1 Abstract—The landslide of Ain El Hammam (AEH) is characterized by a complex geology and a high hydrogeology hazard. AEH's perpetual reactivation compels us to look closely at its triggers and to better understand the mechanisms of its evolution in mass and in depth. This study builds a numerical model to simulate the influencing factors such as precipitation, non-saturation, and pore pressure fluctuations, using Plaxis software. For a finer analysis of instabilities, we use Hill's criterion, based on the sign of the second order work, which is the most appropriate material stability criterion for non-associated elastoplastic materials. The results of this type of calculation allow us, in theory, to predict the shape and position of the slip surface(s) which are liable to ground movements of the slope, before reaching the rupture given by the plastic limit of Mohr Coulomb. To validate the numerical model, an analysis of inclinometer measures is performed to confirm the direction of movement and kinematic of the sliding mechanism of AEH’s slope. Keywords—Landslide, second order work, precipitation, inclinometers. I. INTRODUCTION HE city of AEH is located at 50 km east from the capital of the city of TiziOuzou (Fig. 1). It is the site of the reactivation of an old landslide. The area affected by this movement has increasingly grown, affecting the infrastructure such as roadways and water network in the city: dislocation of buildings, opening cracks in pavements, and broken pipes, etc. To predict the behavior of this slope, under some climatic event, and in addition to numerical modeling using finite element method, the second order work approach is proposed to predict instabilities appearing on the slope before reaching the breaking point using Mohr-Coulomb theory. Consequently, this movement is an interesting case study to model. As the slide’s reactivation appears to have been triggered by local water conditions after a strong rainfall treated by [1], we modeled the problem with a hydro- mechanical finite element formulation. The criterion used to detect instability is the second order work of Hill’s approach [7]. Indeed in the framework of the theory of elastoplasticity, it has been shown theoretically [2]-[4] and experimentally [5]; [6] that ruptures may occur strictly within the plastic limits of a material, when the material exhibits a non-associated flow rule. The soil behavior is mainly elastic-plastic with non- associated flow rules [3]. Therefore, the classic test of tensile strength given by the plastic limit (usually described by the Hizia Zerarka is with the University of Sciences and Technology HouariBoumediene, Algeria (e-mail: zerarkahizia@yahoo.fr). Mohr-Coulomb limit in soils) is not enough. The criterion of the second order works is given by the equation: ݓ ଶ ൌ  :ߪߝ> 0 (1) where σ is the Cauchy stress tensor and ε is the linear strain tensor. In this expression, the two tensors are related by their constitutive relationship. When w 2 is positive (w2 ˃0), the material is stable. Otherwise, a general rupture rule, and a general boundary condition can be defined on the considered solicitation path. Consequently, the material is in an unstable when state w 2 is negative. Moreover, it has also been shown that this test can detect all failure modes observed in soils: localized modes (shear bands, or compaction) and diffuse modes (liquefaction) that do not show the locations of deformations [8]. Fig. 1 Satellite view of the location of AEH landslide In this study, to identify the mechanism of deformation and to predict the spread of the AEH landslide, we used two approaches, the first is the equivalent deviatory strain and the second is the Hill’s criterion. These results are visualized by MATLAB software. Finally, to validate these results, a combination of technical instrumentation such as inclinometric measurement was followed in order to identify the deep of slip surface and to understand the sliding velocity and its direction. Analysis and Prediction of the Behavior of the Landslide at Ain El Hammam, Algeria Based on the Second Order Work Criterion Zerarka Hizia, Akchiche Mustapha, Prunier Florent T World Academy of Science, Engineering and Technology International Journal of Civil and Environmental Engineering Vol:12, No:3, 2018 223 International Scholarly and Scientific Research & Innovation 12(3) 2018 ISNI:0000000091950263 Open Science Index, Civil and Environmental Engineering Vol:12, No:3, 2018 publications.waset.org/10008643/pdf