Futuristic trenches

[YPU]

I have been planning on using Fast and Dirty for my 15mm sci-fi games. Parts of the rules allow players to deploy defensive structures such as barbed wire, baricades bunkers and trenches.
Most of those I have covered but trenches I don't have yet so I've stated experimenting with them. First of these will be your less realistic fully above ground trenches. I actually have board that could support dug in trenches but the game allows placement of trenches far past table set-up and with a variety of lengths and positions.
While building I placed some squire blocks of foam on the sides of the trench to check their fitting before I shaved them down to a sloped hill. Thing is they will be pretty high for their with giving a somewhat unrealistic slope. This got me thinking, what if I make them much more uniform ans straight and paint them like concrete? The inside would still have reinforcements.

I made a quick sketch bellow. Note my trenches are relatively wide as I want to be able to put my washed based gun teams in them.

[Inso]

The trenches should be deep enough that the head does not protrude at all. There will need to be a firestep to step on to fire over the edge of the trench. Apart from that, solid walls will word fine.

[YPU]

Checking my actual tests they do that. I guess I made the guys in the sketch a bit large. A good 2-3 mm above helmet level of based 15mm models. I'm still trying to source a quick and easy material for the firestep. Might just end up using some foamcore.

Still, how do you view the concrete idea? I get that above ground trenches make no sense anyway. Easy target for a slow firing heavy weapon or tank which makes them kind of pointless. But since I am going with above ground anyway would some sort of prefab concrete blocks make at least as much sense as piled up dirt?

[Dr.Falkenhayn]

maybe something like these 

[Inso]

It could be 'sci-fi' concrete... like normal concrete but better

Maybe some sort of Kevlar based concrete with interlinked fibres that make the walls extra tough and resistant to impacts.

Above ground trenches/barriers make perfect sense. In Iraq/Afghanistan, they put hesco everywhere and all your trench is, is a path with a hesco either side... so there is perfect justification for your walls.

Also, what about them being flatpacked and hollow for easy transportation? They get dropped by grav-transport, folded open and filled with water/sand/'sci-fi bullet proof foam' for instant fortifications.

It is sci-fi so there are lots of opportunities to try .

[YPU]

All good tips Inso. I'm thinking the inside components are flatpacked like you say. The outside would be some two component ballistic material with local dirt mixed in as filler. They would be cast in cheap plastic "balloons" on the spot, producing a not entirely uniform but good enough result. Not strong enough to stop all shots by itself but the inside armor plate has it easy after this stuff.

And you make a very good point on the Hesco walls! I'm still not sure if its a good idea if the enemy has access to tanks and the like but then again I don't think modern military has been digging many trenches of late either.

I'm trying to keep the looks simple as many of the sci-fi trenches available look over engineered to me. I'll post a picture of my test piece once its finished.