I tried to install gnome shell on Kubuntu with this commands
sudo apt-get install gnome-shell sudo apt-get install gnome-session
and I just found gnome classic session when logging in, Are there any messing things??
Gnome-Shell and Unity requires a more stricter conformation to newer graphical standards than Kubuntu/Xubuntu/Lubuntu.
First I would confirm that you have the ability to run Unity - Gnome-shell has similar requirements to Unity. See the linked question below.
If you have "no" as any answers or a "segmentation fault" - then you need to have a much closer look to what graphics card you have and what drivers you are using.
Attempting to use Gnome-Shell without the graphics driver prerequisites - gnome-shell will not be displayed and you will "fallback" to gnome-classic.