Dynamic (Window) sampling is one of the most common methods of shallow sampling in both small-scale and large-scale ground investigations. It utilises a Competitor or Terrier type rig to form the sampling holes, the rigs also come with heavy and super heavy dynamic probes. The purpose of the Dynamic Sampling rig is to collect disturbed samples obtained in the form of 1m cores, as well as carrying out Standard Penetration Tests (SPT) and dynamic probing in-situ testing every metre.

As you can see from the photos below, Dynamic Sampling is the ideal method of drilling when conducting site investigations inside structures or sites with restricted access, places where collecting samples would be impossible with other conventional methods of drilling. Dynamic sampling can be utilised to prove the depth of the natural superficial deposits, with Cable Percussion and Rotary drilling suitable for drilling to further depths into the bedrock lithology.


Sampling is often carried out by a one or two-man crew. The metre long cores are recovered in plastic liners which are split and then logged on site by the DCE lead engineer, samples of the cores being selected. The dynamic continuous sampling tube is connected to rods of 1m length and drive into the ground using a hydraulic hammer power by a diesel or petrol driven power pack. The rigs are also able to core through Tarmac and Concrete.

The dynamic probe test involves driving a solid 90-degree cone into the ground as defined by BS1377. This test is particularly useful when used in conjunction with window sampling. Heavy dynamic (DPH) probing involves the driving of a 43.7 mm diameter cone with 50kg hammer dropping 500mm. Super heavy dynamic probing (DPSH) involves the driving of a 50.5mm diameter cone with 63.5kg hammer dropping 760mm.

Standard Penetration Tests (SPTs) are also conducted every metre and at the base of the hole, the number of blows being recorded per 100mm. These tests form a ground strength profile for the borehole, the number of blows being categorised into degrees of strength whether it be a cohesive or granular material.