莫尔-库仑和霍克-布朗强度准则用于评估脆性岩石动态强度的适用性

ESTIMATING THE DYNAMIC STRENGTH OF ROCK USING MOHR- COULOMB AND HOEK-BROWN CRITERIA

基于对新加坡Bukit Timah花岗岩进行的一系列的动力实验,包括单轴压缩、三轴压缩、单轴拉伸和直剪实验,以及对这些实验结果的系统分析,检验莫尔-库仑准则和霍克-布朗准则用于评估岩石动态强度的适用性。研究结果表明,在较低的围压条件下,岩石动态强度大致符合莫尔-库仑强度准则,且强度变化主要是由于粘聚力随加载速率变化引起的。岩石动态强度更好地符合霍克-布朗强度准则,特别是在较高围压下(如大于100 MPa)。

A series of dynamic compression, tension and shear tests were conducted on the Bukit Timah granite of Singapore. The results are analyzed in an effort to examine the validity and the applicability of the Hoek-Brown and Mohr-Coulomb criteria for rock material under dynamic compression. It is indicated that the rock strength can be approximately described by the Mohr-Coulomb criterion at low confining pressure. The change of strength with loading rate is primarily due to the variation of cohesion with loading rate. The dynamic compression strengths are more accorded with the Hoek-Brown criterion, especially under higher confining pressure (higher than 100 MPa).