form of an eigenvector. Then, the raw obtained data were converted into classified maps using GIS and after combining with the given eigenvalues, the final spatial zoning map was prepared based on the used passive defense parameters for the construction of military centers in this province. 
Results and Discussion
The results showed that in this province there are no very suitable and very unsuitable regions. Also, there are regions with the total area of 340.6 square kilometers in this province, which are suitable. Other regions of the province (98.33% of the total area of the province) either have medium desirability or have unsuitable conditions for building safe military centers due to their proximity to cities, inappropriate distance from faults, proximity to industrial centers and mines.
Conclusions
The central and western regions of the Golestan province, which comprise about one-third of the province's area, due to its proximity to cities, inappropriate distance from faults, proximity to industrial centers and mines are inappropriate for the construction of safe military centers. The rest of the province has a moderate location utility and the construction of military centers in these areas requires other indicators and components of military-security management.

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The tradition of storytelling has a very long history and, as an important part of oral literature, is considered very useful for recognizing culture and literature.Nevertheless, the researchers has paid little attention to the traditions of Desān Khāni among Turkmen. This tradition is composed of folk prose or poetic tales in which the singer define them in turn by a kind of musical instrument. This poetic and musical tradition can help us better understand the context of oral literature and its narrative techniques. In spite of key role and important character of this tradition in Turkmen culture, stories in Desān Khāni Tradition share some commonalities with Turkish ethnics in central Asia and Iranian cultures that insist on eclectic feature of this culture and its communicative function. In this article, the author tries to introduce, classify and study the stories of this tradition among Turkmen.

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The folk culture of the Turkmen people, which consists of material and spiritual elements, is important from the sociological, anthropological and psychological points of view. Mirkazemi has compiled an encyclopedia of these elements in Yurt. This research extracts these elements and categorizes them in a library manner and examines them in a descriptive-analytic manner. The socio-cultural origin as a key factor, and other factors such as religion, language, and race from within, and the environment, proximity to ethnic nations, and policies of the governments of Iran and Russia, also affect it from the outside. In the last century, with the establishment of governments, forced settlement, stability and security, literacy, and the passage of time, the mentality and communication have also changed through these elements, the role of which will be examined as well. The climatic color of the work and its realistic style have helped to advance the elements of the novel such as character and characterization, scene and staging, and space and verisimilitude.

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New faunistic and taxonomic data are provided for 18 families of Iranian spiders. Four species, Cryptodrassus liyanicus Zamani & Marusik, sp. n. (♀, Bushehr Province; Gnaphosidae), Mesiotelus khorasanicus Zamani & Marusik, sp. n. (♂♀, Razavi Khorasan Province; Liocranidae), Nurscia minuscula Zamani & Marusik, sp. n. (♀, West Azerbaijan Province; Titanoecidae) and Talanites farsensis Zamani & Marusik, sp. n. (♀, Fars Province; Gnaphosidae), are described as new to science. Clubiona liachviana Mcheidze, 1997 stat. reval. (Clubionidae) is removed from the synonymy with C. alpicola Kulczyński, 1882 and is reported from Armenia, Azerbaijan, Iran and Turkmenistan for the first time; additionally, its previously unknown male is described. The genus Kishidaia Yaginuma, 1960 (Gnaphosidae) and a total of 10 species are recorded in Iran for the first time, and new provincial records are provided for 20 species. Two specimens from Iraq are also reported. Considering the results of this paper, the number of species of spiders known from Iran is increased to 980 species in 329 genera.

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Due to urbanization and consequent environmental problems in Iran, many people have been interested in improving the weather quality. Lack of information about health risks as a result of pollution is a big obstacle which stops policy-making in this regard. The present study examines the type of relationship between low air quality and Tehran citizens’ willingness to pay in order to improve weather quality. To achieve the goals two-stage Heckman method has been used so as to quantify the tendency to pay in people (WTP) for improving weather quality. A sample including 1010 Tehran citizens have been used according to random sampling method and the citizens have been interviewed face to face. The results have revealed that 55.7 percent of respondents are able to pay WTP and monthly average per person has been estimated about 3500 Rials. A Probit model for relationship between endogenous variables and WTP and a regression equation for getting the average willingness to pay have been used and what has been concluded is that age, income and the number of years spent in education have a significant effect on WTP and the women, and those suffering from respiratory diseases and habitants of polluted areas have more willingness to pay than others. Unlike developed countries, most respondents consider the government in charge of weather quality improvement and 44 percent of people were not motivated at all to spend money or make any effort to improve weather quality.

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Abstract: Marun dam with a height of 170m is one of the largest embankment dams in Iran. The dam is a zoned rockfill dam with a central clay core. Due to the importance of safety and stability control of the dam body, a complete monitoring network including different instrumentation systems, has been designed and installed in the dam body. In this paper, the data obtained from the instruments, installed in the clay core, were processed and interpreted. Based on the outcomes, the behavior of the dam body during the construction in the impounding stage and operation period was evaluated and discussed. This study consists of three major parts including: the pore pressure distributions, stress states conditions in the clay core and evaluation of its settlements and deformations in the dam body.

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Level of the water table on reservoir is one of the parameters that effects on seismic behavior of embankment dams. To evaluate the effect of this parameter, Masjed Soleiman dam for a case study has selected. Finite Element model of Masjed Soleiman dam has been constructed considering the Mohr-Coulomb failure criterion for the body of the dam. First, layer analysis was carried out considering 12 layers in end of construction stage. Then, this analysis was continued considering water table and weight of the dam reservoir in steady seepage condition. The 4 earthquake records in the far field condition have been applied horizontally to the bedrock as the input for dynamic analysis and then by considering the result of dynamic analysis was evaluated changing of the maximum acceleration and maximum displacement in time domain. In this study, to perform stability analysis and calculate the factor of safety, critical sliding surface on upstream and downstream that reported by the consultant engineers have been considered and then with Newmark analysis, equal dynamic safety factor, minimum safety factor and applied deformation have been evaluated. Results show that, the level of the water table has not effected on occurred maximum acceleration and maximum displacement. Moreover in critical sliding surface on downstream, with increasing level of the water table, dynamic factor of safety and minimum factor of safety have been increased. But in critical sliding surface on upstream, with increasing level of the water table to 0.6 height of dam, dynamic factor of safety and minimum factor of safety have been decreased and then have been increased.

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Abstract: Level of the water table on reservoir is one of the parameters that effects on the seismic behavior of embankment dams. Water table in embankment dams changes every month of the year. Also changing of water table causes to the change of stress and strain in the body of dam. In this situation, earthquake can always happen. So to evaluate the effect of this parameter, Masjed Soleiman dam as a case study was selected. The Masjed Soleiman dam is a rock-fill type with clay core and a maximum height of 177m located on the Karoon River in the Southwest Iran. This embankment dam is located in Khuzestan province at the distance of 25.5 km to Masjed Soleiman town. Finite element model of Masjed Soleiman dam was constructed. The Mohr-coulomb elasticperfectly plastic constitutive model was taken into account to reflect the soil stress-strain relation. First, layer analysis was carried out considering 12 layers at the end of construction stage. Then, the analysis was continued considering the water table and weight of the dam reservoir in steady seepage condition. The 4 earthquake records in the far field condition were applied horizontally to the bedrock as the input for dynamic analysis. Then, by considering the result of dynamic analysis, changing of the maximum acceleration and maximum displacement in time domain was evaluated. In this study, to perform stability analysis and calculate the factor of safety, critical sliding surface on upstream and downstream, as reported by the consultant engineers, were considered. The semi- empirical Newmark method used for estimating permanent earthquake-related deformation of the slopes is based on the sliding block framework. This conceptual framework approximates the potential sliding mass as a rigid body resting on a rigid sloping base. Using the Newmark method, the equal dynamic factor of safety, minimum factor of safety and applied deformation were evaluated. For studying the water table effect on the behavior of embankment dams, 20 models were used with different water tables in the reservoir. In this study, dynamic analyses were done for 4 earthquake records and for 5 elevations of water table that were considered. Then the seismic response of embankment dam was investigated. The results showed that the level of the water table has low effect on occurred maximum acceleration and maximum displacement. Minimum factor of safety in the downstream critical slip surface was has increased when the water table elevation was increased. But this parameter in the upstream critical slip surface was decreased when the water table elevation was increased. Equal dynamic factor of safety in the downstream critical slip surface was increased when the water table elevation was increased. But the upstream critical slip surface was decreased when the water table elevation was increased to 0.6 height of the dam, and then the equal dynamic factor of safety was decreased. So water table elevation in the upstream wedge was in critical condition when the water table elevation was equal to 0.6 height of the dam. Permanent deformation occurred after the earthquake in the downstream critical slip surface was decreased when the water table elevation was increased but the permanent deformation occurred in the upstream wedge was increased when the water table elevation was increased.

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The people and nation of Central Asia: Turkmans live in the north of Afghanistan and the east of the Caspian sea and at some parts of Turkmenistan and Uzbekistan.Iranian Turk-mans live in the north east of Iran in Turkman Sahra.They have a special, rich and indige-nous culture. There are many fables and beliefs on the making of Turkman carpets. Here we recall the tale of “Agh-Morad”3 . Most of the designs used in the “Pazirik”4 carpet are quite similar to those of Turkman. Turkman carpets are weaved by women in a way that differentiate them from other carpets. Up to 25 colors are being used with approximately 40 designs. Turkman carpets resemble paintings of the museums and royal castles. The raw materials used to weave Turkman carpets are wool, fluff, cotton and thread. The weaving tools are hackle, small knife, scissors and Anavich. Today there are two types of carpets in Turkman Sahra: Satligh (for business) and Tootligh (for own use). Another important aspect contributing nation’s cultural heritage is turkman music which is reminiscent of the people’s old traditions and sensational epics, which they singin bitter sweet sorrows and joyous way. This article discusses about the history of Turkman music and the position of the Bakhshies in Turkman Sahra (the desert of Turkman) and their way of living. Turkman music comprises affectionate, serenading, epic and warlike, festive and ceremony. In view of its style of performance, Turkman music is either, instrumental, vocal or instru-mental-vocal. It is also known as field or mountainside music according to its geographical location. The common musical divisions of Turkman are Mokhammas (pentagonal), Navayee, Ghe’re’ghler and Tashnid or Tajnis. With approximately 500 Maghams (tunes) In Turkman music Turkman’s musical instruments are Dotar, Ney (pipe), Kamancheh (vio-lin-like instrument resting on the ground during performance) and Zanboorak (crossbow). There are people called Porkhan who use music in their medical practices. The fables and folklore of the Turkman people also play Iran’s cultural heritage and reflect the depth of their attitudes, thoughts and ideals and even their way of living. The main part of Turkman folklore is made up of oral literature which includes: -Laleh (a lyric sung by Turkman girls) -Artaki and tales -Ataladi Souzi (proverbs) -Zekr (sonnets and the dagger dance) One of the most important Turkman fables is a tale about their ancestors in which a man named Yafes is introduced as the great ancestor of the Turk and Turkman people. According to folklore the people of Turkman originated from 24 tribes, each of them had a special symbol like eagle, falcon and so on. Among them three are in Iran: Tekkeh, Yamout and Googlang. Turkman people believe in lucky and unlucky days. There is a well-known story called “Agh Pamegh” in this regard.

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High groundwater salinity, a high water table and secondary soil salinization are dominant conditions in eastern Isfahan Province, Iran. This region has a low annual rainfall, high annual evaporation demand, saline soils and limited fresh water supplies. To investigate the effects of irrigation deficit and salinity on cantaloupe (Cucumis melo L. var. cantalupensis) production, a field experiment was performed at the Salinity and Drainage Research Station of Rudasht, 65 km East of Isfahan. Irrigation treatments were T65, T80 and T95 (irrigation after 65, 80 and 95 percent of cumulative evaporation from Class A pan, respectively), each having three replicates. EC of irrigation water was 5.25 dS m-1; irrigation water depth for the whole growing period was 300, 342 and 384 mm, for T65, T80 and T95 treatments, respectively. The results showed that T65 and T80 irrigation treatments significantly reduced fresh yield, number of fruit, fruit weight per plant and water use efficiency. Fresh-fruit yield was 31.73, 38.48 and 54.34 ton ha-1, and water use efficiency was 10.58, 11.25 and 14.16 kg m-3 in T65, T80 and T95 irrigation treatments, respectively. A second order polynomial equation was fitted (R2= 0.99) for production function (yield vs. irrigation water depth). The relationship between water use efficiency and irrigation water depth was also a second order polynomial equation (R2= 0.97). Nitrogen and potassium content of fruits in T65 treatment was higher than T80 and T95 treatments. Effect of irrigation regimes was not significant on P and Na content of fruits, but was significant on Cl- content (P< 0.05). Overall results showed that cantaloupe is a crop sensitive to soil moisture stress.

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Root-knot nematode Meloidogyne javanica is an economically significant plant parasitic nematode in muskmelon farms in Ardestan, Isfahan province, Iran. A two-year experiment was conducted in two muskmelon farms in this region. We assessed the application of 3, 6, and 9 t/ha fresh (unrotten) chicken manure separately or in combination with summer plowing. To evaluate the efficacy of each treatment, the number of galls, egg masses, reproduction factor, plant growth factors, and yield were recorded at harvesting time. The results showed that combining double summer plowing with nine t/ha chicken manure was the most effective treatment for controlling M. javanica. Nematode population indices including: the egg mass number, gall number, total population in root and soil, and reproduction factor, were significantly lower than the control treatment. The application of double plowing with nine t/ha chicken manure treatment caused 83.5%, 79.1%, 80.2%, and 78.3% decreases in egg mass number, gall number, total population per root, and soil, and reproduction factor, respectively. Moreover, total fruit weight and root dry weight in each plot (24 m²) increased by 81.8% and 50.4% compared to the control.


 

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Lately, organizations have become increasingly aware of the value of managing their organizational learning and knowledge. Thus researchers have investigated those processes extensively. Still something is missing in the current discussions of organizational knowledge: organizations do not just learn; they also forget. Knowledge management is creating processes not only for learning and retaining what is important but also for avoiding or unlearning what is not important. Forgetting, like learning, is not simple: it may be detrimental or beneficial, accidental or purposeful. By the way, in all cases, it can significantly affect, in both negative and positive ways, the competitiveness of an organization. In the present study, in addition to the investigation of concept and forms of organizational forgetting, we studied the relationship between purposeful organizational forgetting and charismatic leadership and determined of the amount of organizational forgetting, due to strategic importance of purposeful organizational forgetting. The data necessary for this study were through questionnaires that were given to 165 top and middle managers and supervisors in the supply chain of Iran automobile industry. Correlation analysis of data by chi-square test showed that there is a significant relationship between every dimensions of purposeful forgetting (new and established knowledge) and charismatic leadership.

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Most of the research has been concentrated on the effects of the horizontal components of near-field earthquakes on the dynamic behavior of the embankment dams. In this paper, the effects of the vertical components will be considered. One of the important characteristics of the near-field ground motions, is the noticeable vertical component with the high frequency content that can exceed considerably, in many cases, the horizontal component of the same earthquake. So far, few studies have been done in this area. In order to investigate the effect of the vertical ground motion on the dynamic behavior of embankment dams, a two dimensional numerical model of the Alborz dam is analyzed by using finite difference method which is used in FLAC2D code. It should be noted that the Alborz dam is a rockfill type with clay core and a maximum height of 78 m located on the Babol River in the north of Iran. The Mohr Coulomb elastic perfectly plastic constitutive model was used to simulate the stress-strain behavior of the dam body and its foundation during the static and dynamic loading. Steps of modeling are as follow: At first stage, construction was carried out in 16 layers. At this step, coupling analysis were done in order to simulate the consolidation and build up of pore pressure in clayey core, with respect to the real time of construction for each layer. Then the analyses were continued to modeling of the impounding. So at this stage the reservoir was raised to the normal water level and the model were analyzed to the steady state seepage condition. Records of near-field and far-field were selected from the same earthquake to provide better and more accurate comparison. Before applying the earthquake records to the base of the foundation in the model, they must be modified. So deconvolution analyses were done by using SHAKE2000 code in order to get the target motion with peak ground acceleration of 0.52g at the surface of the foundation (maximum credible earthquake level at the site of Alborz dam). In addition filtering process, baseline correction and conversion the acceleration time history to the stress time history were done. Results of analysis show that the vertical component of near-field ground motion has considerable effect on the magnitude of strains and deformations including: increasing the settlement of the dam crest to about 45 percent, increasing the deformation of the horizontal axis of the dam, reduction of the magnification factor of the dam crest and especially in the case of near-fault, which the occurrence of near-field earthquakes is more probable. Therefore, this issue should be considered in locating the embankment dams regarding the seismic potential and the distance from the fault, and in the design of them.

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From a statistical perspective, internal erosion and piping are from the main causes of failure in earth-rockfill dams. If these dams were located in a narrow valley, the steep slopes of the valley walls can cause increasing in stress transfer in the core. Therefore, the occurrence of hydraulic fracturing phenomenon in this kind of dams is more probable. Bidvaz dam is an earth-rockfill dam with a thin inclined clay core. The dam is located in the Northeast of Iran with a distance of twenty kilometers from the Esfrayen city. It has a height of 66 meters from the foundation and constructed in a narrow valley with a width of 40 meters on river bed and a wall slope of more than 60 degrees relative to horizontal direction. After about seven and a half years of starting first filling, a subsidence was observed at the upstream slope surface of this dam. The initial assessments, based on the data recorded in instruments which were installed inside the body and dam foundation, show at the lower level of the core and adjacent to left abutment, pore water pressure gradually has been increasing and finally reached to the reservoir water pressure, and at the same time effective stress with abnormal rate reduced to zero. These observations confirm the occurrence of internal erosion in the lower levels of the core adjacent to the left abutment. Due to the steep valley walls and noticeable difference of compressibility properties between the core and shell materials, it is expected occurring significant stress transfer in the core especially adjacent to the valley walls. Therefore, the hydraulic fracturing can be considered as a main cause initiating the process of internal erosion in this dam. The main objective of this paper is to assess the validity of this hypothesis. To achieve this purpose, this paper used a three-dimensional numerical model to simulate the behavior of the dam during construction and reservoir filling. This model has improved in the environment of a finite difference software, called FLAC3D. In the formulation of numerical model, the flow and mechanical equations have been solved simultaneously. The 3D model has been calibrated based on the recorded data from the instruments. With using a number valid suggested theoretical and empirical relationships, hydraulic fracturing potential have been calculated and the contour distribution of fracturing pressure at upstream side of the core has been presented. Also, the contour distributions of factor of safety against occurrence hydraulic fracturing phenomenon were determined for all of the suggested relationships at the upstream side of the core. The findings show that, as expected, the steep slopes of valley walls and the difference of the compressibility properties of the core and the shell materials caused significant stress transfer at lower parts of the core and adjacent to the valley walls. Moreover, the values of factors of safety against occurrence hydraulic fracturing phenomenon in upstream side of the core are less than unity near the walls. So, the hydraulic fracturing phenomenon is the one of the main causes initiating the process of internal erosion in the core.

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Today, large dams, including the type of soil or concrete offshore structures are the most important that in water supply needs of human societies play a major role. Dam stability in recent decades has been of particular interest to designers of earth dams. Soil arching in zoned embankment dams is a phenomenon where stresses are transferred from the softer core soils to the stiffer shell soils due to differential movements between the core and shell materials. In these structures, excessive stress transfer due to soil arching will lead to hydraulic fracturing occurrence in the low permeability core soils; which can cause significant internal seepage and erosion problems. This process is usually accompanied by internal erosion of soil particles, which leads to the formation of soil pipes or other erosion features that eventually cause failure of the dam. statistically shown that progressive piping and erosion are the primary contributing factor in 30% to 50% of earth dam failures. The easiest way to prevent hydraulic fracturing from occurring is to ensure that the total stresses along the upstream side of the clay core are always greater than the seepage-induced pore pressures. Thus, some authorities argue that making use of highly soft materials in core of dam which have not enough shear stress to suspend on shell materials is useful. Installation of instrumentation and monitoring during construction and initial operation will help to assess important parameters. Statistics show that the highest number of failures unstable dams, Respectively is related to earth dams, gravity, pebbles, multi-arc and arc. In this research, by modeling the Baft earth dam in finite element software PLAXIS and compare the results with the instrument results, confirmed the authenticity modeling and then, the arching phenomenon has been studied in the earth dam desired. Investigated parameters include the width of the core (core slide slope), the upstream filter layer thickness and compressibility foundation. The effect of the core side slope angle on soil arching between the clay core and the upstream shell was investigated by simulating three different core side slopes for a vertically oriented clay core: 1V:0.25H, 1V:0.33H and 1V:0.50H. To further investigate the impact of transition layer thickness, three different models with upstream filter thicknesses of 1, 3 and 6 m were analyzed. The effect of foundation compressibility on soil arching between the clay core and the upstream shell was investigated by simulating foundation rock having three different levels of compressibility. The elastic rock modulus values used in the current study were: 4×105, 8×105 and 12×105 kN/m2. that the effective parameters between these parameters to reduce of arching, is core slide slope that The core slide flatter ratio arching dramatically reduced. Then the thickness of the layer filter, which increases its thickness is reduced ratio arching. Thicker filter layers also have the additional advantage that, if they are designed properly, they can help prevent erosion of core materials into the downstream soils if a crack in the core does occur. The effect modulus of elasticity of the foundation had little influence and is negligible.