After being set state load, optimized timbering adds support yielding deformation, increases the load-carrying ability and improves the effect of controlling the surrounding rock.

The distinguishing features of the paper are selection of oblique strip and loading transmission, negative yielding line in irregular slab with simple supports, point support and shear split of slab.

Whether an u-steel yielding support could yield depend on the pre-screw forces of the camps and the internal forces of both ends at the u-steel overlap parts.