پديد آورندگان :
زارعي، پروين نويسنده دانشجوي دكتري ژيومورفولوژي، گروه جغرافيا، دانشگاه رازي كرمانشاه , , علايي طالقاني ، محمود نويسنده استاديار ژيومورفولوژي، گروه جغرافيا، دانشگاه رازي كرمانشاه , , طالبي، علي نويسنده ,
چكيده فارسي :
ناپايداري دامنه و وقوع زمين‌لغزش‌هاي سطحي يكي از دغدغه‌هاي اساسي مديران در بهره‌برداري از دامنه‌ها در مناطق كوهستاني مي‌باشد. شناسايي و بررسي عوامل موثر به‌صورت ناحيهاي ميتواند در جهت مقابله با آن و كاهش خسارات مهم و موثر باشد. براي اين منظور مدل‌هاي زيادي ارايه‌شده است كه مدل فرايند محور(فيزيك پايه) طالبي (2008) يكي از آن‌ها است. در اين تحقيق سعي شده است با استفاده از مدل طالبي (2008) ضمن تحليل پايداري دامنه‌هاي منطقه، به بررسي مهم‌ترين عوامل موثر در وقوع لغزش‌هاي سطحي منطقه جوانرود پرداخته شود. اين مدل با درنظرگرفتن ويژگي‌هاي ژيومتري دامنه (پلان دامنه و پروفيل طولي دامنه) ، هيدرولوژي زيرسطحي همراه با ويژگي‌هاي مكانيكي خاك، ضريب پايداري دامنه‌ها را مورد تجزيه‌وتحليل قرار مي‌دهد. براي دستيابي به هدف موردنظر، 12 دامنه شامل 7 دامنه لغزشي و 5 دامنه فاقد لغزش به‌عنوان نمونه مطالعاتي در منطقه جوانرود انتخاب شدند و سپس تمامي متغيرهاي تحليل پايداري شيب از طريق مطالعات ميداني و آزمايشگاهي مورداندازه‌گيري قرار گرفتند تا عوامل موثر در وقوع لغزش شناسايي گردند. شكل پلان دامنه و نيمرخ طولي آن‌ها از طريق مطالعات ميداني و به‌كارگيري نرم‌افزار Arc gis به‌دست‌آمده است . براي اندازه‌گيري ويژگي‌هاي مكانيكي و هيدرولوژي خاك نيز از هر دامنه مقدار 50 كيلوگرم خاك برداشت شد و در آزمايشگاه مكانيك خاك كرمانشاه مورد آزمايش قرار گرفت. سپس به‌منظور محاسبه ضريب پايداري، مدل موردنظر براي كل دامنه‌هاي مطالعاتي اجرا و ضريب پايداري به دست آمد. نتايج نشان داده است كه وقوع لغزش‌هاي سطحي در منطقه جوانرود متاثر از عوامل ژيومتري و ويژگي مكانيكي خاك دامنه مي‌باشد. به‌طوري‌كه دامنه‌هاي همگرا با نيمرخ طولي مقعر و خاك‌هاي با ضريب چسبندگي كم و زاويه اصطكاك داخلي پايين مستعد لغزش مي‌باشند. اين تحقيق همچنين نشان داده است كه روش فرايند محور در ارزيابي ناپايداري دامنه‌ها در منطقه جوانرود كارايي خوبي دارد چراكه در دامنه‌هاي لغزشي دامنه‌هاي (6، 7، 8، 9) ميزان ضريب پايداري با بهره‌گيري از مدل كمتر از 1 و در دامنه‌هاي پايدار ( 1 تا 4) ميزان ضريب پايداري بيش از 1.5 به‌دست‌آمده است.
چكيده لاتين :
Introduction,
Comprehensive and scientific studying of landslide is one of the most important issue in the world that to be considered because of the imposition of the Human and financial losses on the human communities, Achieving to the desired results in the projects, such as route selection, construction of highways and main roads of the mountainous, projects of development of forests and natural pastures in terms of safety and economical depends on studying and attention to the stability of the slopes of area. Lack of attention to this problem can be followed the inevitable of the human and financial losses, lands degradation and sedimentation of the basin. Hence, the results of research have much application in assessment of landslide behavior, and with the identification of the most effective parameters can be entered through its stabilization phase. Due to the complexity associated with the slopes in nature, the process-based (physical base) models able to solve this problem and to identify the most important causes of the landslide. In the world because of the importance of mass movements in countries which are exposed to the risk of landslides, the major studies in this field applied by geo-technical engineers, geologists and geomorphologists .A several models have been developed to predict the risk of landslides, such as the process-based models. Most of these models combined analysis of the stability of slopes (infinity slopes approaches) with hydrological modeling And can be evaluate landslide result of the hydrological conditions In this study, due to the complexities associated with the mechanism of landslide is used from physically based models. These models are based on the laws of physics by which they are based. In these models, the Natural processes are simulated in the laboratory and then these relationships are extended to nature after examining of the existing relationships, we used Process-based model (Talebi (2008)) in this research which combines the morphology and hydrology models with stability analysis to determine the stability coefficient for each slope in the nature.
2-Methodology
2-1-study area
Selection of the studied area with regard to the distribution points of landslide includes the watershed basins (Javanrood, Zalan, Lille, Bazan and Safiabad ) that located between 39 ?34 to 34 ʹ56ʹ North latitude and 46 ?10 to 46 ? 36ʹ Eastern longitude of the northwest part of the folded Zagros.
2-2-matherial and method
The materials used in this study include topographic maps of javanrood ( 1: 50,000), geological maps (1: 100,000), aerial photos (1: 55000) and satellite images of Google Earth, GPS, digital elevation model ( 20 meters ) and Arc gis and Matlab softwares.
This research was done using with the field and laboratory methods .Step of performing of the research can be stated as follows:
1-Preparing database and mapping the distribution of sliding points of the study area
2-determining and measuring of thr required parameters to run model and calculation of the stability coefficient, including morphology parameters, mechanical soil, vegetation, rainfall
3- Performing of the model in Matlab software, evaluating and analysis of the results.
3- Results and discussion
Javanrood is one of the known areas of Kermanshah Province that has many landslid.The vulnerability of the regionʹs geological formations (Gurpi and radiolarites), climatic conditions of the region (cold and sub wet) causes severe weathering of this formations. Resistance of the weathered material on the surface of the slope cause increasing of the thickness and providing of the condition for creation of a landslide in the region. With regard to the complexity of the mechanism of the occurrence of landslide and obtaining precise results, we attempt to study this type of landslide using with physical base model (Talebi 2008).These models can be studied landslide in the slopes with different forms according to the properties of Hydrogeomorphologic and Soil Mechanics of the slopes. The results showed that shallow landslide s in javanrood affected by the topography and mechanical characteristics of the soil that convergent slopes with concave longitudinal profile and soils with low adhesion coefficient and low internal friction angle are prone to landslide. Also according to the results calculated from models, the stability coefficient is obtained less than 1 in slopes (6, 7, 8, 9.) and more than 1.5 in the stability slopes (1-4).
4-Conclusion
The results indicate that the model (Talebi 2008) is useful to assess the stability of individual slopes so that the stability coefficient calculated by the model is obtained less than 1.5 in all sliding slopes. Therefore it can be concluded that the used model which is a combination of topography and hydrology models with stability model of slope can be used as a model-based process (physical basis) to study the stability of slopes in nature.
