As mining progresses to depth, engineering activities face the extreme challenge of high in situ stress. To efficiently measure the deep in situ stress before engineering excavation, an innovative deep in situ stress measurement method capable of the geological core ground reorientation technology and acoustic emission (AE) technology was proposed. With this method, nonorientation geological cores collected from the thousand-meter-deep borehole were reoriented based on the spatial spherical geometry model and borehole bending measurement principle. The distribution of deep in situ stress of an over-kilometer-deep shaft in the Xiangxi gold mine was investigated with real-time synchronized MTS 815 material testing machine and PCI-II AE instrument. The results show that the in situ stress changes from being dominated by horizontal stress to being dominated by vertical stress with depth. The horizontal maximum principal stress and vertical stress gradually increase with depth and reach a high-stress level (greater than 25 MPa) at a depth of 1000 m. The direction of the maximum principal stress is near the north. Meanwhile, to analyze the accuracy of the measured in situ stress comparatively, the stress relief measurements were performed at a depth of 655–958 m in the mine, using the Swedish LUT rock triaxial in situ stress measurement system. The distribution of deep in situ stress obtained by the stress relief method agrees well with that by the AE method, which proves the reliability of the AE in situ stress testing method based on the geological core ground reorientation technology.

中文翻译：

---

地质岩心定向技术在超公里深井筒现场应力测量中的应用

随着采矿工作的深入，工程活动面临着巨大的原地应力挑战。为了有效地测量工程开挖前的深部地应力，提出了一种具有地质核心地层定向技术和声发射（AE）技术的创新型深部地应力测量方法。利用这种方法，根据空间球面几何模型和井眼弯曲测量原理，对从千米深井眼收集的非定向地质岩心进行了重新定向。利用实时同步MTS 815材料试验机和PCI-II AE仪器研究了湘西金矿超公里深井筒的深部地应力分布。结果表明，原位应力随深度的变化从水平应力变为垂直应力。水平最大主应力和垂直应力随深度逐渐增加，并在1000 m深度达到高应力水平（大于25 MPa）。最大主应力的方向在北方附近。同时，为比较分析现场应力测量的准确性，使用瑞典LUT岩石三轴现场应力测量系统在矿井中655-958 m的深度进行了应力释放测量。应力释放法得到的深部地应力分布与声发射法吻合得很好，证明了基于地质核心地面定向技术的声发射地应力测试方法的可靠性。