Research on ground stress test and distribution characteristics in Shuangyashan mining area
Ground stress testing on 30 sets of measuring points at different levels and mining areas in seven mines of Shuangyashan min-ing area by small aperture hydraulic fracturing method was conducted.It was found that the overall Shuangyashan mining area belongs to a high ground stress field,and some areas belong to a super high ground stress field.The maximum horizontal principal stress reached 36.35 MPa,and the stress field type is maily σH＞σv＞σh type.The maximum horizontal principal stress vector map was drawn,indica-ting that the direction of the maximum horizontal principal stress gradually shifted from N86.3°E to N31.3°W from north to south in the mining area,and the type of ground stress field also changed from σH＞σv＞σh gradually turns into σH＞σh＞σv direction.At the same time,using the least squares method for linear regression analysis,the relationship equation between the maximum horizontal principal stress and burial depth in the Shuangyashan mining area is obtained as follows:σH=0.033H+4.675.The relationship equation be-tween the minimum horizontal principal stress and burial depth is as follows:σh=0.017 H+3.465.The relationship between the lateral pressure ratio,horizontal principal stress difference and difference ratio,and the ratio of average horizontal principal stress to vertical principal stress with depth in the Shuangyashan mining area was analyzed.It was found that as the burial depth increases,the lateral stress ratio decreases overall,the principal stress difference increases overall,and the relationship between the ratio of average horizontal principal stress and vertical principal stress and depth is k=195.59/H+0.926 1.It is predicted that after entering the deep mining area of Shuangyashan mining area,the geological structure will be more developed,the trend of rock mass damage will increase,and the diffi-culty of roadway maintenance will increase.Research results has important reference value for the design of Shuangyashan mining area's roadway engineering.
hydraulic fracturingground stresstype of stress fieldlateral pressure ratioprincipal stress difference
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