The base spans an entire bay 1.2 miles (1.9 km) across, and includes six piers, a dry dock, numerous service facilities, and an underground submarine tunnel. The main facilities appear to be located in the eastern part of the bay. Apart from the Xia, the base is also used by Han-Class nuclear attack submarines. There are satellite photos from Google earth.
http://www.fas.org/nuke/guide/china/facility/slbm.htm