TITLE:
Numerical Analysis of Settlement Response of Shallow Footing Subjected to Heavy Rainfall and Flood Events
AUTHORS:
Nadarajah Ravichandran, Tharshikka Vickneswaran, Siddharth Marathe, Vishnu Saketh Jella
KEYWORDS:
Coupled Flow Deformation, Unsaturated Soils, Shallow Footings, Heavy Rainfall, Flood, Drought
JOURNAL NAME:
International Journal of Geosciences,
Vol.12 No.2,
February
24,
2021
ABSTRACT: The US
and many parts around the world have experienced prolonged periods of heavy
rainfall, severe floods, and droughts over the past 50 years. This study
investigates the impacts of extreme hydrological events such as heavy rainfall
and flood on the settlement behavior of continuous footing installed in
unsaturated soil using a coupled Geotechnical-Hydrological finite element
software, PLAXIS 2D. Initially, the effect of different degrees of saturation
on the settlement behavior of the continuous footing of widths 1.5 m, 3.0 m,
and 4.5 m was analyzed by applying a mechanical load. Then the settlement behavior of
the footing was analyzed by applying heavy rainfall of intensity 102 mm/day for
six days. Finally, the settlement behavior of the footing was analyzed by
applying a flood head of 2.5 meters for seven days. The results indicated that
the wetting front movement during heavy rainfall and flooding led to the
weakening of soil strength and stiffness and induced additional settlements.
The additional settlement induced by the flood was significantly higher than
the heavy rainfall. The differential settlement was higher when the rainfall was
applied on one side of the footing. The rebound of the elastic settlement was
uniquely noticed when the flood head receded with time. The results indicated
that not all the settlements were induced by the soil saturation but also due
to the hydrostatic loading due to the flood head. The settlements induced by
the flooding exceeded the allowable settlement of 25 mm, resulting in failure. These
additional settlements caused by heavy rainfall and flood will lead to poor
serviceability of the structures and cause the failure of the footing.