ANALYSIS ON LIMIT TIME OF SUBCRITICAL CRACK GROWTH IN DIFFERENT ROCKS UNDER COMPRESSIVE-SHEAR STRESSES STATE
Subcritical crack growth parameters of double torsion specimens made of ore, lherzolite, marble and granite were tested using Instron1342 type electro hydraulic servo test machine. The relations of the mode-1 stress intensity factor K, versus the subcritical crack growth velocity (V) were obtained by the double torsion constant displacement load relaxation method. The curves of crack relative length (Ib) and crack growth time (t) of four rocks under compressive stresses state were discussed according to subcritical crack growth parameters and subcritical crack growth equation, and the limit time was obtained respectively. The results show that there are turning points on curves of crack relative length (l/h) and crack growth time (t) of all four rocks. Cracks grow stably, i.e. subcritical crack growth, before the turning point. Cracks grow, encounter and integrate catastrophically after the turning point. There is not a gradual stage from crack stability growth to crack instability growth, i.e. rock mass instability is sudden. The curves of crack relative length l/b and crack growth time t move to right with increase of Young modulus, which implies that limit time increases consequently.
JIANG-TENG LI PING CAO DE-SHENG GU CHAO WU
School of Resources and Safety Engineering, Central South University, Changsha, 410083, P.R.China
国际会议
The 7th International Symposium on Rockburst and Seismicity in Mines(2009年第七届国际岩爆与微振动性学术研讨会)
大连
英文
239-244
2009-08-21（万方平台首次上网日期，不代表论文的发表时间）