基于Kaiser效应的地应力差应变测试及区域地应力分布研究

    In-situ stress measurement based on Kaiser effect and differential strain analysis method and regional in-situ stress distribution research

    • 摘要: 以往差应变分析法(DSA)通过估算垂向主应力以求解地应力,使得该方法可靠性较差。基于岩石试样的Kaiser效应,结合差应变法,提出了一种基于Kaiser效应的地应力差应变测试方法(Kaiser-DSA法),并利用Kaiser-DSA法与应力解除法进行了对比,表明Kaiser-DSA法测试结果与应力解除法的测试结果相对误差小,且最大水平主应力方向基本一致;基于地应力测试结果,分析了窑街矿区地应力分布规律,探究了窑街矿区现今地应力场成因。结果表明:窑街矿区区域上受到了挤压构造应力场的作用,残余应力较高;受青藏逆冲推覆作用与F19断层的顺时针剪切作用,该区域地应力场以σH(最大水平主应力)>σv(垂向主应力)>σh(最小水平主应力)型的走滑型应力状态为主;此外,较高的差应力使得该区域回采时围岩体变形破坏严重,动力灾害事件频发。

       

      Abstract: In previous practice, the differential strain analysis (DSA) method, relied upon for estimating vertical principal stress to resolve geological stress, has shown limitations in reliability. Drawing upon observations of the Kaiser effect in rock samples, we introduce the Kaiser-differential strain analysis (Kaiser-DSA) method, amalgamating the Kaiser effect with the DSA method to assess in-situ stress differentials. Comparative evaluation with the stress relief method reveals that the Kaiser-DSA method demonstrates minimal relative error and generally consistent orientation of the maximum horizontal principal stress. Utilizing the findings from in-situ stress testing, this investigation scrutinizes the distribution patterns of in-situ stress in Yaojie Mining Area and investigates the causative factors contributing to the prevailing in-situ stress field. The study elucidates that Yaojie Mining Area is subject to the influence of compressive tectonic stress fields, resulting in elevated residual stress. Influenced by the Qinghai-Tibet thrust nappe action and the clockwise shear action of the F19 fault, the geostress field in this region predominantly manifests a strike-slip stress state typified by σH>σv>σh. Furthermore, the heightened differential stress within this locale exacerbates deformation and damage to the surrounding rock mass during mining activities, thereby exacerbating the frequency of dynamic disaster events.

       

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