The Result of Current Stress Measurement and Stress State Analysis in the Region of Yangbajain-Kangmar in Tibet

This paper provides the magnitudes and directions of current stress measured at different sites in the Yangbajain‐Kangmar region in Tibet. In order to learn the current state of stress in Qinghai‐Tibet plateau and to meet the demands of Qinghai‐Tibet railway construction, we carried out in‐situ stress measurements in the region of Yangbajain‐Kangmar. The measurement sites were located at different tectonic positions, Yangbajain, Lhasa, Quxu and Kangmar, the test depth was between 11 m and 18 m, and piezomagnetic stress gauges were used. The results of stress measurement indicate that the direction of maximum principal stress is mainly NW‐NNW and the values of maximum principal stress is between 3.3 and 10.4 MPa, which are high or middle as compared with the values obtained elsewhere in China. But at Quxu site in the plate suture zone, the value of maximum principal stress is 2.3 MPa, which may indicate that the stress is partially released and the stress state is very complex in the plate suture zone.