The Marchetti flat seismic dilatometer is a reliable and effective technique of measuring the speed of propagation of seismic waves through the ground. The equipment consists of a module of accelerometers combined with an SDMT which allows the measurement of the speed of the shear waves Vs and the compression waves Vp related to the shear modulus G0 and to the confined modulus M0and its density.

Various studies have demonstrated that the Vs values determined from the SSDMT surveys in normally consolidated soils (NC), is repeatable and is the same as that measured using the cross-hole technique although at a much lower cost.. The SSDMT is appropriate for use in any situation in which the SDMT is used, thus improving on the already excellent data the latter provides. The combination of the two tests offers a major contribution to geotechnical investigation.


Advantages and applications

In addition to the CPT and SDMT tests, the use of the SDMT cone allows the measurement of the maximum shear modulus G0 and the confined modulus M0 in a more economical way than by means of pre-bored holes.