Merging all disks in ubuntu
In Linux, Logical Volume Management, or LVM, can be used to create single logical volumes of multiple partitions and hard disks. There are guides available on how to set up and manage logical volumes, e.g. the Ubuntu wiki on LVM or this How-to Geek article.
For home use, just organizing your data over the existing 10 TB volumes may, however, be a far easier solution.