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Abstract It presents the in-situ test on excavation damaged zone(EDZ) evolution of TBM tunnel No.3 in Jinping II hydropower station using digital panoramic borehole camera. Firstly，through the pre-excavated diversion tunnel No.2–1，several boreholes vertical to sidewall of TBM tunnel No.3 are drilled for digital camera，and a series of digital images of borehole wall are obtained during the whole TBM driven time. Afterwards，the images will be digitally processed；geological structural surface and fractures of surrounding rock mass are also analyzed，which makes it possible for the whole procedure of cracks formation，development and close to be obtained. Finally，the depth of damage zone is recognized；the relationship between fractures evolution and TBM construction progress is given；and the mechanism of EDZ evolution is discussed as well. It will not only provide the direct data for geological exploration but also contribute greatly to support design and analysis of deformation behaviors of deep-buried tunnels.
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Received: 11 February 2010
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