The influence of pore geometry and orientation on the strength and stiffness of porous rock

摘要: Abstract The geometry of voids in porous rock falls between two end-members: very low aspect ratio (the the minor to major axis) microcracks and perfectly spherical pores with an unity. Although effect these end-member geometries on mechanical behaviour has received considerable attention, our understanding influence intermediate is much less robust. Here we perform two-dimensional numerical simulations (Rock Failure Process Analysis, RFPA 2D ) better understand pore (from 0.2 1.0) angle axis applied stress 0 90°) under uniaxial compression. Our show that, for a fixed (0.5) compressive strength Young's modulus can be reduced by factor ∼2.4 ∼1.3, respectively, as elliptical rotated from 90°. depends angle. At angles (∼0–10°) increase reduces modulus. higher (∼40–90°), however, increased. (∼20–30°), first then decrease approaches These also highlight that decreases We find analytical solution concentration around single pore, its contribution elasticity, are excellent qualitative agreement simulations. results modelling recent experimental data basalt, but fail capture anisotropy observed experiments sandstone. conclude alignment grains or platy minerals such clays exerts greater sandstones than geometry. Finally, arises result preferentially aligned similar magnitude generated bedding foliation low-porosity metamorphic rocks. presented herein shows rocks containing display stiffness anisotropy, implications preservation destruction porosity permeability, well distribution strain within Earth's crust.