What geophysical knowledge have we learned by the construction of IceCube?
IceCube was initiated as the Antarctic Muon And Neutrino Detector Array (AMANDA) project. Since the sensor array involved drilling deep holes vertically into the Antarctic ice sheet by melting ice, no ice cores were retrieved. The bore holes have, however, been used to construct temperature profiles through the Antarctic ice sheet published in a paper in PNAS. Gathering information of internal temperature is important to understand, for example, basal geothermal heat fluxes and estimating whether or not the ice sheet base is at the melting point and can support liquid water. 

In the glaciological literature, very little has been published but then the projects AMANDA and IceCube have never focussed on such questions.

Price et al. (2002) Temperature profile for glacial ice at the South Pole: Implications for life in a nearby subglacial lake. PNAS, 99, (12), 7844-7847. https://doi.org/10.1073/pnas.082238999