Generation and dissipation of excess pore pressure during pressuremeter tests

Laboratory tests were carried out to simulate pressuremeter testing so that the generation and dissipation of pore water pressure during pressuremeter tests could be studied. A modified triaxial cell was used to accommodate 150 mm hollow cylinder specimens prepared with known stress history. Pore pressures on the cavity wall as well as in the soil mass were monitored during the expansion. The results show that a large magnitude of excess pore pressure gradient is set up around the 'model' pressuremeter where the maximum value is at the cavity wall. This is then followed by radial dissipation of pore pressure, the rate of which depends on the pore pressure gradient.