1、翻译英文Modied MohrCoulomb criterion for non-linear triaxial and polyaxial strength of jointed rocksMahendra Singh n, Bhawani SinghDepartment of Civil Engineering, IIT Roorkee, Roorkee 247667, IndiaAbstract: Rocks encountered in civil and mining engineering elds are invariably jointed and act under tria
2、xial or polyaxial stress conditions. The MohrCoulomb shear strength criterion is the most widely used criterion for jointed rocks. In its present form there are two major limitations of this criterion; rstly it considers the strength response to be linear, and secondly the effect of the intermediate
3、 principal stress on the strength behaviour is ignored. A modied non-linear form of MohrCoulomb strength criterion has been suggested in this study to overcome these limitations. Bartons concept of critical state for rocks has been imbibed in the linear MohrCoulomb criterion to deduce a semi-empiric
4、al expression for non-linear criterion. However, the shear strength parameters of the conventional MohrCoulomb criterion are used in the proposed criterion. The proposed criterion is a simple and rational nonlinear polyaxial strength criterion for anisotropic jointed rocks. In an earlier publication
5、 1 the applicability of the criterion was evaluated for intact rocks. In present paper the criterion is extended to jointed rocks, which are anisotropic in nature. The applicability of the proposed criterion has been veried by applying it to extensive experimental data on triaxial and polyaxial test
6、 results on jointed rocks available from literature. Applicability of the criterion, to explain rock burst conditions for some Indian rocks, is also demonstrated.Keywords: Jointed rock Triaxial Polyaxial Strength criterion Rock burst1. IntroductionRocks encountered in civil and mining engineering ap
7、plica-tions are, in general, jointed and anisotropic in nature. Their strength, under prevailing conning stress conditions, is needed while analysing problems related to deep tunnels, underground excavations and foundations. The strength of jointed rock, as a whole, depends on strength of the intact
8、 rock, joint geometry and surface characteristics of the joints. Depending on joint geometry and joint strength characteristics the rock blocks may undergo sliding, shearing, splitting or rotation at the time of failure. Substantial research has been carried out in past to understand the mechanical
9、behaviour of rock joints 26. The outcome of these studies may be used to analyse the rock mass behaviour if the joints are modelled explicitly.Classication approaches 78 consider the rock mass as an equivalent continuum, and the effect of the oints is considered implicitly. These approaches have fou
10、nd wide acceptability in the eld. Laboratory studies on rocks and model materials have also eld. Laboratory studies on rocks and model materials have also equivalent continuum 913. These equivalent continuum approaches can be used to characterize the rock mass, from which the rock mass strength unde
11、r unconned state may be obtained. The effect of connement (triaxial or polyaxial) may then be included using an appropriate strength criterion. The main objective of the present study is to suggest an approach in which the effect of minor and intermediate principal stress on the strength of jointed
12、rock mass can be obtained with adequate accuracy at any given conning pressure.The strength behaviour of the rocks is generally expressed by a strength criterion. MohrCoulomb strength criterion is the most widely used criterion for intact and jointed rocks as well. As discussed in earlier publicatio
13、n 1, the criterion in its present form suffers from two major limitations: (i) it ignores the non- linearity in strength behaviour, and (ii) the effect of intermediate principal stress is not considered in its conventional form. A non- linear strength criterion for intact rocks was suggested by Sing
14、h et al. 1, which is an extended form of the conventional MohrCoulomb criterion. The intermediate principal stress was also incorporated in the criterion. Using available extensive data from triaxial and polyaxial tests it was shown that the proposed simple criterion works better than the other popu
15、lar criteria in vogue. An important advantage of the proposed criterion is that the conventional MohrCoulomb shear strength parameters are retained as such. In present paper, the criterion proposed for intact rock 1 is extended to jointed rocks. The applicability of the proposed criterion has been v
16、eried by applying it to data base available from literature.2. Triaxial conditionsThe complete derivation of the criterion for intact rocks has already been presented in 1. The criterion was deduced from Bartons concept of critical state in rocks14. Barton 14 states that critical state for any intact rock is dened as stress condition under which Mohr-envelope of peak shear strength of the rocks reaches a point of
