2nd Croatian Conference on Earthquake Engineering 2CroCEE

Mine seals are structures used to serve as protection shields against short term instantaneous pressure loadings like blasts, which could occur in mine cells during serviceability period in combination with possible hydrostatic pressure from ground water. They can also resist accidental loads, like earthquakes, that may occur during the excavation period. In this paper, experiences in modeling and nonlinear finite element analysis of mine seal structures that have preceded the design phase are presented. Namely, for the period of 10 years, more than 20 study cases of mine seals have been modeled and analyzed by the authors. Each separate study case consisted of a number of different model types, depending on various assumptions about prescribed boundary conditions, material used, seal structure adopted, prescribed loading, existence of bolts, existence of openings, etc. For all cases, there have been performed force-displacement progressive failure analyses, with detailed description of the failure mechanism and critical points on the obtained diagrams. The design force-displacement diagrams have been constructed by using an overstrength factor and a material partial safety coefficient. The design limit states criteria have been defined for each study case taken separately. All study cases are presented comparatively in a tabular form according to the aforementioned material and geometrical properties, failure mechanisms and design limit state criteria. Advantages and drawbacks have been discussed comparatively for each seal type. The numerical analyses have been performed by using the in-house UKIM-IZIIS software package FELISA/3M. Willam-Warnke and Drucker-Prager elastic-plastic criteria have been used to account for the material nonlinearity. Models have been built using SOLID iso-parametric finite elements with 20 nodes for modeling of the seal body and LINK elements for modeling of the contact surfaces between the body and the surrounding rocks. This study is believed to have given a valuable insight into modeling and methods for analysis of mine seals structures, useful for practitioners in this field.