Thickness of the backfill area around the cables, lower part (used for multi-layer backfill).

Symbol
$s_{\mathrm{4}}$
Unit
Formulae
$H_{\mathrm{T}} - H_{\mathrm{c}}$
Related
$H_{\mathrm{c}}$
$H_{\mathrm{T}}$
Used in
$R_{\mathrm{q21}}$
$R_{\mathrm{q22}}$
$R_{\mathrm{q31}}$