衝擊荷重作用下之岩石抗壓強度與破壞產狀

岩盤工程相關的研究課題或工程設計常以靜態力學試驗獲得所需的材料靜力參數，但在衝擊荷重作用條件下，岩石材料力學性質則具有顯著的應變率效應，且材料破壞產狀與靜態加載時迥異。故針對地震作用、岩石爆破作業或軍事地下掩體防護工程等涉及動態問題者，如何評估岩石在衝擊荷重作用下的力學特性實有待進一步的實驗探討。有鑒於近二十年岩石動力學在國際岩石力學間的相關研究已逐漸成一趨勢，台灣本土岩石的動態力學特性仍欠缺中高應變率加載條件的試驗研究。因此，本研究利用分離式霍普金森壓桿（Spilt Hopkinson Pressure Bar，SPHB），針對花崗岩、大理岩與砂岩進行中高應變率條件之單軸壓縮試驗，以探討岩石抗壓強度之應變率效應與破壞產狀之變化。研究結果顯示三種岩石的動態單壓強度均隨應變率增加而有遞增之趨勢；岩材強度隨應變率增加的幅度以花崗岩最大、大理岩次之、砂岩最小；此外，透過篩分析進行岩石破碎形態分類，可知岩石的破碎產狀與岩石種類、撞擊能量與試體尺寸有關。

關鍵字

分離式霍普金森壓桿；應變率；單軸壓縮強度；破壞型態

並列摘要

The parameters of rock mechanics in rock engineering design are generally obtained from static tests. However, for a rock system subjected to transient loads (i.e., impact and blast), the material properties, the strength and the failure patterns are strongly influenced by strain rate. Thus, it is necessary to investigate the dynamic response of rock especially in rock blasting, excavation and underground protective structures. In this study, the uniaxial compression tests of granite, marble and sandstone were conducted by using Material Testing System and Spilt-Hopkinson Pressure Bar (SPHB). The strain rate were set up from static to intermediate states, with increasing the strain rate, the results can be concluded as follows: 1. the increment of peak stress varies with rock types, and the rock possessed a higher uniaxial compressive strength and a lower porosity, such as granite, has the most obvious effect of strain rate on peak stress among the three; 2. the failure patterns and fragment degree of rock are related to impact load, rock types and sample size.

並列關鍵字

SHPB ； strain rate ； uniaxial compressive strength ； failure pattern

主題瀏覽