DETERMINATION OF ELASTIC MODULUS，TENSILE STRENGTH AND FRACTURE TOUGHNESS OF BRITTLE ROCKS BY USING FLATTENED BRAZILIAN DISK SPECIMEN ——PART I：ANALYTICAL AND NUMERICAL RESULTS
Wang Qizhi，Jia Xueming
(Dept. of Civil Eng. and Applied Mechanics，Sichuan University，Chengdu 610065 China)
Abstract：The flattened Brazilian disk specimen is proposed to determine elastic modulus，tensile strength and opening mode fracture toughness for brittle rocks in one test simultaneously. According to the results of stress analysis and Griffith’s strength criteria，in order to guarantee crack initiation at the center of the specimen，the loading angle must be greater than a critical value (≥20°)，and hence the minimum relative value of flatten width should be decided accordingly. Based on the recorded load-displacement curve of the specimen’s whole fracture process (including the recorded process after the maximum load)，the theoretical analysis shows that can be determined by the initial linear section， can be determined by the maximum load，and by the minimum load immediately subsequent to the maximum load. The relevant formulas for the calculation of are presented，and the key coefficients in these formulas are calibrated by strict finite element analysis. Some approximate analytical formulas based on mechanics of elasticity are also provided，and their accuracy is demonstrated by the finite element analysis，hence the results obtained from these formulas are reliable.
王启智 贾学明. 用平台巴西圆盘试样确定脆性岩石的弹性模量、拉伸强度和断裂韧度 ——第一部分：解析和数值结果*[J]. 岩石力学与工程学报, 2002, 21(09): 1285-1289.
Wang Qizhi，Jia Xueming. DETERMINATION OF ELASTIC MODULUS，TENSILE STRENGTH AND FRACTURE TOUGHNESS OF BRITTLE ROCKS BY USING FLATTENED BRAZILIAN DISK SPECIMEN ——PART I：ANALYTICAL AND NUMERICAL RESULTS. , 2002, 21(09): 1285-1289.
1Guo H，Aziz N I，Schmidt L C.Rock fracture toughness determination by the Brazilian test [J].Eng.Geol.，1993，33(2)：177～188
2Wang Q Z，Xing L.Determination of fracture toughness by using the flattened Brazilian disk specimen for rocks [J].Eng. Fract. Mech.，1999，64(2)：193～201
3Satoh Y. Position and load of failure in Brazilian test，a numerical analysis by Griffith criterion[J].J. Soc. Mater. Sci. Japan，1987，36(10)：1219～1224
4Wang Q Z. Stress intensity factors of ISRM suggested CCNBD specimen used for mode -Ⅰfracture toughness determination[J].Int. J. Rock Mech. and Min. Sci.，1998，35(7)：977～982
5Cauwellaert F V，Eckmann B.Indirect tensile test applied to anisotropic materials[J].Mater. Struct.，1994，27(1)：54～60
6铁摩辛柯，古地尔.弹性理论[M]. 徐芝纶译. 北京：高等教育出版社，1990
7Griffith A A.Theory of rupture [A].In：Bienzo C B，Burgers W ed. Proc. 1st.Int.Congr.Appl. Mech.[C].[s.l.]：[s.n.]，1924，55～63
2002, Vol. 21 
