  The investigation of dynamics of intense solitary wave groups of collinear
surface waves is performed by means of numerical simulations of the Euler
equations and laboratory experiments. The processes of solitary wave
generation, reflection from a wall and collisions are considered. Steep
solitary wave groups with characteristic steepness up to $kA_{cr} = 0.3$ (where
$k$ is the dominant wavenumber, and $A_{cr}$ is the crest amplitude) are
concerned. They approximately restore the structure after all the considered
interactions. In the course of the interaction with the wall and collisions the
maximum amplitude of the wave crests is shown to enhance up to 2.5 times. A
standing-wave-like structure occurs in the vicinity of the wall, with certain
locations of nodes and antinodes regardless the particular phase of the
reflecting wave group. A strong asymmetry of the maximal wave groups due to an
anomalous set-up is shown in situations of collisions of solitons with
different frequencies of the carrier. In some situations of head-on collisions
the amplitude of the highest wave is larger than in over-head collisions of the
same solitons. The discovered effects in interactions of intense wave groups
are important in the context of mechanisms and manifestations of oceanic rogue
waves.
