基于均匀化理论的多孔岩石循环荷载下破坏机制以及安定性研究

Many geotechnical engineerings are exposed to simultaneous actions of loads and temperature fields , varying usually in a more or less cyclic way, within wide limits. In this case, the magnitude of the ultimate load is not the only factor characterizing the structural safety, but also the amplitude of the variations. The present project is devoted to studying the collapse mechanism of porous rocks subjected to cyclic loadings and to establishing a macroscopic criterion to determine the shakedown limit state, analytically and numerically, and the results will be assessed by experiments, as well. The key idea relies on Melan's statical shakedown theorem and the homogenization theory on the micromechanic models by respecting different solid phases, porosities and rigid inclusions, in order to reflect the effects of the microscopic structure of porous rocks and nature of applied loads on its safety loading domain. Moreover, a mathematical programming, by means of the Finite Element Method and non-linear optimization, will be provided to predict the variable load bearing capacity of porous rocks. The obtained results by this research can surely help promote the application of shakedown analysis on the rock engineerings, and provide a scientific and technical support for the engineering design and evaluation of the stability.

自然条件中的岩土工程往往承受不同性质变值荷载的作用，其长期安全不仅与承受的最大荷载有关，还与荷载的变化范围有关。本项目拟借助理论推导、数值模拟以及试验验证等手段，将均匀化理论与安定性下限定理相结合，通过建立细观力学模型，系统研究多孔岩石在不同循环荷载作用下的破坏机制以及所能承受的安定极限荷载。通过对常规条件和水力耦合条件下多孔岩石不同的固相基质、孔隙率、孔洞分布和坚硬夹杂等因素逐一进行安定性分析，深入研究岩体细观结构和外部荷载性质对其变值荷载承载极限的影响，建立相应的宏观安定准则；并基于有限元思想和非线性优化方法，开发出能高效计算多孔岩石在变值荷载下承载极限的数值程序。本项目有利于完善岩土工程长期安全评定体系，为事故防治和能源高效开发提供可靠的科学依据和技术支撑。

自然环境中岩土工程往往承受不同性质变值荷载的作用，其长期安全不仅与承受的最大荷载有关，更与荷载的变化范围有关。本项目开展了基于以理论推导、数值模拟以及试验验证的研究手段，将均匀化理论与安定性下限定理相结合，通过能够描述多孔材料细观特性的细观模型，系统地研究了多孔岩石在不同循环荷载作用下破坏机制以及所能承受的安定极限荷载。通过对常规条件和水力耦合条件下多孔岩石不同的固相基质、孔隙率、等因素逐一进行安定性分析，研究了岩体细观结构和外部荷载性质对其变值荷载承载极限的影响，建立相应的宏观安定准则；并基于有限元思想和非线性优化方法，开发了计算多孔岩石在变值荷载下的承载极限的数值程序。本项目研究成果可以完善岩土工程的长期安全评定体系，为事故防治和能源高效开发提供可靠的科学依据和技术支撑。

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