Modification method of borehole shear mechanical parameter characterization and its experimental study

The borehole shear test is an important method to quickly measure the shear strength of rock in the field, but its application is limited due to its large measurement error. By analyzing the principle of borehole shear and the research results, it is found that incomplete shear is the reason for the large error of rock borehole shear test, and a correction method of borehole shear method based on the unequal area of pressure and shear was proposed. Experimental equipment was designed to carry out the simulated borehole shear test, and the characterization rules of sandstone shear mechanical parameters under different shear plate parameters were studied, which proved the effectiveness and correction effect of the proposed method. Finally, the applicability of the method was verified by literature data. Specific results are as follows: ① The root cause of large error in rock borehore shear test is that the selection of compression area and shear area is distorted and unequal, the actual shear failure area is le