Here at Substruck, we love ground investigation. At this property in Cork City, we were asked to complete six number dynamic probes and one number dynamic windowless sample as part of a subsidence investigation in a residential property. Dynamic probing is a first cousin of the Standard Penetration Test (SPT). Most international research in dynamic testing has been completed in relation to the SPT.
Interpretation of any blow count record or field test requires care and experience and it is in the grey areas where the fun starts. However, at this property, when the hammer is moving self-weight or ‘penetration without blows’ according to ISO 22476-2:2005 along the area of distress, you can be certain you have the culprit.
A soil sample was also taken to aid in the determination of soil resistance and made ground was found to a depth of three metres. In some instances, it may be difficult to categorically state that underlying soils are in fact ‘made’ without anthropogenic evidence but when pieces of glass and steel are found, proper interpretation is much easier. This soil type or ‘non-engineered fill’ is described by BS8004:2015 as artificially deposited material with little or no controls in place during the process.