Abstract: With the Core disking phenomenon in geological exploration drilling in Sanshandao gold mine as background，the characteristics of the core disking is described in detail.Combined with the theoretical calculation formulas of various in-situ stresses at home and abroad，great numbers of contrasts with the in-situ thickness of core disking are made.Based on the stress measurements and rock test results in mining area，the optimal formulas of calculating the ground stress for thin core disking and thick disking are obtained.The drilling process and the stress distribution of core rock piles are simulated by 3DEC numerical simulation software combined with in-situ stress measurement results at early stage.According to the stress zoning and the optimal formula，the core disking thickness in different stress zoning of rock core piles is deduced.For zone Ⅰ，the maximum principal stress varies from 82 MPa to 83.6 MPa，and the disking thickness is from 7.7 mm to 7.9 mm.For zone Ⅱ，the maximum principal stress varies from 80 MPa to 82 MPa and the disking thickness is from 7.9 mm to 8.36 mm.For zone Ⅲ，the maximum principal stress varies from 76 MPa to 78 MPa，and the disking thickness is from 8.79 mm to 9.31 mm.The tolerance of core disking thickness based on the numerical simulation and theoretical calculation is within 2 mm comparing with field measurement，which provides a useful idea for investigating core disking.

Key words: Core disking, In-situ stress measurement, Theoretical calculation, Numerical simulation, Disking thickness