Angled struts are used to create the roof of a dugout shelter dug into the Martian surface. Excavated regolith is piled on top of the struts which acts as a radiation shield for the inhabitants.
The design is customizable, which allows the width, angle, wall thickness, bin (the things that hold the regolith) thickness to be optimized by the martian crew based on geophysical properties of the local regolith.
*EDIT (2014JUN01) Added support for model making and sheet building. Because if I win, MakerBot will want to print one.
1) Dig out living space of dugout shelter, perform soil analysis ASAP.
2) Find out the percentage of dry and wet ice in regolith - confirm suitability of site.
3) Set angle to less than the angle of repose of the regolith.
4) Set thickness based upon the radiation mitigating properties of the local regolith and latitude of colony. Remember to account for high speed winds.
5) Set wall thickness based on structural properties of the extrusion material being careful to add extra tolerance for any chemicals that may react with extrusion material (e.g. perchlorates).
6) Set thickness and bin width to be large compared with the largest boulders excavated (so that regolith will pour).
7) Print struts and excavate simultaneously.
8) Optionally, allow ices to sublimate out of solution with regolith.
9) Secure struts to each other and to the ground.
10) Pour regolith over structure.
11) Install a door and stairs on one side of the roof.
12) Dump CO2 free regolith on the other side of the roof (preferably the regolith will have water ice in it to make it air-tight).
13) Coat the living space with spray-in foam insulation, which keeps from any dry ice in regolith from entering living space and suffocating colonists.
14) Coat the insulation with an CO2/O2/H2O impermiable membrane (paint?)
15) Move in.
Option - print structure without bottom() function, and fill with transparant water ice to create a dugout greenhouse.