Tahereh Shaghaghi - Master of Science in Geotechnical Engineering, K.N Toosi University of Technology, Tehran, Iran
Mohsen Ghadrdan - Master of Science in Geotechnical Engineering, K.N Toosi University of Technology, Tehran, Iran
Abtin Farshi Homayoun Rooz - Master of Science in Geotechnical Engineering, Kharazmi University, Karaj, Iran.
Mohammad Reza Sabour - Assistant Professor, Department of Civil Engineering, K.N Toosi University of Technology, Tehran, Iran

Because of there are many uncertainties in geotechnical problems, nowadays probable investigation method is very convenient in this field. In this analysis type, the range of variation for each parameter has been considered. Using a probabilistic approach and considering the uncertainty of the parameters, the results are investigated by probabilistic analysis method. In this method the safety factor of a structure is not only a value, actually base on the variability of the parameters, safety factors range is defined which followed by the concept of reliability. In this paper the probabilistic slope stability of saturation soil with considering the variable saturation degree has been studied by using the FORTRAN programming language, application the Monte Carlo method and the analytical relations for unsaturated soils. The results of probabilistic approach in dealing with unsaturated soils show the need for investigating and consideration of uncertainty in parameter of analysis.

Probable investigation, Monte Carlo method, Slope stability, Unsaturated soil