Due to the many-to-many nature, loading from oneside of a bidirectional association can trigger loading of the other side which can further trigger extra data loading of the original side, and so on.
由于many - to - many的特性，在双向关联的一端加载对象会触发另一端的加载，这会进一步触发原始端加载更多的数据，等等。
2
Two cases of loading types were adopted: one was biaxial proportional dynamic loading and the other was axial dynamic loading with one-side constant confining pressure.