Answers to a number of FAQs can be found in the FAQ ppt presentation
Other answers can be found below.
GAS TANK AND GAS CONSUMPTION FOR DILATOMETER TESTING
A 10 litre tank, filled at 200 bar, taking the normal regular readings A and B (and possibly C), permits to execute, in a “medium soil”, say 2 or 3 DMT soundings 20 m long.
Such length will be more if the soil is soft, less if the soil is stiff, because at each depth the system is deflated, and the higher the pressure, the more gas will be consumed.
In general in most “normal” investigation a couple of these tanks will be more than sufficient.
The pressure regulator should be able to provide a regulated output up to 70-80 bar.
In general, for an investigation of a few DMT soundings, a couple of 10 litre tanks are sufficient, and practically always a reserve of gas remains unused.
COHESION AND PHI DETERMINATION.
In saturated clay no method is available as today for determining c’ & Phi’.