Finite Element Analysis of The Undrained Bearing Capacity Factor Nc of Strip Footing

This study explores the influence of soil
weight and embedment depth on the bearing capacity
factor Nc for strip footings using finite element
analysis. Two scenarios were analyzed: a soil body
with weight and a weightless soil body, with
embedment depths ranging from 0 to 5 meters. The
results demonstrate that soil weight significantly
increases the Nc factor compared to the weightless
case, indicating that the Nc factors proposed by
Terzaghi (1943) and Meyerhof (1963), based on
weightless soil assumptions, are conservative,
particularly for deeper foundations. The Nc factor
increases with embedment depth up to a normalized
depth (Df/B) of 3.0 for soil with weight, after which it
declines, while it stabilizes beyond Df/B=3.0 for
weightless soil. Comparisons with past studies show
that the derived Nc factors align closely with Meyerhof
(1963) and Salgado et al. (2004) for shallow depths but
diverge for deeper embedment, exceeding Terzaghi’s
and Meyerhof’s values while remaining lower than
Skempton (1951) and Salgado et al. (2004). These
findings underscore the importance of accounting for
soil weight in bearing capacity calculations,
particularly for deeper foundations. This work
contributes to refining bearing capacity theories and
highlights the critical role of soil weight and
embedment depth in foundation design.