高应力卸荷与水岩作用下软岩流变机理与本构模型研究

Focusing on the rheological mechanism of soft rock under the action of high stress unloading and water rock interaction and basing on the deep environmental stress level, a series of soft rock triaxial unloading rheological tests are carried out considering different confining pressure and partial stress, water content, water sensitive mineral composition and content. The evolution characteristics of soft rock creep deformation and long-term strength with time under the influence of high stress unloading and water-rock interaction is analyzed and the influence of various factors on soft rock creep parameters is explored. The meso-damage characteristics of different mineral structures of the rock samples are analyzed before and after the moisture absorption test and the unloading rheological test. On this basis, the mechanical mechanism of rheological behavior of soft rock under high stress unloading and water rock interaction is revealed. And then, using unloading rock mechanics, rheological mechanics, mineralogy and other interdisciplinary research methods, model parameters intelligent identification based on the Soft-Computing method is developed. Rheological constitutive model of soft rock under high stress unloading and water rock interaction is constructed which achieve the secondary development on the FLAC3D platform. The application research is carried out combined with typical deep burial soft rock tunnel. It provides theoretical and practical basis for enriching and expanding the theory of rock rheology, the deformation control and long-term stability prediction of deep soft rock engineering in hydropower and transportation.

针对高应力卸荷与水岩作用下的软岩流变机理，基于深部环境应力水平，通过开展一系列考虑不同围压及偏应力、含水率、水敏性矿物成分与含量等因素影响的软岩三轴卸荷流变试验，分析高应力卸荷和水岩作用联合影响下的软岩蠕变变形与长期强度随时间的演化特征，探索各因素对软岩蠕变参数的影响规律，研究吸湿试验和卸荷流变试验前后岩样不同矿物结构的细观损伤特征，在此基础上，揭示高应力卸荷与水岩作用下软岩流变的力学机理。进而综合运用卸荷岩体力学、流变力学、矿物学等多学科交叉的研究手段，通过开发基于Soft-Computing的模型参数智能辨识方法，构建高应力卸荷与水岩作用下的软岩流变本构模型，实现在FLAC3D平台上的二次开发，并结合典型深埋软岩隧洞开展应用研究。为丰富和拓展岩石流变力学理论，以及水利水电、交通等领域的深部软岩工程变形控制与长期稳定性预测提供理论和应用基础。

围绕高应力卸荷与水岩作用下的软岩流变机理及本构模型，以典型软岩——页岩为主要研究对象，通过开展一系列不同饱水系数下页岩试样的卸荷流变力学试验，揭示了分级卸围压过程中页岩蠕变时效变形规律，以及蠕变速率、蠕变体积应变等变形参数随饱水系数的演化规律。进而从溶蚀、水化、膨胀、水解作用等角度，提出了软岩吸水后力学性质劣化机理；并基于流变力学理论，提出了高应力卸荷与水岩作用下软岩流变机理。在此基础上，综合运用卸荷岩体力学、损伤力学、流变力学等多学科交叉的研究手段，构建了反映饱水系数影响的软岩非线性黏弹塑性卸荷流变模型，以及反映吸水软化损伤与加载损伤耦合的软岩统计损伤本构模型，通过与试验结果对比验证了上述本构模型的合理性。为水电、油气、矿山、交通等领域的深部软岩工程变形控制与长期稳定性预测提供理论和应用基础。