Generalisation of effective heave pressure considering the effects of small-strain stiffness

Other conference contribution, 2024

Excavation in low-permeable soils is typically followed by delayed heave
during consolidation, which is often restrained by a structural element, affect-
ing the earth pressure. In this paper, system insights on the mechanisms that
control heave pressure are complemented by investigating the effect of small-
strain stiffness. This is enabled by an extension of the Creep-SClay1S model
that considers small-strain stiffness. It is shown that the effect of small-strain
stiffness and its degradation with shear strains can be normalized by consider-
ing a two-dimensional time factor, a geometrical influence factor and the ini-
tial stiffness in the mid-point of the clay layer beneath the excavation. The re-
sults provide guidance on how consideration of small-strain stiffness affect ef-
fective heave pressure, in addition to factors such as excavation geometry,
thickness of clay layer and normalised construction time. The results can be
used in preliminary design and to complement project-specific analyses.
Overall, the research contributes to a deeper understanding of excavation in-
duced earth pressures and, thus, reduces the uncertainty and enables to opti-
mize the volumes of construction material