At high energies the soft and the semihard components of the
scattering amplitude are closely related, and it becomes important to
distinguish between semihard gluons, which participate in hard
parton-parton scattering, and soft gluons, emitted in any given
parton-parton QCD radiation process. A class of models based on QCD
incorporate soft and semihard processes in the treatment of
high-energy hadronic interactions using a formulation compatible with
analyticity and unitarity constraints. In this talk we present a
QCD-based model in which the coupling $\alpha_{s}$ is constrained by
the value of the so called ``dynamical gluon mass'', whose existence
is strongly supported by recent QCD lattice simulations. This frozen
coupling, obtained by means of the pinch technique in order to derive
a gauge invariant Schwinger-Dyson equation for the gluon propagator,
has been adopted in many phenomenological studies. More specifically,
we discuss some recent applications of the model to hadron-hadron
collisions, gap survival probability calculations, and soft gluon
resummation techniques. These results indicate a smooth transition
from nonperturbative to perturbative behaviour of the QCD.