What is the symbolism of an industrial piercing?

"Industrial pericing" refers to any peircing which is commonly found in the "Industrial" sub-culture. They are closely related to Goth/Punk and are frequently characterized by large heavy peircings in ears, lips, eyebrows, noses, cheeks and pretty much anywhere else you can put a hole, and are frequently large peircings (12 gauge or larger) and the jewellery is typically plain and silver/platinum or other metal that looks like steel.