| 摘要 |
<p>A yieldable support element particularly for supporting the ends of mine roof support girders. The support element (2) allowing controlled movement of the support girder when the load reaches a level above which damage could occur, and comprising a hollow tubular housing (3) surrounding the end of the girder and containing a block (4) of foamed concrete or similar material which supports the girder. The compressive strength of the foam concrete determines the yield pressure for the support element.</p> |
