Ground Test Results

I promised to post details of the Ground Test Results a couple of weeks ago, but only now have I got around to it. I must buck my ideas up and get this blog back on track. I am post dating this entry, which is strictly cheating, but it helps me to keep track of the dates and times when things happen(ed). Anyway, I have done it before and had no complaints....... :>)

A typical test bore report from one of the drillings is shown below :

The major gradations down the left hand side are at 1 metre intervals, with 10 minor gradations in each. These are the 100 cm intervals that I mentioned in my posting on 29th September. The length of the bar against each of the 100cm gradations represents the number of hits of the test probe required to shift it the 100cm. In this example you can see that a "false bottom" was briefy seen at just over 3m, with the "proper" bottom (i.e. bedrock reached) shown by the rapid increase in resistance at 5.6m

Most of the test bores looked like this one, which is good as it shows consistency across the site. However, as I reported in my previous post, the incidences of "false bottoms" has led the piling company to opt for a drilled rather than driven pile solution. There is a big difference between driving an inch diameter test probe and an 8 inch pile casing. The former is easily able to drive through a large bolder obstruction, but the latter will not. As you might expect, this will prove to be more expensive.