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

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 σ_H>σ_v>σ_h. 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.