Dilatometer consists of a stainless-steel blade with a thin flat circular expandable steel membrane on one side. Dilatometer is advanced into a borehole from the ground surface and tests are conducted at an interval of 10 to 20 cm. At each interval, the dilatometer is stopped and the membrane is inflated under gas pressure. The readings of inflation of the membrane and the corresponding gas pressure are recorded. There are correlations available to relate the test results with low-strain soil stiffness and liquefaction resistance of the soil.
The equipment is original Marchetti Seismic Dilatometer set with no construction modification and shall include:
• Seismic probe: containing two receivers for the shear wave at the vertical distance of 0.5 m and, optionally a receiver for the compression wave. The electronic board inside the probe is able to amplify and digitize the electrical signals of the receivers according to the D 7400-08 ASTM standard specifications.
• Seismic acquisition control unit, connected to the seismic probe with the same cable of the traditional DMT test and to a laptop computer with a standard USB cable.
• SDMT Elab software for data acquisition and data processing. The wave source, generally a hammer hitting a beam, may be constructed directly by the user according to specifications provided by the manufacturer.