"Sheer Force raises the base power of all moves that have a positive secondary effect by 30%, the secondary effects are ignored. However, this ability is not applied to moves that have a negative effect on the user, such as recoil, two-turn moves, and stat reduction after using certain moves."-Bulbapedia
From this definition, it would seem that moves with no secondary effect at all would gain the boost. So from that:
Earthquake- This one doesn't get a boost.
Earth power- a good secondary effect, so it does get a boost.
Sucker punch-This should count as a positive secondary effect, so it gets a boost.
Ice beam-It has a chance to freeze, so it gets a boost.
Dragon Tail-since this should be positive, it should boost as well.
I'm only going by the definition explained by it. A few of the sites I've checked also agree with this, however, these are only discussion boards, and therefore aren't 100% reliable sources.