DMT TESTING PROCEDURE (Section 4 and Section 5 of the TC16 DMT Report). A brief description is also in the DMT specifications(en/ita). A description covering maintenance, checks and various operative aspects, i.e. a kind of user manual, can be found in the Marchetti 2001 Bali Course maintenance. If the soil is “semiliquid” or is possibly a “niche silt”, please refer to the corresponding headings below.
INFLATION SPEED. The test starts by inserting the dilatometer into the ground. Immediately after the penetration the operator starts inflating the membrane and takes, in » 15 seconds from stopping the penetration, the A-pressure. Then he continues the inflation and takes B in additional » 15 seconds.
C-READING (See Section 5.2 of the TC16 DMT Report or see C-reading). The C-reading is particularly useful in granular soils, where it permits to know the equilibrium pore pressure. In practice it replaces, in sand, a piezometer.
CHECKS FOR QUALITY CONTROL: Section 7 of the TC16 DMT Report and Quality Controls List. As to maintenance: Marchetti 2001 Bali Course p. 29.
DISSIPATIONS (Dissipations or Section 8 of the TC16 DMT Report). Dissipations are used to obtain estimates of the consolidation and permeability coefficients (the faster the dissipation, the higher the permeability).
“NICHE SILTS” (Niche silts). Short (2 min) dissipations are executed in silts to find out if they are “niche silts” i.e. silts where there is appreciable drainage during the duration of the test (» 0.5 min).
DMT IN SEMILIQUID SOILS (DMT execution in semiliquid soils). Provides recommendations concerning the DMT execution in semiliquid soils, where maximum scrupulosity is necessary to obtain accurate results. Small errors, unimportant in medium to hard soils, become important when the readings are small.
FIELD FORMS FOR WRITING DATA. Field forms for writing the data, in case data are not taken automatically: [Field forms DMT] or [Field forms dissipation].