膨胀性软岩水腐蚀损伤断裂力学效应实验研究

Testing study on damage and fracture mechanical effects for swelling soft rock during water corrosion

采用INSTRON1342电液材料伺服试验机和Taylor Horbson Surf CLI2000形貌仪对膨胀性软岩双扭试件进行相同pH溶液(pH=7.7)、不同浸泡时间的亚临界裂纹扩展和膨胀特性的试验研究,分别得到膨胀性软岩亚临界裂纹扩展速度v与应力强度因子KI之间的关系、膨胀性软岩的断裂韧度KIC以及不同浸泡时间下的岩石试样吸水膨胀的变化,通过采用双对数坐标空间对常位移松弛法所测试的不同浸泡时间的膨胀性软岩亚临界裂纹扩展速度v与应力强度因子KI之间的关系进行研究。研究结果表明:lg KI-lg v关系具有良好的线性相关性,膨胀性软岩水腐蚀作用对岩石裂纹的断裂指标影响显著并具有时间效应,而且水腐蚀损伤对膨胀性软岩断裂力学性质有弱化作用,能加快膨胀性软岩亚临界裂纹的扩展。

The subcritical crack growth and swelling of swelling soft rock were studied by double torsion test using Instron1342 type electro hydraulic servo test machine and Taylor Horbson Surf CLI2000 appearance rites in the same liquor（pH=7.7） of different immersion time.Based on testing results,the relationship between velocity（v） of swelling soft rock subcritical crack growth and stress intensity factor（KI）,and the fracture toughness（KIC） and the change of rock-swelling under different immersion time were obtained respectively.The relationship of subcritical crack growth velocity（v） and stress intensity factor（KI） of swelling rock in different immersion time were studied by double logarithm coordinate.The results show that lg KI-lg v relations accord with good linear rule and the fracture mechanics effect of water corrosion action of swelling soft rock is evident and time-dependent,and the water corrosion damage can accelerate subcritical crack growth velocity（v） and can weaken fracture mechanical characteristic of swelling soft rock.