Continuous static and dynamicpenetrometric tests
Penetrometric tests are carried out to obtain a continuous resistance profile of terrain and the consequent geotechnic characterisation of various units identified.
With CPT static testing (Cone Penetration Test), a conical point with a 60° opening is advanced at a constant speed through the ground: the column of shafts that enables the tip to move forwards is protected by a covering tubing with the same diameter as the tip. The tip, the pipe and both together are penetrated in alternation along 10 cm tracts, respectively measuring tip resistance (Rp), lateral resistance (RI) and total resistance (Rt). Said resistance values are correlated with the mechanical characteristics of penetrated ground.
Moreover, CPTU also enables the measurement of neutral pressures present in terrains under investigation, with the use of a special electric tip fitted with a type of sensor (Piezocone).
This investigation method is especially suitable for fine grain material (cohesive and fine sand).
SCPT (Standard Cone Penetration Test) is used to measure a tip’s resistance to penetration (with 60° or 90° opening) using a striker, to reconstruct a resistance profile expressed in the number of strikes per unit of advancement. Known correlations are used to establish a connection between the number of strikes and relative density (RD), and then to obtain other geotechnical parameters, the main one being the angle of friction. This type of testing is particularly suitable for incoherent terrains.
Direct push investigations(environmental sampling)
Environmental sampling takes place by drawing a sample of undisturbed land, using a thick-walled sampler with a piston that is driven into the ground.
The sampler is fitted with an internal transparent PVC core sampler and sample holder.
The drawing of undisturbed samples(Shelby sampler)
The Shelby sampler consists of a galvanised steel core sampler; it is installed in and used to draw samples from undisturbed land. After drawing the sample at a desired depth, the core sample holder is sealed tightly.
