Applicability of Anisotropic Failure Criteria and Associated Application with Layered Rocks

Abstract

This paper examines the applicability of four failure criteria applied to layered rocks, namely, Pariseau’s model, linear empirical equation, nonlinear empirical equation (LEE and NLEE), and Jaeger’s plane-of-weakness model (JPW). A database comprising 282 uniaxial compressive strength (UCS) tests and 1,273 triaxial tests conducted worldwide on layered rocks is compiled. Pariseau’s model is classified as a continuous function, and LEE and NLEE, as well as JPW, are classified as piecewise functions. Nonlinear least squares and traversing methods are used to determine the global minima of the material coefficients in the two types of functions. The goodness of fit of these criteria for the database is evaluated. Two statistical parameters, namely, regression coefficient (R2) and mean absolute percentage error (MAPE) are used for precision assessment. The aforementioned methods and the criteria are further used for evaluating the surrounding rock stability of the eastern slope of Yanshan iron open-pit and the underground powerhouse of the Jinping I hydropower station. The results show that (1) Pariseau’s model is not suitable for layered rocks when n\u2009=\u20092, and the fit is worst in the condition of insufficient triaxial data when n\u2009=\u20091; (2) the MAPE of the empirical equation (LEE and NLEE) is within 20%, with the best predictive accuracy under medium to low confining pressures, and the MPAE of JPW is within 40%, with the best predictive accuracy under high confining pressures; and (3) calculation of the damage area of the slope and underground powerhouse and comparison with the actual damage on the site verify that the empirical equation has the best engineering prediction accuracy under medium to low confining pressure conditions.