Figure 1. Influence of w/h ratio on the post-failure stress-strain behavior of coal (Das, 1986)

From

A Comparative Study of Various Empirical Methods to Estimate the Factor of Safety of Coal Pillars

A. K. Verma

American Journal of Mining and Metallurgy. 2014, 2(1), 17-22 doi:10.12691/ajmm-2-1-3