Answer
Increases by a factor of $8$
Work Step by Step
Here, we have $P=\dfrac{WD^2}{L}$ ...(1)
When the width and depth are doubled.
$P'=\dfrac{(2 W) (2D)^2}{L}=\dfrac{1}{8}\dfrac{WD^2}{L}$ ...(2)
From the equations (1) and (2), we find that when the width and depth are doubled the load increases by a factor of $8$.
