岩体结构面新型本构模型研究

对于涉及需要单独考虑岩体结构面的工程岩体结构分析，采用能反映岩体结构面主要力学特性的合理的本构模型是取得合理解答的关键问题之一。针对在经典连续介质力学理论框架内建立岩体结构面本构模型的缺点，基于岩体结构面的实际受力变形特性，采用直接法建立了一种新型岩体结构面本构模型。所建立的模型依据岩体结构面切向应力变形曲线及剪胀曲线的实际特征，将其分为峰前线性段、峰前非线性段以及峰后软化段，并分别给出了用于描述岩体结构面变形和强度等主要力学特性的数学模型，进而推导建立了结构面各变形阶段的增量型本构模型。最后，编写相关计算程序，采用所建立的新型本构模型以及被广泛采用的Plesha模型对经典的岩体结构面直剪试验成果进行拟合分析。结果表明，所建立的新型本构模型能更为合理的描述岩体结构面的主要力学特性，且模拟能力优于Plesha模型

A new constitutive model for rock discontinuities

For the analysis of the rock engineering concerned with rock discontinuities which should be taken into consideration separately; it is of great importance to adopt the valid constitutive model for rock discontinuities which can account for the major observed mechanical properties of rock discontinuities. Due to the limitation of available constitutive models for rock discontinuities within the framework of classical continuum mechanics, a new constitutive model for rock discontinuities is presented by taking use of the direct methodology based on the strength and deformation behaviors of rock discontinuities. In the presented model, the tangential stress and deformation curve and dilatancy curve are divided into linear part before peak point, nonlinear part before peak point, and softening part after peak point; and the mathematical models which can accurately characterize the major mechanical behaviors of rock discontinuities are given. Then, based on the above-mentioned, the incremental constitutive model for rock discontinuities is developed. Finally, two classical direct shear tests of rock discontinuities are simulated by the developed model and the Plesha’s model which is used widely The results show that the major mechanical behaviors of rock discontinuities can be reasonably described by the presented model. The simulation ability of the presented model is better than the Plesha’s model.