黔西南锦丰金矿地应力测试及分布特征研究

Study on In-situ Stress Measurement and Distribution Characteristics of Jinfeng Gold Mine

黔西南锦丰金矿矿体最大埋深在900 m以上,随着开采深度的增加,应力环境变得极为复杂,巷道围岩失稳问题日益突显。针对黔西南锦丰金矿开发过程中面临的矿体赋存状态复杂、围岩稳定性差等问题,采用套孔应力解除法对锦丰金矿90 m、150 m中段进行现场地应力测试,获得了测点地应力赋存状态。结合研究区域的具体地质背景和相关实测数据资料,利用有限差分软件进一步分析地应力场影响因素。研究结果表明:90 m、150 m中段地应力场处于中高等应力水平,各测点主应力中有2个倾角较小,接近水平应力,1个倾角较大,接近垂直应力,实测σ_(z)基本等于上覆岩层重量γH;最大主应力方位角处于187~245°,整体呈NE-SW向,通过分析地应力场与区域地质构造的内在联系,总体可以推断,实测地应力场分布方向与构造应力方向基本一致;地形差异、断层构造及埋深等因素对地应力场分布特征产生一定影响。

The maximum buried depth of the Jinfeng Gold Mine in southwestern Guizhou is more than 900m.As the mining depth increases,the stress environment has become extremely complex,and the stability of the surrounding rock of the roadway has become increasingly prominent.In this paper,aiming at solving the problems of complex occurrence of ore bodies and poor stability of surrounding rocks in the development of Jinfeng Gold Mine,the stress-relief method of casing hole is used to test the in-situ stress at the 90 m and 150 m level in Jinfeng Gold Mine,and the occurrence state of the in-situ stress at the measuring point is obtained.Combined with the specific geological background of the area and relevant measured data,the influencing factors of the in-situ stress field are further analyzed using finite difference software.The research results show that:the in-situ stress field at the 90 m and 150 m elevations is at a medium stress level;among the principal stresses at each measuring point,two dip angles are small,close to the horizontal stress,and one is large,close to the vertical stress;the measuredσ_(z) is equal to the weight of the overlying strataγH;the maximum principal stress azimuth is between 187-245°,and the overall orientation is NE-SW.Through analyzing the internal relationship between the in-situ stress field and the regional geological structure,it can be inferred that the distribution direction of the measured in-situ stress field is the same as the direction of the tectonic stress;factors such as topographical differences,fault structure,and buried depth all have a certain impact on the distribution characteristics of the in-situ stress field.