Celebrim
Legend
In 3e, a 10 foot unworked stone wall can be tunneled through by four Strength 20 fighters wielding greataxes in about 10 minutes...
Cheers!
The problem here isn't so much the basic idea that everything has a hardness and a toughness. The problem is instead:
1) Assuming a weapon designed to cleave flesh does equal damage to all non-flesh targets.
2) Not having rules for damaging/dulling your weapon when striking a hard surface.
3) Not understanding that an inanimate objects 'hardness' depends in part on its thickness - especially for brittle substances like glass, stone, ice, etc. One-hundred and twenty one inch thick stone plates are not equal to a 10' block of stone.
4) Assuming that a person can keep up the same intensity of labor that they do in a brutal melee to the death for the span of 10 minutes or an hour or the like. This is like suggesting your rate of overland travel should be based on your run speed.
Some suggestions:
1) If the weapon isn't designed to function as a tool for damaging that particular surface, it does only half damage (at best). So, pick axes are fine for busting down the wall. Battle axes on the other hand do half damage and weapons like longswords and arrows do but 1/4. Axes on the other hand would do full damage to wooden doors.
2) If the damage you do to an inanimate object with a blow exceeds the hardness of the weapon you are wielding, the weapon takes damage as well. This also nicely resolves the problem that a high strength individual can also tunnel through a wall without tools under RAW.
3) Scale both the hardness and the hit point of materials by their thickness (up to some reasonable maximum). Even glass actually acquires a fairly reasonable hardness (resistance to damage) after a certain thickness because it stop yielding (and hense shattering). Really hard objects are generally nearly impervious to brute force. Instead, you have to wear them down slowly using very specialized tools.
4) Assume that over a span longer than a minute or two, a character will keep up at most half as many strong attacks as they would in melee. Force endurance checks if the player wants to hustle.
Returning to your legitimate gripe, if 4 strength 20 characters started attacking a solid stone wall with axes made for battle rather than chopping something, I'd apply a hardness about 17 to the wall and cause the axes to do half damage. Without power attack or similar feats, they just aren't going to do credible damage that way, and their axes are going to quickly break if they start forcing them to do work they aren't designed to do. Moreover, even if they get pick axes or other legitimate tools (bag of holding, right?), the work would go slowly. Probably faster than it would in real life, but these are str 20 superheroes after all.