For the tip-to-face roof stability, chock-fram type powered support only be applied to hard top-coal, shield-type powered support and chock-shield-type powered support can be applied to three top-coals.

• 通过分析，为保证端面顶板稳定，支撑式液压支架仅适用于顶煤为硬煤的条件下，掩护式和支撑掩护式支架在三种顶煤条件下均可以适用。