-In your home directory open /.local/share/applications/
-Right click in this folder and create a empty desktop file
-Open this file with gedit and paste this content:
[Desktop Entry]
Type=Application
Icon=user-trash
Name=Trash
Name[de]=Papierkorb
Comment=open trash
Categories=FileManager;Utility;Core;GTK;
Exec=nautilus trash:///
StartupNotify=true
Terminal=false
MimeType=x-directory/normal;inode/directory;
Name[de_DE]=Papierkorb
-Rename the file to trash.desktop
-Restart the GNOME shell with Alt+F2+r
-Type trash in the search and pin it to your Dock.