The extension of conception is ambiguous that the quality of engineering rock body is good or bad, it contains many fuzzy phenomena, this is what fuzzy math to study.
工程岩体质量的好与坏，其概念的外延是不明确的，存在着很多模糊性现象，这正是模糊数学所要研究的。
2
Rocks are non-transparency and brittle. It is difficult to simulate the movement of rock pieces in cut cavity by math and physics.