Experimental study on microscopic damage characteristics of granite under cyclic dynamic disturbances
-
摘要: 為研究循環動力擾動下巖石細觀損傷特性,本文選取花崗巖為研究對象,利用分離式霍普金森壓桿(SHPB)進行循環沖擊試驗,并結合核磁共振系統(NMR),得到了循環動力擾動后花崗巖孔隙度、橫向弛豫時間T2譜分布以及核磁共振圖像(MRI).試驗結果表明:在巖石彈性極限范圍內,動力擾動結束后,巖石材料孔隙度降低;初始與最終橫向弛豫時間T2縮短,循環擾動過程促使了小孔隙生成,大孔隙尺寸與數量減小;孔隙度降低不意味著所有類型孔隙的數量均減少,相反小孔隙數量是增加的,大孔隙數量減少是動力擾動后花崗巖孔隙度降低的根本原因.Abstract: To investigate the microscopic damage characteristics of rock materials under cyclic dynamic disturbance, granite was chosen as the research object, and the split Hopkinson pressure bar (SHPB) was used to outperform the cyclic impact test. Besides, with the nuclear magnetic resonance (NMR) technique, the porosity, crosswise relaxation time T2 distribution and magnetic resonance image (MRI) of the rock sample were obtained. The results show that within the range of the rock's elastic limit, the porosity reduces after the dynamic disturbance. The initial and final transverse relaxation time T2 shortens, which indicates the process of cyclic disturbance causes the formation of small pores, where the size and number of large pores decrease. The decrease of porosity does not mean that the number of all kinds of pores decreases; on the contrary, the number of small pores increases, and the decreased number of large pores is the root cause which leads to the decrease of porosity after dynamic disturbance.
-
參考文獻
[11] Menéndez B, David C, Nistal A M. Confocal scanning laser microscopy applied to the study of pore and crack networks in rocks. Comput Geosci, 2001, 27(9):1101 [12] Přikryl R. Some microstructural aspects of strength variation in rocks. Int J Rock Mech Min Sci, 2001, 38(5):671 [13] Lawler J S, Keane D T, Shah S P. Measuring three-dimensional damage in concrete under compression. Aci Mater J, 2001, 98(6):465 [17] Yue Z Q, Chen S, Tham L G. Finite element modeling of geomaterials using digital image processing. Comput Geotechnics, 2003, 30(5):375 -
點擊查看大圖
計量
- 文章訪問數: 743
- HTML全文瀏覽量: 264
- PDF下載量: 15
- 被引次數: 0
下載:
