水作用下软岩软化与损伤断裂效应的时间相依性

Time-dependence of Damage and Fracture Effect for Strain Softening of Soft Rock Under Water Corrosion

为研究水作用下软岩损伤劣化效应的时间相依性,通过采用RYL-600岩石试验机和Instron1342电液材料伺服试验机对经过水浸泡不同时间后的软岩试验样品进行力学参数以及双扭试件的亚临界裂纹扩展试验,分别得到了软岩含水率、强度与变形参数、亚临界裂纹扩展速度V与应力强度因子KI、断裂韧度KIC等参数,试验结果分析表明:软岩含水率、力学参数等与水岩作用时间具有高度线性相关性,可以通过含水率和弹性模量建立软岩劣化损伤速率D的函数关系;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之间的关系研究,发现lgKI-lgV关系具有极好的线性相关性,而且水腐蚀损伤对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,并且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。因此,进行软岩与水作用损伤断裂效应的时间相依性研究具有重要意义。

In order to study the time-dependence of damage and degradation effect for soft rock under water corrosion, subcritical crack growth of soft rock was studied by double torsion test using Instron1342 type electro hydraulic servo test machine and the mechanics parameters test using RYL-600 rock test machine after marinated soft rock in water for different time. Based on testing results,the rate of water content（ ω ） ,the mechanics parameters,the subcritical crack growth velocity（ V ） ,the stress intensity factor（ KI ） ,and the fracture toughness （ KIC ） were obtained,respectively. The results showed that the rate of water content（ ω ） VS the time of water-rock interaction relations accord with good linear rule and could be used to establish the function relationship of damage and degradation velocity（ D ） for soft rock by means of the rate of water content （ ω） and elasticity modulus（ E ） . The relationship of subcritical crack growth velocity（ V ） and stress intensity factor（ KI ） of soft rock in different time were studied by double logarithm coordinate,and the results showed 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.