  We investigate the Universe at the late stage of its evolution and inside the
cell of uniformity 150-370 Mpc. We consider the Universe to be filled at these
scales with dust like matter, a minimally coupled Galileon field and radiation.
We use the mechanical approach. Therefore, the peculiar velocities of the
inhomogeneities as well as the fluctuations of the other perfect fluids can be
considered nonrelativistic. Such fluids are said to be coupled because they are
concentrated around the inhomogeneities. We investigate the conditions under
which the physical Galileon field, i.e. compatible with results of the latest
gravitational wave experiments GW150914, GW151226, GW170104, GW170814, GW170817
and GW170608, can become coupled. We know that at the background level coupled
scalar fields behave as a two-component perfect fluids: one which mimics a
network of frustrated cosmic string and an another one which corresponds to an
effective cosmological constant. We found a correction for the Galileon field,
which behaves like a matter component.
