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Table 8 Equations of the SF curves for each parameter \(\hbox{m}_i\) and shape factor sub-category

From: Assessing the stability of underground caves through iSUMM (innovative, straightforward, user-friendly, mechanically-based method)

 

\(\hbox{L}/\hbox{h} \le 1\)

\(1 <\hbox{L}/\hbox{h}\le 2\)

\(2<\hbox{L}/\hbox{h} \le 3\)

\(\hbox{L}/\hbox{h} >3\)

\(m_i = 3\)

\(\text{SF} = 1\)

\(0.018\hbox{x}^3+0.0065\hbox{x}^2+1.42\hbox{x}+0.51\)

\(0.026\hbox{x}^3-0.068\hbox{x}^2+1.74\hbox{x}-0.2\)

\(0.015\hbox{x}^3+0.033\hbox{x}^2+1.63\hbox{x}-0.26\)

\(0.031\hbox{x}^3-0.11\hbox{x}^2+2.018\hbox{x}-0.44\)

\(\text{SF} = 2\)

\(0.04\hbox{x}^3+0.18\hbox{x}^2+2.2\hbox{x}+0.84\)

\(0.061\hbox{x}^3-0.056\hbox{x}^2+2.95\hbox{x}+0.18\)

\(0.06\hbox{x}^3-0.033\hbox{x}^2+2.92\hbox{x}+0.13\)

\(0.064\hbox{x}^3-0.077\hbox{x}^2+3.06\hbox{x}+0.027\)

\(\text{SF} = 3\)

\(0.064\hbox{x}^3+0.36\hbox{x}^2+3\hbox{x}+1.75\)

\(0.084\hbox{x}^3+0.13\hbox{x}^2+3.82\hbox{x}+0.8\)

\(0.083\hbox{x}^3+0.14\hbox{x}^2+3.85\hbox{x}+0.65\)

\(0.088\hbox{x}^3+0.085\hbox{x}^2+4.036\hbox{x}+0.48\)

\(\text{SF} = 4\)

\(0.085\hbox{x}^3+0.6\hbox{x}^2+3.7\hbox{x}+2.81\)

\(0.1\hbox{x}^3+0.4\hbox{x}^2+4.51\hbox{x}+1.55\)

\(0.11\hbox{x}^3+0.28\hbox{x}^2+4.93\hbox{x}+1.11\)

\(0.11\hbox{x}^3+0.23\hbox{x}^2+5.12\hbox{x}+0.9\)

\(\text{SF} = 5\)

\(0.11\hbox{x}^3+0.81\hbox{x}^2+4.44\hbox{x}+3.88\)

\(0.13\hbox{x}^3+0.57\hbox{x}^2+5.47\hbox{x}+2.2\)

\(0.13\hbox{x}^3+0.47\hbox{x}^2+5.92\hbox{x}+1.64\)

\(0.15\hbox{x}^3+0.29\hbox{x}^2+6.47\hbox{x}+1.21\)

\(m_i = 8\)

\(\text{SF} = 1\)

\(-0.019\hbox{x}^3+0.49\hbox{x}^2+0.66\hbox{x}+1.13\)

\(-0.013\hbox{x}^3+0.4\hbox{x}^2+1.25\hbox{x}+0.336\)

\(-0.03\hbox{x}^3+0.534\hbox{x}^2+1.17\hbox{x}+0.29\)

\(-0.0007\hbox{x}^3+0.222\hbox{x}^2+2.12\hbox{x}-0.416\)

\(\text{SF} = 2\)

\(0.065\hbox{x}^3+0.09\hbox{x}^2+3.66\hbox{x}+0.31\)

\(0.064\hbox{x}^3+0.082\hbox{x}^2+3.82\hbox{x}-0.072\)

\(0.062\hbox{x}^3+0.082\hbox{x}^2+3.9\hbox{x}-0.17\)

\(0.071\hbox{x}^3-0.0084\hbox{x}^2+4.116\hbox{x}-0.3\)

\(\text{SF} = 3\)

\(0.11\hbox{x}^3+0.36\hbox{x}^2+4.73\hbox{x}+1.5\)

\(0.11\hbox{x}^3+0.3\hbox{x}^2+5.24\hbox{x}+0.66\)

\(0.11\hbox{x}^3+0.25\hbox{x}^2+5.43\hbox{x}+0.44\)

\(0.12\hbox{x}^3+0.18\hbox{x}^2+5.63\hbox{x}+0.27\)

\(\text{SF} = 4\)

\(0.14\hbox{x}^3+0.81\hbox{x}^2+5.57\hbox{x}+2.9\)

\(0.14\hbox{x}^3+0.74\hbox{x}^2+6.32\hbox{x}+1.57\)

\(0.14\hbox{x}^3+0.73\hbox{x}^2+6.56\hbox{x}+1.14\)

\(0.14\hbox{x}^3+0.68\hbox{x}^2+6.81\hbox{x}+0.84\)

\(\text{SF} = 5\)

\(0.17\hbox{x}^3+1.25\hbox{x}^2+6.54\hbox{x}+4.42\)

\(0.17\hbox{x}^3+1.17\hbox{x}^2+7.435\hbox{x}+2.55\)

\(0.18\hbox{x}^3+1.09\hbox{x}^2+7.9\hbox{x}+1.92\)

\(0.18\hbox{x}^3+1.04\hbox{x}^2+8.18\hbox{x}+1.54\)

\(m_i = 16\)

\(\text{SF} = 1\)

\(0.03\hbox{x}^3+0.063\hbox{x}^2+2.31\hbox{x}+0.82\)

\(-0.055\hbox{x}^3+0.96\hbox{x}^2+0.41\hbox{x}+0.81\)

\(-0.066\hbox{x}^3+\hbox{x}^2+0.76\hbox{x}+0.37\)

\(-0.0009\hbox{x}^3+0.3\hbox{x}^2+2.78\hbox{x}-0.74\)

\(\text{SF} = 2\)

\(0.072\hbox{x}^3+0.16\hbox{x}^2+4.61\hbox{x}-0.26\)

\(0.067\hbox{x}^3+0.24\hbox{x}^2+4.46\hbox{x}-0.52\)

\(0.028\hbox{x}^3+0.58\hbox{x}^2+3.7\hbox{x}-0.12\)

\(0.077\hbox{x}^3+0.105\hbox{x}^2+4.9\hbox{x}-0.75\)

\(\text{SF} = 3\)

\(0.1\hbox{x}^3+0.74\hbox{x}^2+5.78\hbox{x}+1.32\)

\(0.11\hbox{x}^3+0.65\hbox{x}^2+6.33\hbox{x}+0.3\)

\(0.1\hbox{x}^3+0.68\hbox{x}^2+6.4\hbox{x}+0.15\)

\(0.11\hbox{x}^3+0.53\hbox{x}^2+6.86\hbox{x}-0.18\)

\(\text{SF} = 4\)

\(0.16\hbox{x}^3+1.15\hbox{x}^2+7.58\hbox{x}+2.7\)

\(0.18\hbox{x}^3+0.87\hbox{x}^2+8.86\hbox{x}+0.9\)

\(0.18\hbox{x}^3+0.84\hbox{x}^2+9.17\hbox{x}+0.44\)

\(0.19\hbox{x}^3+0.76\hbox{x}^2+9.46\hbox{x}+0.15\)

\(\text{SF} = 5\)

\(0.22\hbox{x}^3+1.67\hbox{x}^2+9.16\hbox{x}+4.36\)

\(0.24\hbox{x}^3+1.36\hbox{x}^2+10.74\hbox{x}+1.92\)

\(0.24\hbox{x}^3+1.25\hbox{x}^2+11.37\hbox{x}+1.15\)

\(0.25\hbox{x}^3+1.14\hbox{x}^2+11.73\hbox{x}+0.74\)