考虑损伤阈值影响的岩石脆-延性转化统计损伤本构模型研究

摘要

普通岩石在三向受力状态下随着围压由低到高,会表现出由脆性向延性转化的特征.首先,在深入探讨岩石压缩变形机理与变形过程特征的基础上,并针对Lemaitre应变等价性理论的不足之处,基于能量理论建立了更符合实际情况的损伤模型；其次,从岩石并非一受力就会产生损伤这一客观事实出发,建立了能反映损伤阈值影响的岩石单元强度度量方法与损伤演化模型.最后,在上述模型基础之上,建立了可体现岩石在三轴试验中脆-延性转化特征的统计损伤本构模型及模型参数确定方法.%Common rocks exhibit the characteristics of brittle-ductile transition under triaxial compression with increasing confining pressure.The compression deformation mechanism and characteristics of rock and the deficiency of Lemaitre's strain equivalent theory are discussed,and a damage model according to actual conditions is established by adopting energy theory.Beginning with the objective fact that the rock will not damage when it bears little,the method for measuring microcosmic element strength of rock and the statistical damage evolvement model are established with consideration of the damage threshold.A statistical damage constitutive model is also established based on the above models.It reflects the property of brittle-ductile transition of rock under triaxial compression.The method to determine the model parameters is proposed.The comparison between experimental results and theoretical analyses shows that the model is reasonable and feasible.