Abstract: Through collecting 76 groups of the in-situ stress data in underground water-sealed storage cavern in Chinese mainland, including Zhanjiang, Huangdao, Yantai, Huizhou, Jinzhou, Dalian, the distribution of the vertical stress，the largest horizontal principal stress( ), the minimum horizontal principal stress( ) and the lateral pressure coefficient(k) varying with depth in Chinese mainland are established. Then the features of the in-situ stress are corresponding regression analysed refer to the analysis method of Hoek and Brown. The results indicate that: (1) The shallow in-situ stress in underground water-sealed storage cavern in Chinese mainland show increasing trend with the increase of depth, showed a good linear relationship with depth, and the stress gradient is a little less than 0.027, in Hoek-Brown relation. (2) and are increased with depth, scattered points are mainly distributed in an inclined parallel belt. (3) Lateral pressure ratio k is dispersed when depth is less than 200 m, and centralized when depth is more than 200 m, and the envelope curve of lateral pressure ratio is distributed between the maximum and minimum envelopes of Hoek-Brown curve; it is approach the global distribution law. Through above research, the distribution law of in-situ stress field in underground water-sealed storage cavern in Chinese mainland is analyzed and summarized; it can provide references to the planning, constructing and developing of petroleum (gas) strategic reserve in Chinese mainland.

Key words: underground water-sealed storage cavern, in-situ stress, distribution rule, regression analysis, lateral pressure ratio