Effect of Physical and Mechanical Soil Properties on Landslide in Forest Road Edge (Case Study: Pahnekola District watershed Tajen)

Mass movement has effective role on destruction of roads، pastoral and residential areas and crating the erosion and sediment in watersheds. Many factors are associated with landslide، and study of landslide is differing based on scope and viewpoint. In this study، physical and mechanical properties of 24 sample soil were determined in homogenous units around the forest roads and soil analysis was done in soil laboratory. Results showed that this area is susceptible for landslide and occurrences the hazard increase in northern slopes and soft particles and increase the soil moisture content. Most samples had moderate liquid and plastic index، that increase the water in these soils led to increase the landslide occurrences. Our findings revealed that for road construction and each structure، special attention to physical and mechanical soil properties are necessity، and for each civil action، safety and controller precaution such as drainage and soil stabilization are essential for susceptible areas to mass movement.