Evaluation of slope failure through the assessment of meteorological conditions and earthworks management

Slope failures due to erosion effect are a well-established cause of civil engineering structure disasters. Streams passing at the toe of a slope are a severe threat to geotechnical safety, especially in urbanized areas. To increase global safety, a retaining wall is usually proposed to limit the risk of failure. However, such works could also bring the high danger of a landslide during the construction works if not managed properly. The paper aims at investigating the collapse cause of residential buildings located at the edge of the slope at northwest part of Vietnam, where engineering works were performed to prevent failure due to soil erosion at the toe of the slope. During the retaining wall construction works, the applied excavation method caused significant vibrations and additional dynamic loads that could have affected the bearing capacity of the building foundations. Another cause of failure is associated with heavy precipitation recorded at the site just before the excavation works down the slope. The paper consists of numerical analyses allowing simulation of possible scenarios, including the effect of changing groundwater conditions using the meteorological data collected from the nearby monitoring weather station. The computations were performed using geotechnical software to reflect the in-situ conditions, and the entire process of earthworks performed at the site was carefully analyzed. The numerical analyses involved computations performed for a reinforced slope where a retaining wall was proposed to assure geotechnical safety of the remaining infrastructure after the failure.