A method, system and apparatus for plasma blasting comprises a borehole in soil, a blast probe comprising a high voltage electrode and a ground electrode separated by a dielectric separator, wherein the high voltage electrode and the dielectric separator constitute an adjustable probe tip, and an adjustment unit coupled to the adjustable probe tip, wherein the adjustment unit is configured to selectively extend or retract the adjustable probe tip relative to the ground electrode and a blasting media, wherein at least a portion of the high voltage electrode and the ground electrode are submerged in the blast media. The blasting media comprises wet concrete. The adjustable tip permits fine-tuning of the blast. The blast is used to force the wet concrete into a customized shape within the borehole.