How to meaningfully describe the practical effectiveness of one large bomb versus a series of many small bombs, all else constant? Background:
Given two sets of conventional bombs (constituted of fuel which explodes by way of chemical decomposition reaction) :
Set 1 - One shell of a given volume encasing a given amount of fuel. (1 30cm^3 shell w/ 3 kg TNT) 
Scenario 1: Set 1 is detonated at a location.
Set 2 - Many shells of equal volumes encasing equal amounts of fuel, both cumulatively equating to the respective quantities from Set 1. (3 10cm^3 shells, w/ 1 kg TNT each)
Scenario 2: Each member of Set 2 is detonated at identical locations, in between time intervals long enough so that no detonation interacts with another.
Begin with this naive assumption: Fuel/Volume in Set 1 = Fuel/Volume in Set 2; therefore, the practical effectiveness of detonating Set 1 = the practical effectiveness of detonating Set 2. Clearly this overlooks an important inequality between the two scenarios, namely the quantity of time in which the detonations occur.
This line of thought ultimately leads to an investigation towards a complete description of the relationship between scenario 1 and 2.
My description:
My general description will attempt to start from the term Practical effectiveness and move backwards until reaching the attributes of Set 1 and Set 2, with the hope to then be in a position to meaningfully compare Set 1 and Set 2.
Practical effectiveness : I insist on starting with this ambiguous term in order to authentically represent what I am in fact curious to understand.  I'll resolve the term like so: "the capacity to cause damage" -> "strength of and area covered by overpressure from the resultant blast wave" (note we're ignoring heat, in itself; shock waves; blast wind; fragmentation, etc.) -> "Explosive Power" - > This is where things get a bit dubious for me (and remember, we're holding constant other factors like constituent chemicals, shell wall strength, etc.) "Volume of gas and heat of explosion" -> "Amount of fuel per shell volume per detonation time lapse"
Question:
I'm fairly confident in my description up until "Explosive Power". 
Here are the factors that I believe are pertinent in accurately and meaningfully continuing the description after "Explosive Power" :
Chemical potential energy of bombs, power of explosions, amount of fuel per shell per detonation time lapse, volume of gas and heat produced in shell.
I'm having trouble connecting these factors, however.
I understand that power is work/time, so the same amount of work done in less time indicates greater power; however, I am having trouble intuitively moving from equal potential chemical energy in Set 1 and Set 2 (is this indeed the case?), to unequal overpressure (a force).  
Assuming my terms are adequate, please help to reorganize my description in a more meaningful, intuitively satisfying way, or simply critique my description.  I am not asking so much to fill a technical gap, but do some pedagogical enhancements to clear up a matter for which a small perspective shift might do wonders.
 A: I think your question is a bit too ambiguous to answer properly, but here is one way to consider the situation.
Suppose you've got a nail, and you know it takes 10 Newtons (a made-up value) to make it put a dent in a board.  If you hit the nail with a hammer, with an impulse force which peaks at 1 Newton,  hitting ten times in succession will do nothing.
The point is:  many MANY physical behaviors are strongly nonlinear, so one large impulse force can succeed where hundreds of small impulses will have no effect.
A: That's essentially what a Time On Target attack is all about. There are a couple of ways to use TOT:


*

*"George, you take out this target, John, you take out that target, you over there take out that third target..., and I'll take out this Nth target, with our bombs all within 3 seconds of one another."
The idea is to take out the officers, command post, comm equipment, barracks, and munitions, all at once. This can be extremely devastating to the enemy.

*"George, you aim at this target with time of arrival set to within 3 seconds of 0600; John, you do the same; you over, you do the same thing, too; ..., and I'll do the exactly the same thing as well."
This worked nicely during World War II, but that was because timing and accuracy weren't particularly high.


There's a basic problem with the second approach, which is what you are asking about. If everyone's bombs arrive within (for example) a few tens of feet of the target and a few thousands of a second apart, the first bomb to explode will take out part of the target -- and also all of the other incoming bombs.
If the bombs are spread more widely over space and time, the combined effects are less than additive. A single big bomb is beyond additive. A single 104 kiloton bomb will do a great deal more damage than 10,000 small bombs.
