When performing transient hydraulic pulse tests on porous materials in the laboratory it is implicitly assumed that the accessible pore space of a porous medium and the pressurised fluid-filled cavity are completely saturated with the permeating fluid. In certain instances the pressurised fluid cavity in a hydraulic pulse test can contain an air fraction introduced through either the experimental procedure or released from the unsaturated regions of the porous medium. The purpose of this paper is to examine the influence of an air fraction within the pressurised region, on the estimation of permeability derived from transient hydraulic pulse tests. A series of hydraulic pulse tests conducted on Stanstead Granite was used to estimate the permeability of the rock. It is shown that if the effect of the cavity air fraction is omitted from the analysis of the hydraulic pulse test, the permeability can be underestimated. The paper also presents a discussion of the potential role the air fraction can contribute to discrepancies in the permeabilities estimated from steady-state tests and hydraulic pulse tests.

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The Cobourg Limestone is a low‐permeability argillaceous rock that forms a part of the Paleozoic sedimentary sequence found in southern Ontario, Canada. The limestone has a heterogeneous fabric consisting of nodular regions of calcite and dolomite and argillaceous partings of a similar composition but with a low clay content, which gives the appearance of nominal stratifications. The thermo‐hydro‐mechanical (THM) behavior of the rock is of interest to the proposals for using sedimentary formations as candidate rocks for siting deep geological repositories for the storage of heat‐emitting nuclear fuel waste. The paper presents the results of experiments where THM processes were initiated in an intact cylindrical sample of the Cobourg Limestone containing a central cylindrical fluid‐filled cavity. Biot's classical theory of poroelasticity, extended to include thermal effects, is used to examine the THM response of the fluid cavity due to boundary heating of the cylinder. The rise and decay of thermally induced cavity fluid pressure is used to examine the applicability of the THM modeling. The experiments were conducted on cylindrical samples of the Cobourg Limestone with their axes either along or normal to the nominal planes of the argillaceous partings.

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-The paper presents the results of an experimental evaluation of the permeability of the heterogeneous argillaceous limestone from the Cobourg formation located in southern Ontario, Canada. The low permeability of the limestone necessitated the development of experimental techniques for effectively measuring the permeability of the rock. In particular, we examine the results of pressurization of a fluid-filled co-axial cylindrical cavity of finite length cored into a 150 mm diameter cylinder of the Cobourg Limestone. The orientation of the cavity is either normal to or along the nominal stratifications identified by the argillaceous partings separating the quartzitic phases. Both steady state and transient tests are used to estimate the permeability of the Cobourg Limestone. The paper also investigates the influence of a nominal axial load on the permeability of the rock.