深部围岩流固耦合蠕变-突变全过程演化规律研究

With an increase of coal mining depth, the breakage process of deep surrounding rock will be catastrophic and abnormal without any indication. Engineering disasters such as deformation and failure of roadway often occur in most of the deep mines in our country. These problemes may lead directly to repeated maintenance of roadway and shutdown or halted construction of mine. Geological environment of deep surrounding rock determined geostress, seepage and its synergistic effect which play important role in the process of deformation failure. The process and evolution of instability of deep surrounding rock require further study.Experimental research, theory analysis and numerical simulation should be well combined to study overall process of creep-catastrophy in deep surrounding rock. Based on mining rock mechanics and fluid-solid coupling theory,a fluid-soild coupled mathematical model will be built to describe overall proces of creep-catastrophiy in deep surrounding rock, and the model will be validated and modified through experiment.The starting condition of creep, transform condition or criterion at different evolution periods and starting condition of catastrophy will be determined.By using the dynamic meshes，the self-programming based on finite element method(FEM) is used to simulate the overall process of creep- catastrophy by putting stress，pore pressure and other condition. Analyzing the results of test with the FEM calculation, we will explain the synergistic effect mechanism of stress and seepage,and reveal the evolution law of deep surrounding rock from creep deformation to catastrophy instability in fluid-solid coupling.It can provide academic base for roadway reinforcement, disaster prevention and support design in deep engineering.

随着煤矿开采深度的加大，深部围岩的破坏过程往往发生无前兆的突变或异常，巷道变形失稳等灾害在我国绝大部分深部矿井中频发，导致巷道反复维护乃至矿井的停产和停建。深部围岩所处的地质环境决定了地应力、渗流及其耦合作用在其变形失稳过程中起关键作用，深部围岩变形失稳的过程和演化规律还有待进一步研究。项目采用实验研究、理论分析和数值模拟相结合的方法，研究流固耦合作用下深部围岩的蠕变-突变全过程；基于矿山岩体力学、流变力学和流固耦合理论，建立和验证描述深部围岩的流固耦合蠕变-突变全过程数学模型，确定蠕变发生条件、阶段转化条件(判据)及突变启动条件；施加发生蠕变-突变的应力、孔隙压等参数和条件，采用基于有限元的动网格自编程序模拟蠕变-突变全过程；分析模拟结果与实验结果，阐明应力和渗流的耦合作用机制，揭示流固耦合作用下深部围岩由蠕变变形到突变失稳的演化规律。为深部工程的巷道加固、灾害防治和支护设计提供基础。

深部围岩所处的地质环境决定了地应力、渗流及其耦合作用在其变形失稳过程中起关键作用。项目的主要研究内容为：确定深部围岩蠕变发生条件和突变启动条件、建立流固耦合作用下深部围岩蠕变-突变全过程数学模型、建立变形不同阶段转化条件或判据、分析蠕变-突变的全过程、研究围岩蠕变-突变过程中流固耦合作用机制和深部围岩的失稳机理。基于应变空间理论构建了花岗岩、砂岩和泥岩等深部矿区典型岩石的应变软化数学模型，通过开展高应力条件下的蠕变实验，确定了深部围岩发生蠕变的条件，通过开展岩石渗流-蠕变耦合实验，获得了深部围岩流固耦合蠕变-突变全过程实验曲线，结合岩石峰后应变软化数学模型及岩石蠕变启动条件，建立了流固耦合作用下深部围岩蠕变-突变全过程数学模型，并对数学模型进行验证和修正；基于不同演化阶段的变形特征、变形-时间的函数关系，建立了变形不同阶段转化条件，基于建立的深部围岩蠕变-突变全过程数学模型，施加满足蠕变发生条件、阶段转化条件的应力、孔隙压等参数和边界条件，数值模拟分析了流固耦合作用下深部围岩的蠕变-突变全过程；从试验和数值模拟结果中提取轴向应变、侧向应变、孔隙压等相关参量的变化曲线，探讨了应力和渗流在深部围岩蠕变-突变过程中蕴含的耦合作用机制，揭示了流固耦合状态下深部围岩的蠕变-突变演化规律，阐明了深部围岩的失稳机理。研究成果为深部工程的巷道加固、灾害防治和支护设计提供基础。