Study on the influence of long-term creep deformation of Xiaojiang active fault on regional geo-stress field
Xiaojiang fault is an important geological boundary in southwest China,which exerts certain influence on the long-term stability of Baihetan hydropower reservoir.It is necessary to study the influ-ence characteristics of the creep deformation of the active fault.Based on the geodetic monitoring results of Xiaojiang active fault and its adjacent areas,considering the strike-slip and thrust characteristics of the fault,a three-dimensional numerical generalized model is established to simulate and analyze the temporal and spatial evolution characteristics of the stress field around the fault zone under the long-term creep movement of 10 mm/a.The calculation shows that with the long-term creep of Xiaojiang fault,the surrounding geostress field presents an approximate linear and gentle increasing trend.The maximum principal stress increment of the rock mass near the fault zone in 200 years is about 0.35～0.55 MPa,and the stress increment in 1 000 years is about 1.1～3.3 MPa.After the reservoir impound-ment,the influence area of reservoir water is limited to the periphery of the valley,and the direct influ-ence on the geostress field in large area is not obvious.The relevant research results can provide certain reference for the long-term stability evaluation of the project.
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