جستجوی مقالات مرتبط با کلیدواژه « slope instability » در نشریات گروه « عمران »

Buried pipelines are used to transport water, liquid fuel, gas, oil, etc and they must remain in service in all circumstances such as permanent transverse ground deformation caused by slope instability. In the literature, modeling of soil-pipe interaction is carried out by using two methods of soil-equivalent springs and continuum. In this paper, numerical simulation in domain of continuum is applied to predict the behavior of the pipe embedded inside the slope. Problem modeling has been done in the FLAC 3D software by using finite difference method. The effect of parameters such as pipe diameter and thickness, width of the slope, soil adhesion and internal friction angle of soil on soil and pipe interactions were investigated. Comparison of the present numerical model with other numerical, analytical and physical models, indicates that the maximum displacement of the transverse ground and pipe occurs in the center of the area and reaches zero in the sides. Also, the anchor and force in the pipe are symmetric to the center of the model and reach a maximum value in the center. By taking steps such as increasing the diameter of the pipe, increasing the thickness of the pipe wall and reducing the angle of the slope, the displacements, tensions and strains created in the pipe can be reduced to some extent. On the other hand, the internal angle of friction of the soil and cohesion are effective in increasing the soil's resistance and also reducing the deformations in the pipe.

In a soil mass, a rise in pore water pressure leads to a decrease in the mean effective normal stresses, while the vertical loads due to surcharge may experience small changes. Under such loading, very loose and loose sands may initially experience small volumetric expansion, and then start to contract significantly as failure is approached. These large contractions can lead to the increase in pore water pressure and, consequently, failure of the soil mass under poor drainage conditions. In this paper, an experimental model is used to examine slope instability resulting from rise in water level. It was noticed that the main factor controlling the mode of failure was initial density, but other factors such as method of increase in pore pressure, distribution of pore pressure, and geometry of the test tank also influenced failures.

Landslide is one of natural hazard which often occur in mountainous regions with high precipitation and seismic activity. Iran because of having vast mountainous areas is one of susceptible countries in occurrence of landslide. Case study area of this paper is an instable slope which a village named Gougerd is located on downstream of it. This village is located near Khoy city northwest of Iran in western Azerbayjan province. The purpose of this study is using two different methods in the Geomatics field in order to monitor the probable downward movement of the Gougerd village slope. Differential SAR interferometry (DInsAR) and Global Positioning System (GPS) observation is used as beneficial tools to evaluation and monitoring of surface displacement caused by landslide. 24 SAR images are provided spanning 2003-2010 for InSAR technique processes to study past mechanism of Gougerd slope. Displacement field map and time-series of selected PS pixels are the final products of InSAR analysis which show the range of the occurred mass movement along sensor line-of-sight. Also in order to more accurate evaluation and consideration a geodetic network with ~ 20 stations are constructed on the slope. Dual frequency GPS receivers are applied to do geodetic observations of this network to study present mechanism of the slope by determining the precise horizontal movement at some specific sparse locations. Static mode of GPS observations is done in 3 epochs during 2010-2011 with time interval of about 7 month. Using DInSAR technique beside GPS Geodetic observation method released useful qualitative and quantitative information about downward movement of Gougerd slope. Displacement analyses of both used methods represent significant movement especially on the upstream of Gougerd slope affected by landslide creeping. GPS and InSAR results showed suitable compatibility and prove that these two methods are complementary each other appropriately to illustrate surface slow movement like landslide creeping as we used it in this research.