frostline

n.

冰冻线，冻深线；

Installation for measuring and displaying fluid volume and corresponding use for maintaining below frostline and accessible valving ...
The Effect of Frostline Height Changes on Blown Film Using Metallocene Catalysed Polyethylene
Calculation of frostline penetration in high-voltage cable trench Mt. Elbert Pumped-Storage Powerplant
Frostline (Ben Abbott Novels (Paperback))
Frostline® Frozen Treats
Making Smoothies Is Simple with Frostline®
396 below frostline [loc]
Frost Line
Pore Pressures at a Penetrating Frost line and their prediction
Digging below the ice: Overwintering burying beetles (Coleoptera: Silphidae) survive when they are beneath the frost line