Severe wet spells and vulnerability of urban slopes: case of Singapore.

摘要

Tropical areas like Singapore characteristically receive heavy and prolonged periods of rainfall. During these wet spells, many of the urban engineered slopes become susceptible to landslides, causing much damage to property and causing disruption to urban life. Studies on relationships of wet periods and landslides events reveal that while the weathered materials on urban engineered slopes tend to fail regularly in response to discrete, heavy rainstorm events, they are also closely associated with long periods of antecedent rainfall conditions which often help to reduce the threshold value of discrete rainfall events. Past records of slope failures and recent episodes of failures in Singapore are examined to re-assess this relationship. Study found that there is indeed a close association between the two aspects of any rain event and co-occurrence of the two lead to widespread slope failures.