高应力软岩巷道围岩蠕变特性及时效分区形成机理研究

The problem of large deformation and repeated destruction of soft rock roadway and the quantitative design of supporting parameters have always been hot topics in deep rock mechanics research. The reason is that the study of the formation mechanism of surrounding rock deformation partition is still stay in the rapid loading stage of surrounding rock and the intertexture deformation stage of elastic and creep under static load is neglected. Taking this as the background, this project intends to analyze the root causes of problems in this research field first by revealing the two-stage properties of roadway surrounding rock deformation. Secondly, it is proposed to reveal the formation mechanism of the interrelated loading and unloading paths in the two deformation stages of the surrounding rock, and then to explore the formation mechanism of the surrounding rock deformation partition. Finally, it is planned to make use of the correlation between the fitting curves (straight lines) of upper and lower thresholds of stable creep and residual strength from laboratory tests and the relation curve of radial stress and cyclic stress (straight line) of each deformation partition of surrounding rock which come from theoretical analysis to explore the specific classification, the determination method of the stress and the location of the partition boundary on surrounding rock deformation partitioning. This project will adopt a special method that only considers the starting and ending state of creep and ignores the intermediate process of creep, The results of the study can reflect the creep characteristics of rocks. The research methods and results have important reference value for the further improvement of relevant support theory and the quantitative design of roadway support parameters.

煤矿软岩巷道的大变形与反复破坏问题及支护参数的量化设计问题一直是深部岩体力学研究的热点课题，原因是围岩变形分区形成机理的研究至今尚停留在围岩的快速加载阶段而忽视了静载作用下的弹蠕交织变形阶段。本项目以此为背景，拟采用力学试验、理论分析与数值模拟相结合的研究手段，以仅考虑蠕变起止状态而忽略蠕变中间过程的特殊方法为前提进行研究。通过揭示巷道围岩变形的两阶段特性，剖析该领域问题存在的根源，在此基础上揭示围岩两变形阶段相互关联的加卸载路径改变问题,对围岩变形分区的形成机理开展深入的理论研究，并利用来自于实验室试验的稳定蠕变上下阈值和残余强度的径向应力与环向应力拟合曲线（直线）与来自于理论分析的围岩各变形分区沿径向的径向应力与环向应力关系曲线（直线）之间的关联性探究围岩变形分区的具体类别、分区边界应力及位置的确定方法，为煤矿软岩巷道相关支护理论的进一步完善与支护参数的量化设计提供理论依据。

随着煤炭开采不断向深部转移，深部煤矿软岩巷道的大变形与反复破坏问题及支护参数的量化设计问题成为深部岩体力学研究的研究热点。然而相关难题一直为得到根本解决的重要原因在于深部巷道围岩变形分区机理的研究至今尚停留在围岩的快速加载阶段而忽视了静载作用下的弹蠕交织变形阶段。本项目以此为背景，采用了力学试验、理论分析与数值模拟相结合的研究手段。首先，依据围岩质点沿各自的加卸载路径所经历的加卸载过程，剖析了围岩变形分区的形成机理，建立了能够全面反映围岩两阶段变形属性的围岩应变软化新模型，并提出了围岩变形分区的“基本分区类别”。其次，揭示出稳定弹性模量和塑性硬化模量的性质及确定方法，得出了全面反映围岩蠕变特性的塑性硬化阶段和塑性软化阶段的应力应变分布规律。 最后，给出了可以清楚地反映围岩变形“具体分区类别”的图解法和求解各分区边界应力的图解法和解析法，并由此获得对应于上述“具体分区类别”的围岩分区边界位置的求解方法与解析公式。相关研究可为深部煤矿软岩巷道围岩的长期稳定性控制及支护理论的进一步完善提供理论参考。