冲击地压作为应力敏感型动力灾害，具象化地描述应力在煤岩介质中的空间流动特征，对于冲击地压科学评价与防控具有重要意义。为此，完善了冲击地压应力流理论，指出应力流在时间上表征了应力率，在空间上表征了应力梯度，提出了应力流张量与应力流矢量的概念及计算公式，指出应力流张量描述了不同位置、不同时刻应力的流动趋势，而应力流矢量总是与应力梯度增量方向相同。理论推导表明应力流越大的区域，应力强度因子变化越大，材料可能更易发生断裂破坏。在非线性有限元程序中开发了应力流矢量计算程序，实现了应力流的可视化，通过数值分析还原了单轴压缩试验、单煤层常规开采条件下的动态应力状态，计算结果表明：岩石单轴压缩过程中，应力流矢量呈近水平分布，向外发散；常规开采过程中，垂直方向应力流较大，由顶底板岩层指向中间煤层，水平方向应力流主要指向工作面前方，当开挖距离增大，采空区附近应力梯度明显增大，应力流矢量分布区随工作面前移。通过单轴压缩试验，发现应力流矢量方向与试样破坏变形方向较为吻合，初步验证了应力流与岩体开裂破坏的内在相关性。最后探讨了工程现场的应力流监测方法。研究成果有望为煤矿冲击危险性定量评价与差异化防治措施制定提供直观的认知形式和实用的理论工具。

Coal bump is a stress sensitive dynamic disaster. It is of great significance for scientific evaluation and prevention of coal bump to quantitatively describe the spatial characteristics of stress flow in coal and rock medium.Therefore, the idea of coal bump stress flow theory was improved in this paper, and the idea that stress flow represents the stress rate in time and stress gradient in space was pointed out. The concepts of stress flow tensor and stress flow vector were proposed. It was pointed out that the stress flow tensor describes the flow trend of stress in different locations at different times, and the stress flow vector is always in the same direction as the stress gradient increment. Theoretical derivation shows that the stress intensity factor increases with the stress flow, which could lead to the material failure. The stress flow calculation program was developed using nonlinear finite element method to realize the visualization of stress flow. The dynamic stress states under uniaxial compression test and single coal seam under pillar mining conditions were simulated by the finite element program. The results show that the stress flow vectors are distributed horizontally and diffused outwardly during the process of rock uniaxial compression. In the pillar retention mining process, the stress flow vectors in vertical direction are larger than those in horizontal direction,and the stress flows in vertical direction mainly point from the roof and floor strata to the middle coal seam, while the stress flows in horizontal direction mainly point to the front of the mining face. When the excavation distance increases, the stress gradient near the mined out areas increases significantly, and the distribution of the stress flow vectors moves forward with the mining face.Through the uniaxial compression test, it is found that the stress flow vector directions are consistent  with the failure and deformation directions of the rock sample, which preliminarily demonstrates the internal correlation between the stress flow and rock failure. Finally, the monitoring and analysis method of stress flow in engineering site was discussed. The research work is expected to provide an intuitive cognitive form and a practical theoretical tool for the quantitative evaluation of coal bump risk and formulation of differentiated prevention and control measures.

1 应力流的理论公式

2 应力流与开裂破坏的理论关系探讨

3 应力流数值算例

   3.1 实验室尺度单轴压缩破坏的应力流过程

   3.2 工程尺度常规开采的应力流形成过程

4 讨论

5 结论