A properly dug foxhole (a dug in fighting position for a single soldier) will resist machine gun fire, but not direct hits from explosive shells, although it will provide protection against near misses. A foxhole was ideally dug deep enough you could stand in it without your head showing over the lip, with a fire step on the front so you could fight when needed. Here's an image. http://m.c.lnkd.licdn.com/mpr/mpr/p/5/005/0af/101/12cd520.png An infantry platoon might have 30-40 men, each with their own foxhole, which is almost certainly more rounds of HE than a tank would usually carry, and foxholes are very small targets to direct fire.

However the scenario you describe is NOT how tanks attacked infantry in the Second World War. Tanks suppressed infantry with machine gun and cannon fire, meaning they forced the infantrymen to stay low in the hole and not stand up to shoot or fight. Supporting infantry would then attack the enemy positions without being mowed down by hostile fire. Sometimes the prospect of being overrun by tanks was intimidating enough that the enemy retreated or surrendered before this was needed. This type of tactical relationship is called "combined arms" and it's at the heart of how tanks usually fought in the second world war.

To contest this, defenders almost always used concealment as well as cover. Great pains were taken with defensive systems to make sure foxholes were not obvious to hostile eyes. Once discovered, a position is much more vulnerable both to suppression and outright destruction. A World War Two defensive scheme usually relies much more on being well hidden than it does on being physically impregnable to shelling, with the exception of things like beach defenses. For these kinds of fixed defenses, concrete was used instead of just earthworks. A world war two attacking force must first find each enemy position, and it's the defender's job to make each such discovery expensive.