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| ANALYSIS FOR AXISYMMETRICAL TUNNEL IN THE HOEK-BROWN ROCK MASSES BASED ON PROGRESSIVELY-VARIABLE DISTURBANCE |
| WANG Guoyang，FU Wenxi，DENG Jianhui |
| (State Key Laboratory of Hydraulics and Mountain River Engineering，Sichuan University，Chengdu，Sichuan 610065，China) |
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Abstract The disturbance factor in the generalized Hoek-Brown(HB) criterion (2002 edition)，which is different from selection of a fixed value employed in the existing analysis for underground excavations in HB rock mass，is taken to be progressively decreased from the excavation surface to the elastic-plastic interface. By employing a non-linear non-associated flow rule，it can give a formulation of the critical internal pressure，the radius of plastic zone， stress and displacement，whose values can be determined by numerical integration techniques. The analysis model in this paper is the description of strain-softening in plastic zone for the progressive disturbance of the heavily jointed rock masses，which is triggered by blast damage and stress relaxation due to excavation. The calculation results of an example indicate that the present analysis model can also obtain analytical solutions of elastic-perfectly plastic and elastic-brittle-plastic models by means of different treatment for D，which provides a reference of theoretical solution for testing the degree of progressive disturbance near the excavation surface in practical project.
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2015, Vol. 34 
