This paper presents an interpretation of a pressuremeter test that includes a dissipation phase following an unload-reload loop with pore pressure measurement. These tests were performed with the equipment developed by Jean Lutz SA and tested on Larivot bridge site close to the South abutment (or right bank) of the future new Larivot bridge in Cayenne, French Guyana. It is observed during these tests that unload/reload loop begin largely beyond the creep pressure “pf” in soft clay. In compact sand however this cycle begin near “pf”. In clay, the tests are in accordance with the pressuremeter theory. There is no variation in pore pressure in the elastic phase, with increases and decreases observed during the unload/reload loop in the plastic phase. For this reason, the stress path can be drawn in a modified cam-clay interpretation scheme. It is then shown that, in theory, this allows for the measurement of the unload/reload oedometric index. In practice, unfortunately, these indices are strongly conditioned by the poorly known volume compressibility of water. The possibility of another way of determining odometric characteristics from these tests is discussed. For the dissipation pressuremeter tests, the 50% dissipation times t50% have a close correlation with t50% performed with a piezocone device. Therefore, the presented pressumeter test could be recommended for soft clayey soils or on sites where piezocone could not be used.