# Distance c of multi-layer backfill

Distance c to calculate the resistance of multi-layer backfill.

Symbol
$d_{b3}$
Unit
m
Formulae
$\sqrt{{s_{b3}}^2+{w_{b4}}^2}$
Related
$s_{b3}$
$w_{b4}$
Used in
$R_{q11}$
$R_{q21}$