汾西矿区地应力测试与分析

Measurements and Analysis of Ground Stresses in Fenxi Coal Mining Area

采用小孔径水压致裂地应力测量装置在汾西矿区进行了7个煤矿、24个测点的地应力测量.实测数据表明,汾西矿区地应力场有两种类型:σH>vσ>hσ及vσ>σH>hσ.埋藏相对较深的井区水平应力占明显优势,具有典型的构造应力场特征;所测区域属于低及中等地应力值矿区;最大与最小水平主应力值基本随埋藏深度的增加而增大.但部分测点存在明显的离散性;有些矿井最大水平主应力方向比较一致.但也有些矿井由于开采深度不同,地质构造分布与煤岩性质存在较大差异而出现明显的离散性.基于实测数据,采用回归方法得出地应力与埋藏深度的关系;分析了水平主应力与垂直主应力的比值随埋藏深度的变化.将地应力测量结果应用于巷道支护设计,显著提高了设计的合理性与可靠性,巷道支护状况得到明显改善.

24 points of stress measurements have been finished in 7 coal mines of Fenxi coal mining area by means of the hydrofracturing stress measurement rig with small borehole.The stress measurement data shows that there are two types of ground stress fields in Fenxi coal mining area,i.e.σH>σv>σh and σv>σH>σh the stress fields in deeper coal mines are dominated by horizontal stresses with typical features of tectonic stress fields;The magnitude of the stresses is low to moderate value;The maximum and minimum horizontal principal stresses increase with the increase of buried depth on the whole,but there are obvious dispersion for some testing points.The orientations of the maximum horizontal principal stresses are consistent in some coal mines,but there are great differences in other coal mines because of different mining depths,geological structures,and lithological properties.Based on the field data,The relation between stresses and buried depth is obtained by regression method,the variations for the specific value of the horizontal principal stresses to the vertical stresses with buried depth are analyzed.The stress measurement results have been applied to roadway supporting design,which remarkably increased the rationality and reliability of the design and distinctly improved the roadway supporting state.