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摘要
Evaluation of stress states in backfilled mine stopes (or similar openings), using arching theory, can be largely impacted by the value selected for the earth pressure coefficient, K = sigma'(h)/sigma'(v). Recently, the current study's authors addressed the debate about the value of K near the opening center, based on Rankine's active coefficient (K-a) and at- rest coefficient (K-0). Here, stress ratios in vertical backfilled stopes are numerically assessed (in two dimension, 2D), considering both the independent and related backfill internal friction angle (phi') and Poisson's ratio (nu). Emphasis is placed on the backfill state near stope walls, where local rotation of stresses occurs, so the coefficient (K) and principal stress ratio, K-ps (= sigma'(3)/sigma'(1)), should be distinguished. Parametric analyses indicate that values of K and K-ps depend on the position and the relationship between phi' and nu. Near the opening center, K (= K-ps) is close to K-a when nu or phi' is below a critical value; otherwise the value approaches K-0, defined from nu. Near both walls, K-ps is always close to K-a, while K is near K-0 for related nu - phi' cases and depends on their respective values for independent nu and phi'. Additional simulations conducted with interface elements indicate that the stress ratios near the opening center line are insensitive to interface roughness and are almost identical to values obtained without interfaces, but the stress ratios near walls may change for less rough or smooth interfaces.
- 出版日期2017-10
- 单位西安科技大学
