  The effect of undrained heating on volume change and induced pore pressure
increase is an important point to properly understand the behaviour and
evaluate the integrity of an oil well cement sheath submitted to rapid
temperature changes. This thermal pressurization of the pore fluid is due to
the discrepancy between the thermal expansion coefficients of the pore fluid
and of the solid matrix. The equations governing the undrained
thermo-hydro-mechanical response of a porous material are presented and the
effect of undrained heating is studied experimentally for a saturated hardened
cement paste. The measured value of the thermal pressurization coefficient is
equal to 0.6MPa/&deg;C. The drained and undrained thermal expansion
coefficients of the hardened cement paste are also measured in the heating
tests. The anomalous thermal behaviour of cement pore fluid is back analysed
from the results of the undrained heating test.
