numerical investigation of static failure scenario of concrete gravity dams considering water–crack interaction

This study numerically predicts the failure scenario of a cracked concrete gravity dam caused by water–crack interaction when an overflow occurs due to a reservoir inflow flood. the mixed-mode linear elastic fracture mechanic (lefm), utilizing the extended finite-element method (xfem), is employed to simulate the structure. the modified j-integral is used to consider the body forces and water pressure inside the crack. hydraulic fracture (hf) is effectively modeled using the cubic law and the continuity equation. it is understood that water–crack interaction magnifies the share of mode-i and consequently changes the failure scenario from a ductile mixed-mode manner to a brittle mode-i or a mixed-mode depending on the initial crack level in the case of koyna dam with a full fixed base. it is shown that the catastrophic static failure risk of the koyna dam increases significantly when the initial crack level moves from 15 to 0 m above the dam base, which leads to a minimum safety freeboard requirement when the crack level is below a critical value. it indicates that an initial crack with a length between 1 and 1.9 m at lower submerged levels might trigger instability for the whole dam body even when the reservoir level is below the dam crest. when the initial crack length increases from 1 to 1.9 m, this critical value, which occurs at low-level cracks, and the maximum overflow, which occurs at intermediate-level cracks, varies from about 4.8–8.6 m and 27.5–30.5 m above the dam base, respectively. graphical abstract: [figure not available: see fulltext.].