坝区辉绿岩体的长期剪切流变强度分析研究

Analysis and Research of Long-term Shear Rheology Strength of Dam Zone Diabase

岩体长期剪切流变强度是进行岩体工程长期运行稳定分析的重要基础。以大岗山水电站坝区辉绿岩现场剪切流变试验数据为基础,分别采用等时应力-应变曲线法、非稳定蠕变判别法和稳态蠕变速率法计算获得坝区辉绿岩的长期剪切流变强度,并进行了对比分析。采用等时应力-应变曲线法分析坝区辉绿岩的长期剪切流变强度较为科学合理。与岩体瞬时抗剪强度相比,长期剪切流变强度因裂隙损伤扩展有所降低,坝区岩体长期剪切流变的内摩擦角衰减了30.7%,长期剪切流变的粘聚力衰减了22.6%。

The long-term shear rheology strength of rock mass is an important base to the analysis of long-term operation stability of the rock engineering.Based on field shear rheology test data of dam zone diabase of Dagangshan hydropower station,the long-term shear rheology strength was obtained by stress-strain isochronal curves method,steady-state creep rate method,and nonsteady-state creep method,respectively,and the results were compared and analyzed.The stress-strain isochronal curves method could provide a more scientific and reasonable way for the analysis of long-term shear rheology strength of diabase.Compared with the short-term shear strength,the long-term shear rheology strength by reason of crack damage propagation had some reduction,internal friction angle decreased by 30.7% and cohesion decreased by 22.6%.