Effect of shear strain on particle breakage of carbonate gravel

琉球石灰岩中の砂礫のせん断に伴う粒子破砕とひずみの関係を調べるために琉球石灰岩の砕石を用いて圧密排水せん断試験を実施した。主な結果を以下に示す。(1)粒子破砕は,軸ひずみの増加に伴い破砕がほとんど生じない領域から破砕が顕著に生じる領域そして破砕量の増加割合が徐々に減少する領域へと変化する傾向にある。(2)粒子破砕は,側圧の増加に関わらず軸ひずみ3%付近から10%付近の間で顕著に生じる。(3)表面積は軸ひずみの増加に伴い増大するが,その増加割合は軸ひずみの増加とともに徐々に減少する。(4)せん断中に加えられた消散エネルギーは,軸ひずみの増加にともない増大し,その後消散エネルギーの増加割合は徐々に減少する傾向にある。(5)表面積の増加は粒子破砕に消費される消散エネルギーの増加と関係づけられる。
The consolidated drained shear test was carried out on crushed Ryukyu limestone in order to clarify the relationship between particle breakage and shear strain. Shear test carried out at confining pressures of range from 49kPa to 294kPa. The gravel used was reconstructed from 2mm particle size to 9.5mm. In order to examine the effect of shear strain on particle breakage, the grain size distribution of the sample was examined at stage of various axial strain. The amount of particle breakage was evaluated at the percentage passing of 2mm particle size. The particle breakage was remarkably occurred in range of axial strain from 3% to 10%, regardless of the confining pressure. The surface area of specimen increases with the increase in axial strain. The dissipation energy consumed for friction and particle breakage increases with the increase in the axial strain. It is shown taht the increase in the surface area with particle breakage is related to the dissipation energy for crushed Ryukyu limestone.
紀要論文