Integrated limit equilibrium method for slope stability analysis

Thesis Type: Postgraduate

Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Civil Engineering, Turkey

Approval Date: 2018


Supervisor: ONUR PEKCAN


Limit equilibrium is a well-established concept with successful implementations to slope stability analysis problems. Based on different underlying assumptions, there are numerous limit equilibrium methods (LEMs), yet all of them interpret the system reliability to that of the critical slip surface, which requires iterative optimization procedures to locate. Therefore, a complete analysis framework involves modules to (i) generate/represent, (ii) analyze and (iii) optimize slip surfaces, all of which influence the reliability and time complexity of the solutions. Within this context, many studies were conducted in the past two decades, mostly focusing on improved optimization procedures. However, little effort is available on the development of enhanced surface generation algorithms and analysis strategies. In that regard, the present study introduces Integrated Limit Equilibrium Method (ILEM), wherein novel procedures are incorporated to generate and analyze slip surfaces. Facilitating the optimization process, ILEM generates trial slip surfaces with scaled quadratic splines, which require a minimal number of geometric variables for accurate surface representation. In addition, quadratic functions render it possible to develop a unified formulation of common LEMs with differential equations. The governing equations are derived and closed-form solutions are obtained through analytical integration, eliminating the need for and the error imposed by slice approximation of conventional LEMs. Moreover, high-order numerical integration methods are proven to yield impartial accuracy with reasonable computational effort. The reliability and refined efficiency of ILEM are validated through comparative benchmark testing. With significant improvement over available approaches, ILEM is proposed as an improved limit equilibrium technique for slope stability analysis.