I think their intended target is Hamas and terrorist organizations which have their headquarters deep within Gaza, in the underground tunnels, however, we cannot ignore the government of Israel also have some interest in the chance of seizing land, in the similar manner he have colonized territories which legally belong to the state of Palestine, in the east of the State of Israel. One could have take a look to the situation in the Golan Heights, a territory claimed by Israel which many argue it continues to belong to Syria.
The amount of civilians who have perished to this war is out of proportion, one could argue it is because the high population density within the Gaza strip and the fact terrorist seek to blend with the local population, which have nothing to do with terrorism.