The present study is concerned with the stability of side slope for the highways lying between two canals, eastern Nag Hamady canal and western side canal at Km(70.8).The canals and highway are located on the right bank of the Nile, and pass through the governorates of Assiut and Sohag. The side slope cracks as well as cracks in the asphalt road usually happen after winter closing period in the left side slope of the road. This is attributed to the difference in water levels between the two neighboring canals and soil weakness. The present study deals with this problem and can be divided into two main parts:
• The first part is an experimental work using triaxial test, shear box test, and consolidation test, which are carried out on undisturbed samples to determine physical and mechanical soil properties.
• The second part is the numerical investigation using the obtained soil properties from the experimental work. Two computer programs are used from GEOSTUDIO 2004 library. First (SLOPE/W) is used for slope stability analysis by limit equilibrium method. This program deals with slope stability methods such as Ordinary, Bishop, Janbu and Morgenstern- price methods. The second is the stress analysis program (SIGMA/W).This program is based on finite element technique. The MohrCoulomb yield criteria is used to represent soil layers. Study results showed that slopes at the investigated seating sites are unsafe. The numerical simulation with GEOSTUDIO 2004 is powerful to determine the location of the cracks for highway side slope of eastern Nag Hamadey canal, and is in good agreement with the actual observation in the field. Also, proposed practical methods are suggested to improve stability properties for the highway side slope using piles, cut- off wall to obtain factor of safety, greater than 1.5