Site Investigation

What does a site investigation and ground investigation entail?

Before building a structure, TAL Construction can conduct a site and ground investigation to:

  • Establish the depth of rock, by drilling with one of our many DTH drill rigs. We have done this successfully for County Councils in the past where they wanted to establish rock depths for future Drainage Projects.
  • Carry out Dynamic Probe Tests.
  • Hand-excavate Trial Holes in areas where access is restricted (typical depth up to 2M).
  • Procure undisturbed soil samples to a depth of 10M.
  • Obtain disturbed samples to greater depths.

Why site investigations and ground investigations are useful

Site Investigation and ground investigation techniques are quite useful when trying to ascertain ground conditions in an unknown area. In a short space of time when using the right equipment information can be obtained relating to:

  • depth of rock
  • soil density
  • soil type
  • depth of different soil strata

The dynamic probe test is a penetration test which provides information on the geo-technical properties of a soil. It is a simple and inexpensive test that yields necessary information before considering a construction project.

The test uses a series of 1 metre long rods, with an outside diameter of approx. 50 mm. These rods (manufactured from an alloy steel) have graduations marked every 100mm along their length. The rods are driven into the ground by blows from a slide hammer with a weight of 50 kg falling from a height of 500mm.

The rods are designed such that each rod ends butt-up fully against each other when driving, forming a continuous jointed series with a straight axis. The thread form is specifically designed for resistance to the driving force. Rods are furnished with spanner flats at both ends to facilitate connecting and disconnecting.

The blow count is recorded for every 100mm of driving (N100) and the results presented as a plot of blow count against depth. The blow count indicates the density of the ground testes, and provides the depth of rock in the area.

The complete machine weighs 140kg, stands 2.5m high and measures 750mm wide x 850mm deep when erected. For movement between positions the mast is lowered and the machine wheeled on an integral axle.

As part of the site and ground investigation process, Dynamic Probing provides an excellent method for locating boundaries between strata of differing density and driving resistance as well as comparative assessments of a single stratum across a site. Comparisons between Dynamic Probing results, SPT values and other soil parameters are given in DIN4094. Information on UK practice and correlation data in UK soils was published at the I.C.E. Conference on Penetration Testing in 1988.

 

Interesting Links in relation to site investigation and dynamic probing

Contact us about Site Investigation services

If you are considering working with us in relation to site investigation, or any of our ancillary services, contact us in our Dublin office on 01 6310300 or in our Cork office on 021 4345999.