Infiltration has indeed been made costly and difficult for the North Vietnamese.
From the time.com
The voids usually occur near cracks or joints due to surface water infiltration.
From the en.wikipedia.org
Spies may be given other roles that also require infiltration, such as sabotage.
From the en.wikipedia.org
And they use infiltration rings to measure how fast the ground can absorb water.
From the kentucky.com
The Chinese regime is using Confucius as a cover for infiltration and propaganda.
From the theepochtimes.com
It is also simply a rule of fortress life that infiltration is much to be feared.
From the theatlantic.com
Map of underground water infiltration probability around the Niamey area in 2007.
From the sciencedaily.com
Prognostic significance and mechanism of Treg infiltration in human brain tumors.
From the nature.com
The dissidents have struggled against infiltration on both sides of the border.
From the economist.com
More examples
A process in which individuals (or small groups) penetrate an area (especially the military penetration of enemy positions without detection)
Percolation: the slow passage of a liquid through a filtering medium; "the percolation of rainwater through the soil"; "the infiltration of seawater through the lava"
(infiltrate) cause (a liquid) to enter by penetrating the interstices
(infiltrate) enter a group or organization in order to spy on the members; "The student organization was infiltrated by a traitor"
(infiltrate) pass into or through by filtering or permeating; "the substance infiltrated the material"
(infiltrate) pass through an enemy line; in a military conflict
Infiltration is the unintentional or accidental introduction of outside air into a building, typically through cracks in the building envelope and through use of doors for passage . Infiltration is sometimes called air leakage. ...
Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour. ...
Infiltration is the diffusion or accumulation (in a tissue or cells) of substances not normal to it or in amounts in excess of the normal. The material collected in those tissues or cells is called infiltrate.