Experimental and numerical modeling studies of pore water pressure variations in Subpermafrost groundwater

International audienceDevelopment and degradation of permafrost di-rectly affect numerous hydrogeological processes such as thermal regime, exchange between river and groundwater, groundwater flows patterns and groundwater recharge (Michel, 1994).Groundwater in permafrost area is subdivided in-to two zones: suprapermafrost and subpermafrost which are separated by permafrost. As a result of the volumetric expansion of water upon freezing and as-suming ice lenses and frost heave do not form in a saturated aquifer, the progressive formation of per-mafrost leads to the pressurization of the subperma-frost groundwater (Wang, 2006). Therefore disap-pearance or aggradation of permafrost modifies the confined or unconfined state of subpermafrost groundwater. Our study focuses on modifications of pore water pressures of subpermafrost groundwater which could appear during thawing and freezing of soil. Numerical simulation allows elucidation of some of these processes