关键词: 钻孔偏心　, 空心包体应力解除法　, 地应力修正　, 双极坐标　, 围压率定

Abstract: Based on the principle of the hollow inclusion stress relief method and the confining pressure calibration test, the error caused by borehole eccentricity was analyzed.The eccentric core in the confining pressure test is regarded as an ec centric circular ring compression model on a plane.The bipolar coordinate method is used to derive the stress distribution cal culation formula for this model,and the distribution laws and characteristics of the tangential stress on the inner wall of the small hole under different confining pressures and eccentricities are analyzed through examples.On this basis,combined with the layout angle of the strain rosette in the hollow inclusion and the confining pressure calibration formula,a correction method for the measured rock elastic modulus under eccentricity is proposed.Using the field measured in-situ stress data,the rock elas tic modulus,k coefficient,ground stress components,and principal stresses at each measuring point before and after considering eccentricity are obtained.The results show that:① With increasing eccentricity,the error in the rock elastic modulus deter mined by subsequent confining pressure gradually increases,reaching a maximum of 13.41%;② The influence of eccentricity on the k coefficient,principal stress direction,and inclination angle at each measuring point is very small and can be neglected. ③ Borehole eccentricity has a significant influence on the magnitudes of ground stress components and principal stresses;the errors of the average maximum,intermediate,and minimum principal stresses at the three measuring points are 4.23%,4.19% and 4.24%,respectively,which should not be ignored in practical in-situ stress measurement work.