The core of an earth dant is to be compacted on the wet side of optimum so as to ensure low permeability and flexibility (a nonbrittic snow-attain teletionaltip). You ban the choice of wins a sheepsfoot roller or a smooth wheel roller to compact the soil. To reduce potential shrinkage of the dam core, which is the best piece of equipment to use? If the soil were to be compacted dry of optimum, would it matter?