Fracture under hydrostatic pressure

Hydrogeologic studies in several areas on the east side of the Permian Basin prove that natural dissolution of bedded rock salt is occurring at shallow depths. Fresh groundwater moves downward and laterally under hydrostatic pressure and dissolves salt at depths of 10—250 m to form brine. The resulting brine then moves upward and laterally under hydrostatic pressure until it reaches the surface. Both the fresh water and the brine can move laterally through aquifers and also can move vertically across aquifers or aquitards through fractures, sinkholes and collapse features. 

Harris, J.S., Ward, I.M. and Parry, J.S.C. (1971) Shear strength of polymers under hydrostatic pressure surface coatings prevent premature fracture. J. Mater. Sci., 6,... 

The results of the deformability tests are shown in Figures 9 and 10. The conclusions are similar to the conclusions given by the flow curves. Under the effect of the hydrostatic pressure, the strain to fracture increased, and in this case, the 600 MPa pressure delivered the best results as well. On the other hand, the difference between the upper and... 

More recently there has been a strong interest in the deformation and fracture behavior of plastics under large hydrostatic pressures [31—32]. One should expect — and one observes — that the rigidity of a polymer increases with pressure. Sauer et al. [32] report that a pressure of 3.5 kbar raises the initial Young s moduli of amorphous thermoplastics (PC, PI, PSU, PVC, CA) by a factor of 1.2 to 1.9, that of crystalline polymers by 1.4 (POM) to 7.5 (PUR). Despite the increased rigidity, ductile fracture occurs. The effects are not yet understood in all generality. Following the two major review articles on this subject by Radcliffe [31] and Sauer and Pae [32] the Coulomb criterion corresponds best to most pressure-yield experiments. 

---