Interpretation & Results

Generally adopted formulae for estimating soil parameters from DMT results.

Details on the “niche silts” and ways of getting a reasonable interpretation.

Stress history is important, as it significantly increases moduli and, in sand, liquefaction resistance.

It is well known that oedometer moduli M are not constant, but vary with the applied vertical load.

The Stress History parameter KD by DMT is considerably more sensitive to Stress History than other in situ tools.

DMT dissipation Interpretation, dissipation test in cohesive soils, validation of consolidation coefficient DMT vs. other dissipation tests.

The DMT Material Index ID is an index helpful for identifying the soil composition (sand, silt, clay).

Cu at National Site FUCINO – ITALY, Cu comparisons from DMT and from other tests.

Choosing DA DB to be used in the calculations

In general the before-after variation of DA, DB are modest. In this case the values of DA, DB to be used in the calculations can be taken as their arithmetic average before-after the sounding. However:

If there is an appreciable variation of DA, DB before-after the test.

In this case a “logical” average is better than the “arithmetic” average. For instance, in case of a site composed of a soft layer overlying an hard layer, choose DA, DB closer to the initial DA, DB, that presumably were in effect while investigating the soft layer, mostly in need of adequate DA, DB.

If there are many negative Ed values.

Then the used values of DA, DB  are too high. In this case reduce DA, DB so that there are no negative Ed values (or may be only one or two negative Ed values).

More information in the Note: “On the calibration of the DMT membrane“.

Related Papers

Other Sources