Evaluation of Dominant Modes of Failure of Soil Nail System

This report basically discusses the study and analyses conducted on the chosen project
topic, which is Evaluation of Dominant Modes of Failure of Soil Nail System. The
objective of the project is to quantify the non-quantitative factors that affecting failure of
soil nail system to means of quantitative justification. Firstly, a comprehensive study on
the soil nail system background such as the application, construction sequence, design
methods, design requirements, materials used, etc are essential to get more
understanding on the subject. Identification of uncertainties surround in soil nail system
are necessary as the currently applied design methods are based on factor of safety
which profoundly based on experience without regard to the degree of uncertainty. For
that, hazard and risk related to uncertainties encircle in the soil nail system are identified
through possible pre-failing failure mechanisms. Failure mechanisms consists of nail
pullout failure, nail tendon failure, face failure and overall failure is identified through
the failure modes analysis. Fault Tree Analysis (FTA) is applied to the failure
mechanisms and the precedence events of each failure mechanism are determined. Four
levels of AHP hierarchy model is constructed which consists of the overall goal /
objective, criteria, sub-criteria and alternatives. Factors which have been determined in
FTA are applied as the criteria and sub-criteria while failure mechanisms as the
alternatives. The objective of the analysis is to determine the most probable failure
mechanism in soil nail system. The final result of the AHP is in the forms numerical
priority value for each failure mechanism. The overall consistency and sensitivity of
overall judgments given is checked at the end of the analysis