Numerical Approach for a Rock Mechanics Descriptive Model

摘要

This paper addresses the methodology developed in Sweden for the rock mechanics descriptive model,rnwhich utilized empirical methods such as RMR, Q and GSI but also developed a methodology forrnestimating the strength and deformation properties of the confined rock mass using the numericalrnprogram UDEC. One of the difficulties in describing the rock mass behaviour is assigning thernappropriate constitutive model. With the progress in discrete element software, this limitation may bernovercome as the user is not required to prescribe a constitutive model for the rock mass. In stead thernmicro-scale properties of the intact rock and joints are defined and the macro-scale response resultsrnfrom those properties and the geometry of the problem. In this paper a rock mass is simulated using arndiscrete model and the results compared to the traditional model where the constitutive model isrnprescribed. In the PFC model the behaviour of the rock mass changed from brittle to perfectly plasticrnwith increase in the number of joints. As expected, the presence of joints had a pronounced effect onrnpost peak response of the rock mass. More importantly the post-peak response of the PFC model wasrnnot determined by a user specified constitutive model, while the UDEC results were determined by thernconstitutive model applied to the joints.