การวิเคราะห์เสถียรภาพในงานวิศวกรรมปฐพีโดยวิธีวิเคราะห์ขอบเขตพลาสติก / ชัยวัฒน์ คลังวิจิตร = Stability analyses in geotechnical engineering by the method of plastic limit analyses / Chaiwat Klangvijit
Studies the numerical method of limit analyses and its possibility to apply for solving stability problems in geotechnical engineering. Numerical limit analyses use the finite element method and solve the stability problem mathematically by the technique of linear programming, giving rise to calculation results in terms of rigorous lower and upper bound loads on the true collapse load. Theoretically, calculation results obtained from limit analyses are much more accurate and correct, when compared with other methods available in geotechnical engineering such as the limit equilibrium method. This is because there is no additional assumption or approximation used in the calculation and there is the bound theorems supporting analysis results. However, numerical limit analyses are not widely used for analyzing stability problem in practice. Therefore, this research aims to test and check capabilities of numerical limit analyses whether it is suitable to be used in practice or not. Types of stability problems in the scope of this research are consisted of three categories: 1) analysis of complex bearing capacity of surface strip footings, where there is no theoretical exact solutions or the problem cannot be solved using limit equilibrium method; 2) stability problems of slope and embankment; and 3) stability problems of braced excavation from four actual failure case studies, which was well documented in recent theses. Based on all analses carried out in this research, it can be concluded that numerical method of limit analyses can be applied to solve stability problems in geotechnical engineering, where results of stability analyses are much more accurate and correct than those of the limit equilibrium method. Moreover, numerical limit analyses provide additional capability to analyze complicated problems such as non-homogeneous soil profile or complex loading, by using of finite element principle and computer for performing calculations. Nevertheless, selections of shear strength parameters matching closely with in-situ values are as critical as method of stability analyses in order to yield reliable results of analyses for design. Thus, soil engineers seriously require having best knowledge and profound understanding in geotechnical engineering.
