Multihazard Risk Model for Reliability Analysis of Expansive Soil Landslide Based on T–S Fuzzy Logic

Abstract

The risk level of an expansive soil landslide (ESL) is a key parameter employed for slope stability assessment. It also serves as a starting point for a risk management strategy constructed to mitigate the risk of slope failures and their harmful consequences. However, it is usually underestimated because of the complexity of geological and environmental conditions and the lack of systematic instability categorization. This study develops a probability evaluation method using Takagi–Sugeno (T–S) fuzzy fault tree analysis (T–S FFTA) for qualitative and quantitative risk assessment of the ESL considering soil properties, geological settings, weather conditions, and engineering activities. Fuzzy variables were used to determine the magnitude of the failure. The T–S fuzzy logic enables subjective and reasonable assessment by experts, with a combination of fuzzy variables to describe the relationships among events. Finally, two recent expansive soil landslides in China were investigated, and T–S FFTA was employed to identify their failure modes and critical risk factors.