基于工程混合物理论的饱和裂隙岩体组合本构模型

为了从理论和数值上分析饱和岩体工程的变形和稳定,需要创建饱和裂隙岩体本构模型。根据工程混合物理论,把饱和多孔介质应变分解为骨架应变、固相基质应变和流体基质应变。通过均匀化响应原理建立了饱和多孔介质的势函数本构理论,提出Terzaghi有效应力决定骨架应变、固相基质应力决定固相基质应变和裂隙孔压决定流相基质体应变等本构规律。根据经典岩体力学理论,把饱和裂隙岩体视为由裂隙构成孔隙的饱和多孔介质,建立了饱和裂隙岩体的组合本构模型。算例分析表明:根据本文理论建立的饱和裂隙岩体组合模型能够合理考虑裂隙流体的浮托力,具有较小的孔压系数和各向异性的受力特性。饱和裂隙岩体组合模型可用于海底隧道裂隙围岩在开挖过程中的流固耦合工程特性分析。

Combining constitutive model of saturated fissured rock mass based on engineering mixture theory

In order to analyze the deformation and stability of saturated rock engineering theoretically and numerically,it is necessary to establish a constitutive model of saturated fissured rock mass. Based on engineering mixture theory,the strain of saturated porous medium was divided into skeleton strain and solid matrix strain and fluid matrix strain. The constitutive theory in terms of potential functions was built for saturated porous medium through the homogeneous response principle. The constitutive rules were proposed that skeleton strain was determined by Terzaghi effective stress and solid matrix strain was determined by solid matrix stress and the volumetric strain of fluid matrix was determined by the pressure of fissured pore. According to the classical rock mechanics, the saturated fissured rock mass was regarded as a saturated porous media with fissured pore, and the combining constitutive model was achieved for saturated fissured rock mass. Case analyses show that the combing model of saturated fissured rock mass obtained from the theory of this paper can reasonably take into account the uplift pressure of fissured fluid. It has relatively small coefficient values of pore pressure and anisotropic mechanical features. The combing model of saturated fissured rock mass can be used to study the solid-fluid coupling engineering properties of surrounding fissured rock in the excavation process of channel tunnel.