空心包体应变计地应力分量计算方法及应用

Calculation and application of in-situ stress components in hollow inclusion measurement

为进一步改进和完善空心包体应变计地应力计算方法,基于地应力现场实测过程中空心包体应变计的安装方式,采用线性参数的最小二乘拟合方法对地应力分量计算公式进行了推导,得出了6个地应力分量的改进算法及其标准误差的计算公式。采用实现完全温度补偿并考虑岩体非线性的地应力测量技术,对弓长岭井下矿-160、-220、-280 m 3个水平3个测点进行了地应力现场实测,得到了3组孔壁应变数据。分别使用常规算法和改进算法对3个测点的地应力分量进行计算并分析其标准误差。结果表明:采用改进算法计算得到的地应力分量其标准误差普遍小于常规算法计算地应力分量产生的标准误差,说明改进算法比常规算法具有更高的可靠度。在此基础上,对弓长岭井下矿地应力赋存规律进行了研究。结果显示:矿区地应力场以水平构造应力为主导,最大水平主应力的走向总体上为南东东-北西西方向,最大水平主应力、最小水平主应力和垂直主应力均随深度呈增长关系。

To improve the in-situ stress calculation method applied in hollow inclusion measurement, the formulas to calculate in-situ stress components are deduced by the least squares fitting method of the linear parameter by considering the installation mode of the hollow inclusion strain cell. We obtained a modified calculation method of six in-situ stress components with standard errors. In Gongchangling underground mine, measurements were performed by using the complete temperature compensation technique, and the improved hollow inclusion strain devices are applied at three points with the levels of -160 m, -220 m and -280 m, respectively. Three sets of borehole wall strain data are measured. The results show that the standard error of in-situ stress components calculated by the modified calculation method is less than that calculated by the traditional method. Therefore, the reliability of calculated results is improved by using the modified calculation method. Based on six obtained in-situ stress components calculated by the modified method, the stress states of Gongchangling underground mine are analyzed. The results show that the in-situ stress is dominated by the horizontal tectonic stress field in the mine area. The maximum horizontal principal stress is oriented in SEE-NWW direction. The maximum horizontal principal stress, the minor horizontal principal stress and the vertical principal stress are increased with the depth.