We present recent results on the modeling and numerical simulation of reservoir stimulation in Hot Dry Rocks. Our approach is based on a mechanistically faithful yet mathematically sound model, generalizing Griffith's idea of competition between bulk and surface energies. At each time increment, the fracture and displacement configuration of a reservoir is sought as the minimizer of a global en...

Cracks in a rock mass subjected to a uniaxial stress will be preferentially closed depending on the angle between the fracture normal and the direction of the applied stress. If the prestress fracture distribution is isotropic, the effective elastic properties of such a material are then transversely isotropic due to the preferred alignment of the cracks. Velocity measurements in multiple direc...

Concrete is prone to crack formation in the tensile zone, which is why steel reinforcement is introduced in these zones. However, small cracks could still arise, which give liquids and gasses access to the reinforcement causing it to corrode. Self-healing concrete repairs and seals these small (300 µm) cracks, preventing the development of corrosion. In this study, a vascular system, carrying t...

An experimental study of the influence of autogeneous healing on chloride ingress in cracked concrete is presented. In the study, two concrete mixtures (a Portland cement mix and a blast furnace slag mix), two healing regimes (submerged and fog room regime), two cracking ages (14 and 28 days), and multiple crack widths are used as parameters. An adapted Rapid Chloride Migration testing procedur...

In this section, we want to model a surface with flaws. We model it as a line from which N parallel cracks progress into the 2D material (see Fig. 2). The ensemble of cracks is submitted to a remote mode I loading p∞ as sketched in Fig. 2, but, because of the interactions between the cracks, each crack i (i = 1, ...N) is submitted locally to both a normal traction pi(x) and a shear traction ti(x).

The Sheepbed mudstone, Yellowknife Bay formation, Gale crater, represents an ancient lakebed now exhumed and exposed on the Martian surface. The mudstone has four diagenetic textures, including a suite of early diagenetic nodules, hollow nodules, and raised ridges and later diagenetic light-toned veins that crosscut those features. In this study, we describe the distribution and characteristics...

Here we report on self-assembly of novel multi-hierarchically structured meso(nano)porous colloidal silica particles which have cylindrical pores of 4-6nm, overall size of ∼10μm and "cracks" of 50-200nm. These cracks make particles look like micro-sponges. The particles were prepared through a modified templated sol-gel self-assembly process. The mechanism of assembly of these particles is inve...

When cracks form in a thin contracting layer, they sequentially break the layer into smaller and smaller pieces. A rectilinear crack pattern encodes information about the order of crack formation, as later cracks tend to intersect with earlier cracks at right angles. In a hexagonal pattern, in contrast, the angles between all cracks at a vertex are near 120 degrees. Hexagonal crack patterns are...

We present a general method for analyzing dynamically accelerating multiple co-linear cracks that can be applied to the contexts of plane strain or antiplane shear in an elastic material. The difficulty in solving such problems lies in the fact that the space-time regions containing known data evolve as the crack propagates in an a priori unknown manner. Using an analog to a Dirichlet-to-Neuman...