As a fairly new geotech, I struggle with this as well.
I always look at the site grading, sometimes its obvious an area has been filled. If there isn't a topsoil layer under the fill, there is usually a colour change. The fill will be darker, and often the SPT counts will jump bit after the...
The water table is not an issue. The ground is being thawed by heating the rooms. When I go to check for frozen soil, I am required to dig down to prove that there is no frozen material in the soil. The top four inches usually thaw very quickly, but it takes longer for the soil 6 - 14 inches...
We have been checking a site daily to see if the soil is still frozen in the rooms they are heating. They want to pour the floor slabs as soon as possible, but can't if the floor is still frozen. The soil is 4 - 8 inches of granular A on top of granular B fill or native, fairly clean sand. They...
