流变扰动条件下敏感邻域内岩体微观损伤试验研究

Experimental study on micro-damage of rock mass in sensitive neighborhood under rheological disturbance

处于“敏感邻域”内的流变岩体在扰动载荷作用下,容易发生变形破坏,为从微观损伤角度建立流变岩体进入“敏感邻域”的判别标准,以红砂岩为研究对象,利用RRTS-IV型岩石流变扰动效应试验系统,对不同轴向静载压力下的流变岩体开展流变扰动试验。试验结果表明:(1)当流变岩体处于较高的轴向静载压力时,纵向累计扰动应变曲线将经历减速增长、稳定增长和快速增长3个阶段,且轴向静载压力越大,快速增长阶段越突出。(2)通过分析纵向扰动应变速率与轴向静载压力之间的变化关系,探究不同轴向静载压力作用下的流变岩体对于动态扰动的应变响应特征,并划分不同的扰动敏感区域。(3)处于非敏感区的流变岩体在动态扰动的作用下,岩体中孔隙的扩展和裂纹萌发将受到一定程度的遏制。(4)当流变岩体由过渡区进入弱敏感区和强敏感区时,动态扰动能极大地促进岩体内部微小裂隙萌生和原始裂纹扩展,且动态扰动越接近于强敏感区,孔隙数量增长越显著。

The rheological rock mass in the sensitive neighborhood'is prone to deformation and failure under the action of disturbance load.In order to establish the criterion of rheological rock mass entering the sensitive neighborhood from the perspective of micro-damage,the red sandstone is taken as the research object,and the RRTS-IV rock rheological disturbance effect test system is used to carry out rheological disturbance tests on rheological rock mass under different axial static load pressures.The test results show that:(1)When the rheological rock mass is under high axial static load pressure,the longitudinal cumulative disturbance strain curve will experience three stages of deceleration growth,stable growth and rapid growth,and the greater the axial static load pressure,the more prominent the rapid growth stage.(2)By analyzing the relationship between the longitudinal disturbance strain rate and the axial static load pressure,the strain response characteristics of the rheological rock mass under different axial static load pressures for dynamic disturbance are explored,and different disturbance sensitive areas are divided.(3)Under the action of dynamic disturbance,the pore expansion and crack germination of the rheological rock mass in the non-sensitive area will be restrained to a certain extent.(4)When the rheological rock mass enters the weak sensitive area and the strong sensitive area from the transition zone,the dynamic disturbance can greatly promote the initiation of micro-cracks and the expansion of original cracks in the rock mass,and the closer the dynamic disturbance is to the strong sensitive area,the more significant the increase in the number of pores.