It is hardly possible to ?nd a single rheological law for all the soils.
However theyhavemechanicalproperties(elasticity, plasticity, creep,
damageetc. )that are met in some special sciences, and basic equations
of these disciplines can be applied to earth structures. This way is
taken in this book. It represents the results that can be used as a base
for computations in many ?elds of the Geomechanics in its wide sense.
Deformation and fracture of many objects include a row of important
e?ects that must be taken into account. Some of them can be considered
in the rheological law that, however, must be simple enough to solve the
problems for real objects. On the base of experiments and some
theoretical investigations the c- stitutive equations that take into
account large strains, a non-linear unsteady creep, an in?uence of a
stress state type, an initial anisotropy and a damage are introduced.
The test results show that they can be used ?rst of all to ?nding
ultimate state of structures - for a wide variety of monotonous lo- ings
when e?ective strain does not diminish, and include some interrupted,
step-wise and even cycling changes of stresses. When the in?uence of
time is negligible the basic expressions become the constitutive
equations of the pl- ticity theory generalized here. At limit values of
the exponent of a hardening law the last ones give the Hooke's and the
Prandtl's diagrams.