Geomechanics and Ground Control · Geomechanics · 2 marks · Numerical answer
Subsidence is $s=(S_{max}/2)[1.002-\tanh(4.8x/H)]$. Here x is measured from the inflection point,negative toward panel centre. Find critical panel-width/depth ratio to two decimals.
At the centre of a critical-width panel,s=Smax. Hence tanh(4.8x/H)=−0.998 and |x|/H=atanh(0.998)/4.8≈0.71945. The full critical width spans twice the centre-to-inflection distance,so W/H≈1.4389,or1.44. The sign locates the centre side but the width is positive.
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