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

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。

In previous practice,the differential strain analysis(DSA)method,relied upon for estimating vertical principal stress to re-solve geological stress,has shown limitations in reliability.Drawing upon observations of the Kaiser effect in rock samples,we intro-duce 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 min-imal 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 caus-ative factors contributing to the prevailing in-situ stress field.The study elucidates that Yaojie Mining Area is subject to the influ-ence 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 typi-fied byσH>σv>σh.Furthermore,the heightened differential stress within this locale exacerbates deformation and damage to the sur-rounding rock mass during mining activities,thereby exacerbating the frequency of dynamic disaster events.