Study and analysis slippage in a trenches on Khorramabad-Poldokhtar route

Landslides are among the events occurring on steep slopes and are always accompanied with financial losses and lose of life. Slopes are geotechnical structures, in which slip is expected if the slope angle is not appropriately observed; So it has always been among engineers' concerns to determine the right angle for a dip in a way that not only doesn't it cause excessive excavation, but it also brings about proper stability to the structure. In road projects, especially in mountainous areas, it is necessary to create trenches in the ruggednesses located in the route of the road in order to observe the proper slope of the road. In Lorestan province, a large number of trenches has been created alongeside communication routs due to the mountainous topograghy of the area. In this paper, an occurred slippage in a trench on 35th km in Khoramabad-Poldokhtar rout has been studied by both limit equilibrium and numerical methods. The results of the modeling indicate that the landslide has not yet completely developed. And the tensile cracks in the landslide anticipate that in the absence of an appropriate stabilization of the trenches, a catastrophic event is not uncontemplated