Abstract: Baolingshan tunnel is a key and difficult control engineering in the first section of a certain railway. The depth of survey Borehole DZ-06 is 2 118.00 m, which is the deepest survey borehole in this railway. Appropriate cores were selected at the depths of 2 072.53 m and 2 084.27 m, and in-situ stress test was carried out by anelastic strain recovery method（ASR）. The results show that in the depth range of 2 072.53-2 084.27 m, the average values of the maximum principal stress, intermediate principal stress and minimum principal stress obtained from the two measuring points of ASR method are 59.70, 54.03 and 30.74 MPa respectively. The maximum principal stress is nearly horizontal and the direction is close to SN direction, indicating that the area is dominated by horizontal tectonic stress. The average value of the maximum principal stress test result of ASR method is in good agreement with the regression value from the hydraulic fracturing method test, the consistency of the minimum principal stress test value and the regression value of the hydraulic fracturing method test result is in a reasonable range, and the horizontal principal stress direction test results from the two methods are basically consistent.

Key words: railway tunnel, survey boreholes, in situ stress, ASR method, hydraulic fracturing measurement