PFC2D节理边坡稳定性分析文献
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International Journal of Rock Mechanics & Mining Sciences 40 (2003) 415–424
Technical Note
Numerical analysis of the stability of heavily jointed
rock slopes using PFC2D
C. Wang
a,
*, D.D. Tannant
a
, P.A. Lilly
b
a
School of Mining and Petroleum Engineering, University of Alberta, Petroleum Engineering, Edmonton, Alta., Canada, T6G 2G7
b
Western Australian School of Mines, Curtin University of Technology, Locked Bag 22, Kalgoorlie, Western Australia, 6433, Australia
Accepted 2 January 2003
1. Introduction
The stability of large rock slopes which are susceptible
to rock mass (rotational) failures can be analyzed by
traditional limit equilibrium methods such as Bishop’s
method [1], Janbu’s simplified methods [2] or the later
improved sophisticated methods [3–5] based on assump-
tions regarding the inclination and location of the
interslice forces. To better simulate the actual mechan-
ism of failure, numerical methods, the finite element
method (FEM) in particular, have developed quickly
and are becoming increasingly popular for slope
stability analysis in situations where the failure mechan-
ism is not controlled completely by discrete geological
structures. Duncan [6] and Griffiths et al. [7] summar-
ized the results of a survey on slope analysis using FEM
and provided a number of valuable lessons concerning
the advantages and limitations of the FEM methods for
use in practical slope engineering problems. Never-
theless, the currently widely accepted FEMs are based
on hypothetical stress–strain constitutive models for
intact rocks and have difficulties in simulating multiple
joint sets involved in a large-scale rock mass. These
factors result in inaccuracy in capturing the true
mechanical behavior of a rock mass and therefore bring
about problems in slope stability analysis and slope
design, such as establishing slope failure development
and the final failure surface.
In cases where the candidate failure surface of a rock
slope is not completely controlled by discontinuities, i.e.
the failure of intact rock is also involved, the conven-
tional slope stability assessment methods are not
adequate for design and stability assessment of the
slope [8]. Therefore, it is necessary that reliable rock
mass strength and characteristics of deformational
behavior be used in rock slope design and stability
analysis.
However, with the inherent difficulty of assigning
reliable numerical values to rock mass characteristics, it
is unlikely that ‘accurate’ methods for estimating all the
required rock mass properties will be developed in the
foreseeable future although reliable estimates of the
strength and deformation characteristics of rock masses
are required for almost any form of analysis used for the
design of slopes, foundations and underground excava-
tions [9]. Therefore, obtaining accurate intact rock
properties, reliable discontinuity properties and employ-
ing powerful numerical approaches can provide an
optimum solution to problems such as heavily jointed
rock slope stability.
The discrete element method (DEM) introduced by
Cundall and Strack [10] describes the mechanical
behavior of assemblies of discs (2D) and spheres (3D).
The method is based on the use of an explicit numerical
scheme in which the interaction of the particles is
monitored contact by contact and the motion of the
particles modeled particle by particle. Its recent devel-
opment into a numerical analysis tool—the Particle
Flow Code by Itasca [11,12]—with a capability of
modeling both intact rock and joints, has shown its
power in solving problems related to rock mass. With
this power, a general study on the stability of heavily
jointed rock slope was carried out using PFC2D. In
order to emphasize the two dominant constituents of a
rock mass, the mechanical properties of intact rock and
fractures are studied followed by a study on the stability
of a heavily jointed rock slope. The first part of the
study was aimed at creating a PFC representation of
moderately strong intact rock. The input parameters of
this PFC assembly are then used to create a small model
*Corresponding author. Tel.: +61-8-908-11385; fax: +61-8-904-
01104.
E-mail address: caigen.wang@sog.com.au (C. Wang).
1365-1609/03/$ - see front matter r 2003 Elsevier Science Ltd. All rights reserved.
doi:10.1016/S1365-1609(03)00004-2
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