岩土应变损伤变量测度研究

Variable measure of strain damage of geotechnical materials

岩土材料变形破坏损伤测度关系到其稳定性计算结果的可靠性。在考虑了现有岩土损伤模型不完备性的基础上,分析了岩土材料的损伤值存在上限1的非可达性,提出了以应变对线弹性本构曲线的偏离量(差应变)与应变的比值作为损伤量度的方法。根据试验结果进行计算分析表明,其可对初始损伤和临界损伤进行准确计算。同时,根据岩石脆性破坏试验,指出岩石在由弹性阶段向非弹性阶段过渡时存在材料损伤度的陡增区间,其与岩石材料内部微裂纹的扩展与相互屏蔽作用有关,在这个区间岩石的应变和损伤会出现局部化集中。

The measure of deformation,failure and damage of geotechnical materials concerns the reliability of calculation results.Considering the incompleteness of damage model,it is proposed that the ratio of strain deviation of the linear elastic strain to strain could be used as the damage value.The analysis and calculation results of experiment indicate that the method can calculate preciously the initial and limit damage.On the same time,on the basis of brittle failure test of rocks,it is pointed out that there exists an interval of sudden increase of damage in transition from elastic stage to non-elastic stage of materials,which is related to the extension and mutual blinding of micro-cracks in rock materials.In this interval the strain and damage in rocks may be locally concentrated.