Dynamic Windowless Sampling is useful for undertaking both environmental and geotechnical site investigations. Our Windowless Sampler (Dando Terrier) can carry out disturbed and undisturbed soil sampling, in-situ SPT testing and dynamic probing. Normally the rig is able to drill to depths of 10 – 15 metres below ground level (mbgl) depending on the local geology encountered.  It is ideal for use in Clay geology.  However it may not be able to penetrate through  difficult geology such as dense sand and gravels or rock. This is known as a refusal.

In the event of a refusal (i.e. SPT N value of 50 or more), drilling can be supplemented with Dynamic Probing which involves the driving of a metal cone into the ground through a series of 1-metre length steel rods and recording the number of blows that is required to drive the cone down each 100mm increment. The data obtained can be used to estimate the depths of at the interface between hard and soft strata and to trace the outline of objects buried underground. A limitation with Dynamic Probing is that although it will supply information on ground strength, it is not possible to retrieve any soils samples, so the type of geology being drilled through has to be inferred.

The rig is relatively small and moves on tracks which means it is ideal for small sites where access is restricted. Click here to view the dimensions of the rig