PIACENZA ZONE (FEBRUARY-MARCH 2001)

The system has been used for the execution of two deep tests, carried out using a rig on a small jack-up barge, in order to investigate mainly sandy soils with gravel inter-layers. The drillings have been located on the two projected supports of a new tall bridge on the river Po.

Different from the work previously described, more advantage has been taken of the potentials offered by the wire-line recovery system.

In these soils, the CPTWD method has not been used continuously, but instead intermittent with continuous core. drilling, non coring drilling with MWD and the withdrawal of undisturbed samples, always using the same basic system and without changing the casing.

The withdrawal of the samples and the laboratory tests (along with the data coming from the other drillings made for the same project) allowed to assess the reliability of the CPTWD data, both in term of stratigraphy and in term of detecting the geotechnical properties (i.e. Ø in sandy soils).

Following picture is an example of a penetrometric graphic (Qc, Fs, U, Fr) from 60 to 120 m and one of the c.c. drilling operations in the same hole.