岩石统计损伤软化本构模型及其参数反演

基于岩石微元强度服从幂函数分布的假定提出了损伤变量的一种新形式,由此建立了一个可模拟岩石破裂全过程的统计损伤软化本构模型.该模型含两个待定参数.其中一个可利用岩石三轴试验曲线的峰值点确定;另一个则受到微元强度参数的影响.通过研究微元强度参数对于软化本构模型的影响,提出了合理选择微元强度形式的参数反演方法,由此可最终确定模型参数.计算实例表明该模型能够有效模拟岩石的应变软化特性,应用反演方法确定微元强度参数能够有效提高数值模拟精度.

A Statistical Damage Softening Constitutive Model for Rock and Back Analysis of Its Parameters

A new form of damage variable is obtained on the basis that the rock micro - unit strength is assumed to follow a power distribution, and a statistical damage softening model reflecting the full process of rock failure is established. Two parameters are contained in this constitutive model for the rock, one can be obtained by the peak value of the rock stress - strain curve, the other can be calculated by the micro - unit strength parameter. Based on the relation of consititutive model with the micro-unit strength, a back analysis method is used to obtain micro-unit strength parameter. The results of a numerical example indicate that the model is effective to reflect the behavior of strain softening, and by the back analysis method the precision of numerical simulation can be remarkably increased.