Mathematical Modelling Of The Fracture Of Interchamber Pillars

Abstract

At the Verkhnekamsk potash deposit mining is performed using a room-and-pillar method. There is an effective control method of the state of interchamber pillars—a measurement of horizontal convergence rate of stopes. A theoretical evaluation of relative transverse deformations at which interchamber pillars are fractured was the aim of the work, as well as their nature of change. Computations were performed in a two-dimensional statement for a dual-completion chamber block. Mathematical modelling was carried out using the finite element method. An elastoplastic medium with hardening was used. Mechanical parameters of the medium are taken according to a calibration model of salt specimens’ fracture. A modification of the Botkin and Mirolubov strength criterion adjusted for a plain strain state was adopted as a yield criterion. It was found that an intensive increase in transverse deformations of interchamber pillars occurs when the fracture zone covers about half of their cross-section. The calculated limit strength at which an asymptotic increase in transverse deformations is implemented corresponds to the complete fracture of interchamber pillars. It is an analogue of the stress-rupture strength as well.