Abstract To seek a simple and effective method for the calculation of the stress release ratio in tunnel excavation,a revised method was proposed via the volume loss ratio based on the principle that the stress release ratio was approximately equivalent to the release ratio of displacement. The calculation of the stress release ratios for tunnel in soft rock under different construction schemes was performed in detail and thus the variations of stress release ratios under different construction schemes were analyzed. The calculated results indicated that the stress release ratios were different for various excavation parts of different schemes. In general,the stress release ratio of latter excavated was larger than that of the part excavated earlier due to the disturbance effect of excavation. The average stress release ratio decreased gradually with the improvement of the schemes except for the CD excavation method.
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